| Id | Authors | Title | Year | Subject | Source | Location | Language | Held As | Dave's Notes | Dave's Quotes |
| 172 | Aballay, E. & Insunza, V. | Evaluación de plantas con propiedades nematicidas en el control de Xiphinema index en vid de mesa cv. Thompson seedless en la zona central de Chile | 2002 | Compost & Biocontrol | Journal | Agric Téc; 62 (3); 357-365 | Spanish | Hardcopy:Full; Wordperfect:Full | Field expt. to test the capacity of various plants to suppress the effect of a virus carrying nematode species on vines. The plants tested included rape, thyme and two spp. of marigold (1 Calendula sp. and 1 Tagetes sp.). Only rape was effective in suppressing the nematode | |
| 502 | Abbasi, M.K. & Adams, W.A. | Assessment of the contribution of denitrification to N losses from compacted grassland soil by NO3- disappearance and N2O production during anaerobic incubation | 1999 | Greenhouse Gases; Soil N Dynamics | Journal | Can. J. Soil Sci.; 79 (1); 57-64 | English | Hardcopy:Partial | Lab. expt. to xmeasure the denitrification capacity of soils and the N2O emissions at different depths, using soil samples taken from a wet clay loam under grazed pasture. The ratio between N2O-N evolved and NO3--N lost was greater than 2:1, indicating that not all of the NO3- lost was accounted for as N2O. This may have been because (1) some N2O remained trapped in the soil, (2) some N2O was reduced to N2 or (3) microorganisms (in anaerobic condition and with available C) might be able to (store NO3- in excess of their immediate needs. | Denitrification occurs when nitrate is present in anaerobic or nearly anaerobic microsites.; Compaction .. impairs drainage, which leads to anoxic conditions .. surface wetness coupled with high levels of root-derived OM promotes .. denitrification. |
| 499 | Aber, J.D. & Melillo, J.M. | Nitrogen immobilisation in decaying hardwood leaf letter as a function of initial nitrogen and lignin content | 1982 | Lignin and CBW; Soil N Dynamics | Journal | Can. J. Bot.; 60; 2263-2269 | English | Hardcopy:Full | Modelling the N immobilisation of litters of varying lignin and N content | The highest immobilisation rates .. occur in litters high in both lignin and N .. because total immobilisation increases with lignin content, while rate of decay increases with N content.; early successional and understorey species plus symbiotic N fixers have high N concentrations; and late successional species generally associated with poor site conditions have high lignin concentrations. |
| 878 | Ackermann, R. | Maismulchsaat im langjährigen Vergleich | 2002 | Cover Crops; Tillage | Journal | Landwirtschaft ohne Pflug; 1; 15-17 | German | Hardcopy:Full | 7-year field expt. to study the effect of cultivation (zero tillage, rotovation or ploughing) on conventionally grown maize crops with different winter cover crops (grown on weeds/volunteer crops, mustard or winter rye) and different weed control (chemical, mechanical or a combination of the two). Mustard gave the highest soil inorganic N content in the spring. winter rye the lowest. Zero tillage gave the highest soil inorganic N content after harvest. Reduced tillage with winter rye gave the highest soil moisture content in the spring, conventional tillage the lowest. The DM and energy yields were lowest with zero tillage, with mustard and with purely mechanical weed control. | |
| 1693 | Ackermann, R. | Bodendecker halten Wasser im Boden | 2002 | Cover Crops; Tillage | Journal | Landwirtschaft ohne Pflug; 2; 13-15 | Hardcopy:Full | |||
| 1695 | Ackermann, R. | Alterunkrautung vor der Saat bekämpfen | 2002 | Cover Crops; Tillage | Journal | Landwirtschaft ohne Pflug; 3; 17-18 | German | Hardcopy:Full | ||
| 1696 | Ackermann, R. | Maismulchsaat rechnet sich! | 2002 | Uncategorised | Journal | Landwirtschaft ohne Pflug; 5; 25-27 | German | Hardcopy:Full | ||
| 415 | Adams, G. & Wall, D. | Biodiversity above and below the surface of soils and sediments: linkages and implications for global change | 2000 | Miscellaneous | Journal | Bioscience; 50 (12); 1043-1048 | English | Hardcopy:Full; Wordperfect:Full | Review of existing knowledge on the interaction between above - and belowground organisms and the possible effects of climate change on it | The biological diversity within soils and sediments may be orders of magnitude greater than that above the surface ..; .. activities of organisms dwelling within soils .. or the litter layer (here defined as below-surface biota) involve physiological or ecological interactions with organisms in above-surface habitats.; .. connections between functional groups across the soil and sediment surface can be highly specific and the presence of a particular functional group on one side of the surface can depend on that of another across the surface. |
| 622 | Addiscott, T.M. | Entropy and sustainability | 1995 | Soil (General); Sustainability | Journal | Eur. J. Soil Sci.; 46; 161-168 | English | Hardcopy:Partial | Modelling the soil as an open system based on non-equilibrium thermodynamics. | .. a closed [thermodynamic] system can exchange energy but not matter and open system can exchange both .. the soil is clearly and open system. .. Non-equilibrium thermodynamics describes an open system that tends towards a steady state characterised by minimum production of entropy.; .. perturbing a steady state causes an increase in entropy production but also that, when the perturbation is removed, the system returns towards the steady state with entropy production declining towards an eventual minimum.; The Principle of Minimum Energy provides a useful framework within which sustainability can be discussed. Natural ecosystems are sustainable not least because they become steady states characterised by minimum production of entropy.; .. we should seek agric'l systems that permit the establishment of steady states.Continuous arable agriculture, or even monoculture, may therefore be one of the more sustainable options available. |
| 1497 | Addiscott, T.M. | Tillage, mineralisation and leaching | 2000 | Mineralisation; Soil N Dynamics; Tillage | Journal | Soil Tillage Res.; 53 (3-4); 163-165 | English | Hardcopy:Full; Wordperfect:Full | Review (editorial of a special issue of the journal on tillage, mineralisation and leaching) | .. nitrate can be lost from the land even when no fertiliser is applied at all.; The microbes that are active in mineralising SOM .. particularly enjoy the conditions which they find when soil warm from the summer is re-wetted during early autumn, but this is just when the nitrate they produce is most untimely. .. This naturally produced nitrate is usually responsible for a larger proportion of the nitrate leached from the soil than fertiliser N applied to growing crops in spring ..; Roughly 70% of the N given to winter wheat crops .. is recovered in the harvested grain and straw. Stubble and roots remain in the soil, together with any material exuded from the roots, and together they contain about 15% of the fertiliser in organic form. .. this 15% means that H about 25-30 kg ha-1 of N from fertiliser is added to the soil's organic N each season. .. From 1977 onwards .. more N was given to the crop than it removed and by 1986 a total cumulative excess (of application over removal) of more than 300 kg ha-1 had built up during the 10 years. .. about 45% of this excess, about 145 hkg ha-1 of N, remained in the soil as organic N in 1986. This excess has more 0than doubled since then .. An extra 300 kg ha-1 of organic N in the soil is not necessarily a bad thing. The soil has become potentially more fertile, and roughly 3 Mg ha-1 of C has been sequestrated with the nitrogen. |
| 1498 | Addiscott, T.M., & Dexter, A.R. | Tillage and crop residue management effects on losses of chemicals from soils | 1994 | Soil N Dynamics; Tillage | Journal | Soil Tillage Res.; 30(2-4); 125-168 | English | Hardcopy:Partial | Review of causes of nutrient losses through leaching and run-off from agricultural systems and ways of abating them | . the decline in the practice of applying N fertiliser to autumn-sown crops in the autumn.Research had shown this to be unnecessary, wasteful and polluting .. cereal straw .. always immobilises mineral N when it is incorporated in the soil and some UK farmers are now expressing concern that, where straw has been incorp'd, their autumn-sown crops are now deficient of mineral N in the autumn. |
| 1499 | Agenbag, G.A. & Maree, P.C.J. | Effect of tillage on some soil properties, plant development and yield of spring wheat (Triticum aestivum L.) in stony soil | 1991 | Soil (General); Tillage | Journal | Soil Tillage Res.; 21(1-2); 97-112 | English | Hardcopy:Partial | Long-term field expt. to study the effect of zero tillage on wheat yields on shallow stony soils in south Africa. In four out of six year there was little difference in crops between different tillage treatments. | .. the lower maximum LAI [leaf area index] and yields obtained with no- and tine-tillage in 1981 and 1982 were the result of a combination of higher cone resistance, less mineral N in the soil at seeding and lower plant populations. |
| 623 | Agnelli, V., Trumbore, S.E., Corti, G. & Ugolini, F.C. | The dynamics of organic matter in rock fragments in soil investigated by 14C dating and measurements of 13C | 2002 | Greenhouse Gases; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 53; 147-159 | English | Hardcopy:Partial | In soils derived from sedimentary rocks the fraction coarser than 2 mm, which is called rock fragments, contains considerable amounts of organic C, comprising both humic and non-humic substances. The concentration of organic C in rock fragments is similar to that in fine earth. | The total amount of C in the upper metre of soil has been estimated to be about 1500 Pg. This is large relative to the C stored in biomass and the atmosphere.; Rock fragments .. contributed 4.5% to the total organic C content of the soil.; .. highly altered rock fragments host an active microbial populations.; The bulk OM in both fine earth and highly altered rock fragments in the A1 horizon contained significant amounts of recent C (bomb 14C) .. |
| 1500 | Ahl, C., Joergensen, R.G., Kandeler, E., Meyer, B. & Woehler, V. | Microbial biomass and activity in silt and sand loams after long-term shallow tillage in central Germany | 1998 | Soil Microorganisms; Tillage | Journal | Soil Tillage Res.; 49 (1/2); 93-104 | English | Hardcopy:Full; PDF:Full | Field expt. to compare the effects of ploughing and rotovation on soil microorganisms | The ploughless cultivation system used in our investigation, which is based on a horizontal axis rotary cultivator, led to a reduction in SOM, microbial biomass and microbial activity. This cultivation system changed also the community structure of soil microflora towards fungi. These effects are primarily due a compaction of the bottom parts in the former plough layer at 10-30 cm depth. |
| 624 | Aita, C., Recous, S. & Angers, D.A. | Short-term kinetics of residual wheat straw C and N under field conditions: characterisation by 13C15N tracing and soil particle size fractionation | 1997 | Soil Organic Carbon; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 48 (2); 283-294 | English | Hardcopy:Full | 18-month field expt. to study the C & N fluxes that occur during the decomposition of straw, using stable isotope labelling. | Straw-derived C disappeared rapidly from the >2000 m fraction with an estimated half-life of 53 .. days .. [it] accumulated most rapidly and preferentially in the <50m fraction, which .. accounted for 70% of the residual `13C on day 574.; .. straw-derived C & N pass through the intermediate fractions (50-2000 m) very rapidly. |
| 792 | Al-Yahya, S.A. | Effect of storage conditions on germination in wheat | 2001 | Miscellaneous | Journal | J. Agron. Crop Sci.; 186; 273-279 | English | Hardcopy:Partial; PDF:Full | Expt. to measure the effect of moisture content, temperature and mechanical damage on wheat germination | The percentage germination decreased very slowly at a low moisture level (15%), low temperature (4$C) and low level of damage (0%), while it decreased rapidly at a high moisture level (24%), high temperature (40$C) and high level of damage (30%). |
| 488 | Albiach, R., Canet, R., Pomares, F. & Ingelmo, F. | Microbial biomass content and enzymatic activities after the application of organic amendments to a horticultural soil | 2000 | Compost & Biocontrol; Soil Organic Carbon | Journal | Bioresour. Technol.; 75; 43-48 | English | Hardcopy:Full; Wordperfect:Full | Exptal study of the effect of 5 organic amendments (MSW compost, sewage sludge, ovine FYM, vermicompost and a commercial humic acids solution) on the microbial biomass content and level of selected enzymatic activities. No statistically significant differences in soil microbial biomass between the treatments were found. The treatments gave significant enhancement of soil enzyme activity in the order MSW > ovine manure > sewage sludge > vermicompost/humic acid solution. | |
| 1096 | Alexandratos, N. | World food and agriculture: outlook for the medium and longer term | 1999 | Miscellaneous | Journal | Proc. Natl. Acad. Sci. U. S. A.; 96; 5908-5914 | English | Hardcopy:Partial; PDF:Full | Review of the global food productio situation | The fears of impending food crisis that dominated the thinking of some observers up to about mid-1997 have subsided .. It is now well accepted that, at least over the medium term, there appear to be no major global constraints to expanding world food production at a rate sufficient to match the growth of the effective demand for food.; As in the past, world agricultural production is likely to keep up with, and perhaps tend to exceed, the growth of the effective demand for food. |
| 27 | Alföldi, T., Spiess, E., Niggli, U. & Besson, J.M. | Energy input and output for winter wheat in biodynamic, bio-organic and conventional production systems | 1995 | Biodynamic Farming; Energy in Agriculture; Organic Farming | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 574-578 | English | Hardcopy:Full | 6-year field expt. to compare the efficiency of conventional, organic and biodynamic farming systems. The conventional system had higher yield (by 10-15%) but lower efficiency than the organic systems, using 12%-25% more energy per kg of wheat produced, depending on the fertiliser rate (25 or 50 kg N per ha). The biodynamic system had a poorer energy balance than the organic one on account of the high energy consumption in the composting process. | |
| 123 | Alföldi, T., Wider, P., Niggli, U., Spiess, E., Dubois, D. & Besson, J.M. | Quality investigations in the long-term DOC-trial | 1996 | Biodynamic Farming; Miscellaneous; Organic Farming | Book | Raupp, J. (ed.); Quality of plant products grown with manure fertilisation, Proc. 4th mtg (concerted action AIR3-CT94-1940); | English | Hardcopy:Full; Wordperfect:Full | Expt. to compare the quality of conv'l, organic and biodynamic produce | Market quality (sizing) of biodynamically and organically grown potatoes was 25% lower compared to the conventional potatoes ..; The nitrogen content of biodynamically grown potatoes was 25% higher compared to the other treatments.; In the DOC-trial the nitrogen content of wheat was 10% lower in the two organic treatments than in the conventional wheat.; Neither the protein content nor the baking capacity of wheat was different among the farming systems. |
| 1709 | Allard, B. & Derenne, S. | Oxidation of humic acids from an agricultural soil and a lignite deposit: Analysis of lipophilic and hydrophilic products | 2007 | Uncategorised | Journal | Org. Geochem.; 38; 2036-2057 | English | PDF:Full | ||
| 1381 | Allison, F.E. & Klein, C.J. | Rates of immobilisation and release of nitrogen following additions of carbonaceous materials and nitrogen to soils | 1962 | Soil N Dynamics | Journal | Soil Sci.; 93; 383-386 | English | Hardcopy:Full | Lab. expt. to study the immobilisation of N in soils amended with straw and nitrate fertiliser. A maximum N immobilisation of 1.7% was reached after 20 @days, when 28% [?] of the straw C had been lost as CO2, and the C/N ratio of the residue was then 13.0. The corresponding figures for a soil amended with glucose (Winsor & Pollard, 1956) were 3.7%, 2 days, 40% and 6.2. | .. the quantity of N required by soil microorganisms in the decomposition of carbonaceous materials, such as straw, .. usually vary between 1.1 and 2.0% of the dry weight of readily decomposable plant materials, including the N originally present in the plant material ..; Immobilisation of N proceeded rapidly during the first 7 days, then at a constantly decreasing rate ..; N immobilisation during this initial 3 weeks paralleled closely the rate of H decomposition of the straw, as shown by CO2 evolution.; This difference between .. residual materials reflects .. the presence of lignin and other resistant constituents of the straw. |
| 1167 | Allison, S.D. & Vitousek, P.M. | Responses of extracellular enzymes to simple and complex nutrient inputs | 2005 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 37 (5); 937-944 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to test the reaction of extracellular enzymes to the presence of nutrients in different (simple & complex) forms | Extracellular enzymes are the primary means by which soil microbes degrade complex organic cpds into small molecules that can be assimilated.; .. an enzyme's activity increased when its target nutrient was present in complex but not simple form and C & N were available.; .. microbes produce enzymes according to economic rules, but a substantial pool of mineral-stabilised or constitutive enzymes mediates this response. |
| 1166 | Allison, S.D., Hanson, C.A. & Treseder, K.K. | Nitrogen fertilisation reduces diversity and alters community structure of active fungi in boreal ecosystems | 2007 | Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 39; 1878-1887 | English | Hardcopy:Partial; PDF:Full | Field expt. to test the effect of N deposition on the fungi of a boreal forest | ... N fertilisation reduces fungal taxonomic richness and alters community structure. These responses ... applied to both litter and soil environments. |
| 851 | Allmaras, R.R., Schomberg, H.H., Douglas, C.L. & Dao, T.H. | Soil organic carbon sequestration potential of adopting conservation tillage in U.S. croplands | 2000 | Greenhouse Gases; Tillage | Journal | J. Soil Water Conserv.; 55 (3); 365-373 | English | Hardcopy:Full | Modelling of C cycling in different cropping systems is used to show that changes in crop yields and in harvesting and tillage practices in the U.S. over @the last 30 years has resulted in a steady reduction in the quantity of CO2 released to the atmosphere from arable land and that some time in the last 15 years arable soils changed from being a net C source to a net C sink. | Soil .. C makes up about two thirds of the C pool in the terrestrial biosphere.; .. the estimated annual exchange is about 4% of the SOC pool or 811% of the atmospheric pool.; Components of the SOC pool in cropland have a wide range of susceptibility to decomposition .. half-lives from <1 to >1000 years.; The SOC pool in croplands converted from grasslands was reduced as much as 40% to reach a steady low state by about 1940.; SOC levels in tall-grass prairie soils decreased as much as 60%.; .. the mouldboard tillage system has SOC storage inferior to all other tillage systems ..; A combination of cover crop, double crop, no-tillage and infrequent use of non-mouldboard tillage has .. expanded the C sink.; [Because of] the shift from dominant mouldboard primary tillage in .. 1970 .. to a use on less than 8% of planted cropland in 1993, SOC storage has shifted from a C source to a C sink. |
| 1711 | Almendros, G., Guadalix, M.E., González-Vila, F.J. & Martin, F. | Preservation of aliphatic macromolecules in soil humins | 1996 | Uncategorised | Journal | Org. Geochem.; 24; 651-659 | English | PDF:Full | ||
| 717 | Alphei, J. & Scheu, S. | Effects of biocidal treatments on biological and nutritional properties of a mull-structured woodland soil | 1993 | Soil Microorganisms; Soil N Dynamics | Journal | Geoderma; 56(1-4); 435-448 | English | Hardcopy:Partial | Expt. to study microbial activity in a beechwood mull soil | Woodland mull soils are characterised by low nutrient availability to the soil microflora and the microflora is limited by nutrients or has a high demand on nutrients, particularly N and P.; In general the total soil respiration was increased by these [biocidal] treatments. In addition the NH4+-N content increased continuously ..; In contrast to the control soil no nitrification `occurred.; The flush in CO2 production following chloroform fumigation is known to be caused by decomposition of fumigated organisms in the soil. |
| 1501 | Alvarez, R., Díaz, R.A., Barbero, N., Santanatoglia, O.J. & Blotta, L. | Soil organic carbon, microbial biomass and CO2-C production from three tillage systems | 1995 | Soil Organic Carbon; Soil Microorganisms; Tillage | Journal | Soil Tillage Res.; 33; 17-28 | English | Hardcopy:Partial | Lab. expt. to test the effect of tillage on SOM distribution and mineralisation. Zero-tilled soils, compared with ploughed soils, were more stratified, had more coarse and labile OM and, in the top 5 cm., had twice the microbial biomass (0.43 mg C/g soil), three times the basal respiration (0.33 mg C/g soil) and 1.5 times the metabolic quotient (0.08 mg C/mg biomass C/day). | .. organic C was 42%-50% higher in the no-till soil than in the soil from the plough and chisel tillage systems.; A lower mineralisation intensity of SOM under no-till appeared to be the cause of the organic C accumulation. .. when crops are not buried, fungal growth predominates over bacterial growth .. As a result, the efficiency of the transformation of plant C into microbial C can rise, because fungi have a lower maintenance energy requirement than bacteria and this may lead to the formation of more humified OM. |
| 852 | Amado, T.J.C., Fernandez, S.B. & Mielniczuk, J. | Nitrogen availability as affected by ten years of cover crop and tillage systems in southern Brasil | 1998 | Cover Crops; Tillage | Journal | J. Soil Water Conserv.; 53 (3); 268-271 | English | Hardcopy:Full | In a comparison of conventional and zero tillage systems in Rio Grande do Sulzero tillage showed higher N availability. | After nine years no-tillage with the intensive cropping system resulted in a 24% increase in soil N as compared to conventional tillage; there was no difference in [maize] yield between tillage systems. |
| 1168 | Amato, M. & Ladd, J.N. | Decomposition of 14C-labelled glucose and legume material in soils: properties influencing the accumulation of organic residue C and microbial biomass C | 1992 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 24 (5); 455-464 | English | Hardcopy:Partial | Lab. expt. using 14C labelling to study the decomposition of added glucose and legume materials in 23 soils after 44 and 66 weeks incubation. A close correlation was found between the size of both native and labelled biomass and the properties of the soil, e.g. clay content, CEC, pH, fine pores as a proportion of total pore space, etc. The attaining of maximum biomass took only a few days with glucose but sever months with plant materials and even then the residue could contain some undecomposed .. plant constituents. | .. soil charge, and perhaps soil structure, are the important factors of influence on biomass 14C accumulation. Clearly microorganisms in soils are adsorbed to surfaces within pores.; .. interactions between adsorption of organisms to soil surfaces and pore size distributions are important factors in determining the survival of the soil microflora.; These factors may override such influences as substrate type, concentration and efficiency of utilisation in determining biomass C concentration in soils .. |
| 625 | Ambus, P. | Nitrous oxide production by denitrification and nitrification in temperate forest, grassland and agricultural soils | 1998 | Greenhouse Gases; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 49; 495-502 | English | Hardcopy:Partial | Expt. to study the rate of N2O production from various soils | x; N2O is produced by two mainly biological pathways, namely denitrification and @chemoautotrophic nitrification .. In denitrification N2O is produced as an intermediate compound in a sequence of enzymatic reactions whereby NO3- is reduced to N2. .. In autotrophic nitrification N2O is produced as a result of denitrification by nitrifiers which reduce NO2- under small pressures of O2. .. `Since nitrification activity ceases as O2 is depleted, rapid N2O production is (more likely to be associated with denitrification.; The total N2O production was strongly influenced by landscape position and was especially large in low-lying position with wet organic soils. .. By contrast forest soils produce little N2O .. irrespective of landscape position. |
| 718 | Amelung, W. & Zech, W. | Minimisation of organic matter disruption during particle-size fractionation of grassland epipedons | 1999 | Soil Organic Carbon | Journal | Geoderma; 92; 73-85 | English | Hardcopy:Partial | A study of the methodology of particle-size fractionation using ultrasonic dispersion with a view to avoiding artefacts. The degree of dispersion depended on the energy applied, the climatic origin of the soil samples and the type of sonifier. | |
| 1395 | Amelung, W., Flach, K.W. & Zech, W. | Neutral and acidic sugars in particle-size fractions as influenced by climate | 1999 | Soil Organic Carbon; Soil Microorganisms | Journal | Soil Sci. Soc. Am. J.; 63; 865-873 | English | Hardcopy:Partial | Expt. to compare the saccharide concentrations in soils taken from different latitudes in North America - from Canada to Texas | Plant-derived sugars, especially pentoses, are a source of energy and C for soil fauna and microorganisms. .. the microorganisms re-synthesise primarily hexoses and release them to the soil.; .. saccharides .. tend to accumulate in older SOM with increasing soil depth, relative to even the chemically more stable lignin. .. plant-derived [neutral] sugars were concentrated in sand-size POM, whereas microbe-derived carbohydrates [amino-sugars] accumulated in the clay ..; The growth of microorganisms is more or less proportional to the root input, as will be the production of microbially derived saccharides. |
| 1396 | Amelung, W., Flach, K.W. & Zech, W. | Lignin in particle-size fractions of native grassland soils as influenced by climate | 1999 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 63; 1222-1228 | English | Hardcopy:Partial | Expt. to study the effect of climate on lignin degradation | Lignin is one of the predominant components in grass and root litter. Once the more labile components have been degraded, slowly decomposing lignin dominates the shape of litter decomposition curves.; Particle-size fractionation into clay, silt, fine sand and coarse sand yielded four significantly different lignin pools. The degree of lignin alteration proceeded as particle-size diameter decreased. |
| 1397 | Amelung, W., Zech, W., Zhang, X., Follett, R.F., Tiessen, H., Knox, E. & Flach, K.W. | Carbon, nitrogen and sulfur pools in particle-size fractions as influenced by climate | 1998 | Soil Organic Carbon; Soil N Dynamics | Journal | Soil Sci. Soc. Am. J.; 62 (1); 172-181 | English | Hardcopy:Partial | Expt. to study the C, N and S pools in samples taken from the top 10 cm. of native grassland soils from sites ranging from Canada to Texas | The clay fraction contained about 43% of the total SOC, 56% of the total N and 62% of the total S.; .. apart from foliar lignin, MAT [mean annual temp.] and clay content are the key site-specific parameters influencing SOM dynamics. |
| 541 | Anderson, J.M. | The effects of climate change on decomposition processes in grassland and coniferous forests | 1991 | Soil Organic Carbon | Journal | Ecol. Appl.; 1 (3); 326-347 | English | Hardcopy:Full; PDF:Full | Review of the possible effects of higher atmospheric CO2 concentrations and higher temperatures on the decomposition of plant residues in temperate and boreal regions | .. while mean NPP increases by a factor of ca.20 from tundra to tropical rain forest, MRTs of dead OM decrease by a factor of ca.200, primarily because soil temperatures limit decomposition more than air temperatures limit production.; .. C enrichment without increased nutrient supply resulting in higher C/N or lignin/N ratios and increased polyphenol concentrations in litter. If this low resource quality material decomposes slower than the current litter, negative feedback effects on plant production through reduced nutrient availability and increased C storage in litter pools may result.; White spruce exhibits an H enormous range of aboveground biomass (0.92-23.3 kg/m2) and production (89-2853 g m-2 yr-1) ..; .. a 4$C change in the boreal zone would probably result in a C flux that was increased by <6 Pg/yr. |
| 25 | Anderson, R.V., Coleman, D.C. & Cole, C.V. | Effects of saprotrophic grazing on net mineralisation | 1981 | Mineralisation; Soil N Dynamics; Soil (General) | Book | Clark, F.E. & Rosswall, T. (eds.); Terrestrial Nitrogen Cycles: Processes, Ecosystem Strategies and Management Impacts; 201-216 | English | Hardcopy:Partial | Review of the role of soil fauna - protozoa, nematodes, annelids, arthropods (including collembolans, mites, ants, termites and insects) - in litter processing and nutrient mineralisation. A table is given of production efficiency and the excretory products of the various groups of fauna. | As much as 86% of the autotrophic production and 95% of the heterotrophic production and respiration occur in the belowground component of most ecosystems.; The role of fauna in energetics and mineralisation of C is usually very small .. compared with microfloral activity. However .. their effect on system activity can be significant.; .. earthworm metabolism accounting for less than 10% of the litter energy content .. 6% of the bound N ingested by worms was excreted in a form available to plants. Earthworms process litter, decreasing its C/N ratio ..; Besides increasing litter processing microfauna and mesofauna increase nutrient concentrations in the processed material, because respiratory loss of C results in low C/N ratios.; .. soil fauna .. excrete N, usually as ammonium, urea or amino acids. Because C/N ratios of fauna are higher than .. those of the microflora consumed, N is mineralised. |
| 1170 | Anderson, T.H. & Domsch, K.H. | Application of eco-physical quotients (qCO2 and qD) on microbial biomasses from soils of different cropping histories | 1990 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 22 (2); 251-255 | English | Hardcopy:Partial | Study of microbial metabolic quotient and death quotient on soils under longxterm monoculture and rotation treatments. The metabolic quotient (qCO2) is the @ratio of the basal respiration to the biomass size and is a measure of the CO2 produced per unit biomass and unit time. The death quotient is the biomass C loss per unit biomass and unit time. The average qCO2 (& qD) in this study were 1.1 & 0.65 (3.01 & 1.88) for the monoculture and rotation soils respectively. | .. rate constants of the total biomass under in situ conditions are always lower .. than comparable values derived from .. optimal in vitro conditions.; .. microbial communities may differ with respect to energetic efficiency. The observation that microbial biomasses from plots under long-term M [monoculture] produce .. almost twice as much CO2 per unit cell mass and time and show a death rate which is ca. twice as high as compared to microbial biomasses from continuous CR [rotation] would speak for a higher energy demand in the first group. |
| 1171 | Anderson, T.H. & Domsch, K.H. | The metabolic quotient for CO2 (qCO2) as a specific activity parameter to assess the effects of environmental conditions, such as pH, on microbial biomasses of forest soils | 1993 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 25 (3); 393-395 | English | Hardcopy:Full | Field expt. to study the dependence of the metabolic quotient qCO2 on soil pH. @In acid forest soils (pH around 3) qCO2 was about 2.2 mg CO2-C/g SMB-C/hour, whereas in neutral forest soils the value was about double that. Microbial biomass C as a proportion of total SOC averaged 0.56 in acid forest soils and 2.2 in neutral ones, which compares with 2.6 in agricultural soils. | |
| 1712 | Anderson, T.H. & Joergensen, R.G. | Relationship between SIR and FE estimates of microbial biomass C in deciduous forest soils at different pH | 1997 | Uncategorised | Journal | Soil Biol. Biochem.; 29; 1033-1042 | English | PDF:Full | ||
| 1169 | Anderson, T.H., Domsch, K.H. | Ratios of microbial biomass carbon to total organic carbon in arable soils | 1989 | Green Manure; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 21 (4); 471-479 | English | Hardcopy:Partial | Measurement of Cmic/Corg ratios in soils from long-term agricultural expt.s.The mean biomass C/total organic C ratio was 2.3% and 2.9% under monoculture and rotation respectively, when the soil was amended with chemical fertiliser, around 5% with straw or FYM and up to 4% with green manure ( straw). This latter figure was seen as a transient increase due to the available C in the green manure. The Cmic/Corg relationship is only linear up to an organic C content of 2.5%. Above that it falls off steeply. | `; A wide spectrum of Cmic/Corg ratios ranging from 0.27% to over 7% are reported in the literature. .. the few data .. available from long-term field expt.s correspond well with the [figures] in the present investigation.; .. clay content had only little influence on the Cmic/Corg ratio.; After a change, e.g. in agricultural management, .. soil takes from 20-50 years to move to the new equilibrium state .. the soil microbial biomass responds more quickly to the change than does the amount of OM in the soil .. |
| 331 | Andrade, G., Azcón, R., Bethlenfalvay, G.J. | A rhizobacterium modifies plant and soil responses to the mycorrhizal fungus Glomus mosseae | 1995 | Soil Microorganisms | Journal | Appl. Soil Ecol.; 2; 195-202 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to demonstrate that rhizobacteria & mycorrhizal fungi, acting separ- ately or in concert, may have both positive & negative effects on plants and on soil aggregation | The rhizobacterium had no significant effect on plant biomass production in either soil in the absence of the VAM fungus, but decreased plant growth by more than 30% in its presence. It enhanced the root/shoot and seed/plant ratios in plants of both VAM and non-VAM treatments. Without the VAM fungus, both soils disaggregated. This .. was significantly less severe when the rhizobacterium was present. With the VAM fungus, aggregation increased up to 27% during the expt, but the rhizobacterium did not affect this process significantly. |
| 1714 | Andrews, J.A., Harrison, K.G., Matamala, R. & Schlesinger W.H. | Separation of Root Respiration from Total Soil Respiration Using Carbon-13 Labeling during Free-Air Carbon Dioxide Enrichment (FACE) | 1999 | Uncategorised | Journal | Soil Sci. Soc. Am. J.; 63; 1429-1435 | English | PDF:Full | ||
| 1701 | André, M., Bréchignac, F. & Thibault, P. | Biodiversity in model ecosystems | 1994 | Uncategorised | Journal | Nature (Lond.); 371; 565 | English | PDF:Full | ||
| 332 | Andrén, O., Brussaard, L. & Clarholm, M. | Soil organism influence on ecosystem-level processes - bypassing the ecological hierarchy? | 1999 | Miscellaneous | Journal | Appl. Soil Ecol.; 11; 177-188 | English | Hardcopy:Partial; PDF:Full | Review of soil ecology, arguing that soil ecosystems models only need to be consistent with data at two levels: the ecosystem and the organism levels | |
| 1713 | Andrén, O., Kirchmann, H., Kätterer, T., Magid, J., Paul, E.A. & Coleman, D.C. | Visions of a more precise soil biology | 2008 | Uncategorised | Journal | Eur. J. Soil Sci.; 59; 380-390 | English | PDF:Full | ||
| 1502 | Angers, D.A. | Water-stable aggregation of Québec silty clay soils: some factors controlling its dynamics | 1998 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 47 (1/2); 91-96 | English | Hardcopy:Partial; PDF:Full | Review of exptal. evidence for the mechanism of sequestration of C following changes to the soil management | .. the clay and silt particles of these soils are relatively saturated in OM which leads to highly stable microaggregation. Any additional OM accumulation in the surface soil provided by reduced- or no-till conditions, perennial forage crops or FYM additions would lead to increased macroaggregation and be related to the accumulation of particulate OM. This hypothesis helps to explain the relatively high responsiveness of soil structure, and in particular stable macroaggregation, to changes in cropping systems .. |
| 421 | Angers, D.A. & Caron, J. | Plant-induced changes in soil structure: processes and feedbacks | 1998 | Roots & Rhizodeposition; Soil (General) | Journal | Biogeochemistry (Dordr.); 42; 55-72 | English | Hardcopy:Full; PDF:Full | Review of the role of plants in affecting soil structure | ... roots form macropores which favour fluid transport. They also create zones of failure which help to fragment the soil and form aggregates. This phenomenon is enhanced by the wetting and drying cycles associated with plant growth. Drying also causes shrinkage and strengthening of the soil. Anchorage of roots and the exudation of cementing material stabilises soil structure. Finally, as a source of C, roots and plant residues provide a food source to the microflora and fauna which contribute to structure formation and stabilisation. |
| 1398 | Angers, D.A. & Giroux, M. | Recently deposited organic matter in soil water-stable aggregates | 1996 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 60 (5); 1547-1551 | English | Hardcopy:Full | Expt. to trace the fate of fresh OM in the soil. Recent crop residues comprised 9% of total SOC, 1% of the SOC in microaggregates and 20% of the SOC in waterstable aggregates >1 mm. The water stability of macroaggregates decreased according to cropping in the order hay meadow > wheat/ barley > maize. The half-life of recent maize-derived C in water-stable macroaggregates was 13 years. | .. slaking-resistant macroaggregates are enriched in, and probably stabilised by recently deposited OM.; macroaggregates are stabilised by [more labile] OM such as fungal hyphae, labile carbohydrates and aliphatic compounds that are .. younger than the bulk of the SOM .. while microaggregates would be stabilised by more processed SOM. |
| 1021 | Angers, D.A. & Recous, S. | Decomposition of wheat straw and rye residues as affected by particle size | 1997 | Soil Organic Carbon | Journal | Plant Soil; 189; 197-203 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the decomposition of mature wheat straw and green rye plants cut up into pieces of different sizes, 0.03-10 cm long. Initially finer particles decompose faster than coarser, but after a certain period (which is shorter, the higher the N content of the residue) the finer particles begin to decompose slower than the coarser. | We hypothesise that in this study two dominant opposite effects resulted from increasing residue contact with soil: 1) acceleration of decomposition due to increasing nutrient and water exchange with soil and 2) increase of C stabilisation by soil physical protection. In the case of wheat the response to size could have been a combination of these two effects while in the case of rye the first effect was only transitory.; .. a more even distribution of decomposition sites in the soil .. would allow for better access to nutrients and water.; .. more intimate contact with soil resulted in lower turnover rates owing to protection of microbial biomass and newly-formed organic substances. |
| 1503 | Angers, D.A., Bolinder, M.A., Carter, M.R., Gregorich, E.G., Drury, C.P., Liang, B.C., Voroney, R.P., Simard, R.R., Donald, R.G., Beyaert, R.P. & Martel, I. | Impact of tillage practices on organic carbon and nitrogen storage in cool humid soils of eastern Canada | 1997 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 41 (3-4); 191-201 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare C storage in 8 soils under zero tillage, chisel and mouldboard ploughing. Generally the soils under zero tillage only stored more OM than ploughed soils only in the top 10 cm. | .. under Easter Canadian conditions, where crop production and residue inputs are not affected by tillage, reduced tillage systems would not result in the storage of more SOM in the entire soil profile at least in a 5-10 year period. |
| 28 | Angers, D.A., Lafrance, P., Simard, R.R., Pelletier, F. & Légčre, A. | Temporal variation in soil microbial biomass and activity as influenced by compost and atrazine applications | 1995 | Soil Microorganisms | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 538-543 | English | Hardcopy:Full | 2-year field expt. to measure the effect of compost and herbicides on the quantity and activity of soil microbial biomass. SMB-C and activity were increased by compost application but unaffected by atrazine herbicide. | In a dry season temporal variations in microbial biomass carbon were related to variations in soil water content. |
| 626 | Angers, D.A., Recous, S. & Aita, C. | Fate of carbon and nitrogen in water-stable aggregates during decomposition of 13C15N-labelled wheat straw in situ | 1997 | Soil Organic Carbon; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 48 (2); 295-300 | English | Hardcopy:Partial | 18-month field expt. to study the incorporation of C & N from wheat straw into soil aggregates. During the first 200 days the straw C content in the macroaggregates (>250 m) rapidly increased but subsequently decreased. The proportion of straw C in the fractions <250 m increased throughout the expt. At the end of the expt. about 90% of the residual C from the straw had been incorporated into the soil fractions - about half of it in the 50-250 m fraction. | `; .. the distribution of 15N in the fractions with time was generally similar to (13C except that more 15N than 13C was recovered in the <50 m fraction at the expense of the larger fractions.; .. the C/N ratio decreased with decreasing aggregate size.; .. after 50 days 40% of the added C had mineralised. |
| 877 | Anon | Noch viele Frage offen | 2002 | Clover Sward; Stockless Farming; Tillage | Journal | Landwirtschaft ohne Pflug; 6; 15-17 | German | Hardcopy:Full | A field-scale expt. in direct sowing wheat into a legume sward. White clover is best, but grows so aggressively in the summer that, if the wheat is sown in July/early August (Fukuoka method), the clover out-competes it, so sowing in late August and early September is best. Any later gives poor results. White clover appears to have an allelopathic effect on competing species in summer. Grazing the wheat/clover in late autumn with sheep controls the white clover and stimulates tillering of the wheat. Rather than zero tillage the intention seems to be to plough twice in a 5-year rotation. | Ausgangspunkt fGr den Beginn der Versuche mit Biodirektsaat war die Feststellung, da sich nach 8 Jahren Getreide- und K?rnerleguminosenanbau die Getreideertrge auf den sandigen Boeden bei etwa 20 dt/ha einpegelten und damit der ?kologische Landbau nicht mehr wirtschaftlich war.; Die vom .. Fukuoka empfohlene Methode, Weizen bereits im Juli breitwGrfig im Weiklee zu verteilen, funktioniert deshalb hier offenbar nicht! |
| 1589 | Anon | Farming and fossil fuels | 1975 | Sustainability | Journal | Span; 18 (1); | English | Hardcopy:Partial | Farming is too dependent on fossil fuels. | .. only sunlight, wind, water power (including tides) and geothermal energy can be regarded as inexhaustible.; .. agriculture's prime role up to now has always been to fix massive amounts of energy from the sun ..; .. the development of communities beyond the stage of peasantry has always depended on farmers being able to reap a great deal more than they eat.; .. advanced agriculture is using up several times more energy than is contained in the crops and animals ..; .. the world's agriculture [is] arguably very wasteful in the way some of its primary products (e.g. grains) are used for the production of secondary products such as meat.; It will certainly be essential, for the foreseeable future, to continue to use considerable amounts of fossil fuel in support of world agriculture, even though that amounts to spending capital to balance the current account.; .. [there must be] determined efforts to find ways and means of using less energy in farming .. and using it much more efficiently. |
| 1639 | Anon | Easing farmers' Burden in Nepal | 2003 | Tillage | Website | www.rwc-prism.cgiar.org/rwc/Nepal-story.asp | English | Hardcopy:Full | A brief review of the beneficial effects of zero tillage and small-scale mechanisation on the farmers of southern Nepal. Wheat yields are being raised from an average of 1.6 tons per ha. to around 4 tons per ha. Spread of the news about the advantages of zero tillage by word-of-mouth ensures rapid adoption of the method. | The simplest reduced tillage technique is surface seeding. .. farmers simply toss wheat seed onto moist soil immediately before or after rice harvest. .. even the poorest farmers can practice [it].; To discourage birds from feasting on unprotected seed [they use] a slurry of FYM, in which the seed is soaked before it is placed on the soil.; .. the [Rice-Wheat] Consortium differs from many research partnerships. It does not see itself as simply giving promising options to farmers; instead, it is a partnership in which farmers are welcome to expt., assume ownership and share observations. |
| 1640 | Anon | Partitioning soil respiration | Roots & Rhizodeposition | Website | English | Wordperfect:Full | Review of methods of quantifying the partitioning of belowground respiration between roots & soil, including trad. methods like component integration and root exclusion (by trenching or gap formation) and modern methods using C-13 natural abundance | Trenches were dug 0.5 m outside of the plots to a depth of 70-100 cm (20 cm below the rooting depth) and the roots were excluded with ... fibre-glass sheets... Root contribution to total soil respiration was ... 33% or 123 g C/sq m/yr.; ... expts using 30 m gaps ... to compare vegetation-free soil with nearby vegetated soil ... Respiration rates of roots ranged from 40% to 51% ..; Smaller gap sizes were used ... by Ohashi ... Root respiration accounted for 57% of total soil respiration ...; Rochette ... quantified rhizosphere-respired CO2 from maize (C4) grown on soil previously cropped with wheat (C3) ... rhizosphere respiration contributed up to 43% of total soil respiration ... | ||
| 371 | Antai, S.P. & Crawford, D.L. | Degradation of softwood, hardwood and grass lignocelluloses by two Streptomyces strains | 1981 | Lignin and CBW; Soil Organic Carbon | Journal | Appl. Environ. Microbiol.; 42 (2); 378-380 | English | Hardcopy:Full; PDF:Full | Study of lignocellulose decomposition by bacteria on different substrates. After 12 weeks lignin loss from wood was about 30% and from grass about 42%. The total weight losses of lignocellulose were about 20% and 53% respectively. | .. both Streptomyces strains substantially degraded both the lignin and carbohydrate components of each lignocellulose ..; Lignin degradation by these bacteria includes the oxidation of both aromatic rings and propane side chain `lignin carbons to CO2. Streptomyces trains have been shown to destroy the integrity of both lignified and non-lignified plant cell walls within intact woody plant tissues. |
| 1478 | Aoyama, M. & Nozawa, T. | Microbial biomass Nitrogen and mineralisation-immobilisation processes of Nitrogen in soils incubated with various orgganic materials | 1993 | Green Manure; Mineralisation; Soil N Dynamics | Journal | Soil Sci. Plant Nutr.; 39 (1); 23-32 | English | Hardcopy:Partial | 16-week lab. study of N dynamics in soils amended with chicken manure, clover leaves, FYM, bark compost and rice straw. The maximum increase in biomass N was 4%, 13.6%, 13.5%, 5.8% and 13.4% respectively. The low figure for the bark compost was suppose to be due to the labile portion of the bark having been used up in the composting process, leaving mainly recalcitrant OM. Chicken manure was rapidly mineralised from the start. Clover leaves showed a 2-week lag before mineralis'n started, during which microbial biomass N increased but subsequently rapidly decreased. With FYM and rice straw immobilisation started at once and continued for 4 and 16 weeks respectively. The biomass N increased to a maximum in the first 2 weeks and remained high throughout the immobilisation period. | Hirose (1973) divided .. plant residues into 3 groups: (1) rapid N mineralis'n .. from the beginning of incubation (C/N ration 5.6-11.3); (2) N mineralis'n started just after limited N immobilisation (C/N ration 15.3-20.6); (3) N immobilisation occurred from the beginning of incubation and continued for a long .. time (C/N ration 37.1-64.4). |
| 719 | Arocena, J.M. & Opio, C. | Prescribed fire-induced changes in properties of sub-boreal forest soils | 2003 | Miscellaneous | Journal | Geoderma; 113; 1-16 | English | PDF:Full | Field expt. to study the effect of forest fire on the soil | We observed higher soil pH, exchangeable Ca, Mg, K and Na and base saturation in burnt plots compared to unburnt plots.; Fires dramatically alter nutrient cycling through volatilisation, substrate transfer, in the form of particulate matter, smoke and ash, as well by inducing nutrient losses and leaching. ... Fires influence long-term nutrient supply through loss of OM and cations bound to burned forest floor.; ... the reduction in CEC and the generation of thermal cracks in feldspars and other soil aggregates could accelerate weathering due to increased surface area and result in loss of K, Ca & Mg through leaching. |
| 203 | Arshad, M.A. & Martin, S. | Identifying critical limits for soil quality indicators in agro-ecosystems | 2002 | Soil (General) | Journal | Agric. Ecosyst. Environ.; 88; 153-160 | English | Hardcopy:Partial | A qualitative discussion of the question of soil quality indicators. Guidelines for monitoring soil quality are proposed, involving eight steps, of which steps 4 to 7 are: select a set of indicators, select a reference point (baseline value) for each indicator, specify the critical limits for each of the selected indicators, transform the indicators into a soil quality/sustainability index. | .. selection of soil indicators will vary with societal goals .. the following seem to be suitable indicators for crop production in most cases: OM, topsoil depth, infiltration, aggregation, pH, electrical conductivity, suspected soil pollutants and soil respiration. Crop yield can be used as an integrator of the foregoing soil indicators. |
| 1504 | Arvidsson, J. & Hankansson, I. | A model for estimating crop yield losses caused by soil compaction | 1991 | Soil (General) | Journal | Soil Tillage Res.; 20 (2-4); 319-332 | English | Hardcopy:Partial | Modelling the effects on crop yields of soil compaction caused by traffic, recompaction after ploughing, persistence of plough-layer compaction after ploughing and subsoil compaction. | |
| 1172 | Ashman, M.R., Hallett, P.D. & Brookes, P.C. | Are the links between soil aggregate size class, soil organic matter and respiration rate artefacts of the fractionation procedure? | 2003 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 35 (3); 435-444 | English | Hardcopy:Full; PDF:Full | Expt. to study how variations in aggregate fractionation procedures influence the chemical and biological properties of different sized soil aggregates | .. the chemical and biological properties of aggregates depend on the fractionation procedure. .. the observed relationships between aggregate size and other properties, for example biological activity, must be interpreted in terms of the disruptive mechanisms used to fractionate aggregated soil. .. the aggregate hypothesis has serious weaknesses, the aggregates measured being largely an artefact of the chosen method of separation. .. future work should also consider biological activities at soil pore surfaces. It is at the surface of these channels that parameters such as oxygen supply, plant roots, root exudates and fresh OM inputs first interact with the soil. Biological processes in this region are therefore likely to be more important than those occurring in the bulk soil. |
| 831 | Askegaard, M. & Eriksen, J. | Growth of legume and non-legume catch [cover] crops and residual-N effects in spring barley on coarse sand | 2007 | Cover Crops; Green Manure; Soil N Dynamics | Journal | J. Plant Nutr. Soil Sci.; 170 (6); 773-780 | English | Hardcopy:Partial | Field expt. to measure the growth and residual N of various cover crops | .. the legume cover crops had a significantly larger aboveground dry-matter production and N content in the autumn than the non-legumes. The autumn N uptake of the non-legumes was 10-13 kg N ha-1 in shoots and approx. 9 kg ha-1 in the roots. The shoot N content of white clover .. was 55-67 kg ha-1 and the root N content .. was approx. 25 kg ha-1. [Its] N fertilizer-replacement values in a `following unfertilised spring barley [was] 120 .. kg N ha-1 .. |
| 1479 | Askegaard, M., Olesen, J.E. & Kristensen, K. | Nitrate leaching from organic arable crop rotations: effects of location, manure and catch crop | 2005 | Cover Crops; Soil N Dynamics | Journal | Soil Use Manag.; 21 (2); 181-188 | English | Hardcopy:Partial; PDF:Full | Field expt. to test the effects of legumes and cover crops on nitrate leaching | Leaching losses from the crop rotation with grass-clover green manure & without @catch crops were 104, 54 & 35 kg N ha-1 yr-1 on the coarse sand, the loamy sand and the sandy loam respectively. There was no effect of manure application or time of ploughing-in the grass-clover green manure crop on the accumulated nitrate leaching from the entire rotation.; The inclusion of catch crops in the rotation with grass-clover green manure decreased nitrate leaching by 38% for the coarse sand .., 30% for the loamy sand .. and 26% for the sandy loam .. |
| 1715 | Asman, W.A.H., Sutton, M.A. & Schjřrring, J.K. | Ammonia: emission, atmospheric transport irnd deposition | 1998 | Uncategorised | Journal | New Phytol.; 139; 27-48 | English | PDF:Full | ||
| 969 | Augris, N., Balesdent, J., Mariotti, A., Derenne, S. & Largeau, C. | Structure and origin of insoluble and non-hydrolyzable aliphatic organic matter in a forest soil | 1998 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 28 (1/2); 119-124 | English | Hardcopy:Full; Wordperfect:Full | Field expt. to study the very recalcitrant aliphatic material in a loamy forest soil, which are shown to be related to cutans and suberans from plants and comprise 5% of the total SOC and 25% of the total humin in this soil. | A new family of insoluble non-hydrolysable highly aliphatic bio-macromolecules was discovered recently in .. the cuticle and periderm of a number of higher plants and named cutans and suberans respectively .. These bio-macromolecules are characterised by an unusually high resistance to drastic base and acid hydrolyses .. based on a network of long saturated hydrocarbon chains. .. the structure .. is quite different from that of lignins, previously considered as by far the most resistant constituents in higher plants. |
| 1173 | Aulakh, M.S., Doran, J.W., Walters, D.T. & Power, J.F. | Legume residue and soil water effects on denitrification in soils of different texture | 1991 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 23 (12); 1161-1167 | English | Hardcopy:Full | Lab. expt. to study the effect of water content and amendment with legume residues on the rate of denitrification in soil | Total N losses via denitrification .. were lowest .. at 60% WFPS and greatest at 90% WFPS.; .. incorporated low C/N-ratio plant residues .. apparently increases denitrification through increased microbial activity.; Total N losses from residue amended soils at 60% WFPS were 1-2 orders of magnitude higher than those from soils without residue. |
| 1399 | Aulakh, M.S., Doran, J.W., Walters, D.T., Mosier, A.R. & Francis, D.D. | Crop residue type and placement effects on denitrification and mineralisation | 1991 | Mineralisation; Soil N Dynamics | Journal | Soil Sci. Soc. Am. J.; 55; 1020-1025 | English | Hardcopy:Full | Lab. expt. to study the N mineralisation and losses from soil treated with surface-applied or incorporated plant residues | x; Denitrification was greatest during the first 8 d, as was CO2 evolution. Initial denitrification with surface-placed residues was less than with incorporated residues, but cumulative losses over 35 d did not differ significantly.; Substantial N immobilisation occurred with .. incorporated or surface-placed .. residue with wide C/N ratios .., whereas, with low C/N-ratio vetch, significant mineralisation occurred. After 35 d, 51% & 36% of N in incorporated & surface-placed vetch residue respectively was mineralised. |
| 445 | Aulakh, M.S., Khera, T.S., Doran, J.W. & Bronson, K.F. [5 pp. only] | Denitrification, N2O and CO2 fluxes in rice-wheat cropping systems as affected by crop residues, fertiliser N and legume green manure | 2001 | Greenhouse Gases; Green Manure; Soil N Dynamics | Journal | Biol. Fertil. Soils; 34; 375-389 | English | Hardcopy:Partial | Four-year field study of an irrigated rice-wheat rotation are presented. The effects of including the green manure sesbania in the rotation and of incorporating crop residues were observed. | The atmospheric concentration of N2O is increasing at a current rate of about 0.25% per year. N2O is emitted from agricultural soils by both denitrification and nitrification processes. The total amount of N2O emitted globally from N`fertilised soils is estimated to be 1.5 Tg N2O-N per year, which represents about (10% of the total N2O-N emission to the atmosphere.; .. up to 50% of the fertiliser N applied to wetland rice remains unaccounted for in 15N-balance studies .. substantial amounts of applied fertiliser N and green manure N (2333%) are lost via nitrification and denitrification during rice cropping.; .. the inclusion of sesbania .. green manure in an irrigated rice-wheat cropping system on porous soils results in a greater crop productivity and reduces nitrate leaching to lower soil depths as compared with chemical fertilisers. |
| 1103 | Avery, A.A., Prakash, C.S., McHughen, A., Trewavas, A.R. & Gregori, T.R. de | What kind of farming works best? | 2005 | Organic Farming | Journal | Science; 307; 1410-1411 | English | Hardcopy:Full | Letter criticising Pimentel's review of the book Mendel in the Kitchen: a Scientist's View of Genetically Modified Foods, by Fedoroff and Brown, and Pimentel's response | The Soil and Water Conservation Society says that herbicide-based low- and no-tillage cropping systems are the most sustainable ever ..; .. many long-term studies have shown a 10 to 40% org. yield deficit.; .. organic approaches would reduce the use of fossil energy in corn production by about 30 percent, due to not using synthetic fertiliser, but .. only by using far more land per ton of food produced. Replacing synthetic nitrogen fertiliser would require at least a fourfold increase in manure applications or equivalent green manure crops.; Worldwide, crops are cultivated on 11% of the world's land area .. the World Health Organisation recently reported that 3.7 billion people are malnourished. |
| 204 | Baggs, E.M., Rees, R.M., Castle, K., Scott, A., Smith, K.A. & Vinten, A.J.A. | Nitrous oxide release from soils receiving N-rich crop residues and paper mill sludge in eastern Scotland | 2002 | Greenhouse Gases; Soil N Dynamics | Journal | Agric. Ecosyst. Environ.; 90; 109-123 | English | Hardcopy:Partial | The incorporation of crop residues (especially those with a low C/N ratio like legumes or horticultural crops rather than high C/N residues like cereal straw) @can result in increased N2O emission from the soil. For example, incorporation of lettuce residues can temporarily increase N2O emission by up to 1.1 kg N2O-N per ha. during the first two weeks. In the expt.s reported here fields containing vegetable residues (from previous lettuce and calabrese crops) were treated with paper mill sludge and then cultivated by one of three methods - rotary tillage, ploughing (to 15 cm. depth) and deep ploughing (to 35 cm. depth). The N2O emission was monitored to see if the paper mill sludge reduced it. In fact the rate of emission increased, especially after deep ploughing. | Emissions of N2O are of concern because of the role of this gas in the greenhouse effect and the destruction of the ozone layer. .. emissions from agricultural systems are now thought to contribute 6.2 Tg N2O-N per year to the total global source strength of 17.7 Tg N2O-N per year. |
| 1480 | Baggs, E.M., Rees, R.M., Smith, K.A. & Vinten, A.J.A. | Nitrous oxide emission from soils after incorporating crop residues | 2000 | Greenhouse Gases; Soil N Dynamics | Journal | Soil Use Manag.; 16; 82-87 | English | Hardcopy:Full | Measurement of N2O emissions from soils under different management systems over 54-104 days. The highest total emission occurred after rotary tilling of lettuce residues and the lowest with unfertilised winter wheat. | @; N2O emissions were temporarily raised after .. ploughing of bare soil .., probably due to decomposition of labile root material ..; .. larger emissions were measured after incorporation of material with a low C/N ratio .. The large emissions from lettu |
| 945 | Baggs, E.M., Watson, C.A. & Rees, R.M. | The fate of nitrogen from incorporated cover crop and green manure residues | 2000 | Cover Crops; Green Manure; Soil N Dynamics | Journal | Nutr. Cycl. Agroecosyst.; 56 (2); 153-163 | English | Hardcopy:Partial | Expt. to study the effect on N availability of the incorpor'n of overwintering cover and green crops. Available N, and hence potential N leaching and emission, was reduced compared with bare ground. | Vegetation that had regenerated naturally was as effective as sown cover crops at taking up N over winter & in returning N to the soil for the following crop. |
| 1175 | Bahri, H., Dignac, M.F., Rumpel, C., Rasse, D.P., Chenu, C. & Mariotti, A. | Lignin turnover kinetics in an agricultural soil is monomer specific | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 38; 1977-1988 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the turnover kinetics of lignin in an arable soil on a molecular basis | Lignin monomers were released by CuO oxidation .. Individual C4-derived phenols displayed contrasting accumulation rates in soils over time, confirming the monomer-specific nature of their transformation kinetics. In proportion to total lignin phenols in soils, syringyl & cinnamyl phenols from maize accumulated faster than their vanillyl counterparts. Consequently the turnover kinetics of lignin-derived V-moieties may be slower than those of S and C ones. |
| 1505 | Bailey, K.L. & Lazarovits, G. | Suppressing soil-borne diseases with residue management and organic amendments | 2003 | Compost & Biocontrol; Soil Microorganisms | Journal | Soil Tillage Res.; 72; 169-180 | English | Hardcopy:Full; PDF:Full | Review of the effect of organic amendments on soil-borne diseases | .. residue management practices and various forms of organic amendments do contribute to the suppression of soil-borne diseases .. With residue management systems for common root-rot control, crop residue (OM) and its subsequent breakdown results in biological and chemical processes that can directly affect this pathogen's viability and survival through the restriction of available nutrients and the release of natural antimycotic substances with varying inhibitory properties. Carbon released from crop residues contributes to increasing soil microbial activity and so increases the likelihood of competition effects in the soil. The placement of the residue in soil can lead to the displacement of the pathogen from its preferred niche, diminishing the pathogen's ability to survive. The benefits of applying organic amendments for disease control are incremental, generally slower acting than chemical fumigants or fungicides, but may last longer and their effects can be cumulative. |
| 1176 | Bailey, V.L., Smith, J.L. & Bolton, H. | Fungal-to-bacterial ratios in soils investigated for enhanced C sequestration | 2002 | Soil Organic Carbon; Soil Microorganisms; Tillage | Journal | Soil Biol. Biochem.; 34 (7); 997-1007 | English | Hardcopy:Partial | Expt. to assess the relative contributions of fungi and bacteria to microbial biomass and the F/B ratios and activity of soils from various ecosystems, including agricultural land | Within the pairs of study soils those that were tilled had lower fungal activities and stored C [quantities] than those that were managed to native or notill systems. .. soils that had higher absolute fungal activities also had more total soil C & .. fungal activity was correlated with total soil C. .. increased fungal activities, more than F/B ratios, were associated with increased soil C. Practices that involved invasive land management decreased fungal activity & stored soil C compared to similar soils that were less intrusively managed. |
| 1104 | Bais, H.P., Vepachedu, R., Gilroy, S., Callaway, R. & Vivanco, J. | Allelopathy and exotic plant invasion: from molecules and genes to species interactions | 2003 | Allelopathy; Miscellaneous | Journal | Science; 301 (5638); 1377 - 1380 | English | Hardcopy:Full; PDF:Full | Lab. expt. to show that spotted knapweed, an invasive species in western U.S.A., displaces native species by exuding the phytotoxin catechin, which inhibits native species' growth and germination | Plants use sophisticated signal transduction cascades to sense and respond to biotic and abiotic stresses.; ... Ca2+-signalling may play a role in the phytotoxic action of (-)-catechin in susceptible species.; ... the allelochemical triggers a wave of reactive oxygen species initiated at the root (meristem, which leads to a Ca2+ signalling cascade, triggering genome-wide changes in gene expression and ultimately death of the root system. |
| 1400 | Bajracharya, R.M., Lal, R. & Kimble, J.M. | Erosion effects on carbon dioxide concentration and carbon flux from an Ohio alfisol | 2000 | Greenhouse Gases; Soil Organic Carbon; Soil (General) | Journal | Soil Sci. Soc. Am. J.; 64; 694-700 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to determine the relationshsip between CO2 flux from soil and the degree of erosion | @; Seasonal patterns in soil air CO2 concentrations (ranging from a winter low of 0.56 mL L-1 to a summer high of 20.90 mL L-1) predominated over more subtle differences (20-80% variation) due to erosion phase effects; ..., which appeared to be indirect t |
| 627 | Balabane, M. | Turnover of clay-associated organic nitrogen in the different aggregate-size classes of a cultivated silty loam | 1996 | Mineralisation; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 47 (3); 285-291 | English | Hardcopy:Partial | Expt. using 15N to study the rate of N mineralisation in macro- and microaggregates | .. N mineralisation from macroaggregates is faster than from microaggregates.; Clay-N .. may be protected against degradation within micropores in microaggregates.. N turnover may be faster [also] because of the presence of large fresh plant debris rich in available C that enhances microbial activity.; .. macroaggregates contain additional organic C with a fast turnover compared to microaggregates.; .. material external to both clay- and silt-sized aggregates was largely proteinaceous, while internal material resembled humic acids.; .. recently immobilised N associated with clay is rapidly sequestered in microaggregates. |
| 970 | Baldock, J.A. & Skjemstad, J.O. | Role of the soil matrix and minerals in protecting natural organic materials against biological attack | 2000 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 31 (7-8); 697-710 | English | Hardcopy:Full; PDF:Full | Review of research on the protection of SOM by minerals | OM may range in size and complexity from simple monomers or organic acids to mixtures of complex biopolymers aggregated together in the form of cellular debris.; OM enters the soil as pieces of organic debris having a chem. structure and C/N ratio similar to that of the materials from which they were derived and a particle size >20 m. .. As these organic particles are decomposed, the more labile components of the residues are preferentially utilised and particle size decreases, leading to a conc'n of the more chemically recalcitrant structures (e.g. lignin & alkyl structures) in the 2-20 m size fraction. .. As the content of O-alkyl C decreases, the second stage of decomposition is initiated. Lignin is decomposed, resulting in changes to the chemical structure of the residual lignin polymer and a reduction in the quantity of aromatic C. The decompos'n of lignin is performed [pre]dominantly by fungi.. Lignin degrading organisms do not gain energy or assimilate from lignin degrad'n but benefit through an exposure of labile O-alkyl C buried within lignin/polysaccharide structures. The most biologically stable form of org. C found in soils is alkyl-C. |
| 881 | Baldock, J.A., Masiello, C.A., Gélinas, Y. & Hedges, J.I. | Cycling and composition of organic matter in terrestrial and marine ecosystems | 2004 | Lignin and CBW; Soil Organic Carbon | Journal | Mar. Chem.; 92; 39-64 | English | Hardcopy:Full | Review of recent research into the composition, degradation and stabilisation of the different forms of organic matter in the soil | Microbial utilisation of the carbohydrate-rich and protein-poor litters typical of terrestrial systems generally results in a loss of carbohydrate and an increase in the concentration of protein (due to the immobilisation of inorganic N) and [of] lipid and lignin (due to their greater biochemical recalcitrance). Recalcitrant components such as ... black carbon would also accumulate if present.; Where mechanisms of biological stabilisation are active, organic molecules that are potentially labile may accumulate and be preserved. |
| 628 | Balesdent, J. | The significance of organic separates to carbon dynamics and its modelling in some cultivated soils | 1996 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 47 (4); 485-493 | English | Hardcopy:Partial | An expt. to study the turnover of C in various separates from long-term field xexpt.s with maize, using 13C natural abundance measurement | Primary particle-size fractions coarser than 50 m had short lives and could be associated with the plant structural compartment of models. .. None of the chemical separates .. were enriched either in young or old C. .. The results showed neither a sequential relation between fulvic acids and humic acids nor a resistance of non-hydrolysable material. The range of lifetimes of soil C seems to be determined more by physical position and protection than by the chemical nature of SOM. |
| 1177 | Balesdent, J. & Balabane, M. | Major contribution of roots to soil carbon storage inferred from maize cultivated soils | 1996 | Mineralisation; Roots & Rhizodeposition; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 28 (9); 1261-1263 | English | Hardcopy:Full; Wordperfect:Full | Expt. to measure the contribution of roots to the soil storage of C from maize xresidues. The total aboveground production was 730 g C m-2, the harvest index @about 52% and the aboveground residue 380 g C m-2. The belowground biomass was estimated to be 152 g C m-2, giving a root/shoot ratio of 40%. The corresponding quantities of C accumulated in the soil were 57 and 36 g C m-2 yr-1 for root and shoot respectively. | .. the large accumulation [of root-derived material] was partially due to a slower decay of root-derived C compared to aboveground C. .. Two processes are known to lower the decay rate and to increase the stabilisation-to-mineralisation ratio of C in soils: on one hand the higher lignin/N ratio in root material compared to leaves and stalks (i.e. 32 and 11 in the present study respectively) and, on the other hand, the direct introduction of root-derived products into the soil clay matrix, which tends to physically protect them from microbial degradation.; .. maize is known to have a belowground production lower than perennial cereals and grasses .. |
| 1022 | Balesdent, J., Besnard, E., Arrouays, D. & Chenu, C. | The dynamics of carbon in particle-size fractions of soil in a forest-cultivation sequence | 1998 | Soil Organic Carbon | Journal | Plant Soil; 201 (1); 49-57 | English | Hardcopy:Partial; Wordperfect:Full | Study of OM of crop and forest origin in forest and forest-derived arable soils | .. the decay rates of soil C were one order of magnitude higher under cultivation than under forest. .. All size fractions appeared to be de-protected to the same extent. A progressive transfer of silt-sized C to clay-sized C was nevertheless suspected and attributed to the decreasing stability of fine siltsized microaggregates with cultivation.; The turnover times of maize-derived OM [from forest soils first cultivated 40 years ago] was the same as that observed in similar soils cultivated for centuries. This indicated that the new conditions induced by cultivation were reached in the very first years after forest clearing and that the high initial SOM content and high mineralisation rate of initial OM did not affect the dynamics of newly incorporated C. |
| 1506 | Balesdent, J., Chenu, C. & Balabane, M. | Relationships of soil organic matter dynamics to physical protection and tillage | 2000 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 53 (3-4); 215-230 | English | Hardcopy:Partial | Review of work on the physical protection of OM in soils and the effects of tillage on it. Some of the SOM (mostly from the slow pool of small-sized SOM) is protected from bio-degradation by being included inside microaggregates, which can be dispersed by tillage and weather. | In virgin and zero tillage systems a substantial part of SOM lies above the mineral soil as litter or even in the soil as dead tree stumps.; Cultivating a virgin soil [causes] a drop in SOM concentration .. ranging from 10 to 55% of the native C.; An accumul'n of biological activity and biomass at the surface under NT practices has been reported .. As most SOM is concentrated on the surface, the environment of biodegradation is that of the top few cm. |
| 849 | Balesdent, J., Mariotti, A. & Boisgontier, D. [5 pp. only] | Effect of tillage on soil organic carbon mineralisation estimated from 13C abundance in maize fields | 1990 | Mineralisation; Soil Organic Carbon; Tillage | Journal | J. Soil Sci.; 41; 587-596 | English | Hardcopy:Partial | An expt. using 13C abundance to study the quantity and distribution of maizederived C in soil from a 17-year trial under three different tillage systems | The conventional tillage accumulated 1.1 kg C per sq.m. of maize-derived C and the no-tillage treatment 0.8.; .. mineralisation of the initial organic C during the expt. was doubled in the conventional tillage plot compared with the no-tillage plot. .. Although the mineralisation rate was lower in the no-tillage treatment than in the conventional tillage treatment, the returns of maize C were also lower, so that the final total C content was similar in both treatments. |
| 1178 | Balesdent, J., Mariotti, A. & Guillet, B. | Natural 13C abundance as a tracer for studies of soil organic matter dynamics | 1987 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 19 (1); 25-30 | English | Hardcopy:Partial | A method is described for measuring the long- and medium-term turnover of SOM, based on the variations of 13C natural isotope abundance induced by the repeated xcultivations of a plant with a high 13C/12C ratio (C4 photosynthetic pathway) on a soil that has never carried any such plant. The method is applied to two soils - one former meadow and one former forest, which had been continuously cropped with maize for 13 and 23 years respectively. 13C is defined as: ((Rsample/Rstandard)1)*1000K, where R is the isotope ratio 13C/12C of the sample. The values of 13C `for atmospheric CO2, C4 plants and C3 plants are about -7K, -12K (range -9 to 19K) and -27K(range -23 to -40K) respectively. The percentage x of C coming from the new C4 plants is calculated from the equation: A = x/100.A1 + (1-x/100.A0),where At is the ratio 13C/(12C + 13C) at time t. | After 13 years 22% of total organic C had turned over in the system studied. |
| 1509 | Ball, B.C. & Ritchie, R.M. | Soil and residue management effects on arable cropping conditions and N2O fluxes under controlled traffic in Scotland 1. Soil and crop responses | 1999 | Soil N Dynamics; Soil (General) | Journal | Soil Tillage Res.; 52 (3-4); 177-189 | English | Hardcopy:Partial; Wordperfect:Full | Partial results of an expt. to study how the intensity and distribution of soil compaction just before sowing @influenced crop performance, soil conditions and emissions of N2O. | Tractor traffic on wet soil can .. increase denitrification by a factor of 34.; Compaction of moist soils is important when air-filled porosity is reduced to below the commonly quoted critical level for satisfactory aeration of 0.1 m3 `m-3. [10%]; Our heavy compaction treatment only caused problems with crop growth when applied to wet soil that remained wet during early growth. This resulted in air-filled porosities of generally less than 0.1 m3 m-3 and cone resistances and bulk densities of nearly 2 MPa and 1.4 Mg m-3 throughout the topsoil. The latter are close to the critical values for barley growth of 2.5 MPa and 1.41 H Mg m-3 on the same soil type .. A critical value of BD of 1.48 Mg m-3 was quoted by Styk and Sochaj (1992) .. |
| 1507 | Ball, B.C., Lang, R.W., Robertson, E.A.G. & Franklin, M.F. | Crop performance and soil conditions on imperfectly drained loams after 20-25 years of conventional tillage or direct drilling | 1994 | Soil (General); Tillage | Journal | Soil Tillage Res.; 31 (2-3); 97-118 | English | Hardcopy:Partial | Expt. to compare soil and yields after long-term ploughing and zero tillage | Soil aeration, strength and structure were more favourable under ploughing than under direct drilling. BD and soil strength did not show any long-term progressive changes in the long-term direct drilled treatment. Weather and drainage status varied markedly between seasons and determined the number of available workdays during the harvesting and tillage period. Available workdays influenced crop responses to reduced tillage more than soil type or physical condition. In some seasons workdays were insufficient to permit the high standard of management necessary for successful reduced tillage, especially direct drilling. |
| 1508 | Ball, B.C., Parker, J.P. & Scott, A. | Soil and residue management effects on cropping conditions and N2O fluxes under controlled traffic in Scotland 2. N2O, soil N status and weather | 1999 | Greenhouse Gases; Soil N Dynamics | Journal | Soil Tillage Res.; 52 (3-4); 191-201 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to assess the effect of xsoil compaction on crop performance and N2O emission. | @; Compaction increases N2O emissions by increasing water-filled porosity and increasing the likelihood of anaerobic soil conditions and denitrification.; Incorporated crop residues can also increase N2O emissions, particularly after ploughing in the autu |
| 1510 | Ball, B.C., Scott, A. & Parker, J.P. | Field N2O, CO2 and CH4 fluxes in relation to tillage, compaction and soil quality in Scotland | 1999 | Greenhouse Gases; Soil N Dynamics; Tillage | Journal | Soil Tillage Res.; 53 (1); 29-39 | English | Hardcopy:Partial; Wordperfect:Full | An expt. to see how tillage practices, soil conditions and weather interact to xinfluence greenhouse gas emissions. CH4 is removed from the atmosphere as a result of oxidation in aerobic soils - the rate of removal is greater in untilled than in tilled soils. N2O emission from soil is increased by synthetic fertiliser or FYM application, by soil compaction and by wet conditions. Rainfall on untilled soil is liable to increase N2O emission and decrease CO2 `emission as a result of reduced porosity and gas diffusivity. The greater CH4 abstraction in zero tillage systems is not enough to compensate for the greater N2O emission. | Periods of low CO2 and high N2O flux under no-tillage were associated with reduced gas diffusivity and air-filled porosity caused by heavy rainfall. |
| 446 | Balota, E.L., Colozzi-Filho, A., Andrade, D.S. & Dick, R.P. | Microbial biomass in soils under different tillage and crop rotation systems | 2003 | Soil Microorganisms; Tillage | Journal | Biol. Fertil. Soils; 38; 15-20 | English | Hardcopy:Full; PDF:Full | 22-year expt. in southern Brasil to effect of tillage and cropping treatments on the microbial biomass in soils. | Averaging across crop rotations in the 0- to 5-cm depth showed a 100%, 54% and 39% increase of MBC, MBN and MBP respectively for NT over CT.; On average NT resulted in an increase of 30% Cmic/Corg percentage over CT.; .. the wider C/N biomass of NT would suggest that NT plots have a greater proportion of fungal compared to bacterial biomass [F/B] than CT. .. reduced soil disturbance favours establishment and maintenance of fungal hyphal networks. |
| 1511 | Balota, E.L., Colozzi-Filho, A., Andrade, D.S. & Dick, R.P. | Long-term tillage and crop rotation effects on microbial biomass and C & N mineralisation in a Brazilian Oxisol | 2004 | Mineralisation; Soil Microorganisms; Tillage | Journal | Soil Tillage Res.; 77; 137-145 | English | Hardcopy:Partial; Wordperfect:Full | Field expts to examine the effect of crop rotation & tillage treatment on C & N mineralisation, microbial biomass C, metabolic quotient & basal respiration | No tillage systems increased total C by 45%, microbial biomass by 83% and MBC/ total C ratio by 23% at 0-50 mm depth over CT. C & N mineralisation increased 74% with NT compared to CT systems for the 0-200 mm depth. Under NT the metabolic quotient (CO2 evolved per unit of MBC) decreased by 32% averaged across soil depths..; No tillage .. increased total C conc'ns over CT by 45, 34 & 14% in (the 0-50, 50-100 & 100-200 mm depths..; Generally .. qCO2 decreases in more stable systems, while the incorporation of residues to soil increases qCO2 .. soils under CT provide less OM and MBC but a larger metabolic quotient than NT.; The values of microbial biomass C/total C varied from 11.6 to 14.8 mg g-1 under H CT & from 11.8 to 16.8 mg g-1 under NT.; The values of basal respiration varied from 5 to 10 g CO2-C g-1 per day under CT and from 5 to 10 g CO2-C g-1 per day under NT ..; On average the C mineralisation under NT was 50% greater than CT.; The values of N mineralisation during 24 days of incubation varied from 0.05 hto 0.09 g N g-1 per day under CT and from 0.07 to 0.22 g N g-1 per day under NT.; On average NT had 78% greater N mineralisation than CT .. |
| 447 | Bardgett, R.D. & McAlister, E. | The measurement of soil fungal:bacterial biomass ratios as an indicator of ecosystem self-regulation in temperate meadow grasslands | 1999 | Organic Farming; Soil Microorganisms | Journal | Biol. Fertil. Soils; 29 (3); 282-290 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the microbial biomass and F/B ratio in fertilised and unfertilised grassland | [title contd. in temperate meadow grasslands]; ... F/B biomass ratios ... were consistently and significantly higher in the unfertilised than the fertilised grasslands. There was also some evidence that microbial biomass ... was higher in the unfertilised than in the fertilised grasslands.; ... soil food-webs of intensive systems were found to be consistently dominated by bacterial pathways of decomposition, whereas soils of long-term organic systems were dominated by fungal pathways. An additional feature of the organically managed grassland soils was a high total microbial biomass, relative to soils of intensive grassland systems.; ... fungi are known to be adversely affected by high amounts of mineral N. |
| 582 | Bardgett, R.D., Denton, C. & Cook, R. | Below-ground herbivory promotes soil nutrient transfer and root growth in grassland | 1999 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Ecol. Lett.; 2; 357-360 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effect of nematode root herbivory on white clover plants and on adjacent ryegrass plants | Low levels of white clover root infection by clover cyst nematodes increased root growth by 141% & 219% in the host plant & the uninfected neighbouring [rye]grass respectively. Root infection increased the size of the soil microbial biomass in the root zone and the transfer of 15N from the host plant to the soil & the neighbouring grass. These data suggest that low amounts of below-ground herbivory may increase the transfer of plant C & N below-ground, leading to increases in root growth and soil nutrient recycling in grasslands. |
| 333 | Bardgett, R.D., Streeter, T., Cole, L. & Hartley, I. | Linkages between soil biota, nitrogen availability and plant nitrogen uptake in a mountain ecosystem in the Scottish Highlands | 2002 | Mineralisation; Soil Microorganisms; Soil N Dynamics | Journal | Appl. Soil Ecol.; 19; 121-134 | English | Hardcopy:Partial; PDF:Full | Field expt. to study N mineralisation in a poor acid soil | At the onset of plant growth in May, the microbial N pool was at its lowest (1.8% of total N) and available N was sequestered by the severely N-limited microbial biomass. At this time plant N requirement appears to have been met by the use of internal reserves of N in roots. Significant net mineralisation of N was not detected until microbial demands for N had been satisfied in June. Peak rates of N mineralisation corresponded to maximal plant biomass and shoot N content .. in July, whereas microbial sequestration of N was found to be most intense in late season when plant demands had subsided after senescence. |
| 1179 | Bardgett, R.D., Wardle, D.A. & Yeates, G.W. | Linking above-ground and below-ground interactions: how plant responses to foliar herbivory influence soil organisms | 1998 | Miscellaneous; Soil Microorganisms | Journal | Soil Biol. Biochem.; 30 (14); 1867-1878 | English | Hardcopy:Full; PDF:Full | [title contd.: influence soil organisms (review)] Review of current knowledge of how defoliation of plants can affect the surrounding soil, which happens mainly because defoliation affects carbon allocation and root exudations and also because it affects the quality of plant litter entering the soil. | .. heavy grazing and hence frequent or more severe plant defoliation, favours fast cycles, dominated by labile substrates and bacteria, while light grazing supports slow cycles, dominated by more resistant substrates and fungi. |
| 1617 | Barnes, J.P. & Putnam, A.R. | Evidence for allelopathy by residues and aqueous extracts of rye (Secale cereale) | 1986 | Allelopathy | Journal | Weed Sci.; 34; 384-390 | English | Hardcopy:Partial | Expt. to test the effect of rye on a range of weeds and other plants | Residues of .. rye .. reduced total weed density by 69% and total weed biomass by 32% over a control mulch of poplar excelsior .. [and] reduced total weed biomass by 68% to 95% when compared to controls with no residue.; Under simulated no-till conditions rye residues reduced emergence of lettuce and proso millet by 58% and 35% respectively.; .. allelopathy .. appears to be a viable strategy for weed suppression in agroecosystems. |
| 1180 | Barraclough, D. | The direct or MIT route for nitrogen immobilisation: a 15N mirror image study with leucine and glycine | 1997 | Mineralisation; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 29 (1); 101-108 | English | Hardcopy:Full; PDF:Full | Lab. expt. to test whether N from amino-acids is assimilated by microbes directly (followed by release of surplus N) or whether it follows the MIT route @(complete mineralisation to NH4+, then assimilation by the microbes | The results showed clearly that the conventional MIT route was not operative |
| 709 | Barrett, D.J., Richardson, A.E. & Gifford, R.M. | Elevated atmospheric CO2 concentrations increase wheat root phosphatase activity when growth is limited by phosphorus | 1998 | Phosphorus Cycling | Journal | Funct. Plant Biol.; 25 (1); 87-94 | English | Hardcopy:Partial | An expt. in which wheat seedlings were grown under adequate and limited xphosphorus treatments at ambient and elevated CO2 concentrations. Under P @deficiency and elevated CO2 pressure only, there was an increase in phosphatase activity, which originated from the plant roots rather than from root-associated microorganisms. This phenomenon may increase the rate of mineralisation of soil P with the anthropogenic increase of the atmospheric CO2 content. | |
| 771 | Barrett, P.R.F., Littlejohn, J.W. & Curnow, J. | Long-term algal control in a reservoir using barley straw | 1999 | Miscellaneous | Journal | Hydrobiologia; 415; 309-313 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of loose barley straw on algal growth | Populations of cyanobacteria, diatoms and unicellular green algae in a potable supply reservoir have been suppressed continuously since 1993 by repeated @treatments of barley straw.; 48 g/m3 had rotted in 3 years (approximately 1100 days), so the [mean dail dose] over this period was 0.04 g/d/m3. This .. is an indication of the level of activity of the anti-algal substances released during straw decomposition. .. It also emphasises the importance of applying the straw in a manner which allows decomposition to occur. The disadvantage of applying straw in a form which rots quickly is that it is necessary to repeat the treatments at more frequent intervals, thus adding to the work load. |
| 1181 | Barrios, E., Buresh, R.J. & Sprent, J.I. | Organic matter in soil particle size and density fractions from maize and legume cropping systems | 1996 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 28 (2); 185-193 | English | Hardcopy:Partial | Lab. study of OM in soil from a 4-year expt. in Kenya, using size-density fractionation, by which the sand-size fraction of the soil is further fractionated by density. The light fraction obtained by flotation of the sandsize fraction (150-3000 m and <1.13 g/cm3) is the fraction most sensitive to change of cropping system. | .. SOM in the sand-size fraction (> 53 m) is often more labile that SOM in the clay- and silt-size fractions. SOM in the sand-size fraction has been termed POM by Cambardella and Elliott. .. during humification parts of SOM become more associated with mineral particles and thus occur in particles of higher density. |
| 1182 | Barrios, E., Buresh, R.J. & Sprent, J.I. | Nitrogen mineralisation in density fractions of soil organic matter from maize and legume cropping systems | 1996 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 28 (10/11); 1459-1465 | English | Hardcopy:Partial | Lab. study of N mineralisation in size-density fractions of soil from a 4-year expt. in Kenya fractionated by density. The quantity of N in the light fraction @obtained by flotation of the sand-size fraction (150-3000 m and <1.13 g/cm3) correlated with N mineralisation of the whole soil. | Pools with a rapid turnover rate are assumed to have an important role in N availability because SOM dynamics and N cycling are closely linked through the processes of N mineralisation and immobilisation.; While whole-soil N mineralisation provides a measure of available N in the soil, amount of light fraction N may complement this information by providing a relative indication of biologically mediated N availability from labile SOM. |
| 1512 | Basic, F., Kisic, I., Butorac, A., Nestroy, O. & Mesic, M. | Run-off and soil loss under different tillage methods on Stagnic Luvisols in central Croatia | 2001 | Tillage | Journal | Soil Tillage Res.; 62 (3-4); 145-151 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to test the effect of different tillage treatments on soil loss and runoff | .. the conventional up and down the slope ploughing is the least favourable tillage method. It leads to the highest erosion, whereas ploughing across the slope and no-tillage are much more effective in terms of erosion control. |
| 793 | Basic, F., Kisic, I., Nestroy, O., Mesic, M. & Butorac, A. | Particle size distribution (texture) of eroded soil material | 2002 | Tillage | Journal | J. Agron. Crop Sci.; 188; 311-322 | English | Hardcopy:Partial | Study of soil eroded from an erosion-susceptible soil on a slope under six different tillage treatments | .. erosional drift was generally richer in silt and clay particles. .. more silt particles were found in erosional drift than in plot soil. .. the correct choice of tillage (no-tillage and ploughing across the slope) .. can protect the soil on a slope. |
| 629 | Batjes, N. | Total carbon and nitrogen in the soils of the world | 1996 | Greenhouse Gases; Soil Organic Carbon; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 47; 151-163 | English | Hardcopy:Partial | An estimate of the amount of C and N in the world's soils, broken down by region and soil type | Three main reservoirs regulate the C cycle on earth: the oceans (39,000 Pg C), the atmosphere (750 Pg C) and terrestrial systems (2200 Pg C). Although the soil-vegetation C pool is small compared with that of the oceans, potentially it is much more labile in the short term.; Total soil C pools for the entire land area of the world .. amounts to 2157-2293 Pg C in the upper 100 cm. SOC is estimated to be .. 1462-1548 Pg C in the upper 100 cm. .. An estimated 695-748 Pg of carbonate-C is held in the upper 100 cm of the world's soils. .. Global amounts of soil N are estimated to be 133-140 Pg N for the upper 100 cm.; .. about 10 Pg N is held in the plant biomass .. |
| 794 | Battikhi, A.M. & Suleiman, A.A. | Effect of tillage system on soil strength and bulk density of vertisols | 1999 | Tillage | Journal | J. Agron. Crop Sci.; 183 (2); 81-89 | English | Hardcopy:Partial | Expt. to investigate the effect of the type (chisel or mouldboard ploughing) and timing of tillage on the soil strength and BD | Results indicated that R1 [residue incorporation in August] gave significantly higher BD than R2 [residue incorporation in October], while the different tillage treatments had no significant effect. Soil strength was significantly lower under T1 [mouldboard ploughing] and R2 than under the other treatments. |
| 1401 | Bauer, A. & Black, A.L. | Quantification of the effect of soil organic matter content on soil productivity | 1994 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 58 (1); 185-193 | English | Hardcopy:Partial | An expt. to measure the effect of SOM content on wheat yields, holding soil water and N content constant | The contribution of 1 Mg OM per ha to soil productivity across the range of 64 to 142 Mg OM per ha was calculated as equivalent to 35.2 kg per ha for spring wheat total serial dry matter and 15.6 kg per ha for grain yield. |
| 1645 | Bayliss-Smith, T.P. | The Ecology of Agricultural Systems | 1982 | Agricultural Ecology | Book | Bayliss-Smith, T.P.; The Ecology of Agricultural Systems; | English | Hardcopy:Partial | Agricultural ecosystems in different parts of the world are described and compared, particularly in respect of their energy inputs and outputs. There are some useful tables of figures, especially on energy expenditure. | .. the effects of the Green Revolution upon crop yields .. have been substantial. This 3-hectare holding [in southern India] .. produced in 1975 57% more food energy than 20 years previously. .. This increased yield has, however, required a 111% increase in energy inputs, partly labour and partly fertilisers, etc. As a result the overall energy ratio has fallen to 9.7 [from 13.0] ..; .. the farmer and his family do less agricultural work than formerly, preferring to employ casual labourers instead. .. the more prosperous farmers are seeing their land as a business rather than a way of life .. |
| 1513 | Bazzofi, P., Pellegrini, S., Rocchini, A., Morandi, M. & Grasselli, O. | The effect of urban refuse compost & different tractors tyres on soil physical properties, soil erosion & maize yield | 1998 | Compost & Biocontrol; Soil (General) | Journal | Soil Tillage Res.; 48 (4); 275-286 | English | Hardcopy:Partial; PDF:Full | 3-year field expt. to test the effect on soil of traffic with low-pressure tyres and of urban-waste compost applied at the maximum permissible rate (64 Mg/ha, which gives 627 kg N, 102 kg P and 384 kg K per ha). Compost decreased run-of and oil erosion, increased soil BD and slightly decreased maize yields compared to chemically fertilised plots. Use of low-pressure tyres reduced soil erosion and compaction and increased maize yields. | The application of a high rate of compost may .. induce negative effects such as soil pollution from heavy metals and plastics residues. It can also result in nitrate losses, particularly in autumn and in the early winter. |
| 1023 | Bearden, B.N. & Petersen, L. | Influence of arbuscular mycorrhizal fungi on soil structure and aggregate stability of a vertisol | 2000 | Soil Microorganisms | Journal | Plant Soil; 218 (1/2); 173-183 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of AM fungi on the soil structure | There are combined effects of increased hyphal length, root growth and presumably microbial activity in the mycorhizosphere on aggregate stability.; .. the effects of mycorrhiza on aggregate stability of a vertisol apparently increased with increasing aggregate size as would be expected according to the hierarchical model for aggregation ..; .. AM fungi had no effect on the amount of particles smaller than 20 m.; .. in situations of good root growth the changed root environment associated with AM fungal colonisation together with the hyphae are responsible for the structural stability. |
| 720 | Beare, M.H. & Bruce, R.R. | A comparison of methods for measuring water-stable aggregates: implications for determining environmental effects on soil structure | 1993 | Soil (General) | Journal | Geoderma; 56 (1/4); 87-104 | English | Hardcopy:Partial | Expt. to compare different methods of fractionating soil, which showed that the stability and size distribution of the aggregates can be strongly influenced by the method of soil pre-treatment. The soils sampled ranged from a loamy sand to a loam, with organic C contents from 6.7 to 24.4 g/kg respectively. | |
| 1183 | Beare, M.H., Blair, J.M. & Parmelee, R.W. | Resource quality and trophic responses to simulated throughfall: effects on decomposition and nutrient flux in no-tillage agroecosystem | 1989 | Mineralisation; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 21 (8); 1027-1036 | English | Hardcopy:Partial | Expt. to quantify the effects of simulated throughfall additions from rye and clover on soil microorganisms and nutrient fluxes in the soil. Clover residues had greater decomposition rate, net mineralisation, concentration of main nutrients, microbial density and microfaunal densities than rye. | For plant residues with high C/element ratios nutrient immobilisation may dominate over mineralisation until microbial demands are met. .. The importance of exogenous nutrients to net fluxes of elements from decomposing litter has only recently received attention. Two primary sources are recognised: (1) mineral soil pools accessed via fungal hyphal translocation and (2) accumulation of nutrients from bulk precipitation and/or throughfall at the residue surface. |
| 1402 | Beare, M.H., Cabrera, M.L., Hendrix, P.F. & Coleman, D.C. | Aggregate-protected and unprotected organic matter pools in conventional- and no-tillage soils | 1994 | Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 58 (3); 787-795 | English | Hardcopy:Partial | An expt. to measure the sizes of different SOM pools in soils under different tillage treatments. The weights of aggregate-protected and unprotected C in the top 15 cm of zero tillage soils were found to be 17.2 and 74.2 g per sq.m. respectively and, in conventionally tilled soils, 8.5 and 74.7 g per sq.m. Macroaggregates are those aggregates in the range 250-2000 m. | .. macroaggregates in NT soils provide an important mechanism for the protection of SOM that may other wise be mineralised under CT practices.; .. macroaggregate-protected pools of C are more labile than the unprotected pools .. unprotected pools of SOM are more exposed and thus more highly processed than the protected pools.; .. smaller microaggregates (53-106 m), presumably .. released during the decay of larger microaggregates, had more labile pools of unprotected C, which are probably derived from previously occluded, less humified OM.; .. largest aggregates (>2000m) .. are the least stable and .. most heavily impacted by cultivation.; Disruption of macroaggregates also markedly reduced N2O emissions in our study. Intact aggregates of NT surface hsamples released much more N2O than those of CT .. |
| 1403 | Beare, M.H., Hendrix, P.F. & Coleman, D.C. | Water-stable aggregates and organic matter fractions in conventional- and notillage soils | 1994 | Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 58 (3); 777-786 | English | Hardcopy:Partial | An expt. to study the effects of different tillage systems on water-stable aggregates and aggregate-associated SOM. | Thirteen years of CT and NT .. have resulted in an 18% greater standing stock of SOC in the plough layer (0-15 cm) of NT (30.7 Mg C per ha) than of CT (26.1 Mg C per ha). Because the average annual input of aboveground .. residues were very similar, the differences in SOM content can best be attributed to differences in the assimilation and decomposition of SOM under the two tillage regimes.; In CT macroaggregates (>250m) were fewer and less stable than those of NT.; POM C & N were found .. to be a relatively constant percentage of whole-soil C (36%) and N (34%), regardless of tillage practice.; .. but the quantity of POM was nearly 20% higher in NT than in CT.; .. whole soil POM accounts for much of the SOM lost with cultivation of native sod and .. NT practices can significantly reduce these losses. |
| 334 | Beare, M.H., Hu, S., Coleman, D.C. & Hendrix, P.F. | Influences of mycelial fungi on soil aggregation and organic matter storage in conventional and no-tillage soils | 1997 | Soil Organic Carbon; Soil Microorganisms; Tillage | Journal | Appl. Soil Ecol.; 5; 211-219 | English | Hardcopy:Full; PDF:Full | Expt. to study the influences of fungi on soil properties in soils under different tillage treatments | NT soils retain higher standing stocks of C and have a greater percentage of water-stable macroaggregates than CT soils. Macroaggregates from NT also have higher concentrations of SOM and a much lower dispersion potential than those of CT.; .. densities of total fungal hyphae were significantly higher in NT than in CT. .. bacterial populations were significantly higher in CT ..; .. there is a much greater vertical stratification of fungal populations in NT than in CT soils, where their populations are more uniformly distributed over the profile.; The higher fungal populations of NT were also accompanied by higher concentrations of acid-hydrolysable carbohydrates and a greater contribution of microbial- than plant-derived sugars to the total carbohydrate pool.; .. the influence of fungi on soil aggregation is more directly related to the production and consumption of soil carbohydrates rather than hyphal entanglement.; .. fungi contribute significantly to the stabilisation of soil aggregates, but .. fungal biomass constitutes only a portion of the potentially mineralisable OM associated with aggregates. |
| 561 | Beare, M.H., Parmelee, R.W., Hendrix, P.F. & Cheng, W. | Microbial and faunal interactions and effects on litter nitrogen and decomposition in agro-ecosystems | 1992 | Soil Microorganisms; Soil N Dynamics; Tillage | Journal | Ecol. Monogr.; 62 (4); 569-591 | English | Hardcopy:Partial | Field expts to study the effect of microbial populations on the decomposition of plant litter in conventional and zero tillage systems | .. [the results] indicate a much greater effect of litter placement (surface v. buried) than tillage practice on the compos'n of decomposer communities & on patterns of litter decompos'n & N flux. ..bacteria.. were 7-9.. times greater.. [&] fungi.. 3-4.. times more abundant on buried litter that on surface litter. .. buried litter decompos'n rates averaged 2.5 times higher than those of surface litter..; .. a higher proportion of C [was] channelled through the fungifungivore chain in NT, while C was more equally distributed between fungal and bacterial chains.. in CT.; .. interactions between fungi and fungivorous microarthropods may be responsible for 60% of the net N losses from litter .. over the first 71 days of decay .. |
| 503 | Beauchamp, E.G. | Nitrous oxide emission from agricultural soils | 1997 | Greenhouse Gases; Soil N Dynamics | Journal | Can. J. Soil Sci.; 77 (2); 113-123 | English | Hardcopy:Full | A review of current knowledge of N2O emissions from agricultural soils. Management practices to reduce N2O emissions from agro-ecosystems are listed. | .. there is much uncertainty about the actual contributions of agricultural @practices to global loading of N2O in the atmosphere.; The N2O build-up to 310 ppbv has been attributed to increasing anthropogenic activities ..; .. agriculture's share is presently 81% of anthropogenic N2O emissions.; The effectiveness of N2O as a global warming gas .. is estimated to be more than 250 times that for `CO2.; N2O currently accounts for 2-4% of the total global warming potential, although another recent estimate is as high as 15%.; The denitrification and nitrification processes are the major sources of N2O production in agricultural soils. .. Nitrification is a microbial process requiring aerobic conditions and is dependent primarily on NH4+ supply. .. Denitrification is an anaerobic process carried our by mainly facultative heterotrophic bacteria is dependent on organic C and NO3- (or other N oxides) concentrations.; .. crops recover approximately 50% of the applied N. Also less than 50% of the N in many crops is taken off as grain. ..; .. biologically fixed N should contribute less to global hatmospheric N2O loading than chemically fixed N .. |
| 51 | Beauchamp, E.G. & Hume, D.J. | Agricultural soil manipulation: the use of bacteria, manuring and ploughing | 1997 | Soil Microorganisms; Tillage | Book | Elsas, J.D. van, Trevors, J.T. & Wellington, E.M.H. (eds.); Modern Soil Microbiology; | English | Hardcopy:Partial; Wordperfect:Full | Review of the effects of agricultural operations on bacterial populations and activity in the soil | .. different practices such as tillage methods or manure application affect the size and activities of microbial populations.; Soil conditions for microorganisms are influenced by water content, soil compaction, structure and texture.; .. aerobic microbial activity increases with water content until air diffusion is restricted. Maximum rates of respiration, nitrification and mineralisation occur at the highest water content at which soil aeration remains non-limiting. At about 60% WFP there is a sharp transition to O2-limiting conditions. |
| 853 | Beauchamp, E.G., Voroney, R.P. | Crop carbon contribution to the soil with differing cropping and livestock systems | 1994 | Greenhouse Gases; Soil Organic Carbon; Stockless Farming | Journal | J. Soil Water Conserv.; 49 (2); 205-209 | English | Hardcopy:Full | A mathematical model to estimate the quantity of crop C returned to the soil as FYM on a livestock farm. The harvest index of crops, defined as the usable yield divided by the total biological yield excluding roots, is around 0.4 for wheat, barley and soya beans and 0.5 for maize. The proportion of feed C recovered in manure varies from 0.10 for poultry to 0.40 for non-lactating cattle. | .. more C will remain in the soil at any point in time with livestock manure compared with an equivalent quantity of a leguminous crop.; .. approximately 0.40 of the dry biomass is made up of C.; .. root and exuded C makes up [approximately] 0.20 of the total crop C for [maize, soya beans] and cereal crops. |
| 504 | Beauchemin, S., N'dayegamiye, A. & Laverdičre, M.R. | Effets d'apport d'amendements ligneux frais et humifiés sur la production de pomme de terre et sur la disponibilité de l'azote en sol sableux | 1990 | Lignin and CBW; Soil N Dynamics | Journal | Can. J. Soil Sci.; 70 (4); 555-564 | French | Hardcopy:Full | Expt. to study the effect of amending the soil with chipped wood (with or without nitrogenous fertiliser) on the yield of potatoes. In the first year after application of wood chips the potato yield was reduced by 9 t/ha compared with the control. To raise the yield back to the control level it would be necessary to add an additional 1.92 kg N per ton of wood chips applied. In the second year after wood chip application the potato yield was similar to that of the control. | |
| 505 | Beauchemin, S., N'dayegamiye, A. & Laverdičre, M.R. | Effets d'amendements ligneux sur la disponibilité de l'azote dans un sol sableux cultivé en pomme de terre | 1992 | Lignin and CBW | Journal | Can. J. Soil Sci.; 72 (2); 89-95 | French | Hardcopy:Full | Field expt. in which potatoes were grown in a soil amended with wood chips or nitrogenous fertiliser or a combination of them both. The decomposition of the wood caused an immobilisation of N, which was not significantly greater with fresh wood chips than with composted ones. By comparing the uptake of N in the case of a plot receiving 150 kg/ha nitrogenous fertiliser alone with that in a plot receiving the same rate of nitrogenous fertiliser plus 50 t/ha of wood chips, it was calculated that an additional 46 kg N/ha would be have to be applied with the wood chips to counterbalance the amount of immobilisation that occurred. | |
| 506 | Beauchemin, S., N'dayegamiye, A. & Laverdičre, M.R. | Phytotoxicité des matériaux ligneux frais et compostés utilisés comme amendements organiques de sols | 1992 | Lignin and CBW | Journal | Can. J. Soil Sci.; 72 (2); 177-181 | French | Hardcopy:Full | Expt. to test the effect of fresh and composted tree clippings (mainly from maple, birch, spruce and pine) on the germination of cress seeds | Water-soluble products extracted from fresh ligneous materials decreased the rate of germination of cress very significantly compared with those obtained from composted tree clippings. Grinding the clippings further reduced the germination rate through the apparent liberation of more phytotoxic products.; Les problemes de phytotoxicite sont generalement plus frequents ! partir de residus de coniferes ..; .. les substances toxiques les plus frequemment retrouvees dans la majorite des especes d'arbres sont les tannins et les polyphenols. |
| 1010 | Becana, M., Dalton, D., Moran, J., Iturbe-Ormaetxe, I., Matamoros,M. & Rubio, M. | Reactive oxygen species and antioxidants in legume nodules | 2000 | Green Manure | Journal | Physiol. Plant; 109; 372-381 | English | Hardcopy:Partial; PDF:Full | Review of research into the anti-oxidants that are secreted in the root nodules of leguminous plants to protect them from oxidative stress | Aerobic metabolism is an inherently dangerous process for all organisms. The @risks arise because, although O2 itself is relatively non-reactive, it has the potential to be partially reduced to form reactive oxygen species, including the superoxide radical (O2), hydroxyl radical (OH) and hydrogen peroxide (H2O2). Metabolic processes involving electron transport such as photosynthesis, `respiration and N2-fixation, invariably generate ROS as by-products.; Reactive oxygen species are a ubiquitous danger for aerobic organisms. This risk is especially elevated in legume root nodules due to the strongly reducing conditions, the high rates of respiration, the tendency of leghaemoglobin to autoxidise, the abundance of non-protein Fe and the presence of several redox H proteins that leak electrons to O2. Consequently, nodules are particularly rich in both quantity and diversity of anti-oxidant defences. |
| 49 | Becker, B. | Sustainability assessment: a space and time perspective | 1998 | Sustainability | Book | El Bassam, N., Behl, R.K. & Prochnow, B. (eds.); Sustainable Agriculture for Food, Energy and Industry, vol.1; 19-26 | English | Hardcopy:Full | An analysis of differing approaches to assessing sustainability according to differing space and time scales. System theory is useful in sustainability assessment, which can be done on various levels from plot and farm up to national and global. Indicators of sustainability and the criteria for selecting them are discussed. Sustainability policies are based on different kinds of considerations, according to the scale. | .. for translating sustainability into measurable terms, the spatial and temporal dimensions of the system to be analysed need to be defined ..; .. with increasing scale, policy decisions are more and more normative and value-guided, possibly even irrational, rather than based on hard scientific facts. |
| 807 | Beckett, J.L. & Oltjen, J.W. | Estimation of the water requirement for beef production in the United States | 1993 | Stockless Farming | Journal | J. Anim. Sci.; 71; 818-826 | English | Hardcopy:Partial; PDF:Full | Modelling beef production to estimate direct and indirect water consumption. The model predicts 3,682 l of water per kg of boneless beef, compared with previous estimates of over 20,000 l per kg. Beef cattle were fed an average of 28 kg maize and, in some areas, 23 kg of wheat per year. Average water consumption per animal was 742,000 l per year, comprising 31,500 l drinking water and 710,000 l (mainly) irrigation. At slaughter average bodyweight was 500 kg, dressed carcass was about 60% of bodyweight and boneless beef was 66.7% of carcass. In the U.S. there was 1.9, 2.2 and 3.2 million irrigated hectares of pasture, lucerne and maize respectively. Average calf, heifer and bull weights were 136, 272 and 680 kg respectively. | Irrigation is the major cost of water in U.S. beef production. |
| 1184 | Bedrock, C.N., Cheshire, M.V., Williams, B.L., Solntseva, I., Chapman, S.J., Chudek, J.A. & Goodman, B.A. | Identification of nitrogenous components of fungal and bacterial origin immobilised in decomposing wheat straw by NMR spectroscopy using 15N CPMAS | 1998 | Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (1); 113-115 | English | Hardcopy:Full; PDF:Full | One-year field expt. to study the products of microbial immobilisation from wheat straw in mesh bags buried at 6-cm depth in the soil. The biomass in the straw was mainly fungi. | .. the bacterial contribution to the biomass was .. below 5%.; The straw samples when recovered were shown to be enriched to between 2 and 14 atom% N, `indicating transfer of 15N from soil to straw samples. |
| 686 | Beguin, P. & Aubert, J.P. | The biological degradation of cellulose | 1994 | Lignin and CBW | Journal | FEMS Microbiol. Rev.; 13 (1); 25-58 | English | Hardcopy:Partial | Review of the enzymatic degradation of cellulose | Cellulolytic microorganisms play an important role in the biosphere by recycling cellulose, the most abundant carbohydrate produced by plants. Cellulose is a simple polymer, but it forms insoluble, crystalline microfibrils, which are highly resistant to enzymatic hydrolysis. All organisms known to degrade cellulose efficiently produce a battery of enzymes with different specificities, which act together in synergism.; Total hydrolysis of cellulose into glucose, which could be fermented into ethanol .. is not yet economically feasible. |
| 786 | Bekoff, M. | Deep ethology, animal rights and the great ape/animal project: resisting speciesism and expanding the community of equals | 1997 | Agricultural Ethics | Journal | J. Agric. Environ. Ethics; 10 (3); 269-296 | English | Hardcopy:Partial | The evolutionary and comparative study of animal cognition can shed light on questions of animal protection and animal rights. | .. the real question does not deal with whether individuals can think or reason, but rather with whether or not individuals suffer.; .. individuals count and .. it is essential to avoid being speciesist cognitivists ..; Narrowminded primatocentrism and speciesism must be resisted in our studies of animal cognition and animal protection and rights. Line-drawing into 'lower' and 'higher' species is a misleading speciesist practice .. |
| 448 | Bell, J., Smith, J., Bailey, V.L. & Bolton, H. | Priming effect and C storage in semi-arid no-till spring crop rotations | 2003 | Priming Effect; Soil Organic Carbon; Tillage | Journal | Biol. Fertil. Soils; 37 (4); 237-244 | English | Hardcopy:Partial; PDF:Full | Expt. using 14C-labelled straw to study the effect of tillage, crop rotation and crop residue input on the mineralisation of soil C. | .. the frequent addition of crop residue can stimulate C loss through microorganism metabolism and that .. loss may be greater than the loss from tillage.; .. limiting the frequency of residue inputs may help build C in the soil.; .. C inputs have a greater effect on mineralisation of residual C [than] disturbance .. with priming becoming more pronounced as the fungal/bacterial (F/B) ratio in the soil increases.; Bacteria quickly metabolise the soluble C cpds associated with recent residue inputs.. fungi are more efficient at metabolising residual C .. Increases in priming when fungi are more numerous can be attributed to cooperative decomposition with bacteria. In cooperative decomposition fungi break down more resistant C complexes in residues and simpler C compounds become available for bacterial consumption. |
| 29 | Bell, M.A. | Long-term changes in maize yields and soil chemical properties of a tropical Vertisol | 1995 | Soil (General) | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 140-147 | English | Hardcopy:Full | Field expt. to identify the causes of chlorosis and yield reduction in maize | Three factors are likely to be involved in the increase in ... chlorosis ... and the reduction in yields observed ... (1) a deterioration in soil structure and thus poor drainage; (2) an increase in HCO3- due to release from the chalk subsoil and from ... irrigation water ...; (3) a decrease in root activity or ... rooting depth primarily due to (1) above. |
| 48 | Benbrook, C.M. | Society's stake in sustainable agriculture | 1990 | Sustainability | Book | Edwards, C.A. et al. (eds.); Sustainable Agricultural Systems; | English | Hardcopy:Partial | Sustainable agriculture is defined and conditions for sustainability are detailed:- | 1.; soil resources must not be degraded in quality; ;2.; water resources must be managed in a way .. that crop needs are satisfied; ;3.; the system must be economically viable, returning producers an acceptable profit; ;4.; social expectations and norms must be satisfied; ;5.; the food and fibre needs of the population; [must be satisfied];6.; the biological and ecological integrity of the system must be preserved through management of:.. genetic resources,.. crop pests,.. nutrient cycles,.. and animal health; . |
| 932 | Bending, G.D. | Litter decomposition, ectomycorrhizal roots and the 'Gadgil' effect | 2003 | Soil Microorganisms | Journal | New Phytol.; 158; 228-229 | English | Hardcopy:Full | Review of the Gadgil effect and its implications for litter decomposition | Gadgil & Gadgil .. found that, when ectomycorrhizal roots were excluded from Pinus radiata litter, the rate of litter decomposition increased dramatically. This Gadgil effect was attributed to stimulated colonisation and exploitation of litter by ectomycorrhizal fungi at the expense of litter-decomposing saprotrophs ..; [It] appears to be limited to organic soil horizons, which have a low N availability and .. fluctuations in moisture content. |
| 1185 | Bending, G.D., Turner, M. & Burns, I. | Fate of nitrogen from crop residues as affected by biochemical quality and the microbial biomass | 1998 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (14); 2055-2065 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the net mineralisation of N during the decay of various plant residues, including mature leaves and petioles of Brussel sprouts, ryegrass, sugar beet, French beans and potatoes | The quality components controlling net N mineralisation changed during decomposition, with water-soluble phenolic content significantly correlated with net N mineralisation at early stages and water-soluble N, followed by cellulose, at later stages. C/N and total N were correlated with net N mineralisation towards the end of the incubation only. |
| 893 | Benner, R., Fogel, M., Sprague, K. & Hodson, R. | Depletion of 13C in lignin and its implications for stable carbon isotope studies | 1987 | Lignin and CBW; Soil Organic Carbon | Journal | Nature (Lond.); 329; 708-710 | English | Hardcopy:Full; PDF:Full | Lab. expt. to show how the gradual lignin enrichment of plant material as it decomposes in the soil results in a corresponding depletion in its content of naturally occurring C-13 | The structural polysaccharides, cellulose and hemicellulose, account for 57-77% of herbaceous and woody plant tissues. Both cellulose and hemicellulose were typically enriched in 13C by 1-2K relative to whole-plant material.; Lignin accounts for 17-31% of the biomass of woody tissues and 4-9% of the biomass of herbaceous tissues, but contains ca.50% more carbon per unit weight than cellulose and thus accounts for a greater percentage of the total carbon than indicated by a dry weight percentage. ... lignin was depleted in 13C by 2-6K relative to whole-plant material and by 4-7K relative to cellulose.; ... most of the fractionation against 13C which can be measured in lignin occurs during biosynthesis of phenylalanine and tyrosine.; ... under aerobic and anaerobic conditions, the polysaccharide components of vascular plants, such as Spartina, are degraded two to five times more quickly than the lignin component, which results in the gradual enrichment of plant detritus in lignin-derived carbon4-8. |
| 500 | Berg, B., Ekbohm, G., Johansson, M.B., McClaugherty, C., Rutigliano, F. & Santo, A.V. de | Maximum decomposition limits of forest litter types: a synthesis | 1996 | Soil Organic Carbon | Journal | Can. J. Bot.; 74; 659-672 | English | Hardcopy:Partial | Estimating final decomposition levels of forest litter using long-term decomposition data | The limit values estimated varied with litter type. They ranged from about 35% to about 100% decomposition ..; .. although it was possible to estimate .. limit values for litter mass loss by using asymptotic functions, such limit values do not necessarily reflect the proportion of litter that is completely undegradable. .. the estimated proportion could reflect a fraction that is fairly stable but nevertheless decomposes very slowly.; The fact that allophanic OM exists shows that infinite storage is possible .. allophanic OM may be regarded as an extreme case, with high Fe and Al contents .. Good support for non-allophanic long-term storage also exists .. |
| 971 | Bergen, P. van, Bull, I., Poulton, P.R. & Evershed, R.P. | Organic geochemical studies of soils from the Rothamsted Classical Experiments: I. Total lipid extracts, solvent insoluble residues and humic acids from Broadbalk Wilderness | 1997 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 26 (1/2); 117-135 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the lipid, insoluble and humic fractions of SOM | The lipid extracts of soils from the grazed and stubbed areas were markedly different from those from the wooded area and reflected the mixed vegetation cover .. In marked contrast, the pyrolysis data from the insoluble OM & humic fractions of the soils did not reflect the compos'n of the lignin comprising the overlying vegetation, but rather showed evidence of amino acid moieties probably present as polypeptides. The absence of the lignin signal is possibly due to rapid diagenetic changes .. influenced by the slightly alkaline pH of the soil. |
| 162 | Bergkvist, G. | Effect of white clover and nitrogen availability on the grain yield of winter wheat in a three-season intercropping system | 2003 | Clover Sward; Green Manure | Journal | Acta Agr Scand B-S P; 53 (3); 97-109 | English | Hardcopy:Partial | 3-year field expt. to study the effect of undersown white clover on two successive crops of winter wheat | Clover reduced grain yield in the first crop of wheat and increased it in the second.; .. competition from clover needs to be kept small when wheat is at the tillering stage. |
| 721 | Bernoux, M., Cerri, C.C., Neill, C. & Moraes, J.F.L. de | The use of stable carbon isotopes for estimating soil organic matter turnover rates | 1998 | Soil Organic Carbon | Journal | Geoderma; 82; 44-58 | English | Hardcopy:Partial | Review of math'l methods of estimating soil C pools and turnover rates | x; 13C represents approximately 1.11 atom% of the earth's carbon, but biological material varies around this average value as a result of isotopic discrimination during biological .. processes. All plants discriminate against 13C during photosynthesis but to different degrees, depending on their photosynthetic pathway. Stable isotope abundances are expressed .. as the deviation of the isotopic ratio of the sample from that of an arbitrary standard:(aa13C = [(Rsample - Rstandard)/Rstandard] x 1000Kwhere Rsample = 13C/12C in the sample and Rstandard = 13C/12C in the PDB standard(RPDB = 0.0112372). Terrestrial plants with the C3 (Calvin cycle) pathway have 13C values in the range -13 to -20K. Plants with the C4 (Hatch-Slack) pathway H have higher 13C values, ranging from -19 to -9K. The isotopic composition of SOM closely resembles the isotopic composition of the vegetation from which it was derived, because the fractionation during decomposition is small relative to the original fractionation during C fixation. |
| 630 | Besnard, E., Chenu, C., Balesdent, J., Puget, P. & Arrouays, D. | Fate of particulate organic matter in soil aggregates during cultivation | 1996 | Soil Organic Carbon; Tillage | Journal | Eur. J. Soil Sci.; 47 (4); 495-503 | English | Hardcopy:Partial | Expt. using 13C natural abundance to trace what happens to POM from a native forest soil after cultivation | Amongst the several pools of SOM, plant residues i.e. light or POM, is very sensitive to changes in soil management and is rapidly depleted on cultivation of virgin soil.; POM is a labile fraction of SOM which is thought to be physically protected from biodegradation when within soil aggregates.; On cultivation the amount of total POM decreased from 60.9 mg g-1 soil to 54.0 and `19.6 mg g-1 after 7 and 35 years. In all soils most POM was free, i.e. outside stable aggregates, although this proportion decreased from 73 to 58% with cultivation. The loss of POM with cultivation was then due mainly to free POM.; The kinetics of decrease of free and occluded POM from the forest were very different. Free POM decreased very rapidly at the beginning and the decrease was consistent with a loss of 8% per year. Occluded POM decreased only after 7 years and the rate of decrease was about 3% per year. |
| 449 | Bethlenfalvay, G.J., Andrade, G. & Azcón-Aguilar, C. | Plant and soil responses to mycorrhizal fungi and rhizobacteria in nodulated or nitrate-fertilised peas (Pisum sativum L.) | 1997 | Green Manure; Soil Microorganisms | Journal | Biol. Fertil. Soils; 24 (2); 164-168 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of VAM fungi and rhizobacteria on soil aggregate status and on the root and shoot development of a leguminous plant. The microorganisms did not affect shoot development in nodulated plants. With N-fertilised plants the fungus enhanced plant growth, while the bacterium inhibited shoot growth, VAM root colonisation and nodule formation, but enhanced the root/shoot and seed/shoot ratios. | Both the VAM fungus and the rhizobacterium enhanced [the water-stable] aggregation of the soils, in spite of their apparent antagonism.; The two rhizoorganisms affected both plants and soil and these effects were modified by the source of N input - through N fixation or fertilisation. |
| 450 | Bethlenfalvay, G.J., Cantrell, I.C., Mihara, K.L. & Schreiner, R.P. | Relationships between soil aggregation and mycorrhizae as influenced by soil biota and nitrogen nutrition | 1999 | Soil Microorganisms; Soil (General) | Journal | Biol. Fertil. Soils; 28 (4); 356-363 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of mycorrhizal fungi on soil aggregation. The primary influence on aggregate stability was hyphal length. The first 3 weeks were a lag phase in mycorrhizal development, during which bacteria increased, causing a decline in water-stable aggregation. In weeks 3-6 there was a rapid development of mycorrhiza accompanied by a correspondingly rapid increase in WSA. | |
| 1618 | Beyer, L. | The chemical composition of soil organic matter in classical humic compound fractions and in bulk samples - a review | 1996 | Lignin and CBW; Soil Organic Carbon | Journal | Z. Pflanz. Bodenkunde; 159; 527-539 | English | Hardcopy:Partial | Review of recent SOM research with regard to the chemical composition of humus | While it is commonly assumed that humus is primarily formed from the aromatic structures of lignin, the major contribution of long-chain aliphatics to the composition of humus is rarely mentioned. In a summary of research results from the literature the average content of the main components is: 22% aromatic, 25% alkyl, 46% O-alkyl and 10% carboxylic. |
| 451 | Beyer, L., Sieling, K. & Pingpank, K. | The impact of a low humus level in arable soils on microbial properties, soil organic matter quality and crop yield | 1999 | Soil Organic Carbon; Soil Microorganisms | Journal | Biol. Fertil. Soils; 28 (2); 156-161 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of low SOM levels on microorganisms and yields | Microbial biomass C (Cmic) and enzyme activities decreased in soils with a low TOC level ..; The considerably low TOC level is thought to be caused by the intensive cultivation carried out in the last 20 years .. in the last 2 decades the ploughing depth in arable soils has generally increased from 20 to 35 cm .. the rate of SOM decomposition during the last 20 years has increased because of better aeration due to a deep tillage system and a high fertiliser supply, `especially the extremely high N supply of up to 320 kg ha-1 in some years.; .. an annual straw application is not sufficient to regenerate the SOM and to maintain the level of humic compounds.; We found no significant decrease in crop yield in the soils with a low TOC level. |
| 1186 | Biederbeck, V.O., Campbell, C.A., Rasiah, V., Zentner, R.P. & Wen, G.A. | Soil quality attributes as influenced by annual legumes used as green manure | 1998 | Green Manure; Soil (General) | Journal | Soil Biol. Biochem.; 30 (8/9); 1177-1185 | English | Hardcopy:Partial; PDF:Full | 6-yr field expt. to study the effect of increased cropping intensity and of annual legumes on quality | .. most of the soil biochemical & physical attributes assessed were significantly improved (compared to F-W [fallow-heat]) by increasing cropping intensity [continuous wheat] and by using the GM [green manure] systems.; .. soil quality attributes such as C and N mineralisation, wet aggregate stability and light fraction OM were more strongly influenced by the green manure and Cont. W [continuous wheat] systems than was total organic C or N. |
| 795 | Bilalis, D., Efthimiadis, P. & Sidiras, N. | Effect of three tillage systems on weed flora in a 3-year rotation with four crops | 2001 | Tillage | Journal | J. Agron. Crop Sci.; 186 (2); 135-141 | English | Hardcopy:Full; Wordperfect:Full | Field expt.s to determine the effect of different tillage systems on weed populations. The population densities of annual weeds was lowest under zero tillage, while that of perennial weeds was highest. | The highest density and mean dry weight in the first rotation crop were measured under NT because [absence of] tillage did not destroy weeds. In the rotation crops that followed, the lowest mean density and mean dry weight were measured in NT, because germination conditions were not favourable, resulting in the decrease of PF. |
| 1024 | Birkett, M., Chamberlain, K., Hooper, A. & Pickett, J. | Does allelopathy offer real promise for practical weed management and for explaining rhizosphere interactions involving higher plants? | 2001 | Allelopathy | Journal | Plant Soil; 232; 31-39 | English | Hardcopy:Partial; PDF:Full | Review of allelopathic effects and their possible use in weed control | .. allelopathy is any direct or indirect harmful or beneficial effect by one plant (including microorganisms) on another through production of chemical cpds that escape into the environment. .. its effect depends on a chemical cpd being added to the environment. It is thus separated from competition, which involves the removal or reduction of some factor from the environment that is required by some other plant or microorganism sharing the habitat.; .. allelopathy can involve more sophisticated activities in addition to large inundation of the rhizosphere with biocidal material .. & can extend to signalling systems. |
| 1514 | Birkás, M., Jolánkai, M., Gyuricza, C. & Percze A. | Tillage effects on compaction, earthworms and other soil quality indicators in Hungary | 2004 | Tillage | Journal | Soil Tillage Res.; 78; 185-196 | English | Hardcopy:Partial; PDF:Full | Survey of tillage practices in Hungary and their effect on soil compaction and earthworm populations | Seven categories of the subsoil compaction were identified ..according to their depth and characteristics within the soil profile.; .. plough-pan compaction from previous tillage practices was observed at a depth of 25-30 cm. This zone had a penetration resistance of 3.75 MPa. After the third year disc-pan compaction became evident, reaching the critical penetration resistance (3.75 MPa) after the fifth year. The compaction continued to increase during years 7-10, reaching a maximum of 4.6 MPa. Meanwhile the disk-pan became extended to the soil surface because of a reduction in the discing depth. The compaction also became extended to the former plough-pan, resulting in a joint compacted layer at a depth of 17.5-27.5 cm.; .. the soil condition can be improved or maintained by planting a soil-loosening cover crop. However, the loosening effect of the cover crop may not be sufficient to alleviate severe plough-pan compaction if the penetration resistance exceeds 3 MPa and the extent of the compacted layer exceeds 6-8 cm. |
| 1187 | Blagodatskaya, E.V. & Anderson, T.H. | Interactive effects of pH and substrate quality on the fungal-to-bacterial ratio and qCO2 of microbial communities in forest soils | 1998 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 30 (10/11); 1269-1274 | English | PDF:Full; Wordperfect:Full | Field expt. to study the effect of pH & substrate quality on F/B ratios & specific respiration rate in forest soils | Soil pH influenced the percent F/B ratio to a greater degree than substrate and the effect of pH was more pronounced under beech than under spruce. Mean percent F/B respiratory ratios (rounded) of 74 (beech) & 84 (spruce) were found at high pH (ca.6) & ratios of 94 (beech) & 90 (spruce) were found at low pH (ca.3.0) .. `The metabolic quotient qCO2 was strongly affected by soil pH. .. Particularly at (low pH, the qCO2 was higher under spruce as compared to beech. .. With increasing fungal presence the qCO2 declined. The Cmic/Corg ratio was only affected by pH. |
| 335 | Blagodatskaya, E.V., Blagodatsky, S.A., Anderson, T.H. & Kuzyakov, Y. | Priming effects in Chernozem induced by glucose and nitrogen in relation to microbial growth strategies | 2007 | Priming Effect; Soil Microorganisms | Journal | Appl. Soil Ecol.; 37; 95-105 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the relation between priming effect & microbial growth strategy | @; The production of unlabelled extra CO2 induced by glucose was completed after 3 days and amounted to about 15-19% of the microbial biomass-C. The presence of real or apparent PE depended on the level of added C & N. An apparent positive PE was observed |
| 687 | Blake, A. | Rotation is key to conversion without stock [Elm Farm expts.] | 1995 | Stockless Farming | Journal | Farmers Weekly; ; | English | Hardcopy:Full | 10th November edition. The financial and agronomic viability of the 1987-95 Elm Farm trials is briefly reviewed. Under the present set-aside and arable area payments schemes and organic premiums the gross margins are acceptable. | Red clover has a phenomenal ability to accumulate N above ground - [up to] about 400 kg/ha/yr.; Pure red clover is not the most practical .. he advocates a 50/50 clover grass mixture .. worth sacrificing some nitrogen accumulation to keep on top of weeds and boost soil structure.; .. weeds are symptomatic of a poor crop rather than its cause. .. Good establishment is critical [to weed control]. .. combination power harrow/drill boosts establishment and helps young cereals compete with weeds. |
| 205 | Bloem, J., Lebbink, G., Zwart, K.B., Bouwman, L.A., Burgers, S.L.G.E., Vos, J.A. de & Ruiter, P.C. de[abstract only] | Dynamics of microorganisms, microbivores and N mineralisation in winter wheat fields under conventional and integrated management | 1994 | Mineralisation; Soil Microorganisms; Soil N Dynamics | Journal | Agric. Ecosyst. Environ.; 51 (1-2); 129-143 | English | Hardcopy:Partial | Expt. to monitor the changes in microorganisms and available N under conventional and 'integrated' management | Fungal biomass was about 100-fold lower than bacterial biomass. .. Average N mineralisation was 30% higher in INT. The differences are attributed to the approximately 30% higher OM content of INT.; N mineralisation was relatively low in winter. .. Considerable mineralisation rates after harvest confirmed the need for measures to stimulate immobilisation during periods without crop uptake. |
| 52 | Bloem, J., Ruiter, P.C. de & Bouwman, L.A. | Soil food webs and nutrient cycling in agroecosystems | 1997 | Organic Farming; Soil Microorganisms | Book | Elsas, J.D. van, Trevors, J.T. & Wellington, E.M.H. (eds.); Modern Soil Microbiology; | English | Hardcopy:Partial; Wordperfect:Full | Review of experimental work comparing the role of soil organisms in nutrient cycling in conventional and integrated agricultural systems | In natural ecosystems mineralisation of OM is the main source of nutrients for plant growth and there is a reasonable balance between mineralisation and nutrient uptake.; Integrated farming involves a shift from directly feeding the plant with mineral nutrients to feeding the soil organisms with OM, thereby indirectly feeding the plant through nutrient mineralisation by soil organisms. |
| 1188 | Bloem, J., Ruiter, P.C. de, Koopman, G.J., Lebbink, G. & Brussaard, L. | Microbial numbers and activity in dried and rewetted arable soil under integrated and conventional management | 1992 | Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 24 (7); 655-665 | English | Hardcopy:Partial | Field expt. to compare the numbers and activity of soil microorganisms in conventional and 'integrated' agroecosystems | @; Under integrated management .. bacterial numbers, O2 consumption and N mineralisation, respectively, were 1.6, 2.1 and 1.8 times higher than under conventional management ..; In contrast with microbial numbers microbial activity was significantly affec |
| 1013 | Blok, W., Lamers, J., Termorshuizen, A. & Bollen, G.J. | Control of soil-borne plant pathogens by incorporating fresh organic amendments followed by tarping | 2000 | Compost & Biocontrol | Journal | Phytopathology; 90 (3); 253-259 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to test the effect on soil pathogens of anaerobic conditions engendered by organic amendments and a plastic cover | After 15 weeks, survival of Fusarium .., Rhizoctonia solani and Verticillium dahliae in inoculum samples buried 15 cm deep was strongly reduced in amended covered plots in both experiments. The pathogens were not or hardly inactivated in amended non-covered soil or non-amended covered soil. |
| 174 | Blombäck, K., Eckersten, H., Lewan, E., Aronsson, H. [abstract only] | Simulations of soil carbon and nitrogen dynamics during seven years in a cover crop expt. | 2003 | Cover Crops; Soil Organic Carbon; Soil N Dynamics | Journal | Agric. Sys.; 76 (1); 95-114 | English | Hardcopy:Partial | This study aimed, with the use of simulation models, to quantify the effect of several years incorporation of cover crop material into the soil on SOM storage, N mineralisation capacity and risk of N leaching. | After 6 years of cover crop treatment, simulated SOM content had increased by less than 2%, but the N-mineralis'n capacity had increased by 25%, corresponding to 37 kg N ha-1. With a continuous annual use of cover crops only a few per cent of the extra mineralised N was leached. Without a succeeding cover crop, however, 30% of N from the increased mineralisation was leached. The results indicated that the decomposition rate increased immediately after frost events. |
| 281 | Blumenthal, J.M., Russelle, M.P. & Lamb, J.F.S. | Subsoil nitrate and bromide uptake by contrasting alfalfa entries | 1999 | Green Manure; Soil N Dynamics | Journal | Agron. J.; 91; 269-275 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the uptake of N from the subsoil by lucerne. There was similar N uptake by all lucerene varieties tested apart from one non-N-fixing areity, which removed 38% more nirtrate from the subsoil than the rest. | @; .. soil inorganic N concentrations and NO3- leaching losses are smaller under deeply rooted perennial crops such as alfalfa than under annual crops such as maize.; .. diverse alfalfa entries differed by up to 20% in N uptake from top-dressed fertiliser |
| 498 | Boadi, D.A., Wittenberg, K.M. & Kennedy, A.D. | Validation of the sulphur hexafluoride (SF6) tracer gas technique for measurement of methane and carbon dioxide production by cattle | 2002 | Greenhouse Gases | Journal | Can. J. Anim. Sci.; 82; 125131 | English | Hardcopy:Partial | An expt.al comparison of two methods for measuring the CH4 and CO2 production of xcattle. The mean CH4 production was 134 litres per day and the mean CO2 production was 1900 litres per day. | |
| 854 | Boardman, J. | An average soil erosion rate for Europe: myth or reality | 1997 | Soil (General) | Journal | J. Soil Water Conserv.; 53 (1); 46-50 | English | Hardcopy:Full | This paper discredits Pimentel's figure for the soil erosion rate in the United Sates and Europe of 17 tons/ha/year and questions whether an average erosion rate for a whole continent has any validity. | The figure of about 17 t/ha/yr (Pimentel et al. 1995) is of no value, as it is a mean of a range of figures obtained from plot expt..; .. there are independent estimates of erosion rates from field monitoring schemes in Europe that suggest, if we have to use average figures, then 1 and 5 t/ha/yr is a realistic estimate, but that there is considerable variability in space and time. |
| 1636 | Bodruzzaman, M., Meisner, C.A., Hossain, A.B.S., Sadat, M.A. & Amin, M.R. | Tillage options for wheat in Bangladesh | ? | Tillage | Website | English | Hardcopy:Full | Various tillage methods for establishing wheat after rice are discussed, including surface seeding. The yields from surface seeding are comparable with those from conventional tillage and better than those from farmers' practice. | .. surface seeding is the most appropriate technique of wheat cultivation specially in lowland areas where the land has excess moisture .. The optimum moisture for surface seeding is 35%. But it can be determined easily by walking through the field. If the footprint draws water .. that means the soil is at the optimum condition .. Determination of optimum moisture is important. Excess or less moisture may result in poor germination. .. the cow-dung coated seed is broadcast over the field by hand @ 120 kg/ha. | |
| 1025 | Bohlen, P.J., Edwards, C.A. & Edwards, W.M. | Earthworm community structure and diversity in exptal agricultural watersheds in Northeastern Ohio | 1995 | Tillage | Journal | Plant Soil; 170 (1); 233-239 | English | Hardcopy:Partial | Earthworm populations and species were studied in different tillage systems in seven exptal plots over a period of three years. The effects of location, weather and tillage were observed. | The greatest earthworm diversity and highest earthworm population levels occurred in a no-tillage watershed and a watershed that had previously been in ryegrass and long-term no-till. |
| 1026 | Bolan, N.S. | A critical review of the role of mycorrhizal fungi in the uptake of phosphorus by plants | 1991 | Phosphorus Cycling; Soil Microorganisms | Journal | Plant Soil; 134; 189-207 | English | Hardcopy:Partial | Review of the mechanisms for the uptake of P by mycorrhizal fungi | Mycorrhizae .. are formed by most vascular plants except for a few belonging mainly to the Chenopodiaceae, Cruciferae, Cyperaceae, Juncaceae and Proteaceae.; Although soil solution Pi constitutes only a small proportion of total P (<1%), plants derive most of their immediate P requirements from this source. Most of the Pi is adsorbed onto the soil surfaces or precipitated as Fe and Al phosphates in acid soils and as Ca and Mg phosphates in alkaline .. soils.; Organic P occurs as soluble P in soil solution, as insoluble P adsorbed onto soil particles or as a component of SOM. .. inositol phosphate, phospholipids and nucleic acid are the predominant compounds.; In soils with large capacities to adsorb phosphate the rate of release of phosphate from soil particles becomes the major limiting step in the supply of P to plants. |
| 1716 | Bolinder, M.A., Angers, D.A., Giroux, M. & Laverdčre, M.R. | Estimating C inputs retained as soil organic matter from corn (Zea Mays L.)? | 1999 | Uncategorised | Journal | Plant Soil; 215; 85-91 | English | PDF:Full | ||
| 6 | Bollen, G.J. & Volker, D. | Phytohygienic aspects of composting | 1996 | Compost & Biocontrol | Book | Bertoldi, M. de, Sequi, P., Lemmes, B., & Papi, T. (eds.); The science of composting; | English | Hardcopy:Partial; Wordperfect:Full | Review of current knowledge of the sanitising aspect of the composting process | The majority of plant pathogens do not survive exposure to conditions prevailing during composting of infested plant residues. The most resistant pathogens are heat-resistant viruses and biotrophic root-infecting fungi. Most soil-borne viruses need nematodes or fungi for infection of the host plant. Since the vectors are destroyed during composting when properly performed, the product is not infectious.; Inactivation and destruction of pathogens is caused by: 1) heat generated during the first phase of composting, 2) toxicity of decomposition products, 3) enzymatic breakdown & 4) microbial antagonism. |
| 1027 | Boller, B.C., Nösberger, J. | Symbiotically fixed nitrogen from field-grown white and red clover mixed with ryegrasses at low levels of 15N-fertilisation | 1987 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 104; 219-226 | English | Hardcopy:Partial | A field study to determine the yield of symbiotically fixed N from clover/grass mixtures. In the seeding year the annual yield of clover N derived from symbiosis averaged 131 and 83 kg/ha with and without N fertiliser respectively. In the first production year the figures were 308 and 232 kg/ha. | .. clover-to-grass transfer of fixed N contributed up to 52 kg N/ha (17 kg N/ha on average) to the N yield of the mixtures.; .. a large proportion of clover in the mixture is necessary for N transfer to become a significant source of N for the grass ..; .. three prerequisites must be met for high yields of fixed N (>200 kg N/ha/yr) in a legume/grass mixture: a) the .. conditions must allow for a forage yield of >10 t DM/ha/yr; b) the proportion of legumes in the mixture must be 50% or higher; c) the legume must obtain 70% or more of its N from symbiotic fixation. |
| 1615 | Bond, W. & Grundy, A.C. | Non-chemical weed management in organic farming systems | 2001 | Miscellaneous; Mulch; Organic Farming | Journal | Weed Res. (Oxf.); 41; 383-405 | English | Hardcopy:Partial; PDF:Full | Review of weed-control methods in organic systems, including mulching and living mulches | A living mulch of Portulaca oleracea (purslane) from seed broadcast before transplanting broccoli suppressed weeds without affecting crop yield. Often the primary purpose of a living mulch is to improve soil structure, aid fertility or reduce pest problems and weed suppression may be merely an added benefit. In cereals an understorey of clover has been shown to improve soil fertility and reduce pest and disease problems in addition to suppressing weeds.; When the growth of a living mulch is not restricted, or when soil moisture is inadequate, even a relatively vigorous crop like potato may suffer from competition and loss of yield. Yield loss was also recorded in transplanted cabbage because of competition for light and moisture with a clover living mulch, but timely mowing of the clover prevented competition in transplanted broccoli.; .. the depth of mulch needed to suppress weed emergence is likely to make transport costs prohibitive unless the material is produced on the farm .. a 3-cm layer of compost was needed to prevent the emergence of annual weeds .. shredded hnewspaper at 0.8-1.4 t ha-1 was effective in suppressing most annual and some perennial weeds in sweet corn, soya bean and tomato. A cut ryegrass mulch spread between planted rows of tomatoes and peppers was more economic than cultivation. .. Organic mulches have the advantage of being biodegradable, but decomposition may result in a temporary reduction in soil mineral N. In addition, the natural phytotoxins released when organic materials decompose may not only inhibit the growth of weeds but also that of the crop plants. |
| 175 | Bonny, S. | Is agriculture using more and more energy? A French case study | 1993 | Energy in Agriculture | Journal | Agric. Sys.; 43; 51-66 | English | Hardcopy:Partial | Energy used in agriculture is compared over the years since 1958. Energy consumed per ton of wheat at the farm gate (specific energy) peaked in the late seventies and, by 1990, had declined to about 1960 levels | n\a |
| 1515 | Borin, M., Menini, C. & Sartori, L. | Effects of tillage systems on energy and carbon balance in north-eastern Italy | 1997 | Energy in Agriculture; Greenhouse Gases; Tillage | Journal | Soil Tillage Res.; 40; 209-226 | English | Hardcopy:Full | Energy and C balances were compared over seven years in three cropping systems with different intensities of tillage - conventional, ridge tillage and noxtillage. The lower fuel consumption and higher SOM content resulted in less CO2 emission into the atmosphere with the conservation tillage methods. On the other hand the average energy costs necessary to produce the unit of production remained more or less constant in the three systems. | Often when farmers change to no-tillage they notice a decreasing yield [which] .. is .. economically greater than the savings obtainable by the reduction in tillage intensity; no-tillage management is also more difficult because of weed control and requires more technical knowledge.; The poor yields obtained until now in no-tillage might be the consequence of less favourable soil conditions (e.g. low porosity, low water storage, low temperature, surface water ponding) owing to the shorter history of these plots, and more weeds.; The energy output is less with the simplified tillage systems because of the lower yield obtained ..; .. the total energy saving is.. 32% with NT.; .. the unploughed treatments have stored a higher amount of organic C in the soil on average than with CT: h.. 770 kg ha-1 yr-1 for.. NT; The average annual consumption of diesel for running the machinery in .. NT was around .. a third of that of CT.. |
| 1189 | Bosatta, E. & Agren, G.I. | Theoretical analysis of microbial biomass dynamics in soils | 1994 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 26 (1); 143-148 | English | Hardcopy:Partial | Modelling the dynamics of soil microbial biomass. The graph of the microbial biomass C/total soil C ratio against the age of the OM declines steeply at first and then levels out, approaching a steady state. | .. soil microbial biomass responds much more rapidly than SOM as a whole to changes in management ..; .. relationships between the microbial biomass C and the soil C .. are dominated by the ratio between microbial growth and microbial mortality. |
| 885 | Bossio, D.A., Scow, K.M., Gunapala, N. & Graham, K.J. | Determinants of soil microbial communities: effects of agricultural management, season and soil type on phospholipid fatty acid profiles | 1998 | Organic Farming; Soil Microorganisms | Journal | Microb. Ecol.; 36; 1-12 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the factors affecting microbial communities in soil under different agricultural management systems | The relative importance of various environmental variables in governing the compos'n of microbial communities could be ranked in the order: soil type > time > specific farming operation (e.g. cover crop incorpor'n or side-dressing with mineral fertiliser) > management system > spatial variation in the field.; Microbial biomass carbon, ... nitrogen and substrate-induced respiration were consistently lower in conventional than in organic and low-input plots. This difference was significant when all sample dates were considered together, but organic and low-input plots did not differ significantly from one another. |
| 336 | Bossuyt, H., Denef, K., Six, J., Frey, S.D., Merckx, R. & Paustian, K. | Influence of microbial populations and residue quality on aggregate stability | 2001 | Soil Microorganisms | Journal | Appl. Soil Ecol.; 16 (3); 195-208 | English | Hardcopy:Full; PDF:Full | Expt. to test the connection between aggregate formation, fungal & bacterial populations and residue quality | Adding mineral nitrogen together with low-quality residue to the soil had a significant negative effect on the formation of large macroaggregates.; There was no significant difference between high-quality and low-quality minus N treatments in the formation of aggregates. This is consistent with the lack of an effect on total biomass and the total carbon .. Bacterial biomass dominated in the high-quality treatment whereas fungal biomass dominated in the low- quality treatment.; fungi have a large influence on macroaggregate formation. Hyphal entanglement is .. the most important contribution of fungi in the formation of aggregates. .. polysaccharide-mediated binding by fungi is largely underestimated. .. bacteria had little influence on aggregate formation. |
| 631 | Bossuyt, H., Six, J. & Hendrix, P.F. | Rapid incorporation of carbon from fresh residues into newly formed stable microaggregates within earthworm casts | 2004 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 55 (2); 393-399 | English | Hardcopy:Full; PDF:Full | Field expt. to study the effect of earthworms on aggregate formation | Earthworms helped to form large macroaggregates (>2000 %m). These large macroaggregates contained 4 times more stable microaggregates than those from samples without earthworms.There was more POM within & between microaggregates in macroaggregates in presence of earthworms. The larger amounts of OM [7x more] inside stable microaggregates in casts than in bulk soil after 12 days of incubation `(140mg 13C kg-1 soil compared with 20mg 13C kg-1 soil) indicates that these microaggregates are formed rapidly around freshly incorpor'd residues within casts. |
| 1190 | Bossuyt, H., Six, J. & Hendrix, P.F. | Protection of soil carbon by microaggregates within earthworm casts | 2005 | Soil (General) | Journal | Soil Biol. Biochem.; 37 (2); 251-258 | English | Hardcopy:Full; PDF:Full | Field expt. to determine the effect of earthworms on the formation of soil aggregates and the protection of SOM | ... in the presence of earthworms the C protected by microaggregates within large macroaggregates was a significant pool and 22% of this C pool was newly added C. ... these results clearly indicate the direct involvement of earthworms in providing protection of soil C in microaggregates within large macroaggregates, leading to a possible long-term stabilisation of soil C. |
| 1404 | Bossuyt, H., Six, J. & Hendrix, P.F. | Aggregate-protected carbon in no-tillage and conventional tillage agroecosystems using carbon-14 labelled plant residue | 2002 | Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 66 (6); 1965-1973 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the protection of SOM in surface and sub-surface soils | more young C .. is accumulated in the sub-surface soil of CT than NT, but this C is not stabilised in the long term.. short- and long-term stabilisation of C is higher in the soil surface layers under NT compared with CT. This C stabilisation occurs mainly at the microaggregate level.; The microaggregate- & microwithin-macroaggregate-protected C pools are .. still <5% of the total C pool, indicating that most of the protected C is assoc'd with silt & clay particles. |
| 1516 | Boström, U. | Earthworm populations (Lumbricidae) in ploughed and undisturbed leys | 1995 | Tillage | Journal | Soil Tillage Res.; 35 (3); 125-133 | English | Hardcopy:Partial | A study of earthworm populations in ploughed and undisturbed leys. | Rotary cultivation killed 61-68% of the earthworm biomass. The ploughing that followed increased mortality by a further estimated 12% and 9% .. One year later earthworm abundance in the ploughed treatments was similar to that in the undisturbed lucerne ley .. |
| 1028 | Bottner, P., Pansu, M. & Sallih, Z. | Modelling the effect of active roots on soil organic matter turnover | 1999 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Plant Soil; 216 (1/2); 15-25 | English | Hardcopy:Partial; PDF:Full | 2-year lab. expt. to compare the decomposition of 14C-labelled plant residues in 2 different soils with and without active root systems | Two .. phases in the decomposition processes .. (1) During the initial fast .. @stage, labile 14C-material stimulated microbial activities and N immobilisation, increasing the 14C-microbial biomass. In the presence of living roots, competition between microorganisms and plants for inorganic N weakly lowered the measured and predicted total 14C mineralisation and resulted in a lower plant productivity [and N uptake] compared to subsequent growths. (2) In contrast, beyond 3-6 months, when the labile material was exhausted, during the slow .. stage, the presence of living roots stimulated the mineralisation of the recalcitrant plant residue-14C in the sandy soil and of the humified-14C in the clay soil.; The presence of roots led to a progressive replacement of the labelled microbial biomass derived from the initial plant material by unlabelled microbial biomass derived from the root deposited carbon. |
| 722 | Bouma, J. & Droogers, P. | A procedure to derive land quality indicators for sustainable agricultural production | 1998 | Soil (General) | Journal | Geoderma; 85; 103-110 | English | Hardcopy:Partial | An attempt to define land quality indicators as the ratio of the actual wheat productivity and the potential productivity given a specified level of risk of nitrate leaching | Land quality was defined by the World Bank as the condition of land relative to the requirements of land use, including agricultural production, forestry, conservation and environmental management.; [According to the] Food and Agricultural Organisation, sustainable land management combines technologies, policies and activities aimed at integrating socio-economic principles with environmental concerns so as to simultaneously maintain and enhance production and services, reduce the level of production risk, protect the potential of natural resources, .. prevent the degradation of soil and water quality, be economically viable and [be] socially acceptable. |
| 1646 | Boustead, I. & Hancock, G. F. | Handbook of Industrial Energy Analysis [2 pp. only] | 1979 | Energy Resources | Book | Boustead, I. & Hancock, G. F.; Handbook of industrial energy analysis; | English | Hardcopy:Partial | The energy content of various materials, artefacts and systems is estimated. | A table gives the energy content of various fuels. |
| 30 | Bowerman, P., Davies, D.B. & Jones, A.E. | The long-term effects of straw incorporation on winter wheat yields | 1995 | Soil (General); Tillage | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 448-452 | English | Hardcopy:Full | Field expt. to compare the effects of straw burning and chopped straw incorporation by ploughing or discing on winter wheat yields. Some reduction in wheat yield occurred, especially when chopped straw was incorporated by dicing, but generally the loss in yield was insignificant. | ... burning straw was an important aid to sustainable agriculture ... because it ... reduc[ed] grass weed populations [and] made reduced cultivations viable.; ... burning has encouraged the practice of non-plough primary tillage. these techniques are faster than ploughing and usually lead to better quality seedbeds. |
| 372 | Boyle, C.D., Kropp, B.R. & Reid, I.D. | Solubilisation and mineralisation of lignin by white-rot fungi | 1992 | Lignin and CBW; Mineralisation | Journal | Appl. Environ. Microbiol.; 58 (10); 3217-3224 | English | Hardcopy:Partial | Lab. expt. using 14C-lignin labelled wood to quantify the CO2 and water-soluble products formed from lignin under the action of white-rot fungi. Lignin degradation is a two-stage process - first the production of water-soluble products, which then act as precursors for the second stage, the mineralisation of these products to CO2. | .. nutrient N appears to inhibit lignin degradation by all species, although [with some species] this inhibition can easily be masked by its pronounced stimulation of growth.; .. pH and manganese affected lignin degradation by different species differently. |
| 1647 | Boyle, G. | Renewable Energy: Power for a Sustainable Future [1 p. only] | 1996 | Energy Resources | Book | Boyle, G.; Renewable Energy: Power for a Sustainable Future; | English | Hardcopy:Partial | Vegetable oils as a source of energy | Vegetable oils have an energy content of about 37-39 GJ/ton, similar to that of diesel (about 42 GJ/ton) and superior in this respect to ethanol (30 GJ/ ton).; Simple chemical processing of vegetable oil, by 'esterifying', i.e. combining it with ethanol or methanol, leads to a superior diesel substitute, which does not foul engines. |
| 1191 | Bradley, R.L. & Fyles, J.W. | A kinetic parameter describing soil available carbon and its relationship to rate increase in C mineralisation | 1995 | Mineralisation; Priming Effect; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 27 (2); 167-172 | English | Hardcopy:Full | Modelling the mineralisation of SOC. A kinetic parameter AC is proposed as a measure of the available C pool. | .. important nutrients such as N and S mineralise stoichiometrically with C and .. available C is necessary as an energy source for heterotrophic microorganisms.; Living root systems have positive effects on SOM decomposition and the priming of stable native humus compounds in soil. .. Norton etal. estimated the C flow from ponderosa pine seedlings into the bulk soil at >30% (of recently fixed CO2. |
| 1105 | Bradshaw, W. & Holzapfel, C. | Evolutionary response to rapid climate change | 2006 | Miscellaneous | Journal | Science; 312 (5779); 1477 - 1478 | English | Hardcopy:Full; PDF:Full | Review of present knowledge of the reaction of plants and animals to climate change | Over the past 40 yrs species have been extending their ranges toward the poles and populations have been migrating, developing or reproducing earlier in the spring than previously. These range expansions & changes in the timing of seasonal events have generally been attributed to phenotypic plasticity, that is, the ability of individuals to modify their behaviour, morphology or physiology in response to altered environmental conditions. .. However, recent studies show that over the recent decades climate change has led to heritable genetic changes in populations of animals as diverse as birds, squirrels and mosquitoes. |
| 88 | Brandsćter, L.O. & Riley, H.C.F. | Plant residues for weed management in vegetables | 1999 | Clover Sward; Green Manure | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of a 3-cm-thick green mulch on weed growth | A main concern in living-mulch cropping systems is yield depression because of competition... An alternative approach, which does not cause such competition problems, is surface mulching with harvested legume material produced on an adjacent area to that of the vegetables.; Both one and two applications of fresh grass-clover mulch controlled weeds germinating from seed, which dominated in this white cabbage experiment. There was little extra benefit from mulching (twice compared to once ..; the mulch levels .. received 1350 g m-2 .. the area needed for mulch production was 2.88 times the area mulched. |
| 422 | Breemen, N. van, Finlay, R., Lundström, U.S., Jongmans, A.G., Giesler, R. & Olsson, M. | Mycorrhizal weathering: a true case of mineral-plant nutrition? | 2000 | Soil Microorganisms | Journal | Biogeochemistry (Dordr.); 49 (1); 53-67 | English | Hardcopy:Partial | Study of ectomycorrhizal fungi in coniferous forests | .. these pores [in rocks under coniferous trees] were formed by .. organic acids exuded by .. mycorrhizal fungi. .. ectomycorrhizal mycelium represents a greatly extended .. surface area for the absorption of nutrients. .. mycelium is able to penetrate, and most probably create, micro-sites, which are inaccessible to plant roots and isolated from bulk soil solution phenomena. Dissolved products could be translocated to the host plant roots, by-passing the soil solution .. and competition for nutrient uptake by other organisms. |
| 723 | Breemen, N. van, Lundstroem, U.S. & Jongmans, A.G. | Do plants drive podsolisation via rock-eating mycorrhizal fungi? | 2000 | Soil Microorganisms | Journal | Geoderma; 94; 163-171 | English | Hardcopy:Partial | Podsols from coniferous forest sites in Finland and Sweden were examined for evidence of fungal participation in soil formation. | Weathering and supply of nutrients derived from minerals to plants is known to be stimulated by plant-symbiotic mycorrhizal fungi. .. ectomycorrhizal fungi drill innumerable narrow cylindrical pores .. into weatherable minerals .. The fungi probably form micropores by exuding strongly complexing low-molecular weight organic acids at their hyphal tips, causing highly local dissolution of aluminium silicates.; In the precipitation/adsorption theory [of podsol formation] water soluble organic acids, mainly relatively high-molecular-weight fulvic acids, derived from partial decomposition of OM .., complex and dissolve Fe and Al from primary and secondary minerals .. |
| 163 | Breland, T.A. | Green manuring with clover and ryegrass cover crops undersown in small grains: crop development and yields | 1996 | Cover Crops; Green Manure | Journal | Acta Agr Scand B-S P; 46; 30-40 | English | Hardcopy:Partial | Field trials to compare cereal monocultures with cereals undersown with three cover crops - Italian ryegrass, white clover and subterranean clover - with and without N fertiliser. The cover crop biomass N at ploughing were 17-94, 37-155 and 41-243 kg N/ha respectively. The grain yields were 83-94%, 84-110% and 84100% of the yields in monoculture. | Loss of main-crop yield frequently occurs with undersowing.; Weeds were reduced by undersowing ..; The mean grain [wheat] yields across N levels .. were 2893, 2852, 4032 and 3227 kg/ha for monoculture, ryegrass, white clover and subterranean clover respectively.; .. up to 50-60 kg/ha of the clover-derived N on the 0-N [unfertilised] plots was potentially plant-available. This is equivalent to 32-39% of white clover biomass N at ploughing.; .. wheat plants were able to utilise the mineralised clover N better than fertiliser N. |
| 452 | Breland, T.A. | Modelling mineralisation of plant residues in soil: effect of physical protection | 1997 | Mineralisation; Soil Organic Carbon; Soil Microorganisms | Journal | Biol. Fertil. Soils; 25 (3); 233-239 | English | Hardcopy:Partial; PDF:Full | Modelling the decomposition of clover residues in soil. In the model the estimated C/N ratio of the microbial biomass had to be reduced from 8 to 6. This may be because the real C/N ratio is initially low (3-4) and gradually increases becasue of succession from bacterial- to fungal-dominated biomass. | |
| 453 | Breland, T.A. & Hansen, S. | Comparison of the difference method and 15N technique for studying the fate of nitrogen from plant residues in soil | 1998 | Allelopathy; Priming Effect; Soil N Dynamics | Journal | Biol. Fertil. Soils; 26 (3); 164-168 | English | Hardcopy:Partial | Lab. expt. to compare two methods of measuring the mineralisation of N from white clover residues in soil under ryegrass. There was evidence of a priming effect by the clover on SON. | .. the clover amendment led to a reduction in plant growth and uptake of N, most likely because of allelopathy ..; Towards the end of the expt. cloverinduced N in the biomass declined .., while mineralised N due to the clover amendment increased .. The results strongly suggest that this increase was caused by a real stimulation of humus N mineralisation by clover amendment .. |
| 507 | Bremer, E., Janzen, H.H. & Johnston, A.M. | Sensitivity of total, light-fraction and mineralisable organic matter to management practices in a Lethbridge soil | 1994 | Green Manure; Organic Farming; Soil Organic Carbon | Journal | Can. J. Soil Sci.; 74 (2); 131-138 | English | Hardcopy:Full | Study of soil samples from a 40-year expt. to determine the effect of various management practices, including native grass and various wheat rotations with or without fallow, nitrate fertiliser, grass/lucerne and FYM. | Light fraction OM accounted for 9-24% of the SOC and 2-17% of the SON.; .. the half-life of LF-OM .. may be similar or somewhat greater than the 2 years (range 1-6 yr) estimated for .. Australian conditions.; .. at least part of the SOM associated with the heavy fraction is also relatively labile. Various studies have indicated that a decomposable pool of SOM is associated with clay-size particles .. |
| 946 | Bremner, J.M. | Sources of nitrous oxide in soils | 1997 | Greenhouse Gases; Soil N Dynamics | Journal | Nutr. Cycl. Agroecosyst.; 49; 7-16 | English | Hardcopy:Full; PDF:Full | Review of current knowledge of the origin on N2O & NO emissions from soil | .. most, if not all, of the N2O evolved from soils is produced by biological processes .. little, if any, is produced by chemical processes such as chemo@denitrification.; .. most of the N2O evolved from soils under aerobic or semianaerobic conditions is produced by nitrifying microorganisms and that most of the N2O evolved from soils under anaerobic conditions is produced by denitrifying microorganisms.; .. most of the NO evolved from soils is not, as initially assumed, produced by denitrifying bacteria during reduction of nitrate but by the chemoautotrophic bacteria responsible for nitrification of ammonium in soils. Production of NO during nitrification in soils usually greatly exceeds production of N2O ..; .. N2O production by nitrifying bacteria in soils is markedly increased by addition of nitrifiable forms of fertiliser N & of plant residues. |
| 610 | Brentrup, F., Küsters, J., Kuhlmann, H. & Lammel, J. | Application of the Life Cycle Assessment methodology to agricultural production: an example of sugar beet production with different forms of nitrogen fertilisers | 2001 | Energy in Agriculture | Journal | Eur. J. Agron.; 14; 221-233 | English | Hardcopy:Partial; PDF:Full | Field expt. to assess the usefulness of LCA in quantifying the environmental impact of agricultural systems | ... the environmental effects of acidification and eutrophication contributed most to the total Eco-indicator value.; ... all analysed fertilising systems particularly contribute to the environmental problems of acidification & eutrophication. This is mainly due to emissions of ammonia and nitrate on the field. |
| 1717 | Bridge P. & Spooner, B. | Soil fungi: diversity and detection | 2001 | Uncategorised | Journal | Plant Soil; 232; 147-153 | English | PDF:Full | ||
| 1648 | Briggs, D. & Courtney, F. | Agriculture and Environment | 1985 | Tillage | Book | Briggs, D. & Courtney, F. ; Agriculture and environment: The physical geography of temperate agricultural systems ; | English | Hardcopy:Partial | Tillage and its effects on the SOM content, biological activity and structural stability are examined. Tillage causes a decline in OM content and reduced biological activity. | .. tillage of grassland soils leads to a slow but persistent decline in the content of OM.; The improved aeration of tilled soil seems to encourage the chemical oxidation of the organic residues ..; Many of the organisms which inhabit the soil are severely affected by tillage.; .. tillage leads to reduced biological activity.; Tillage may directly injure the animals and thus decimate .. their population. |
| 64 | Brinton, W.F. & Evans, E. | Plant performance in relation to oxygen depletion, CO2-rate and volatile fatty acids in container media composts of varying maturity | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the effect of varying compost maturity on the growth of plants in compost-amended media | .. a number of important interrelated factors played a role in determining plant effects arising from immature composts. The causal mechanism was most likely elevated CO2 evolution and VFA [volatile fatty acid] production, elevated ammonia levels, along with oxygen deprivation and hydrogen sulphide production in containers during growth. |
| 972 | Brodowski, S., Rodionov, A., Haumaier, L., Glaser, B. & Amelung, W. | Revised black carbon assessment using benzene polycarboxylic acids | 2005 | Soil Organic Carbon | Journal | Org. Geochem.; 36 (9); 1299-1310 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test and improve the accuracy of estimates of black carbon in soils | |
| 554 | Brown, M.T. & Herendeen, R.A. | Embodied energy analysis and emergy analysis: a comparative view | 1996 | Energy in Agriculture | Journal | Ecol. Econ.; 19; 219-235 | English | Hardcopy:Full | Review comparing the two methods of quantifying the energy consumption of an agricultural system - embodied energy analysis and emergy analysis | Emergy is defined as the energy of one type (usually solar energy) that is required to produce something. Energies of different types ... are expressed in the equivalent solar energy required to make them. Embodied energy analysis ... uses strictly the heat energy of fuels and does not include environmental energies. The embodied energy in goods and services ... does not include the environmental support that is derived from solar, geophysical and tidal energies that drive all economies.; Energy analysis includes the service input of humans in all evaluations and does so by considering that the work output of humans is one of several multiple outputs and therefore the total emergy support to humans is assigned to their work. Embodied energy analysis routinely does not include human service inputs to processes ... When it does, [it] considers their work output to be only some fraction of the total fuel energy used in their support. |
| 31 | Brown, S.A., Cook, H.F. & McRae, S.G. | Investigations into soil organic matter as affected by organic farming in south-east England | 1995 | Organic Farming; Soil Organic Carbon | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 189-200 | English | Hardcopy:Partial | Field expt. to compare the organic matter and humic acid contents and the age of the humic acid on organic and conventional arable, horticultural and pasture farms. | The pasture farms ... were characterised by high levels of old ... HA. It was not possible to differentiate between organic and conventional pastures ... The horticultural farms were characterised by ... high levels of young HA ... The organic horticultural farms had higher total SOM levels ... the arable farms had the lowest HA levels, reflecting rare manure applications and frequent tillage. ... The organic arable farms [had] higher SOM levels that the conventional arable farms. |
| 542 | Brown, S.L. & Schroeder, P.E. | Spatial patterns of aboveground production and mortality of woody biomass for eastern U.S. forests | 1999 | Energy Resources | Journal | Ecol. Appl.; 9 (3); 968-980 | English | Hardcopy:Partial | Estimating the aboveground production and mortality of woody biomass (APWB & MWB) of hard- and softwood forests. Root and soil C pools are not included. Fine litter fall (leaves, twigs and reproductive parts) is given as 4.5, 4.0 and 3.2 Mg/ha/yr for hardwood, pine and spruce/fir forest respectively. | APWB for hardwood forests .. averaged 5.2 Mg/ha/yr. For softwood forests APWB .. averaged 4.9 Mg/ha/yr.; For hardwood forests MWB .. averaged 1.1 Mg/ha/yr. The average MWB for softwood forests was 0.6 Mg/ha/yr ..; .. 33% of the preharvested biomass was left as slash.; The amount of dead wood in eastern forests typically ranges from 10% to 20% of the aboveground biomass. .. Rates of decomposition .. can range from 4% to 10% or even higher. |
| 855 | Bruce, J.P., Frome, M., Haites, E., Janzen, H.H., Lal, R. & Paustian, K. | Carbon sequestration in soils | 1999 | Greenhouse Gases; Soil Organic Carbon; Tillage | Journal | J. Soil Water Conserv.; 54 (1); 382-389 | English | Hardcopy:Full | A review of the contribution of improved farming practices to the C sequestration levels in soils | World soils constitute a principal C pool of 1500 to 2000 Pg in SOC and 800 to 1000 Pg as soil inorganic C (SIC) .. Grassland and forest soils tend to lose from 20 to 50% of the original SOC content .. within 40 to 50 years after land use change. .. Estimates of historic loss of SOC from the cultivated soils of the world .. range from 41 Pg to 55 Pg. .. Assuming recovery of 50% of the historic soil loss, the C sequestration potential of world cropland over the next 50 to 100 years may be on the order of 20 to 30 Pg. This equals 7 to 11% of emissions from fossil fuels combustion at 1990 levels over 50 years. Soils of North America account for about 22% of the terrestrial C pool. The total SOC pool to a depth of 1 metre is 267 Pg. for North America .. The cropland area in the United States is about 170 Mha or about 19% of the total land area.; .. adoption of practices with reduced tillage can result in significant accumulation of soil C.; C gains under no-till ranged from -4 to +10 Mg/ha (mean = +3 Mg/ha).; .. the average rate of C accumulation can .. be estimated .. as about 0.3 Mg/ha/year. |
| 808 | Bruckmaier, R.M. & Blum, J.W. | Responses of calves to treadmill exercises during -adrenergic agonist administration | 1992 | Greenhouse Gases | Journal | J. Anim. Sci.; 70; | English | Hardcopy:Partial | Expt. on 24 male Simmental calves to test their reaction to clembuterol at rest and at work. Their bodyweight was 88 kg at the beginning of the expt., 95 kg @after 2 weeks and 138 kg after 6 weeks. The CO2 production was about 0.4 l/min at rest and about 1.2 l/min when walking at 1.5 km/h, rising to about 2 l/min at 3 km/h. | |
| 373 | Bruns, M.A., Stephen, J.R., Kowalchuk, G.A., Prosser, J.I. & Paul, E.A. | Comparative diversity of ammonia oxidiser 16S rRNA gene sequences in native, tilled and successional soils | 1999 | Soil N Dynamics; Tillage | Journal | Appl. Environ. Microbiol.; 65 (7); 2994-3000 | English | Hardcopy:Partial | Expt. to test the effects of soil disturbance on the populations of autotrophic ammonia oxidiser (AAO) bacteria. Compared with native soils tilled soils have higher numbers (but lower genetic diversity) of culturable AAOs, higher nitrate and lower ammonium levels. | Nitrification, the microbial oxidation of ammonium to nitrate, can lead to significant N losses from ecosystems by producing potentially mobile forms of N. .. Although autotrophic nitrification is carried on in two steps by two distinct groups of bacteria, the ammonia oxidisers and nitrite oxidisers, the former is responsible for the rate-determining first step. AAOs thus play a key role in determining whether systems retain or lose N. .. Nitrification rates vary widely in soils and are thought to be controlled principally by ammonium concentration, temperature, moisture and oxygen.; The relatively lower genetic diversity of AAO .. in tilled soils may have been due to repeated ploughing disturbance, which would reduce niche heterogeneity in the soil. |
| 1192 | Bruun, S., Luxhoi, J., Magid, J., Neergaard, A. de & Jensen, L.S. | A nitrogen mineralisation model based on relationships for gross mineralisation and immobilisation | 2006 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 38; 2712-2721 | English | Hardcopy:Partial; PDF:Full | Modelling nitrogen mineralisation and testing the model against the results of lab. incubation expts. | .. the relationship between net N mineralis'n & respiration is largely unaffected by the chemical compos'n of the plant material other than the C/N ratio. This means that the chemical composition of the plant material may primarily influence N mineralis'n through its effect on C mineralisation. |
| 632 | Bruun, S., Thomsen, I.K., Christensen, B.T. & Jensen, L.S. | In search of stable soil organic carbon fractions: a comparison of methods applied to soils labelled with 14C for 40 days or 40 years | 2008 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 59; 247-256 | English | Hardcopy:Partial | Lab. expt. to test the effectiveness of various commonly-used methods for the isolation of a stable fraction of SOC | Acid hydrolysis,photo-oxid'n & treatment with a chem. oxidant [NaOCl or Na2S2O8] consistently removed more 40-yr-old C than 40-day-old C, which suggests that the isolated fractions contained a large prop'n of material with a relatively rapid turnover.. The thermal treatment removed more 40-yr-old C than 40-day-old C. |
| 1193 | Buchmann, N. | Biotic and abiotic factors controlling soil respiration rates in Picea abies stands | 2000 | Roots & Rhizodeposition | Journal | Soil Biol. Biochem.; 32 (11/12); 1625-1635 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the factors affecting forest soil respiration rates | .. mineral soil resp'n seemed to contribute a major fraction to the total soil @CO2 flux (>60%)... Microbial resp'n seemed to dominate the respiratory CO2 loss from the forest floor (>70%). |
| 32 | Buckles, D. | Velvetbean in the farming systems of Atlantic Honduras | 1995 | Green Manure | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 426-434 | English | Hardcopy:Full | Review of the application of velvet beans as a slash-and-mulch green manure crop in Honduras. Use of velvet beans allows annual maize cropping, as compared with 3 maize crops in 7 years in the traditional maize-bush-fallow rotation. | The aggressive legume smothers competing vegetation ... labour dedicated to land preparation is reduced ...; Adopters of velvet bean rotations cultivate on average 40% more winter maize than farmers who do not ...; ... the thick shallow-rooting cover created by velvet bean destroys deeper rooting vegetation and loosens the soil, occasionally provoking landslides during heavy rainfall.; ... the fertiliser effects of velvet beans [are] the most important reason for using the technology ... |
| 600 | Buckley, D.H. & Schmidt, T.M. | Diversity and dynamics of microbial communities in soils from agro-ecosystems | 2003 | Soil Microorganisms | Journal | Environ. Microbiol.; 5 (6); 441-452 | English | Hardcopy:Partial; PDF:Full | Field expt. using ribosomal RNA to study the diversity & dynamics of microbial populations of soils under differing agricultural management | .. long-term mgmnt practices are more likely to influence microbial community compos'n than are contemporary land-use or plant community compos'n.. Temporal changes in microbial community compos'n were observed to occur at scales that are relevant to seasonal events. In addition, it was demonstrated that cultivation has a significant impact on the compos'n of soil microbial communities and that the effects of cultivation on these communities are long lasting. |
| 886 | Buckley, D.H. & Schmidt, T.M. | The structure of microbial communities in soil and the lasting impact of cultivation | 2001 | Soil Microorganisms | Journal | Microb. Ecol.; 42 (1); 11-21 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the microbial community structures in soils under different agricultural management | Microbial community structure was observed to be remarkably similar among plots that shared a long-term history of agricultural management despite differences in plant community composition and land management that have been maintained on the plots in recent years. In contrast, microbial community structure differed significantly between fields that had never been cultivated and those having a long-term history of cultivation. |
| 930 | Bulson, H.A.J. | Is there life without livestock? | 1996 | Green Manure; Stockless Farming | Journal | New Farmer and Grower; ; | English | Hardcopy:Full | A report of trials of stockless organic rotations at Elm Farm. A one-year red clover ley, cut-and-mulched, gave the highest accumulation of N and the highest yield of a following wheat crop. Wheat after potatoes gives a higher yield than wheat after wheat, probably because (1) the later ploughing of the green manure before the potato crop ensures a greater N accumulation, (2) potato haulm has a lower C/N ratio than wheat straw and therefore is less likely to immobilise N and (3) cultivation between the potato rows to control weeds may stimulate N mineralisation. Soil structure, P and K levels were all maintained and weeds, pest and diseases did not increase. OM levels declined. | .. the rotation design is a critical factor.; Given current levels of direct financial support for arable crops and set-aside, our research indicates that organic stockless systems may be economically viable .. |
| 113 | Bulson, H.A.J., Welsh, J.P., Stopes, C.E. & Woodward, L. | Stockless organic farming in the UK: potential & limits 1988-95 | 1996 | Green Manure; Organic Farming; Stockless Farming | Book | ; Proc. 11th IFOAM Conference, Copenhagen, August 1996; | English | Hardcopy:Full | Financial and agronomic viability of the 1988-95 Elm Farm trials is reviewed. Under the present set-aside and arable area payments schemes and organic premiums the gross margins are acceptable. Weeds, pests and diseases were not a problem. Design of rotations was important. When two successive courses of wheat were grown, the second one did poorly. But, if they were separated by a course of beans, they both did well. Wheat in the third course after red clover and potatoes did particularly well, probably because the clover had a longer growing season before the spring-grown potatoes than before winter wheat and therefore the soil accumulated more N. Also, the inter-row cultivation of the potato crop could have stimulated more rapid mineralisation of the N present. | .. rock phosphate has been applied during the green manure phase .. The level of P and K increased significantly over time across all three rotations .. the level of OM .. declined .. from over 3% to around 2.5%. .. However, .. the expt. was established after a five-year ley when OM levels were high. .. over time the BD of the soil at 12-24 cm. depth reduced .. in all three rotations, although there was no significant relationship in the top 12 cm. .. The maintenance of soil K levels may be the result of .. a clay content of around 18%, which appears to release sufficient K .. |
| 1194 | Bundt, M., Widmer, F., Pesaro, M., Zeyer, J. & Blaser, P. | Preferential flow paths: biological 'hot spots' in soils | 2001 | Soil (General) | Journal | Soil Biol. Biochem.; 33 (6); 729-738 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the biological characteristics of preferential flow paths | The organic C conc'ns were approximately 10-70% higher in the preferential flow paths than in the matrix. The organic N conc'ns were also enriched in the preferential flow paths, as well as the effective cation exchange capacity and the base saturation. Microbial biomass determined with the fumigation-extraction method was 9-92% higher in the preferential flow paths than in the soil matrix. |
| 1382 | Burdon, J. | Are the traditional concepts of the structures of humic substances realistic? | 2001 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Sci.; 166 (11); 752-769 | English | Hardcopy:Partial | Review of the current state of knowledge about the structure of humic substances | .. humic substances are very complex mixtures and .. have no single formula.; .. humic substances are almost entirely mixtures of plant components and microorganism components and their microbial decomposition products.; Humic substances are brown or black and this could occur in several ways ..: (i) char .. (ii) fungal melanins .. (iii) polyquinones .. (iv) some minerals e.g. MnO2.; .. char - black charcoal-like material .. formed by the burning of plant cover.; .. the molecular weight of lignin .. is probably approximately 250,000 daltons. .. the true molecular weight of humic substances is of the order of 1000 .. |
| 156 | Buringh, P. | Organic carbon in the soils of the world | 1984 | Greenhouse Gases; Soil Organic Carbon | Book | Woodwell, G.M. (ed.); The Role of Terrestrial Vegetation in the Global Carbon Cycle: Measurement by Remote Sensing; | English | Hardcopy:Partial | The loss of OM in the world's soils due to forest clearing is estimated. | .. the annual loss of organic C from the world's soils is between 2.5 and 7.4 @x 1015 g, with 4.6 x 1015 g being considered a realistic estimate.; A soil with a BD of 1.5 and a C content of 3% in the 0-25 cm layer, 1% in the 25-50 cm layer, 0.3% in the 50-75 cm layer and 0.1% in the 75-100 cm layer contains 165 t C/ha.; The 1500 x 106 ha of cropland in the world are used to grow food for about four billion people.; The increase in the peat layer is approximately 0.5 mm to 1 mm per year. .. Thus histosols appear to be absorbing approximately 200 x 1012 g C annually. |
| 543 | Burke, I.C., Lauenroth, W.K. & Coffin, D.P. | Soil organic matter recovery in semi-arid grasslands: implications for the Conservation Reserve Programme | 1995 | Soil Organic Carbon; Tillage | Journal | Ecol. Appl.; 5 (3); 793-801 | English | Hardcopy:Full | Expt. to compare the soil properties of natural grassland, fields cultivated for about 50 years and fields that were formerly cultivated but had been abandoned for about 50 years | .. SOM, silt content, microbial biomass, potentially mineralisable N and potentially respirable C were significantly lower on cultivated fields than on native fields. .. Abandoned fields .. were not significantly different from native fields with respect to microbial biomass, potentially mineralisable N or respirable C. .. 50 years is an adequate time for recovery of active SOM and nutrient availability, but recovery of total SOM pools is a much slower process.; Tillage increases erosion and decomposition through physical mixing, degradation of soil aggregates and enhanced contact of litter and interaggregate SOM with decomposing organisms. .. Several decades of continuous cultivation have led to losses in surface SOM .. of between 20% and 40%.; Losses of fine soil particles and total SOM are not likely to be recovered over human time scales, since they represent pools that are accumulated over pedogenetic periods.; .. no-tillage systems have been found to result in a decreased nutrient availability relative to cultivated fields .. and .. a lag in the response of N availability to changes in total or active SOM. |
| 1680 | Burke, J.I., Thomas, T.M. & Finnan, J.M. | Bi-cropping of winter wheat and white clover | 1998 | Clover Sward | Website | http://www.teagasc.ie/research/reports/crops/4316/eopr-4316.asp | English | Hardcopy:Partial; PDF:Full | Field expt. to test the growing of wheat in clover sward. Yields were only about 20% of conventional. | .. early sowing in good conditions is an essential pre-requisite in a bi- cropped production system.; Although grain yields were disappointing beneficial effects of the bi-cropping system were evident. Slug damage to cereals was lower .. and earthworms were more prevalent in bi-cropped areas. .. some evidence was obtained of biological control of aphids .. |
| 374 | Butler, J.L., Williams, M.A., Bottomley, P.J. & Myrold, D.D. | Microbial community dynamics associated with rhizosphere carbon flow | 2003 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Appl. Environ. Microbiol.; 69 (11); 6793-6800 | English | Hardcopy:Partial | Expt. in using 13C-labelled plants to study the way root-deposited photosynthate (rhizodeposition) is cycled in soil microbial communities. Fungi ended up consistently more labelled than bacteria. There was a marked difference in the pattern of labelling between gram-positive and gram-negative bacteria. | .. root-deposited photosynthate serves as an important C source for microorganisms in the vicinity of growing roots. In turn, plant rely on the microbially mediated decomposition of organic materials for their supply of nutrients.; Plant nutrient availability is controlled, to a large extent, by the cycling of this and other organic materials through the soil microbial community. |
| 1718 | Butler, S.J., Vickery, J.A. & Norris, K. | Farmland Biodiversity and the Footprint of Agriculture | 2007 | Uncategorised | Journal | Science; 315; 381-384 | English | PDF:Full | ||
| 454 | Buyanovsky, G.A. & Wagner, G.H. | Changing role of cultivated land in the global carbon cycle | 1998 | Greenhouse Gases; Soil Organic Carbon; Tillage | Journal | Biol. Fertil. Soils; 27; 242-245 | English | Hardcopy:Full; PDF:Full | Review of the published work on the sequestration of C in agricultural soils. It is suggested that cultivated land may constitute the missing C sink in the xworld C balance. Globally there is 1.5 x 109 ha of arable land and 3 x 109 ha of grassland, which together comprise 30% of the earth's land surface. In North America, depending on soil type and weather, 0.15-0.52 Mg ha-1 yr-1 has been sequestered since 1975 as a result of improved cropping. Zero tillage could increase these figures by 15-20%. | Under wheat monocrop (with mineral fertiliser), C accumulated at a rate of 50 (g m-2 year-1 . A 3-year rotation (corn/wheat/clover) with manure and N applications sequestered 150 g m-2 year-1 of C.; Typically 20-40% of the native SOM is lost when virgin lands are converted to agriculture.; Annual productivity of warm season grasses .. is about 4.5 Mg ha-1 C (2.15 Mg of aboveground biomass and 2.35 Mg belowground).; [between 1890 and 1940] .. grain productivity of fertilised wheat increased .. from 0.9-1 to 1.5-1.6 Mg ha-1 year-1 and in the following 50 years it more than doubled to 4.2 Mg ha-1. TNAP [total net annual production] increased from 2-3 Mg C ha-1 in 1950 to 4-5 Mg C ha-1 in 1988. |
| 1406 | Buyanovsky, G.A., Aslam, M. & Wagner, G.H. | Carbon turnover in soil physical fractions | 1994 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 58; 1167-1173 | English | Hardcopy:Partial | An expt. using radiocarbon-labelled crops to study the residence time of OM in different fractions of the soil. The residence time increaed with decreasing | The most labile fraction of SOM was plant fragments with turnover time ranging from 1 to 3 years ..The macroaggregates with partially processed C showing turnover from 1 to 3 years contrasted with microaggregates that included more highly humified C having a residence time of about 7 years.; .. aggregates 2 to 1 mm represent only 4 to 5% of total soil mass and <6% of C .. The fraction 1 to 0.5 mm represents about 23 to 25% of the soil and contains about one third of the total C. .. The residence time of C in [this] fraction initially was about 1.5 years .. for the fraction 0.5 to 0.25 mm. the calculated residence time of C is about 3 years or greater.; .. organic C in microaggregates has a residence time of about 7 years.; .. a mean residence time for C in the silt fraction is about 400 years and that for clay is about 1000 years. |
| 337 | Buyer, J.S. & Kaufman, D.D. | Microbial diversity in the rhizosphere of maize grown under conventional and low-input systems | 1996 | Green Manure; Organic Farming; Soil Microorganisms | Journal | Appl. Soil Ecol.; 5; 21-27 | English | Hardcopy:Partial | The 15-year-old Farming Systems Trial at the Rodale Institute compares three treatments - conventional, organic using FYM and organic using leguminous green manure. Soil samples from the rhizosphere were taken from each treatment and compared for diversity and evenness [of distribution ?] of fungi and bacteria. No significant difference was found between the three treatments. This was consistent with the Rodale results reported by Wander, Traina, Stinner et al. (Plant and Soil, 170, 1995). | Soil microbiological diversity has been used as an index for soil quality .. Agricultural management practices might well have an impact on microbial diversity, .. soil health, crop health and yield and sustainability. According to one hypothesis a more complex microbial community will result in greater yield stability. However, there is little direct evidence to support these concepts .. |
| 1174 | Bĺĺth, E. & Anderson, T.H. | Comparison of soil fungal/bacterial ratios in a pH gradient using physiological and PLFA-based techniques | 2003 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 35 (7); 955-963 | English | Hardcopy:Partial; PDF:Full | Field expt. to test the effect of pH on F/B ratios | The biomass-C estimated with SIR was about 0.5% of the SOC in soils with pH 3, but increased to about 2.5% at pH 7.; The F/B ratio measured using the selective inhibition technique decreased significantly with increasing pH from about 9 at pH 3 to approximately 2 at pH 7 ...; Since the selective inhibition method is not a direct measurement of biomass, ... it only provides information about the respiratory activity of the fungal & bacterial components of the total biomass after carbon amendment. It should therefore perhaps be regarded as an activity indicator and the resulting ratio should be called a F/B respiration ratio or a F/B activity ratio. |
| 438 | Bőth, B. & Kling, M. | Root development of leek in a cropping system with red clover | 2001 | Soil N Dynamics | Journal | Biol. Agric. Hortic.; 19 (2); 143-155 | English | Hardcopy:Partial | Field expt. to study the root development of leeks at differing row spacing (0.5 and 0.7 m) after the incorporation of red clover residues into the soil | In the 0-0.15 m soil layer root intensity was higher and lateral distribution more .. in the control .. than in the clover treatment.; Due to the slow lateral root proliferation the N uptake between the rows in the clover treatment with 0.7 m row distance was lower .. As a result higher amounts of mineral N were left between the rows in the [0.7 m clover] treatment, where it constituted a risk of N leaching .. |
| 87 | Břdker, L. & Thorup-Kristensen, K. | Effect of green manure crops on root rot and arbuscular mycorrhizal fungi in pea roots | 1999 | Compost & Biocontrol; Green Manure | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of the incorporation of green manures into the soil on root-rot and AM fungi on a subsequent crop of peas | Most reports show a disease-suppressive effect of most org. amendments. .. these 2 years of field trials clearly showed that it is possible both to increase and suppress root pathogens by using green manure crops. Several mechanisms are involved when organic amendments affect occurrence of root diseases. Which ones becomes the most important in a specific situation may berelated to many edaphic factors and the specific pathogens involved. |
| 1405 | Bünemann, E.K., Steinebrunner, F., Smithson, P.C., Frossard, E., Oberson, A. [abstract only] | Phosphorus dynamics in a highly weathered soil as revealed by isotopic labelling techniques | 2004 | Phosphorus Cycling | Journal | Soil Sci. Soc. Am. J.; 68; 1645-1655 | English | Hardcopy:Partial | Soils from two crop rotations (continuous maize and maize-crotolaria) were incubated with a plant residue or with inorganic P. Analysis showed a shift towards microbial P and organic P after plant residue amendment. | |
| 131 | Cadisch, G. & Giller, K.E. | Soil organic matter management: the roles of residue quality in C sequestration and N supply | 2001 | Lignin and CBW; Soil Organic Carbon; Soil N Dynamics | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Review of the factors affecting OM transformation in soil | @; .. during the incubation time of 1 year the recalcitrant 13C-depleted lignin did not exert a major influence on the isotopic signature of the remaining material, providing evidence against a direct lignin pathway to SOM formation. It is thus likely tha |
| 1195 | Cadisch, G. & Giller, K.E. | Estimating the contribution of legumes to soil organic matter build-up in mixed communities of C3/C4 plants | 1996 | Green Manure; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 28 (6); 823-825 | English | Hardcopy:Full; PDF:Full | Field expt. to evaluate a method of calculating the contribution of legumes to xSOM accumulation in soil using 13C natural abundance | @; In the pure grass pasture the 13C value of the whole soil was 5-9K smaller than that of the rainforest (-28K) due to the input of C from the C4 grass. The soil 13C values of the grass-legume sward were intermediate between the rainforest and pure grass |
| 1029 | Cadisch, G., Handayanto, E., Malama, C., Seyni, F. & Giller, K.E. | N recovery from legume prunings and priming effects are governed by the residue quality | 1998 | Lignin and CBW; Mulch; Soil N Dynamics | Journal | Plant Soil; 205; 125-134 | English | Hardcopy:Partial; PDF:Full | Lab. study of the effect of legume pruning residue quality on N cycling | .. N recovery from added residues by the first subsequent crop is usually within the range of 10-30% for tropical legume residues.; .. N recoveries from residues in the second and following crop cycles are often only 5% or less of the amount originally applied.; Secondary products of lignin degradation, together with microbial/protein metabolites and polyphenols, are thought to be the main building blocks of SOM ..; .. in legume residues poor quality is associated not so much with low N contents but with large amounts of lignin and/or active polyphenols.; residues high in lignin or active polyphenols .. decompose slowly and contributed little to the plant N uptake in the short term.; .. plant residues rich in N with small lignin contents enhanced crop performance through direct nutritional contributions, whereas residues with high C/N ratio and lignin content do so through mulching effects ..; .. the most reliable predictor of both short- (0-7 wks) and medium-term (8-21 wks) pruning N recovery in this expt. was the ability of the extractable polyphenols to bind proteins.; There was little evidence from our results that slowly decomposing residues increase the soil-residue mineralisation potential in the longer term. |
| 962 | Cairns, M.A., Brown, S.L., Helmer, E.H. & Baumgardner, G.A. | Root biomass allocation in the world's upland forests | 1997 | Energy Resources; Sustainability | Journal | Oecologia; 111 (1); 1-11 | English | Hardcopy:Full; PDF:Full | Calculation of the root/shoot ratio of the world's forests, based on a review of the existing data in the literature. The mean root/shoot ratio for temperate forests was about 0.25.The aboveground biomass density of temperate hardwood forests ranged from 45 to 127 and the belowground from 12 to 30 Mg/ha. | |
| 894 | Calabrese, E. & Baldwin, L. | Toxicology rethinks its central belief: hormesis demands a reappraisal of the way risks are assessed | 2003 | Miscellaneous; Organic Farming | Journal | Nature (Lond.); 421; 692-693 | English | Hardcopy:Full; Wordperfect:Full | Review of approaches to toxicology and health risk assessment, claiming that existing approaches are based on false assumptions and advocating an approach based on hormesis, applicable to all types of toxins | The most fundamental concept used in toxicology to determine risk assessment ... is the dose-response relationship, for which two models have traditionally been used. The threshold model is used in the assessment of risks for noncarcinogens and the linear non-threshold model to extrapolate risks to very low doses of carcinogens. ... the most fundamental shape of the dose response is neither threshold nor linear but U-shaped and hence both current models provide less reliable estimates of low-dose risk. This U-shape is ... called hormesis |
| 153 | Callaghan, T.V., Lawson, G.J., Scott, R. & Whittaker, H.A. | Fuels from non-woody plants | 1981 | Energy Resources | Book | Twidell, J. (ed.); Energy for Rural and Island Communities; | English | Hardcopy:Partial | Figures given for capture of solar radiation by vegetation, including crops grown for bio-fuel. | .. the amount of energy fixed annually by the world's vegetation is about ten times the world's annual use of energy. |
| 724 | Cambardella, C.A. & Elliott, E.T. | Methods for physical separation and characterisation of soil organic matter fractions | 1993 | Soil Organic Carbon | Journal | Geoderma; 56 (1/4); 449457 | English | Hardcopy:Partial | Expt. to compare different methods for fractionation of soil | The small macroaggregate fraction (250-2000 m) .. contained 52-60% of the total SOC and 51-68% of the total SON. .. no-till management can improve or maintain the macroaggregate structure of cultivated soil .. 18% of the total soil C and 25% of the total soil N was associated with fine-silt-size particles having a density of 2.07-2.22 g cm-3 isolated from inside macroaggregates (enriched labile fraction or ELF). |
| 1408 | Cambardella, C.A. & Elliott, E.T. | Carbon and nitrogen dynamics of soil organic matter fractions from cultivated grassland soils | 1994 | Soil Organic Carbon; Soil N Dynamics | Journal | Soil Sci. Soc. Am. J.; 58 (1); 123-130 | English | Hardcopy:Full | Soil was fractionated by physical methods and the OM in each fraction was quantified in respect of weight, density and rate of mineralisation. One fraction that stood out in terms of the quantity and mineralisability of its organic component was named the 'enriched labile fraction' (ELF). | .. soil was wet-sieved .. to obtain four aggregate fractions: (i) >2000m (large macroaggregates), (ii) 250 to 2000 m (small macroaggregates), (iii) 53 to 250 m (microaggregates) and (iv) <53 m (silt- plus clay-size particles).; We disrupted small macroaggregates and microaggregates into their constituent parts using a probe-type ultrasonic unit.; Four size fractions were isolated from the sonicated small macroaggregates: (i)250 to 2000 m, (ii) 53 to 250 m, (iii) 20 to 53 m and (iv) <20 m. The three smaller size fractions were also isolated from sonicated microaggregates. Fine-silt- and clay-size material were isolated by sequential centrifugation.; Finally they carried out; density flotation of the size fractions to yield discrete size-density fractions, all of which were originally contained within the aggregate structure of the soil.; Twenty percent of the total SOC and 8.5% of the total SON .. was associated with fine-silt-size (2-20 m) particles having a density of 2.07 to 2.22 g/cc. isolated from small macroaggregates. This fraction consistently had the highest percentage of the total SOC & N .. and, because of its properties, will subsequently be referred to as the ELF.; .. the ELF os labile but maybe physically protected from decomposition within the aggregate structure of the soil.; We postulate that the ELF is a by-product of microbial activity ..; The recovered size particles, usually obtained by sedimentation, may consist of an unknown mixture of free OM, primary particles and organo-mineral particles. |
| 201 | Campbell, B.M., Bradley, P. & Carter, S.E. | Sustainability and peasant farming systems: observations from Zimbabwe | 1997 | Sustainability | Journal | Agr. Human Values; 14 (2); 159-168 | English | Hardcopy:Partial | The possibility of assessing the sustainability of peasant farming systems is discussed. | There are problems relating to; selected indicators or performance criteria, spatial scale or boundaries and temporal scale. While there is certainly a need for more rigorous analysis of sustainability issues, there is limited outlook for an approach based on indicators.; Peasant systems are politically guided management systems, whose boundaries are the state, not the field or the farm. |
| 1409 | Campbell, C.A. & Zentner, R.P. | Soil organic matter as influenced by crop rotations and fertilisation | 1993 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 57 (4); 1034-1040 | English | Hardcopy:Partial | On a semi-arid prairie site the SOM levels were measured over a 24-year period. SOM was maintained or increased in the case of relatively well-fertilised highyielding crops, but decreased when the crop was poor. | Soils with high initial levels of OM are more likely to show decreases and are more difficult to maintain or increase.; .. roots may be more important than aboveground crop residues in contributing to the maintenance of SOM.; .. the amount of OM in the top 0.15 m depth of soil will vary depending on the amount and N content of the crop residues returned to the land. |
| 508 | Campbell, C.A., McConkey, B.G., Zentner, R.P., Selles, F. & Curtin, D. | Long-term effects of tillage and crop rotations on soil organic C and total N in a clay soil in southwestern Saskatchewan | 1996 | Soil Organic Carbon; Soil N Dynamics; Tillage | Journal | Can. J. Soil Sci.; 76; 395-401 | English | Hardcopy:Partial | The results of an 11-year expt. to study the effect on the soil of various rotations and tillage practices under spring wheat crops. The organic C and total N concentrations were higher in the soil under zero tillage, as was the rate of C sequestration. | |
| 509 | Campbell, C.A., Zentner, R.P., Liang, B.C., Roloff, G., Gregorich, E.G. & Blomert, B. | Organic C accumulation in soil over 30 years in semi-arid south-western Saskatchewan: effect of crop rotations and fertilisers | 2000 | Soil Organic Carbon | Journal | Can. J. Soil Sci.; 80 (1); 179-192 | English | Hardcopy:Partial | Modelling SOC dynamics in the surface soil under various treatments and rotations, including wheat, rye, flax and fallow. The efficiency of conversion of crop residue C to SOC in the 30-year expt.al period averaged 14.1% for all treatments and ranged from 18.1 for the continuous wheat with NP fertiliser to 10.0 for the fallow-wheat-wheat rotation. In the periods 1967-75 and 1990-95 the efficiency for continuous cropping with NP fertiliser averaged 38.0 and 26.5 respectively. In the intermediate period the conversion efficiency was very low, due to very dry weather. | |
| 1164 | Campbell, C.J. & Laherrere, J.H. | The end of cheap oil | 1998 | Energy Resources | Journal | Sci. Am.; 278 (3); 78-83 | English | Hardcopy:Full | Review of the estimates for the size and longevity of available oil reserves | .. within the next decade the supply of conventional oil will be unable to keep up with demand.; From an economic perspective, when the world runs completely out of oil is .. not directly relevant: what matters is when production begins to taper off. .. we conclude that the decline will begin before 2010.; The earth's conventional crude oil is almost half gone.; .. global discovery [of oil] peaked in the early 1960s and has been falling ever since.; There is only so much crude oil in the world and the industry has found about 90 percent of it. |
| 202 | Campbell, M. | Dirt in our mouths and hunger in our bellies: metaphor, theory-making and systems approaches to sustainable agriculture | 1998 | Agricultural Ecology; Sustainability | Journal | Agr. Human Values; 15 (1); 57-64 | English | Hardcopy:Partial | A critique of the concept of sustainable agriculture widely used in current research | The metaphor of the food system dominant in current research approaches to sustainable agriculture mirrors the productionist paradigm, which reduces our relationship to land and food to the production and consumption of commodities. The enactment of the familiar values of nourishment and hospitality is what the goal of sustainable agriculture would amount to in terms of our day-to-day lived experience. |
| 89 | Campiglia, E., Caporali, F., Bŕrberi, P. & Mancinelli, R. | Influence of 2-, 3-, 4- and 5-year stands of alfalfa on winter wheat yield | 1999 | Green Manure | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to test the suitablity of lucerne as a green manure for wheat | .. a satisfactory winter wheat yield can be achieved without any mineral N fertilisation, provided that [lucerne] is grown as a preceding crop for a minimum of 3 years.; One of the major effects of alfalfa is its well-known ability to fix symbiotically large amounts of atmospheric N, most of which is carried over to succeeding crops. The amount of N fixed can range from 174 kg `N ha-1 in the first growing year to 466 kg N ha-1 in the third year. |
| 1518 | Cannell, R.Q. & Hawes, J.D. | Trends in tillage practices in relation to sustainable crop production with special reference to temperate climates | 1994 | Tillage | Journal | Soil Tillage Res.; 30 (2-4); 245-282 | English | Hardcopy:Partial | Review of tillage practices in relation to the concept of sustainability | Conservation tillage practices can increase the OM content, aggregate stability and cation exchange capacity (CEC) of the topsoil. However, BD and penetrometer resistance are also increased, especially with zero tillage. .. in some soils biopore formation in zero or minimally tilled land can modify the soil for water movement and for root growth and function.; In Europe, yields of winter cereals have also been similar after traditional and simplified tillage but yields of spring cereals have sometimes been less after direct drilling than ploughing.; In Europe although erosion is less obvious it is believed to be increasing, but minimum tillage is not widely used. This is because of the need to remove at least some straw for successful minimum tillage .. In the more moist cooler conditions of Europe grass weed proliferation is another constraint .. |
| 313 | Carpenter-Boggs, L., Reganold, J.P. & Kennedy, A.C. | Biodynamic preparations: short-term effects on crops, soils and weed populations | 2000 | Biodynamic Farming | Journal | Am. J. Alternative Agr.; 15 (3); 110-118 | English | Hardcopy:Partial; Word:Full | Field expt. to study the effect of biodynamic preparations on crops & soil | Crop yield, crop quality and soil fertility were similar in plots treated with mineral NPK fertilisers, biodynamic compost or non-biodynamic compost.; Biodynamic sprays altered soil and grain N chemistry, but the effects are of unknown biological significance.; In general, soils and crops treated with biodynamic preparations showed few differences from those not treated. Application of composts with or without the preparations produced similar crop yields ... but any additional short-term benefits from biodynamic prep's remain questionable. |
| 439 | Carpenter-Boggs, L., Reganold, J.P. & Kennedy, A.C. | Effects of biodynamic preparations on compost development | 2000 | Biodynamic Farming; Compost & Biocontrol | Journal | Biol. Agric. Hortic.; 17; 313-328 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of biodynamic additives on composting | Biodynamic-treated composts maintained an average 3.4$C higher temp throughout xthe eight-week active composting period ..; BD-treated piles respired CO2 at a @10% lower rate & had a larger ratio of dehydrogenase enzyme activity to CO2 production.; Final samples of BD-treated composts also had 65% more nitrate than control piles. Biodynamic prep'ns thus effect discernable changes in compost chem. & microbial parameters.; BD compost does not need to be turned. |
| 1410 | Carpenter-Boggs, L., Reganold, J.P. & Kennedy, A.C. | Organic and biodynamic management: effects on soil biology | 2000 | Biodynamic Farming; Organic Farming; Soil Microorganisms | Journal | Soil Sci. Soc. Am. J.; 64; 1651-1659 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effects of biodynamic prep'ns on soil microorganisms | Both biodynamic and non-biodynamic composts increased soil microbial biomass, respiration, dehydrogenase activity, soil C mineralised in 10 d (MinC), earth@worm population & biomass & qCO2 .. No significant differences were found between soils fertilised with biodynamic vs. non-biodynamic compost. Use of biodynamic field sprays was associated with more MinC & minor differences in soil microbial fatty acid profiles .. There were no other observed effects of the biodynamic prep'ns. Organically & biodynamically managed soils had similar microbial status & were more biotically active than soils that did not receive org. fertilis'n. Org. mgmt enhanced soil biological activity, but additional use of the biodynamic prep'ns did not significantly affect the soil biotic parameters tested. |
| 1519 | Carpenter-Boggs, L., Stahl, P.D., Lindstrom, M.J. & Schumacher, T.E. | Soil microbial properties under permanent grass, conventional tillage and notill management in South Dakota | 2003 | Soil Microorganisms; Tillage | Journal | Soil Tillage Res.; 71 (1); 15-23 | English | Hardcopy:Partial | Expt. to determine how zero- and conventional tillage affect the microbial properties of the soil, as compared with permanent grassland. | Most measures of microbial activity were similar in the two annually cropped management systems but [very much] less than under permanent grass.; Soils managed under permanent grass contained approximately 160% greater labile C and 50% greater microbial biomass and supported approximately 150% greater dehydrogenase enzyme activity, 50% greater respiration and 180% greater acid phosphatase activity than no-till and conventionally tilled soils, which were similar in these measures.; .. only alkaline phosphatase activity and C mineralised in 12 days were significantly different under no-till and conventional tillage, both greater under no-till. |
| 566 | Carreiro, M.M., Sinsabaugh, R.L., Repert, D.A. & Parkhurst, D.F. | Microbial enzyme shifts explain litter decay responses to simulated nitrogen deposition | 2000 | Lignin and CBW; Soil Microorganisms | Journal | Ecology; 81 (9); 2359-2365 | English | Hardcopy:Full; PDF:Full | Field (litter-bag) expt. to measure the effect of simulated N deposition (20 and 80 kg N/ha/yr) on the enzyme activity of soil microorganisms | .. natural systems near industrialised and agricultural areas .. receive N inputs of up to 60 kg/ha/yr, compared with fluxes of 0.5 to 2 kg N/ha/yr at more isolated sites.; .. N deposition may be having a negative impact on the ligninolytic activity and perhaps abundance of white rot fungi ..; For the lowlignin dogwood litter both the high and low N additions increased the litter decay-rate coefficient by 26% .. for the high-lignin oak litter the low and high N treatments depressed the decay rate coefficient by 15% and 25% respectively, increasing the litter mean residence time from 3.4 yr to 4.0 yr and 4.5 yr. |
| 539 | Carrión, J.S., Parra, I., Navarro, C. & Munuera, M. | Past distribution and ecology of the cork oak (Quercus suber) in the Iberian Peninsula: a pollen-analytical approach | 2000 | Miscellaneous | Journal | Divers. Distrib.; 6 (1); 29-44 | English | Hardcopy:Partial; PDF:Full | Review of the palynological evidence for the past distribution of the cork oak | ... the cork oak survived regionally during the Upper Pleistocene and was important during a mid-Holocene replacement of a local pine forest by Quercusdominated communities. This phenomenon appears linked to the recurrence of fire and reinforces the value of the cork oak for reforestation programmes in fireprone areas.; Q. suber and Q. ilex often replace deciduous Quercus forests after the first evidence of human action. ... it can be detected as an anthropogenically induced succession towards Q. suber and P. pinaster and its fire-derived understorey Phillyrea. |
| 132 | Carter, M.R. | Organic matter and sustainability | 2001 | Soil (General); Sustainability | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Review of factors affecting soil sustainablity | In contrast to natural ecosystems, agroecosystems are open and complex, with major exports of primary production (i.e. harvest) and inputs of nutrients and energy, and have additional economical and sociological components with their own driving variables (e.g. demands of society for agricultural goods). |
| 282 | Carter, M.R. | Soil quality for sustainable land management: organic matter and aggregation interactions that maintain soil functions | 2002 | Soil (General) | Journal | Agron. J.; 94; 38-47 | English | Hardcopy:Partial; PDF:Full | Review of the factors contributing to the concept of soil quality. The estimated turnover times for SOM fractions is: litter, 0.5-2 yrs; microbial biomass, 0.10.4 yrs; POM, 1-8 yrs; LF, 1-15 yrs; OM in macroaggregates, 1-23 yrs; OM in microaggregates, 3-80 yrs; OM in silt+clay, 5-1000. LF (light fraction) is a transitory pool of OM between fresh residues and humified SOM. | |
| 1520 | Carter, M.R. | A review of conservation tillage strategies for humid temperate regions | 1994 | Tillage | Journal | Soil Tillage Res.; 31 (4); 289-301 | English | Hardcopy:Partial | n/a | Appropriate conservation tillage practices for such regions may make judicious use of cultivation to address soil and climatic constraints, and use tillage for straw incorporation .. |
| 510 | Carter, M.R., Angers, D.A., Gregorich, E.G. & Bolinder, M.A. | Organic carbon and nitrogen stocks and storage profiles in cool humid soils of Eastern Canada | 1997 | Soil Organic Carbon | Journal | Can. J. Soil Sci.; 77 (2); 205-210 | English | Hardcopy:Full | Study of soils from 16 sites to determine the size and soil profile distribution of their OM stocks. The SOC content varied from 0.5 to 2.2% and the C/N ratio from 8.3 to 13.8 [with one anomalous figure of 17.1 from a site - a silty loam humic Gleysol under continuous silage maize]. | |
| 511 | Carter, M.R., Angers, D.A., Gregorich, E.G. & Bolinder, M.A. | Characterising organic matter retention for surface soils in Eastern Canada using density and particle-size fractions | 2003 | Soil Organic Carbon | Journal | Can. J. Soil Sci.; 83 (1); 11-23 | English | Hardcopy:Partial | Study of soils from existing short- to long-term agricultural expt.s to determine the quantity and distribution of SOM | .. grass and forest soils, which contain relatively high concentrations of OM, generally gave more POM than arable soils. .. the clay- plus silt-sized OM can be considered as an inherent measure of the capacity of any one soil to store OM, while the POM fraction is a dynamic pool closely affected by soil management and recent C inputs.; .. OM exists as a continuum in soil from strongly stabilised to non-protected forms. .. although the POM is considered labile, its rate of decomposition would be dependant on the chemical characteristics of the organic inputs.; Macroaggregates (> 250 m diam.) formed by root-microbe-OM and mineral particle interactions, contain C in various fractions such as POM, LF, microbial biomass and microaggregates. Only C in the latter can be considered to be protected, as the other fractions are relatively labile.; The POM constituted about 20% of the total SOC, while LF was generally below 7%. .. about 60% of organic C was stored in WSA [water-stable aggregates]. |
| 1521 | Carter, M.R., Gregorich, E.G., Angers, D.A., Donald, R.G. & Bolinder, M.A. | Organic C and N storage and organic C fractions in adjacent cultivated and forested soils of eastern Canada | 1998 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 47 (3-4); 253-261 | English | Hardcopy:Partial; Wordperfect:Full | Study to compare the organic C and N in varied soils from adjacent forested and cultivated sites. Cultivation decreased the mass of organic C (35%) and total N (10%) in some soils, but increased them (by 25% and 37%) in others. | In general losses of SOM in eastern Canada due to a shift of land use from forest to arable agriculture were less than values reported for prairie soils. The shift from forest to agriculture, however, had a marked effect on soil light fraction C and microbial biomass C, but less influence on macro-organic C. In some cases use of forages restored or increased the level of SOM and organic C fractions. |
| 1522 | Catt, J.A., Howse, K.R., Christian, D.G., Lane, P.W., Harris, G.L. & Goss, M.J. | Assessment of tillage strategies to decrease nitrate leaching in the Brimstone Farm Experiment., Oxfordshire, UK | 2000 | Mineralisation; Soil N Dynamics; Tillage | Journal | Soil Tillage Res.; 53; 185-200 | English | Hardcopy:Partial; Wordperfect:Full | Half the plots were direct-drilled with minimum tillage & half were ploughed. In the first two years the ploughed plots showed greater nitrate concentrations in both the drains & the run-off. When the minimum tillage plots were ploughed, the nitrate conc'n in the drainage water increased till it slightly exceeded that in the continuously ploughed plots. This indicates that N that had been stored in the soil of the minimum-tillage plots was being mineralised. | .. mineralis'n of SOM is a rather irregular process, largely but not entirely dependent on soil moisture, & can be delayed for several yrs by dry conditions. |
| 1523 | Causarano, H. [abstract only] | Factors affecting the tensile strength of soil aggregates | 1993 | Soil (General) | Journal | Soil Tillage Res.; 28 (1); 15-25 | English | Hardcopy:Partial | The dependence of soil tensile strength on water content, OM content, aggregate size and the interaction of these factors was studied. | .. tensile strength depended mainly on water content.; For the clay soil .. a large OM content appeared to strengthen wet soil aggregates and weaken dry ones.; The tensile strength of the smallest aggregates was about 50% higher than the biggest ones. |
| 592 | Cavazzoni, J., &Volk, T. | Assessing long-term impacts of increased crop productivity on atmospheric CO2 | 1996 | Greenhouse Gases; Sustainability | Journal | Energ. Policy; 24 (5); 403-411 | English | Hardcopy:Full | Increased crop productivity alleviates CO2 release to the atmosphere | Cereal production has increased approximately threefold in the last forty years or so .. perhaps 90% of increased cereal production from 1950 to the present is attributable to increased yields..; After accounting for .. the C released into the atmosphere via fossil fuel energy inputs for crop production, the assessment here indicates that increased crop productivity will alleviate CO2 release to the atmosphere primarily by preventing additional land cultivation.; From a global perspective the present C debt of approximately 160 Pg C due to land cultivation would have been .. 260 Pg C or more, were it not for the higher cereal yields brought about by increasing fossil fuel inputs since 1950.; .. the effective C sink of 6 Mg per hectare per year for cropland converted to energy crops because of yield increases corresponds to about 240 GJ per hectare per year, which would provide renewable primary energy for roughly 20 hectares of cereal land at 13 GJ per hectare per year (the average 1982 commercial energy input for cereal production in industrialised regions). This implies that the average energy needs of increased crop productivity would be generally supplied if productivity increases are such as to allow about 5% of cropland to be freed and converted to energy crops (neglecting crop residue bio-energy utilisation). |
| 567 | Cavigelli, M. & Robertson, G.P. | The functional significance of denitrifier community composition in a terrestrial ecosystem | 2000 | Soil Microorganisms; Soil N Dynamics | Journal | Ecology; 81 (5); 1402-1414 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to test whether differences in the denitrifier microbial community compos'n in soil from two different fields (one conventionally tilled arable & @the other never tilled) affected the rates of denitrification & N2O production. Compared with the successional field, in the arable field the enzymes involved in N2O production were more inhibited by O2 & less sensistive to pH & there were relatively less active nitrous oxide reductase enzymes, which reduce N2O to N2. | .. native microbial community composition regulates an important ecosystem (function in these soils.; .. the shape of the rN2O [rate of N2O production] curve with increasing oxygen was different for each denitrifying community. |
| 778 | Chadwick, D.R., John, F., Pain, B.F., Chambers, B.J. & Williams, J. | Plant uptake of nitrogen from the organic nitrogen fraction of animal manures: a lab. expt. | 2000 | Mineralisation; Stockless Farming; Soil N Dynamics | Journal | J. Agr. Sci.; 134; 159-168 | English | Hardcopy:Partial | Lab. study of the mineralisation of organic N in various animal manures, the C/N ratio of which ranged from 3.7 for poultry manure to 14.8 for cattle manure. | @; .. organic materials with C/Norg ratios of 15 or more will initially immobilise N, whilst C/Norg ratios of <15 will result in mineralisation and the lower the C/N ratio the greater the mineralisation rate.; N mineralisation was generally greatest from |
| 1411 | Chan, K.Y. & Heenan, D.P. | Lime-induced loss of soil organic carbon and effect on aggregate stability | 1999 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 63 (6); 1841-1844 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of liming on the protection of SOM | Three years after lime application at a rate of 1.5 t ha-1, increases in water stability of macroaggregates were observed despite significant losses in OC in the limed soils.; OC lost as a result of liming was mainly (up to 84% of total loss) in the form of light fraction (specific gravity <1.8) bound to macroaggregates. ... a given level of aggregate stability was achieved at a lower SOC level in limed soil (e.g. total C level for a 50% aggregate stability was 13.0 `and 17.8 g kg-1 for limed and unlimed soils respectively). |
| 1524 | Chan, K.Y., Heenan, D.P. & Oates, A. | Soil carbon fractions and relationship to soil quality under different tillage and stubble management | 2002 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 63 (3-4); 133-139 | English | Hardcopy:Partial | 12-year expt. to determine the effect of different tillage and residuemanagement treatments on the soil C fractions | .. the largest differences [between the treatments] existed in the top 0.05m [of the soil], where a difference of 8.0 g/kg (equivalent to 5.2 t ha-1) was found between the extreme treatments (direct drilled/stubble retained .. and conventional cultivation/stubble burnt ..). Tillage had a much greater effect in reducing total C than stubble burning, accounting for 80% of the total difference between the extreme treatments in 0-0.05 m layer .. with tillage preferentially reducing the particulate organic C (POC) (>53 m) (both free and associated POCs) ..; Furthermore, tillage was related to the decline in mineralisable nitrogen (MN) due to the loss of POC, especially the free POC fraction. POC was a more sensitive indicator of soil quality changes under different tillage and stubble management than TOC. |
| 1106 | Chancellor, W.J. & Goss, J.R. | Balancing energy and food production, 1975-2000 | 1976 | Energy in Agriculture | Journal | Science; 192 (4236); 213-217 | English | Hardcopy:Partial | Review of current energy use in agriculture and predictions of future trends, including a table of world land use and annual potential photosynthetic product. xThe world annual insolation is said to be 1682 x 107 kcal/ha. | |
| 1196 | Chantigny, M.H., Angers, D.A., & Rochette, P. | Fate of carbon and nitrogen from animal manure and crop residues in wet and cold soils | 2002 | Soil Organic Carbon; Stockless Farming; Soil N Dynamics | Journal | Soil Biol. Biochem.; 34 (4); 509-517 | English | Hardcopy:Full; PDF:Full | Expt. to study C & N dynamics in soils during winter after various organic amendments | @; The level of O2 consumption rates in amended soils was in decreasing order pig slurry=alfalfa > cattle manure=maize. Average O2 consumption rates were not significantly correlated to the total organic C, total N, lignin content or C/N ratio of the amen |
| 1412 | Chantigny, M.H., Angers, D.A., Prévost, D., Vézina, L.P. & Chalifour, F.P. | Soil aggregation and fungal and bacterial biomass under annual and perennial cropping systems | 1997 | Soil Microorganisms; Soil (General) | Journal | Soil Sci. Soc. Am. J.; 61; 262-267 | English | Hardcopy:Full | Field expt. over three growing seasons to study the effect of different crops on soil aggregation and soil microbial biomass | .. the MWD of water-stable aggregates was higher under reed canary grass .. and timothy than under broad beans or wheat. Intermediate values were found under alfalfa & brome grass.; Close correlations were found between MWD & both fungal glucosamine & bacterial muramic acid.; .. the close relationship with fungal glucosamine suggests that fungi played a dominant role in soil macroaggregation |
| 895 | Chapin, F.S. | New cog in the nitrogen cycle | 1995 | Mineralisation; Soil N Dynamics | Journal | Nature (Lond.); 377; 199-200 | English | Hardcopy:Partial; PDF:Full | Review of recent research on the uptake of organic N compounds by a pine spp., which suggests that, while the mineralisation of organic N is the rate-limiting step in fertile ecosystems, in infertile systems plants also use DON and that the polyphenols such as tannin, which occur in high concentrations in plants on infertile soils and are exuded from the plant roots, may bind the DON so as to enhance the supply of organic N to the plant and give them a competitive edge over plants that prefer to use ammonium or nitrate as their N source. | `; Arctic plants readily absorb amino acids4 and grow more rapidly on organic than on inorganic sources of nitrogen. In addition, ectomycorrhizal and ericoid mycorrhizal fungi, which are common in infertile soils, directly break down proteins in SOM, absorbing and transferring the resulting amino acids to their host plants without nitrogen being mineralised to inorganic form. |
| 896 | Chapin, F.S. & Ruess, R.W. | The roots of the matter | 2001 | Plant C&N Allocation; Soil Organic Carbon | Journal | Nature (Lond.); 411; 749-752 | English | Hardcopy:Full; PDF:Full | Review of recent research into soil respiration and the proportion of it that is derived from roots and their associated symbiotic mycorrhizae | Photosynthesis by terrestrial vegetation accounts for about half of the C that annually cycles between Earth and the atmosphere. Although above-ground plant production is relatively well documented .., the quantity of C that plants transfer below ground is not well known. ... large components of belowground plant production, such as exudation of org. compounds by roots and transfer of carbohydrates to associated mycorrhizal fungi, are difficult to study non-destructively and have not been estimated. Estimates of the contribution of root respiration to total CO2 efflux from soil range from 10% to 90%, with methodological uncertainties accounting for most of this variation.; ... relative to temperate forests, boreal vegetation allocates a higher proportion of fixed C to belowH ground structures7. ... at least half of the soil respiration in these systems is derived from roots and mycorrhizae.; The ratio of plant-associated respiration derived from roots to that from their symbiotic mycorrhizae remains a mystery.; .. root respiration increases exponentially with increases in soil temp. |
| 593 | Chapman, P.F. | The energy costs of materials | 1975 | Energy in Agriculture | Journal | Energ. Policy; ; | English | Hardcopy:Partial | The need to know the energy required to produce materials and the conventions adopted to calculate it | .. the energy conversion efficiency for generating electricity is 23.85% |
| 3 | Chardon, W.J. | The role of the soil in phosphorus cycling | 2000 | Phosphorus Cycling | Book | Weidema, B.P. & Meeusen, M.J.G. (eds.); Agricultural data for Life Cycle Assessments, Vol 2, Agric. Econ. Res. Inst.; | English | Hardcopy:Partial; Wordperfect:Full | Review of current knowledge on how phosphorus cycles in the soil | On a world scale a net transport of P to the oceans occurs, maintained by weathering of minerals and by erosion. .. In general, more P has to be added than is taken off by the crop to compensate for P becoming less available for plant uptake. In regions with a surplus of animal manure, P contents of the soil can become very high, creating problems due to eutrophication of surface waters.; When organic fertilisers (e.g. compost, animal manure and sewage sludge) are applied, mineralisation has to take place before plants can take up P.; After application of inorganic P fertilisers to a soil, or when P has been released from organic fertilisers by mineralisation, several reactions with the soil can take place: adsorption ..; absorption ..; immobilisation ..; and precipitation .. Adsorption of P mainly occurs onto hydroxides of iron or aluminium. |
| 611 | Chaves, B., Neve, S. de, Hofman, G., Boeckx, P. & Cleemput, O. van | Nitrogen mineralisation of vegetable root residues and green manures as related to their (bio)chemical composition | 2004 | Green Manure; Mineralisation; Soil N Dynamics | Journal | Eur. J. Agron.; 21; 161-170 | English | Hardcopy:Partial; PDF:Full | 4-month lab. expt. to study the N dynamics of vegetable root decomposition | All fine roots, except these of Brussel sprouts, showed a net N release throughout the incubation. All large roots showed a slight N immobilisation at the start of the incubation, but at the end of the incubation a small net N release was observed, except for Brussel sprouts. The roots of Brussel sprouts immobilised N throughout the entire incubation. The leaves of the green manures released more N than both stems (only for white mustard) and roots.; The large roots of cabbages released maximum 13% of their N and the N released from fine roots was between 20 and 25% of total N. The overall N mineralisation (large + fine roots) of the cabbages was on average 15% of total N, which was lower than for the roots of other annual plants, like the leek roots (50% of total N) and the green manures roots (16 and 28% of total N). |
| 1481 | Chaves, B., Neve, S. de, Piulats, L.M., Boeckx, P., Cleemput, O. van & Hofman,G. | Manipulating the N release from N-rich crop residues by using organic wastes on soils with different textures | 2007 | Soil N Dynamics | Journal | Soil Use Manag.; 23; 212-219 | English | Hardcopy:Full; PDF:Full | Field expt. to study the effect of compost, sawdust and straw on the N mineralisation of vegetable residues and the effect of malting sludge and vinasses on the re-mineralisation of the N in spring | .. incorporation of green waste compost and sawdust did not significantly increase microbial biomass N and did not lead to a significant N immobilisation of crop residue-N. .. straw did increase microbial biomass N and showed a good N immobilisation potential... During spring, there was no consistent remineralisation of immobilised N after the addition of malting sludge or vinasses... |
| 702 | Chen, R.S. & Kates, R.W. | World food security: prospects and trends | 1994 | Miscellaneous; Sustainability | Journal | Food Policy; 19 (2); 192-208 | English | Hardcopy:Partial | Review of the possibilities of feeding the world's human population in the 21st century | In 1990 we estimate that 15-35 million people were at risk of famine, 786 million were vulnerable to chronic undernutrition and hundreds of millions suffered from micronutrient deficiencies .. and other nutritional impairments.; A normative scenario to achieve food security in the .. world of 2060 requires widespread acknowledgement of food as a human right, large increases in food production and income, a pervasive global safety net and the capacity to cope with surprise.; Speculative and clearly optimistic, our .. scenario offers multiple pathways for achieving a food-secure world. |
| 7 | Chen, Y., Chefetz, B. & Hadar, Y. | Formation and properties of humic substance originating from composts | 1996 | Compost & Biocontrol | Book | Bertoldi, M. de, Sequi, P., Lemmes, B., & Papi, T. (eds.); The science of composting; | English | Hardcopy:Partial; Wordperfect:Full | Review of exptal work to study the formation and properties of humic substances in composts | Humic substances constitute a large fraction of the OM in compost and they are its most active fraction, due to their effects on soil ecology, structure, fertility and metal complexes and on plant growth.; .. HA extracted from mature compost exhibits more aromatic structures and carboxyl groups and less carbohydrate components than that from immature compost. .. In soils the addition of composts was found to stimulate growth beyond that provided by mineral nutrients, presumably because of the effects of HS. |
| 1605 | Chen, Y., Tessier, S. & Rouffignat, J. | Soil bulk density estimation for tillage systems and soil textures | 1998 | Soil (General) | Journal | Trans. ASAE (Am. Soc. Agric. Eng.); 41 (6); 1601-1610 | English | Hardcopy:Partial | Modelling the bulk density of soil on the basis of 60 previously published studies. Clay content and OM content are major determinants of soil bulk density. Tillage modifies BD in different ways, depending on tillage type, depth, secondary tillage, soil texture and OM content. | |
| 1609 | Cheng, W. | Rhizosphere feedbacks in elevated CO2 | 1999 | Priming Effect; Soil Microorganisms | Journal | Tree Physiol.; 19; 313-320 | English | Hardcopy:Full; Wordperfect:Full | Modelling the link between the increased rhizosphere input in response to elevated CO2 and the rate of SOM decomposition | Depending on specific plant and soil conditions, the increased C input to the rhizosphere can result in an increase, a decrease or no effect on SOM decomposition and nutrient mineralisation. Three mechanisms may account for these inconsistent results: (1) the preferential-substrate-utilisation hypothesis; (2) the priming-effect hypothesis; & (3) the competition hypothesis i.e. competition for mineral nutrients between plants and soil microorganisms.; If the increased (rhizosphere substrate input in response to elevated CO2 reduces microbial utilisation of original SOM.., a negative feedback exists as the substrate-preference hypothesis states, so that SOM decompos'n decreases.If the increased rhizosphere input .. results in an increase in overall microbial biomass turnover rate.., a positive feedback exists as the priming hypothesis states, so that SOM decomposition increases. Under highly .. nutrient-limited conditions the increased rhizosphere input in response to elevated CO2 may intensify the competition for .. nutrients between roots & microorganisms and result in a decrease in C substrate usage, a reduced substrate utilisation efficiency .. and a lower amount of microbial biomass. This pattern fits the competition hypothesis well. |
| 1413 | Cheng, W., Johnson, D.W. & Fu, S. | Rhizosphere effects on decomposition: controls of plant species, phenology and fertilisation | 2003 | Priming Effect; Roots & Rhizodeposition | Journal | Soil Sci. Soc. Am. J.; 67; 1418-1427 | English | Hardcopy:Partial; PDF:Full | Expt. to study the priming effect of plant roots on SOM decompos'n by comparing the rate of C loss from soil with wheat, soya bean and no plant growing in it. | @; .. rhizosphere respiration may range from 30 to 80% of total belowground CO2 efflux.; The rhizosphere priming effect was responsible for a major portion of the total soil C efflux.; Different plant species produce rhizosphere priming of different magni |
| 1197 | Cheng, W., Zhang, Q., Coleman, D.C., Carroll, C.R. & Hoffman, C.A. | Is available carbon limiting microbial respiration in the rhizosphere? | 1996 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 28 (10/11); 1283-1288 | English | Hardcopy:Partial; PDF:Full | Field/lab. expt. to study the effect of plant roots on microbial respiration. There was a threshold of available C saturation in the rhizosphere, equal to about 0.1 mg water-soluble C/g soil, above which microbial respiration was not limited by available C. | .. carbon availability in the rhizosphere is much higher than in the bulk soil.; .. we employed the concept of C availability index (CAI: the ratio of basal respiration to substrate-induced respiration).; The CAI values of the rhizoplane and the rhizosphere soils in the field maize experiment were close to 1, indicating that available C was not a limiting factor for microbial respiration ..; .. the conversion of plant C into microbial biomass in the rhizosphere is very low, i.e. 13%. The mineral nutrient supply in the rhizosphere may severely limit microbial growth and activities. |
| 633 | Chenu, C., & Plante, A.F. | Clay-sized organo-mineral complexes in a cultivation chronosequence: revisiting the concept of the 'primary organo-mineral complex' | 2006 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 596-607 | English | Hardcopy:Partial; PDF:Full | Field expt. to test whether Christensen (1996)'s primary organo-mineral complexes, characterised as the primary structure of soils as defined by soil texture, really did consist of primary particles | .. many of the so-called <2-m particles were in fact nanometre- to micrometresized microaggregates, in which OM was encrusted by minerals .. We conclude that true primary organo-mineral complexes do not correspond to reality & must be regarded as conceptual entities. |
| 133 | Chenu, C., Arias, M. & Besnard, E. | The influence of cultivation on the composition and properties of clay-organic matter associations in soils | 2001 | Soil Organic Carbon; Tillage | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to assess the effect of cultivation on the OM present in the <2 m particle size fraction | Cultivation decreases SOM stocks, in particular labile fractions, such as POM. OM in the <2 m fraction of soils is less depleted by cultivation. This is ascribed to the slow turnover rate of <2 m SOM, due to its chemical nature and presumably also to its protection from decomposition by the clay minerals. |
| 1691 | Chervonyj, A. | Research project on RCW technology on rye (Secale cereale) for 1997-98 | 1999 | Lignin and CBW | Website | www.sbf.ulaval.ca/brf | English | Hardcopy:Partial | Two-year field expt. to test the effect of chipped branch wood on the soil and on a crop of rye. Wood from various broad-leaved tree species was used. On some plots forest litter [or topsoil ?] was also added. The rye yields varied with species of wood applied in the order Carpinus [hornbeam ?] > sycamore > false acacia > oak > lime > alder > hazel > aspen > birch > willow. In a poor soil the last four species actually reduced the rye yield compared with the untreated control. As for humus and organic C content, goat willow and aspen gave the best results. Hazel and lime also did well. Oak was the worst, followed by sycamore. | Under the RCW influence chemical and physical characteristics of the soil have improved significantly .. Thus, the content of humus, OM, hydrolysed [available] N, moveable phosphorus, exchangeable calcium, magnesium etc. in the soil has increased considerably. |
| 634 | Cheshire, M.V., Bedrock, C.N., Williams, B.L., Chapman, S.J., Solntseva, I. & Thomsen, I.K. | The immobilisation of nitrogen by straw decomposing in soil | 1999 | Soil N Dynamics | Journal | Eur. J. Soil Sci.; 50; 329-341 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the immobilisation of N during straw decomposition | The total N content of the straw increased as long as the soil was not too wet, such that there was overall immobilisation.; ... N immobilisation is mainly a biotic process in which fungal activity plays a much greater role than bacterial biomass.; ... fungal biomass was much greater than that of bacteria.; ... immobilisation of N is primarily caused by fungi as they decompose the straw. |
| 15 | Chesson, A. | Plant degradation by ruminants: parallels with litter decomposition in soils | 1997 | Lignin and CBW | Book | Cadisch, G. & Giller, K.E. (eds.); Driven by Nature: Plant Litter Quality and Decomposition. C.A.B. International; | English | Hardcopy:Partial; Wordperfect:Full | Review of substances making up plant cell walls and their degradation in the stomachs of ruminants and in the soil | |
| 1525 | Chivenge, P.P., Murwira, H.K., Giller, K.E., Mapfumo, P. & Six, J. | Long-term impact of reduced tillage and residue management on soil carbon stabilization: implications for conservation agriculture on contrasting soils | 2007 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 94; 328-337 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effects of different methods of tillage and residue management on SOM | In clay soils organic C accumulation, primarily within the fine sand fraction, can be enhanced by reducing disturbance due to tillage. In contrast, SOC build- up in sandy soils is hardly affected by reduced tillage practices and can only be accomplished by manipulating the coarse SOM fractions through additions of organic inputs. |
| 796 | Chon, S.-U. & Kim, J.-D. | Biological activity and quantification of suspected allelochemicals from alfalfa plant parts | 2002 | Allelopathy; Green Manure | Journal | J. Agron. Crop Sci.; 188; 281-285 | English | Hardcopy:Partial | Expt. to study the autotoxic effect of different parts of the lucerne plant | To escape the problems of autotoxicity the common field recommendation is to delay seeding of alfalfa after alfalfa for at least 2 weeks and in some cases up to 2 years.; .. leaves, stems, roots and seeds of alfalfa 'Vernal' were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. .. Among nine phenolic compounds assayed for phytotoxicity on root growth of alfalfa, coumarin, trans-cinnamic acid and o-coumaric acid .. were the most inhibitory. |
| 1198 | Chotte, J.L., Ladd, J.N. & Amato, M. | Sites of microbial assimilation and turnover of soluble and particulate 14C- labelled substrates decomposing in a clay soil | 1998 | Priming Effect; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 30 (2); 205-218 | English | PDF:Full | Incubation of soluble (glucose, starch) and particulate (plant residue) organic substrates in soil to test the importance of substrate-soil-matrix relationships in the processes of SOM decomposition and the location of microorganisms. A priming effect was observed mainly in the first 3 days, when large amounts of indigenous biomass C disappeared from the soluble-amended soil, being replaced by substrate biomass C and thus leaving total amount of biomass C unchanged. In the residue-amended soil the particulate OM offered new sites for microorganisms, so the total biomass C increased. | There was little or no turnover of 14C apparent within the first 3 d, as indicated by high (0.60) [= 60%] growth efficiencies.; .. biomass 14C located in the light fraction (Lf >250 mm) had disappeared by 66 d.; True priming effects, H the stimulation of the decomposition of non-biomass 12C compounds, may result in part from the accelerated death of biomass 12C.; .. although the origins of this extra C mineralised from soil organic pools have not yet been evaluated ... evidence suggests that this primed C is derived from the turnover of dead cells by secondary populations.; .. a soil has a given capacity to protect microorganisms. Above this threshold biomass C within the soil matrix is rapidly preyed upon.; .. one should .. split the biomass compartment .. into two different pools, one associated with fresh POM, the other stabilised within existing microaggregates, these compartments having different residence time. |
| 206 | Choudhary, M.A., Akramkhanov, A. & Saggar, S. | Nitrous oxide emissions from a New Zealand cropped soil: tillage effects, spatial and seasonal variability | 2002 | Greenhouse Gases; Soil N Dynamics; Tillage | Journal | Agric. Ecosyst. Environ.; 93 (1); 33-43 | English | Hardcopy:Partial | Expt. to compare the N2O emissions from plots under conventional tillage, zero tillage and sheep-grazed permanent pasture. there was no significant difference @in N2O emission rate between the zero tillage and the conventional tillage, but that from the permanent pasture was significantly lower. | The N2O emissions measured from this occasionally sheep-grazed permanent pasture were one half of those reported for intensively grazed by dairy stock.; The `strong correlation between N2O emissions and soil water content in all treatments suggests that the high rainfall and .. drainage characteristics are important in the assessment of N2O fluxes from those fields. |
| 50 | Christen, O. | No more definitions please! Some reflections about the ideas and principles of sustainable agriculture | 1998 | Sustainability | Book | El Bassam, N., Behl, R.K. & Prochnow, B. (eds.); Sustainable Agriculture for Food, Energy and Industry, vol.1; 48-52 | English | Hardcopy:Full | Sustainable agriculture should be dealt with in a framework of research priorities, instead of focusing on definitions. | Since research into sustainable agricultural systems with very slow but extremely important processes like e.g. decline or improvement of soil fertility, changes in vegetation etc. the research should be long term.; .. the organisation of research has to be changed from a top-down to a ;more farmer orientated approach. |
| 635 | Christensen, B.T. | Physical fractionation of soil and structural and functional complexity in organic matter turnover | 2001 | Soil Organic Carbon; Soil (General) | Journal | Eur. J. Soil Sci.; 52 (3); 345-353 | English | Hardcopy:Full; PDF:Full | Review of soil research based on the physical fractionation of the soil into three parts: clay-, silt- and sand-sized primary mineral-associated OM, secondary (micro- and macro-) aggregations of the primary particles and, thirdly, the structurally intact soil | .. OM .. provides a reservoir of energy and nutrients in the soil that buffers ecosystems against perturbations.; Uncomplexed [i.e. non-mineral associated] OM consist mainly of particulate partly decomposed plant .. residues, but can also encompass fungal hyphae, spores, faecal pellets,.. root fragments .. [It] is neither a readily available nor a major source of mineral N .. it can be a source of readily available C and energy to the decomposers.; Small microaggregates (<20m) contain little if any occluded OM and the main agents in the stabilisation .. are microbial products, root exudates, polyvalent cations and other persistent binding agents.; A continuous input of plant litter .. may be crucial for the formation of macroaggregates. |
| 1526 | Christian, D.G. & Bacon, E.T.G. | A long-term comparison of ploughing, tine cultivation and direct drilling on the growth and yield of winter cereals and oilseed rape on clayey and silty soils | 1990 | Tillage | Journal | Soil Tillage Res.; 18 (4); 311-331 | English | Hardcopy:Partial | 10-year field expt. to study the effects of tillage methods on the growth and yield of crops. On average yields were only depressed by 2% by zero tillage and, in some cases, were up to 7% higher than with ploughing. | .. differences in yield between cultivation treatments were small and inconsistent. Oilseed rape yielded significantly more after direct drilling than ploughing because of better establishment and uniformity of growth. The success of continuous reduced tillage depended on both burning crop residues and good weed control.; The expt.s were conducted .. burning straw residues. .. When straw cannot be burnt, direct drilling and shallow tillage systems have proved to be unsuitable on a medium clay soil.; Reduced tillage systems .. are unlikely to be more widely adopted by farmers in the U.K. their future lies in parts of the world where soil and water conservation are of greater importance .. |
| 1527 | Christian, D.G. & Miller, D.P. | Straw incorporation by different tillage systems and the effect on growth and yield of winter oats | 1986 | Tillage | Journal | Soil Tillage Res.; 8; 239-252 | English | Hardcopy:Partial | Field expt. to compare the effectiveness of different tillage systems to incorporate straw residues | On both chopped straw and stubble establishment of winter oats was best after straw incorporation by tine cultivation, followed by ploughing and worst after direct drilling. Plough based systems produced the highest plant dry weights. |
| 773 | Christian, D.G., Bacon, E.T.G., Brockie, D., Glen, D., Gutteridge, R.J. & Jenkyn, J.F. | Interactions of straw disposal methods and direct drilling or cultivation on winter wheat grown on a clay soil | 1999 | Tillage | Journal | J. Agr. Eng. Res.; 73; 297-309 | English | Hardcopy:Partial | The results are presented of a nine-year expt. in continuous winter wheat production to compare the wheat yields after zero tillage or after ploughing to 5, 15 or 25 cm. The straw from the previous crop is either burnt, chopped and spread or baled and led away. Irrespective of tillage method, straw burning always gave the greatest yield. The yields were reduced by the following amounts if other methods of dealing with the straw were used: chopping and spreading - 33%, 5 cm. deep incorporation - 20%, 15 cm. incorporation - 1%, 25 cm. incorporation - 9%. | .. sowing cereals after shallow cultivations or by direct drilling in the presence of straw residues is unreliable and may restrict both early crop growth and yield. .. Ploughing at least to 15 cm. depth is recommended in order to improve reliability in crop establishment .. and to help maintain crop yield .. |
| 283 | Chung, I.M. & Miller, D.A. | Effect of alfalfa plant and soil extracts on germination and growth of alfalfa | 1995 | Allelopathy; Green Manure | Journal | Agron. J.; 87 (4); 762-767 | English | Hardcopy:Partial | Lab. expt. to test the effect of aqueous extracts of different parts of lucerne plants on the germination and seedling growth of lucerne | .. all aqueous extracts significantly reduced seed germination .. Flower extracts were the most inhibitory at all concentrations, while the extract of the mixture of all plant parts was the least inhibitory. .. Seed extract reduced germination to 39% .. the flower extract caused the greatest reduction in hypocotyl length (28%) when compared with other part extracts. |
| 284 | Chung, I.M. & Miller, D.A. | Allelopathic influence of nine forage grass extracts on germination and seedling growth of alfalfa | 1995 | Allelopathy; Green Manure | Journal | Agron. J.; 87 (4); 676-772 | English | Hardcopy:Partial | Lab. expt. to determine the allelopathic effect of nine forage grasses on lucerne | Alfalfa [lucerne] germination ranged from 64% for tall fescue extracts to 91% for the control. .. Timothy extracts caused the lowest survival percentage [of lucerne seedlings] of 59%, compared to the control of 88%. |
| 285 | Chung, I.M. & Miller, D.A. | Natural herbicide potential of alfalfa residue on selected weed species | 1995 | Allelopathy; Green Manure | Journal | Agron. J.; 87 (5); 920-925 | English | Hardcopy:Full | Lab. expt. to demonstrate the inhibiting effect of an aqueous extract of lucerne on the germination and establishment of various weeds. There was 44% inhibition of germination in the case of fat hen. | |
| 314 | Churchill, D.B., Horwath, W.R., Elliott, L.F. & Bilsland, D.M. | Low - input, on - farm composting of high C:N ratio residues | 1996 | Compost & Biocontrol; Stockless Farming | Journal | Am. J. Alternative Agr.; 11 (1); 7-9 | English | Hardcopy:Partial | Composting ryegrass on the field in windrows which are turned several times. | .. compost perennial ryegrass straw on-farm by forming windrows and turning them either zero, two, four or six times throughout the year with a commercial straddle-type turner. No water beyond normal rainfall and no N other than that contained in the straw was added. The volume of straw was reduced by up to 88% with four or six turns over 20 to 24 weeks. The average internal temperature of the straw windrows reached a maximum of 54$C. with four turns. |
| 1528 | Clapp, C.E., Allmaras, R.R., Layese, M.F., Linden, D.R. & Dowdy, R.H. | Soil organic carbon and 13C abundance as related to tillage, crop residue & N fertilisation under continuous corn management | 2000 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 55 (3-4); 127-142 | English | Hardcopy:Partial | 13-year expt. to study the effect of tillage and crop residue input on SOM under continuous maize. With annual tillage the SOM declined slightly, with or without @crop residue input. It remained unchanged at 55 Mg ha-1 with zero tillage and no residue input, but increased by about 14% with zero tillage and residue input combined. The corresponding proportions of maize-derived C in the SOM after 13 years were 0.1, 0.05 and 0.15 respectively for the three treatments. These proportions were not affected by the application of N fertiliser. | The half-life for decomposition of the original or relic SOC was longer when stover was returned, shortened when stover was harvested and N applied and sharply lengthened when stover was not harvested and N was partially mixed with the stover. Separating SOC storage into relic and current crop sources has significantly improved our understanding of the main and interacting effects of tillage, crop residue, and N fertilisation for managing SOC accumulation in soil. |
| 321 | Clar, U., Becker, K. & Susenbeth, A. | A mobile mask technique for measuring gas exchange in cattle | 1993 | Greenhouse Gases | Journal | Anim. Res. Dev.; 37; 48-58 | English | Hardcopy:Full | Expt. to measure the exhalation of CO2 by cattle. 5 adult oxen with an average liveweight of 564 kg were tested at rest and pulling a load. | xThe rate of exhalation of CO2 was 2.25 and 7.38 l/min for resting and pulling animals respectively. |
| 806 | Clar, U., Becker, K., Susenbeth, A. | A mobile mask technique with gas meter for measuring gaseous exchange in cattle | 1992 | Greenhouse Gases | Journal | J. Anim. Physiol. Anim. Nutr.; 67(3); 133-142 | English | Hardcopy:Partial | Expt. to compare a mobile mask technique for measuring gas exchange in cattle with the conventional respiration chamber method. The average liveweight of the xoxen was 564 kg. The CO2 production rate was about 2.25 l/min for oxen at rest and 7.33 l/min for oxen working. | |
| 1649 | Clark, C. | The Economics of Subsistence Agriculture | 1967 | Agricultural Ecology | Book | Clark, C. & Haswell, M; The Economics of Subsistence Agriculture; | English | Hardcopy:Partial | The productivity of subsistence agriculture is examined. Data is given on yields and labour requirements in primitive agriculture | Even at these low levels of productivity there is a certain amount of trade in agricultural produce; and with a comparatively productive system of shifting agriculture, as among the Hanunoo, it becomes substantial and regular. .. some 10-15 per cent of the agricultural product is traded. |
| 286 | Clark, M.S., Horwath, W.R., Shennan, C., & Scow K.M. | Changes in soil chemical properties resulting from organic and low-input farming practices | 1998 | Cover Crops; Organic Farming; Stockless Farming | Journal | Agron. J.; 90 (5); 662-671 | English | Hardcopy:Partial; PDF:Full | 8-year study to compare an organic system depending on FYM applications and winter cover crops, a conventional system receiving synthetic fertiliser inputs and a low-input system using cover crops and animal manure during the first 3 years and cover crops and synthetic fertiliser for the remaining 5 years. | After 4 years soils in the organic and low-input systems had higher SOC, soluble P, exchangeable K and pH. Ceasing manure applications in the low-input system in Year 4 resulted in declining levels of organic C, soluble P and exchangeable K.; Differences in total N appeared to be related in part to inputs, but perhaps also to differing efficiency of the farming systems at storing excess N inputs: the low-input system appeared to be most efficient and the conventional system .. least efficient.; .. organic and low-input farming .. results in small but important increases in SOC and larger pools of stored nutrients, which are critical for long-term fertility maintenance.; .. the manure inputs were important in increasing organic C. |
| 947 | Clemens, J. & Ahlgrimm, H.J. | Greenhouse gases from animal husbandry: mitigation options | 2001 | Greenhouse Gases | Journal | Nutr. Cycl. Agroecosyst.; 60; 287-300 | English | Hardcopy:Partial | Review of sources of greenhouse gas emissions in animal farming and their mitigation. CO2 is emitted as a result of animal metabolism and of microbial action during storage and field application of manure, but is not considered in detail in this review. | |
| 155 | Clements, R.O. & Asteraki, E.J. | Development of a low-input bi-cropping system for growing cereals in an understorey of white clover | 1993 | Clover Sward | Book | ; White clover in Europe: state of the art, REUR Technical Series 29, FAO; | English | Hardcopy:Partial; Wordperfect:Full | Review of research on the feasibilty of growing cereals in a clover sward | .. winter wheat and spring barley appeared to be the most compatible for maintaining the clover sward. However spring barley may require agrochemical suppression of the clover for good establishment.; Pest and disease problems to date using the clover understorey system have been much reduced, although the reasons for this are not clear. |
| 688 | Clements, R.O. & Donaldson, G. | Clover and cereals - low-input bi-cropping | 1997 | Clover Sward; Stockless Farming | Journal | Farm. Conserv.; 3 (4); 12-14 | English | Hardcopy:Full | Field trials on the growing of cereals through a permanent sward of white clover. The cereal yields from bi-cropping were only 50-60% of those from conventional cropping. Advantages are: reduced pests and diseases (partly because of reduced rain splash), less weed, more earthworms, reduced soil erosion. | Initially a sward of pure white clover is established in the spring (sown alone or undersown in a spring-sown barley silage whole crop) and in the autumn (mid to late September) the clover is defoliated either by machine and ensiled or grazed by sheep. .. The cereal is then direct drilled into the clover. .. In spring .. a small amount of N is needed (around 50 kg N/ha ..) .. |
| 423 | Cleveland, C., Nemergut, D., Schmidt, S. & Townsend, A. | Increases in soil respiration following labile carbon additions linked to rapid shifts in soil microbial community composition | 2007 | Soil Microorganisms | Journal | Biogeochemistry (Dordr.); 82 (3); 229-240 | English | Hardcopy:Partial | Lab. expt. to study the effect of adding DOM to soil on the soil's microbial community composition | @; .. additions of DOM caused a rapid & large increase in soil CO2 flux .. [which] coincided with profound shifts in the abundance of certain members of the soil microbial community.. natural DOM inputs may drive high rates of soil respiration by stimulat |
| 207 | Cleveland, C.J. | The direct and indirect use of fossil fuels and electricity in USA agriculture, 1910-1990 | 1995 | Energy in Agriculture | Journal | Agric. Ecosyst. Environ.; 55; 111-121 | English | Hardcopy:Partial; PDF:Full | Energy cost of labour is not included, but the need to include it in some situations is recognised. Energy cost of a capital input is obtained by multiplying its financial depreciation by the energy intensity (energy per financial unit) of the input. | The lack of a generally accepted accounting procedure led many analysts to omit the energy cost of labour (e.g. Leach, 1976). .. A common approach [to the measurement of the energy cost of capital] is to assess the energy required to produce a tonne of steel .. in a capital good .., the energy required to operate it and maintain it over its lifetime and then to allocate that energy over the expected lifetime of the [good] .. One problem with this approach is that the energy cost of materials changes with time .. |
| 401 | Clough, A. & Skjemstad, J.O. | Physical and chemical protection of soil organic carbon in three agricultural soils with different contents of calcium carbonate | 2000 | Soil Organic Carbon | Journal | Aust. J. Soil Res.; 38; 1005-1016 | English | Hardcopy:Partial | Lab. measurement of the amount of organic C physically protected within aggregates and through polyvalent cation-OM bridging. 11-43% OC was found in the clay fractions and 17-51% in the silt fractions. 17-40% of organic C was chemically protected in a condensed aromatic form, probably charcoal. | |
| 556 | Cogliastro, A., Domon, G. & Daigle, S. | Effects of waste-water sludge and wood-chip combinations on soil properties and growth of planted hardwood trees and willows on a restored site | 2001 | Lignin and CBW | Journal | Ecol. Eng.; 16; 471-485 | English | Hardcopy:Full; PDF:Full | Study of the effect of sewage sludge and chipped wood on young trees. | @; .. the combination of a large quantity of wood chips (200 m3/ha) with a small quantity of sludge (62-125 kg N/ha) led to a balanced foliar N/P ratio and to a reduction of N mineralisation in the soil. The rate of release of resources can be adjusted by |
| 948 | Cole, C.V., Duxbury, J., Freney, J.R., Heinemeyer, O., Minami, K., Mosier, A.R., Paustian, K., Rosenberg, N., Sampson, N., Sauerback, D. & Zhao, Q. | Global estimates of potential mitigation of greenhouse gas emissions by agriculture | 1997 | Greenhouse Gases | Journal | Nutr. Cycl. Agroecosyst.; 49; 221-228 | English | Hardcopy:Partial; PDF:Full | Out of a worldwide total of 1727 Mha of arable land, 822 Mha were originally forest and 438 Mha were grassland. | The emissions of CO2, CH4 and N2O from agriculture together account fort approximately one fifth of the annual increase in radiative forcing of climate change. When land use changes involving biomass burning and soil degradation are included the overall radiative forcing amounts to one third of the (anthropogenic impact. .. CH4 and N2O are the major contributors to agricultural impacts, as the agricultural sector produces about 50% and 70% respectively of the total anthropogenic emissions of these gases.; This shows a current global stock of organic C in cultivated lands 167 Pg C and a historical loss from these soils of 55 Pg c. .. They estimated global losses of soil C since 1860 to be 30 Pg C (15% of the total 170 Pg C lost from vegetation and soils) or 41 Pg C since the beginning of settled agriculture. |
| 287 | Colla, G., Mitchell, J.P., Joyce, B., Huyck, L., Wallender, W., Temple, S.R., Hsiao, T. & Poudel, D.D. | Soil physical properties and tomato yield and quality in alternative cropping systems | 2000 | Cover Crops; Organic Farming | Journal | Agron. J.; 92 (5); 924-932 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of a change from conventional to low-input and organic tomato growing | No differences in .. soil BD and water-holding capacity were found.; Tomato yields did not differ among systems in either year. Fruit quality was highest in the conventional 4-year system.; Winter cover cropping .. has been shown to increase soil water retention and infiltration and to decrease soil surface strength.; High infiltration rates can increase irrigation needs and the cover crops can deplete soil moisture as they mature. |
| 1199 | Collins, H.P., Elliott, E.T., Paustian, K., Bundy, L.G., Dick, W.A., Huggins, D.R., Smucker, A.J.M. & Paul, E.A. | Soil carbon pools and fluxes in long-term corn belt agroecosystems | 2000 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 32 (2); 157-168 | English | Hardcopy:Partial; PDF:Full | Field expt. to the sizes of C pools and fluxes in arable soils | x; Measurement of the natural abundance of 13C made it possible to follow the in@fluence of continuous maize on SOC accumulation. The active pools comprised 3-8% of the SOC with an average field MRT of 100 d. The slow pools comprised 50% of SOC in the surface and up to 65% in subsoils. They had field MRTs from 12-28 y for C4-C and 40-80 y for C3-derived C depending on soil type and location. Notill management increased the MRT of the C3-C by 10-15 y above conventional (tillage. The resistant pool (Cr) decreased from an average of 50% at the surface to 30% at depth. |
| 1529 | Comia, R.A., Stenberg, M., Nelson, P., Rydberg, T. & Hĺkansson, I. | Soil and crop responses to different tillage systems | 1994 | Tillage | Journal | Soil Tillage Res.; 29; 335-355 | English | Hardcopy:Partial | 8-year expt. to study the effect of tillage on soil properties, plant development and crop yield. The differences were small. | At most sites and during most years of the expt. the alternative tillage systems resulted in greater yields than conventional tillage. However, the differences were often not significant .. |
| 208 | Conforti, P. & Giampietro, M. | Fossil energy use in agriculture: an international comparison | 1997 | Energy in Agriculture | Journal | Agric. Ecosyst. Environ.; 65; 231-243 | English | Hardcopy:Partial | Energy output/input ratios for crop production are compared for 75 countries. They are highest in countries with primitive agriculture, such as Uganda, Niger and the Central African Republic, and lowest in the countries with industrialised agriculture. Four countries (Japan, New Zealand, Switzerland and Finland) have a ratio of less than one, showing a net energy loss. Labour, animals and transport were not included in the calculations. | .. the rate of consumption of fossil energy is certainly faster than that of its production. This implies that current agricultural techniques are unsustainable in the long run .. |
| 889 | Conrad, R. | Soil microorganisms as controllers of atmospheric trace gases (H2, CO, CH4, OCS, N2O and NO) | 1996 | Greenhouse Gases; Soil Microorganisms | Journal | Microbiol. Rev.; 60 (4); 609-640 | English | Hardcopy:Partial | Review of biological controls on the emission of certain gases from the soil | The most dramatic change in the past was that from an anoxic to an oxic atmosphere. This change occurred slowly over about 2.5 Gyr and was caused by the emergence of oxygenic photosynthesis.; .. in agricultural soil microorganisms are present at billions per g of soil and constitute a biomass of approximately 500 kg of C per ha, which corresponds to about 1 sheep per 100 m2 [100 sheep per ha].; .. the existence of a temperature optimum .. is an unambiguous indication of a biological reaction. |
| 1200 | Constantinides, M. & Fownes, J.H. | Nitrogen mineralization from leaves and litter of tropical plants: relationship to nitrogen, lignin & soluble polyphenol concentrations | 1994 | Lignin and CBW; Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 26 (1); 49-55 | English | Hardcopy:Partial | Lab. expt. to study the decomposition of leaves and litter from various leguminous and non-leguminous tropical plants. The results of this study differed from those of other studies of leguminous plant residues, where soluble polyphenols or polyphenol/N ratios correlated better with rates of net N release than initial N content or lignin/N ratios. | .. the percent of leaf N accumulated was most highly correlated with initial N concentration. Phosphorus and the ratios lignin/N and (lignin+polyphenol)/N also strongly correlated with N accumulation .. Over our wide range of materials initial soluble polyphenols were secondary to initial N .. |
| 1201 | Cook, B.D. & Allan, D.L. | Dissolved organic carbon in old field soils: total amounts as a measure of available resources for soil mineralization | 1992 | Mineralisation; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 24 (6); 585-594 | English | Hardcopy:Partial | Lab. measurement of C & N mineralisation during a 210-day incubation of soil from five previously cultivated old fields. The initial potentially mineralisable organic C & N ranged from 14% to 26% and from 14% to 33% of total SOC and SON respectively. | .. there was no obvious relationship between DOC and instantaneous rates of mineralisation.; It is assumed that all the dissolved substances are labile and utilised rapidly. However, recalcitrant molecules may represent a significant portion of the DOC. |
| 1202 | Cookson, W.R., Cornforth, I.S. & Rowarth, J.S. | Winter soil temperature (2-15şC) effects on nitrogen transformations in clover green manure amended or unamended soils; a laboratory and field study | 2002 | Green Manure; Soil N Dynamics | Journal | Soil Biol. Biochem.; 34 (10); 1401-1415 | English | Hardcopy:Partial; PDF:Full | Expt. to study the effect of fluctuating winter temperatures in a temperate region on the release of N from plant residues | Nitrate-N was the dominant form of mineral-N throughout the incubation expt. in amended soil incubated at 10 or 15$C.; Gross nitrification was initially (756 days) inhibited in amended soil incubated at 2 or 5$C, causing an accu`mulation of NH4+-N. However, after 77 days at 2 or 5$C, gross nitrification rates (increased, such that NO3--N increased to concentrations which were greater than those of NH4+-N. This suggests that nitrifying bacteria took longer to acclimatise to the cold conditions [<10$C] than ammonifying microorganisms.; Decreasing soil temperature from 15 to 2$C caused an initial increase in mineral-N, which was quickly followed by rapid immobilisation of mineral-N; gross immobilisation rates were up to 2.8-fold greater than gross mineralisation rates. Similarly, under field conditions microbial biomass N and gross immobilisation increased with decreasing soil temperature, suggesting there was population growth of adapting micro-flora.; This research has shown that significant mineral-N is released from soil amended with clover residues at temperatures as low as 2$C.Therefore, the incorporation of N-rich plant material should be delayed until spring to avoid winter N leaching. |
| 455 | Corbeels, M., Hofman, G. & Cleemput, O. van | Simulation of net N immobilisation and mineralisation in substrate-amended soils by the NCSOIL computer model | 1999 | Mineralisation; Stockless Farming; Soil N Dynamics | Journal | Biol. Fertil. Soils; 28; 422-430 | English | Hardcopy:Full; PDF:Full | Modelling soil N dynamics, compared with expt'l data, for 4 org. treatments | Net mineralisation was detected earliest for the sunflower-stalk treatment (on day 14), while the other treatments showed no net mineralisation until day 52. These differences in lag periods were presumably related to the different C/N ratios of the substrates.; .. microorganisms utilise available N from the soil environment when decomposing organic material that has a high C/N ratio, which is afterwards released at a slower rate by subsequent microbial colonisers.; The C/N ratio of bacteria is an important factor in N mineralis'n & is known to change with time.. a distinction between an autochthonous (decomposing native SOM) and a zymogenous microbial population (decomposing added residues), each with a fixed C/N ratio, change[s] the C/N ratio of the total microbial biomass |
| 90 | Cormack, W.F. | Testing a stockless arable organic rotation on a fertile soil | 1999 | Organic Farming; Stockless Farming | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Full; Wordperfect:Full | A report of the same expt. as in Cormack (1997), except that the soil aggregate stability and N content are not reported here. | See Cormack (1997). |
| 158 | Cormack, W.F. | Testing the sustainability of a stockless arable rotation on a fertile soil in Eastern England | 1997 | Stockless Farming | Book | ; 3rd ENOF concerted action workshop, Ancona, Italy; | English | Hardcopy:Full | A report, after one complete rotation, of a field-scale expt. in stockless arable farming conducted at A.D.A.S., Terrington, on 10 ha of silty clay loam.The rotation used was: potatoes, winter wheat, spring beans and spring wheat. The results were good on both agronomic and financial criteria. SOM, aggregate stability, N, P & K content and crop yields are reported. | Organic crops have yielded well ..; .. the organic rotation has been consistently more profitable than the conventional.; However, profitability has been dependent on .. price premiums and on arable aid and set-aside payments.; .. the .. expt. shows that such a [stockless organic] rotation may be .. more profitable than conventional, at least on a water and nutrient-retentive soil.; .. perennial weeds .. are increasing.; Soil available phosphorus declined .. Reddzlaag (calcined calcium alumino-phosphate, 14% P) .. was applied .. |
| 933 | Cornelissen, J.H.C. & Thompson, K. | Functional leaf attributes predict litter decomposition rate in herbaceous plants | 1997 | Miscellaneous; Soil Organic Carbon | Journal | New Phytol.; 135; 109-114 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the correlation between leaf litter decomposition rates and various attributes of the leaves of grasses and herbaceous dicot plants | Graminoid monocots had physically tougher leaves with higher silicon contents than did herbaceous dicots and this corresponded with the lesser decomposibility of the former. Total base content of living leaves was a good predictor of litter decomposition rate.. In the monocots litter decompos'n rate was strongly predicted by leaf potassium content .. In the dicots the relationship between total leaf base content & litter decompos'n rate was not unambiguously explained by growth-related leaf attributes, possibly because of the considerable calcium uptake by dicots, which varies according to calcium availability in the soil. |
| 1590 | Cornforth, J.W. | Energy out of agriculture: plants as a source of fuel and power | 1975 | Energy Resources | Journal | Span; 18 (1); 10-11 | English | Hardcopy:Full | The use of energy crops and plant wastes. Various methods of getting usable energy from photosynthetic biomass are considered. | .. by some plants (e.g. sugar cane), growing as a crop in ideal conditions .. the best performance that can be attained at present is around 3% .. of the total [solar] radiation incident on the land throughout the year. .. 1% fixation of solar energy .. is the maximum attainable now .. in temperate climates ..; A tropical forest can fix solar energy at a rate of 90 MJ/sq m/year or more. .. Tropical swamps can reach 140 MJ/sq m/year .. |
| 209 | Cowell, S.J. & Parkinson, S. | Localisation of UK food production: an analysis using land area and energy as indicators | 2003 | Energy in Agriculture; Stockless Farming | Journal | Agric. Ecosyst. Environ.; 94 (2); 221-236 | English | Hardcopy:Partial | Comparison of various categories of imported and U.K.-produced food in respect of the transport energy and the area of land used. Tables are given of the distance travelled and the land requirements of each category of food. | .. based on the land use indicator, localisation of UK food production is possible, although this would involve considerable changes in individuals' food consumption patterns.; .. meat and other animal products require the largest land area in the UK ..; Since plant products can be produced more efficiently (mass per ha) than animal products for human consumption, a reduction in consumption of animal products in favour of plant products is likely to facilitate the localisation of food production. .. meat products have yields as low as 0.2 t/ha, whereas grain yields range from 4.4 to 6.8 t/ha. .. about 50% of the UK consumption of cereals is by livestock.; .. another survey shows that the percentage of vegetarians in the UK has grown to 7%, a doubling in the last ten years .. |
| 1610 | Coűteaux, M.M., Bottner, P. & Berg, B. | Litter decomposition, climate and litter quality | 1995 | Soil Organic Carbon | Journal | Trends Ecol. Evol.; 10 (2); 63-66 | English | Hardcopy:Full; PDF:Full | Review of the factors affecting the rate of litter decomposition | Litter decompos'n is controlled by three main factors: climate, litter quality and the nature and abundance of the decomposing organisms. Climate is the dominant factor in areas subjected to unfavourable weather conditions, whereas litter quality largely prevails as the regulator under favourable conditions. |
| 375 | Craft, C.M. & Nelson, E.B. | Microbial properties of composts that suppress damping-off & root rot of creeping bentgrass caused by Pythium graminicola | 1996 | Compost & Biocontrol | Journal | Appl. Environ. Microbiol.; 62 (5); 1550-1557 | English | Hardcopy:Partial; PDF:Full | Lab. & field expt. to investigate possiblc connections between the microbial activity of a compost and its potential to suppress soil-borne diseases | .. suppression of Pythium diseases of creeping bentgrass in batches of brewery sludge and Endicott biosolids composts, and possibly in other suppressive composts .., is related directly to the microbial activities in the composts.; Disease suppressiveness was .. reduced or eliminated in heated composts. Amending heated composts with smallamounts of non-heated compost restored suppressive properties and partially restored microbial populations to wild-type levels. |
| 376 | Crawford, D.L. & Crawford, R.L. | Microbial degradation of lignocellulose: the lignin component | 1976 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 31 (5); 714-717 | English | Hardcopy:Full; PDF:Full | 700-hour lab. expt. to study the decomposition of lignin in soil, using wood labelled with 14C-phenylalanine. | The cellulose in our substrates may speed lignin degradation by acting as .. an additional source of energy for lignocellulose degraders in soil .. lignin degradation .. requires a readily metabolisable substrate such as cellulose. |
| 607 | Crawford, D.L. & Crawford, R.L. | Microbial degradation of lignin | 1980 | Lignin and CBW | Journal | Enzyme. Microb. Technol.; 2; 11-22 | English | Hardcopy:Full | Review of existing knowledge of the microbial degradation of lignin | Much of the lignin bio-synthesised by plants is mineralised and returned to the xatmosphere as CO2.; certain fungi of the white rot group, and possibly other @fungi and bacteria, completely decompose lignin to CO2 and water. Other fungi and bacteria apparently degrade lignin incompletely.; [with] white rot fungi .. lignin degradation proceeds by way of extracellular mixed-function oxygenases and dioxygenases, which catalyse demethylations, hydroxylations and ring-fission reactions within a largely intact polymer, concomitant with some release of low molecular weight lignin fragments.; White-rot fungi deplete carbohydrate and lignin simultaneously as they decay wood, although some species actually decompose the lignin .. in preference to the cellulosic components. |
| 377 | Crawford, D.L., Crawford, R.L. & Pometto, A.L. | Preparation of specifically labelled 14C-(lignin) and 14C-(cellulose)lignocelluloses and their decomposition by the microflora of soil | 1977 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 33 (6); 1247-1251 | English | Hardcopy:Partial; PDF:Full | 700-hour lab. expt. to study the decomposition of natural lignocellulose in soil, using wood @labelled by feeding plants with 14C-phenylalanine or 14C-glucose to label the lignin and the cellulose respectively. After 700 hours about 4% of the lignin and 28% of the cellulose had been mineralised to CO2. There was a lag of several weeks before significant mineralisation of lignin took place. | The lags are probably the result of the mechanism of decomposition .. Considerable preliminary attack on the polymeric structure,particularly of lignin, must occur before appreciable oxidation to 14CO2 is possible.; .. the cellulosic components of lignocelluloses would be completely recycled .. within relatively short times .. Lignin components, on the other hand, would likely accumulate over time .. and are important in processes such as humification. |
| 725 | Cross, A.F. & Schlesinger, W.H. | A literature review and evaluation of the Hedley fractionation: applications to the biogeochemical cycle of soil phosphorus in natural ecosystems | 1995 | Phosphorus Cycling | Journal | Geoderma; 64; 197-214 | English | Hardcopy:Full; PDF:Full | Review of published results on the P content and extracts (fractions) in different soil types. Total soil P varies between 0.1 and 0.75 g/g soil. The labile P (sum of resin and bicarb extracts), which is the form of P available to plants, is 2-10% of total soil P. SOP is 5-35% of total P, depending on soil type - it increases with soil weathering. | .. the total soil P pool decreases as a function of soil development.; .. the dominant processes that regulate the soil P cycle are the geochemical reactions.; .. the pool of primary phosphate declines and the stable organic pool increases during soil development. .. phosphorus becomes geochemically fixed to the iron and aluminium oxides in the more highly weathered soils. |
| 856 | Crovetto, C.C. | No-till development in Chequen Farm and its influence on some physical, chemical and biological parameters | 1998 | Tillage | Journal | J. Soil Water Conserv.; 53 (3); 194-199 | English | Hardcopy:Partial | A report on changes in soil qualities on a farm in Chile that has been under zero tillage for many years. Soil qualities (including microbiological activity) and crop yields have improved. | After 38 years of absence of tillage the soils present today have superior physical, chemical and biological properties that increase crop yields.; Notill improves the OM levels ..; The mesofauna of the no-till soil in general was strongly favoured as compared to till soil. .. during the period studies, insects, acarus, nematodes, centipedes, worms, platyhelminths, molluscs and crustaceans made a higher count than that of the soil under traditional till. |
| 65 | Cunha Queda, A.C., Vallini, G., Agnolucci, M., Coelho, C.A., Campos, L. & Sousa, R.B. de | Microbiological and chemical characterisation of composts at different levels of maturity, with evaluation of phytotoxicity and enzymatic activities | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the stability, microbiology and phytotoxicity of various composts | During the active phase the most easily biodegradable materials are transformed & partially mineralised; the OM becomes stabilised as a consequence of the intense microbial activity. The curing phase is characterised by the conversion of part of the stabilised OM into humic substances. Thus, while reaching compost stability can be regarded as the result of high-rate microbial reactions occurring throughout the active phase of the process, compost maturity appears .. as the effect of the curing phase.; .. the compost C/N ratio depends on the ratio between relative contents in carbon and nitrogen in the initial matrix, on the presence of organic fractions refractory to biodegradation in the initial substrate and on the dynamic evolution of the composting process. |
| 456 | Curci, M., Pizzigallo, M.D.R., Crecchio, C., Mininni, R. & Ruggiero, P. | Effects of conventional tillage on biochemical properties of soils | 1997 | Soil Microorganisms; Tillage | Journal | Biol. Fertil. Soils; 25 (1); 1-6 | English | Hardcopy:Full; Wordperfect:Full | Field expt. to study the effect of different tillage regimes on the distribution in the soil of various microbially derived enzymes and microbial biomass | .. the influence of three conv'l tillage systems (shallow ploughing, deep ploughing & scarification) at different depths on the distrib'n & activity of enzymes, microbial biomass & nucleic acids in a cropped soil was investigated.; Activity in the upper layer (0- 20 cm) was higher in the plots tilled by shallow ploughing and scarification than in those tilled by deep ploughing. |
| 288 | Curran, B.S., Kephart, K.D. & Twidwell, E.K. | Oat companion crop management in alfalfa establishment | 1993 | Green Manure | Journal | Agron. J.; 85 (5); 998-1003 | English | Hardcopy:Full | Field expt. to compare various methods of establishing a lucerne crop, especially with and without oats as a companion crop. (Oats are sown with lucerne to reduce erosion and weeds before the lucerne is established.) The best lucerne yield in the first year was in the hand-weeded plot without oats. This and the herbicide-treated plots were much less weedy than the plots with oats and the control plot, which had no weed-control treatment. In the second year, however, all treatments gave similar yields and were practically weed-free. | |
| 416 | Daily, G.C. & Ehrlich, P.R. | Population, sustainability and Earth's carrying capacity | 1992 | Sustainability | Journal | Bioscience; 42 (10); 761-771 | English | Hardcopy:Partial | Sustainability is discussed in terms of the environmental impact of the world's population, an estimate of available resources and the relationship between the two. | Given the current technologies, levels of consumption and socio-economic organisation, has ingenuity made today's population sustainable? The answer to this is clearly no .. |
| 544 | Daily, G.C. & Ehrlich, P.R. | Socioeconomic equity, sustainability and Earth's carrying capacity | 1996 | Sustainability | Journal | Ecol. Appl.; 6 (4); 991-1001 | English | Hardcopy:Full | Review of the relationship between sustainability and socioeconomic equity | .. inequalities themselves help perpetuate poverty, which generates vicious cycles involving deleterious and sometimes irreversible impacts on bio-physical components of Earth's life-support systems. .. they hinder cooperation among parties of differing socioeconomic status - co-operation purportedly required for averting potentially disastrous population- & environment-related problems.; Social carrying capacity is the maximum popul'n size that an areas can sustain under a given social system .. social CC is necessarily smaller than bio-physical CC ..; What may be needed are structural changes in the economy, so that children no longer constitute sources of income, but are converted into consumer durables - expensive items that compete for consumption expenditures with [TV] .. and the like.; .. it is imperative to find ways of reducing the scale of the human enterprise .. empowering Homo sapiens to end today's overshoot and return to sustainable numbers and lifestyles. |
| 1203 | Dalenberg, J.W. & Jager, G. | Priming effect of some organic additions to 14C-labelled soil | 1989 | Green Manure; Priming Effect; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 21 (3); 443-448 | English | Hardcopy:Partial | Lab. expt. to establish the magnitude of the priming effect of various soil organic amendments. Of the substrates added only the pure amino-acids (which are not present in nature) left a negative carbon balance in the soil. | All other substrates ... left enough residues, including biomass, to fully compensate for the loss due to priming. The fear of the 'humus-eating effect of green manures' thus is unfounded ..; If priming leads to extra decomposition of SOM, then only fraction (a) [fresh plant residues] can be involved. [but] In our soil fraction (a) was no longer present .. [so] .. biomass was the only source of C that could be primed in our soil .. |
| 949 | Dalgaard, T., Halberg, N. & Kristensen, S. | Can organic farming help to reduce N-losses? Experiences from Denmark | 1998 | Organic Farming; Stockless Farming | Journal | Nutr. Cycl. Agroecosyst.; 52; 277-287 | English | Hardcopy:Partial; PDF:Full | Modelling is used to compare N losses in conventional and organic dairy and pig farming | .. pig farming was found to have a higher N-efficiency than dairy farming. Organic pig production had a lower N-efficiency and a higher N-surplus per kg meat than conventional pig production. .. Organic dairy farming had a higher N-efficiency and a lower N-surplus per kg milk than conventional dairy farming.; .. a positive correlation between livestock density and N-surplus ha-1 was found for dairy farming. For all simulated livestock densities, fodder feeding intensities and soil types, organic systems showed a lower N-surplus per unit of milk produced than conventional systems. .. the present Danish milk production could be achieved with a 24% lower total N-surplus ..if conventional dairy farming with 1.7 LSU ha-1 is converted to organic dairy H farming with 1.1 LSU ha-1 [and] average N-surplus per t milk and average N-surplus per ha in Denmark could be reduced by 25% and 50% respectively.; Animal production intensity was measured in LSU ha-1, where 1 LSU (Livestock Unit) corresponds to one 550 kg dairy cow, 3 sows or 30 porkers produced per year. |
| 210 | Dalgaard, T., Halberg, N. & Porter, J.R. | A model for fossil energy use in Danish agriculture used to compare organic and conventional farming | 2001 | Energy in Agriculture; Organic Farming | Journal | Agric. Ecosyst. Environ.; 87; 51-65 | English | Hardcopy:Full; PDF:Full | Modelling energy use in conventional and organic agriculture | The energy use was generally lower in the organic than in the conventional system, but yields were also lower. Consequently, conventional crop production had the highest energy production, whereas organic crop production had the highest energy efficiency. |
| 1008 | Dam, A.M. van | Understanding the reduction of nitrogen leaching by cover crops | 2006 | Cover Crops; Soil N Dynamics | Book | Dam, A.M. van; Understanding the reduction of nitrogen leaching by cover crops; | English | Hardcopy:Partial; Wordperfect:Partial | Lab. expt. to study the factors affecting the nitrogen uptake of cover crops | .. sowing date determines the potential N uptake capacity of the cover crop. x.. the simulated uptake capacity of a cover crop exceeds 200 kg N ha-1 when the crop is sown in the first half of August. For rye, the uptake capacity decreases on average by 3.3 kg N ha-1 per day postponement of sowing.; For a maximum N availability to the succeeding crop, a rye cover crop on a sandy soil is best incorporated in soil three months before the planting the next crop. Deviations up to a month from the optimal date had only a small effect on N available to (the next crop (2 kg N ha-1). |
| 1204 | Danso, S.K.A., Palmason, F. & Hardaarson, G. | Is nitrogen transferred between field crops? Examining the question through a sweet blue lupin (Lupinus angustifolius)-oats (Avena sativa) intercrop | 1993 | Green Manure; Soil N Dynamics | Journal | Soil Biol. Biochem.; 25 (8); 1135-1137 | English | Hardcopy:Full | Field expt. to investigate the transfer of N from lupin to oats. The authors purport to demonstrate that there is no transfer. | .. legumes in an intercrop have a diminished soil N uptake ability, enabling an intercropped non-N2-fixing crop to absorb more N than it would when cropped alone. The contribution from this soil N-sparing effect was shown in crop rotation studies to be more important than N transfer. This was the case in our `study, as revealed by the 15N enrichment in sole oats vs. mixed oats; a (significant N transfer would have been indicated if mixed oats had a lower 15N enrichment than sole oats, which was not so. |
| 1414 | Dao, T.H. | Tillage and crop residue effects on carbon dioxide evolution and carbon storage in a paleustoll | 1998 | Greenhouse Gases; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 62 (1); 250-256 | English | Hardcopy:Partial | Field expt. to compare the soil respiration and microbial biomass of soils under plough and zero tillage | The proportion of soil OC respired in the 60-day period was twice as great under MP [ploughing] than NT [zero tillage], accounting for 0.42% to 0.58% and 0.19% to 0.22% respectively.; Daily average temperatures in the 0- to 2.0-cm depth were 0.5$ to 3.4$C higher under MP than NT, increasing microbial ATP, `biomass C and CO2 fluxes. |
| 512 | Davenport, J.R. & Thomas, R.L. | Carbon partitioning and rhizodeposition in maize and brome grass | 1988 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Can. J. Soil Sci.; 68 (4); 693-701 | English | Hardcopy:Full | Modelling the belowground C deposition of the two crops. Calculated on the same weight of aboveground dry matter (10,000 kg/ha) brome and maize yield 3125 and 2500 and 562 and 674 kg/ha from the root and extra-root depositions respectively. (Extra-root material means all rhizodeposits other than root tissue.) Only 10% of all C assimilated by maize goes belowground, whereas 40% does in the case of brome grass. | The amount of C input into the soil determines the substrate for soil microorganisms and is, therefore, the controlling factor in the relationship between crops and soil structure .. maize being a crop that has been identified as detrimental to sustained stable soil structure, while brome grass provides a definite enhancement of soil structure. |
| 1611 | Dawson, T. & Fry, R. | Agriculture in nature's image | 1998 | Sustainability | Journal | Trends Ecol. Evol.; 13 (2); 50-51 | English | Hardcopy:Full; PDF:Full | Review of research into farming that mimics nature | .. the natural ecosystem of any region is adapted to .. resource constraints and therefore provides a site-specific model for sustainability if well mimicked by agriculture.; Alley cropping has largely failed in Africa .. because of insufficient knowledge of where the plants extracted their resources and/ or their phenological patterns of resource use and .. insufficient attention to farmers' immediate economic needs.; Any mimic system designed with a view to sustainability should .. be designed within an adoption framework with clear links to the farmers who will use it. There may be long time lags between implementation and pay-back, so part of the mosaic should supply short-term profits for the farmer.; Conventional agriculture is focused on short-term gains ..; There will be no universal recipe for .. sustainable agriculture; what works for the tropics is not likely to work for south Australia because of different climatic, ecological and socio-economic constraints. |
| 59 | Dazhong, W. & Pimentel, D. | Energy flow in agroecosystems of north-east China | 1990 | Agricultural Ecology | Book | Gliessman, S.R. (ed.); Agroecology - researching the ecological basis for sustainable agriculture; | English | Hardcopy:Partial | Energy inputs and outputs are estimated in three different farming systems - traditional organic, commune and state farm - in Hailun county, China.Tables are given for the various inputs and outputs of each crop system and each livestock system and for the yields of crops and crop residues. Labour is reckoned as 6 MJ per eight-hour day. Horses are reckoned as 50 MJ per five-hour day. | no quotations |
| 338 | Debosz, K., Petersen, S.O., Kure, L.K. & Ambus, P. | Evaluating effects of sewage sludge and household compost on soil physical, chemical and microbiological properties | 2002 | Compost & Biocontrol | Journal | Appl. Soil Ecol.; 19 (3); 237-248 | English | Hardcopy:Partial; PDF:Full | Expt. to test the effects of org. wastes (composted household waste & processed sewage sludge) on a wide range of soil physical and microbiological properties | In general effects of waste amendment were positive but moderate compared to the dynamics observed in unamended soil and mainly occurred in the first several weeks after amendment. .. there were no accumulated effects of waste amendment on the fraction of soil in wet-stable aggregates or on the microbiological properties tested, which supported the observation .. that effects of organic wastes were transient. |
| 1530 | Deen, W. & Kataki, P.K. | Carbon sequestration in a long-term conventional versus conservation tillage experiment | 2003 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 74 (2); 143-150 | English | Hardcopy:Partial; PDF:Full | 25-year field expt. to compare the yields of maize under zero tillage and under chisel and mouldboard ploughing, with or without secondary tillage | The ZT treatments had a higher SOC concentration in the surface layer compared to other tillage treatments ... However ... method of tillage ... also influenced soil bulk density. When SOC was calculated using an equivalent soil mass basis, SOC storage in the 0-40 cm layer, which encompasses a typical plough layer in eastern Canada, was not affected by time or method of tillage. |
| 402 | Degens, B.P. | Macro-aggregation of soils by biological bonding and binding mechanisms and the factors affecting these: a review | 1997 | Soil (General) | Journal | Aust. J. Soil Res.; 35; 431459 | English | Hardcopy:Partial | Review of the literature dealing with labile mechanisms of bonding (through adhesive organic compounds) and binding (through fungal hyphae and roots) involved in stabilising soil into macroaggregates (>250m) | Carbohydrate C that is microbial in origin appears to be most effective in stabilising soil into aggregates.; .. fungal hyphae hag been consistently found to stabilise soil into aggregates by physical enmeshment of soil particles.; Roots appear to stabilise soil into aggregates by enmeshment of soil particles, frequently in conjunction with VAM hyphae.; The contribution of mycorrhizal hyphae to the stabilisation of soil into macroaggregates may be prolonged compared with that of saprophytic hyphae. |
| 1205 | Degens, B.P. | Decreases in microbial functional diversity do not result in corresponding changes in decomposition under different moisture conditions | 1998 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 30 (14); 1989-2000 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of microbial diversity on microbial community functioning in soil | .. the decompos'n function of soil with reduced functional diversity can be diminished under optimum moisture conditions, but is not invariably reduced when assessed under sub-optimal moisture conditions. .. decreases in the functional diversity of soil microbial communities may not consistently result in declines in soil functioning.; The high degree of functional redundancy in soil microbial communities may result in there being no effect of changes in microbial diversity on the function of the communities. |
| 1206 | Degens, B.P. & Sparling, G.P. | Changes in aggregation do not correspond with changes in labile organic C fractions in soil amended with 14C-glucose | 1996 | Soil Organic Carbon; Soil (General) | Journal | Soil Biol. Biochem.; 28 (4/5); 453-462 | English | Hardcopy:Partial | 56-day lab. expt. to study the changes in carbohydrate content, microbial biomass and aggregation in a sandy soil amended with glucose | @; In this sandy soil changes in carbohydrate C fractions, 14C microbial biomass and 14C [microbial] products were not consistently related to changes in aggregate stability. .. Our results contrasted with investigations of loam and clay soils, where aggr |
| 339 | Degens, B.P., Sparling, G.P. & Abbott, L.K. | Increasing the length of hyphae in a sandy soil increases the amount of water-stable aggregates | 1996 | Soil Microorganisms; Soil (General) | Journal | Appl. Soil Ecol.; 3; 149-159 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of hyphal length on aggregation in a sandy soil | .sand grains in the aggregates appeared to be linked together only by hyphae .. indicating little involvement of microbial polysaccharides in stabilising the aggregates.; The amounts of dry-stable aggregates .. were generally increased by 63-147% in the amended soils compared to non-amended soils and 27 to 33% of these aggregates were water-stable aggregates ..; Mycorrhizal hyphae may be more important than saprophytic hyphae in stabilising aggregates because aggregates stabilised by the hyphae can persist in .. soil for up to 22 weeks after the plants had died .. the effect of saprophytic fungi in stabilising aggregates can be transitory.; .. the resulting hyphal length was more strongly correlated with aggregation in the soils containing greater than 67% sand compared to those soils containing more silt and clay. |
| 612 | Delgado, A. & Torrent, J. | Phosphate-rich soils in the European Union: estimating total plant-available phosphorus | 1997 | Phosphorus Cycling | Journal | Eur. J. Agron.; 6; 205-214 | English | Hardcopy:Partial | Expt. to find a reliable method to measure soil total plant-available P | xIn the 12 soils tested total P (organic + inorganic) averaged 775 mg kg-1 soil, @total P uptake averaged 110 mg kg-1 soil and the total plant-available P averaged 170 mg kg-1 soil. |
| 857 | Delgado, J.A. & Follett, R.F. | Carbon and nutrient cycles | 2002 | Phosphorus Cycling; Soil Organic Carbon | Journal | J. Soil Water Conserv.; 57 (6); 455-464 | English | Hardcopy:Full | Review of the literature on the role of SOM in agricultural soils, especially its role in nutrient recycling. For the release of nutrients from crop residues the C/nutrient ratio is critical. The soil C pool is split into organic and inorganic in the ratio 1.9/1, is 3.2 times that in the atmosphere and 4 times that in terrestrial vegetation. The SOC pool can be divided into three: active C (mainly live microbes and microbial products) with a turnover of 1-5 years, the slow pool, which is physically protected and has a turnover of 20-40 years, and the passive pool, which is recalcitrant and turns over in 200-1500 years. Greater clay content increases the protection of SOM from mineralisation. 58% of the N and 70% of the P in FYM is mineralised. | C can contribute positively to soil quality by improving porosity, available water holding capacity and cation exchange capacity ..; SOM contributes to a better soil structure and aggregate formation .. serves as a storage form of N, P, and S and helps in the cycling of essential nutrients.; C management should coordinate the mineralisation of nutrients from crop residues & other organic sources with the time of greater uptake during the growing season.; Although total N deposition [from the atmosphere] can vary depending on the region, it is low on average. .. the total deposition at North Platte .. for 2000 was about 4 kg N/ha, while at Big Springs it was .. 7.2 kg N/ha. |
| 211 | Delve, R.J., Cadisch, G., Tanner, J.C., Thorpe, W., Thorne, P.J. & Giller, K.E. | Implications of livestock feeding management on soil fertility in the smallholder farming systems of sub-Saharan Africa | 2001 | Stockless Farming; Soil N Dynamics | Journal | Agric. Ecosyst. Environ.; 84 (3); 227-243 | English | Hardcopy:Partial; PDF:Full | Expt. to compare the effect on cattle of feeding them barley straw, either alone or with one of three different additives (two forage legumes and poultry manure). The N content of the faeces was examined, as was the partitioning of N between faeces and urine. The rate of mineralisation of N was measured when the faeces from the various diets were incubated [with soil ?], as compared with when the feed itself was incubated, to assess the effect of the feed passing through the cattle. | A choice must be made between the allocation of organic resources: whether they should be used for livestock feed or as organic fertilisers in crop production. Animal manures are of major importance in nutrient cycling but generally of poor quality to supply plant nutrients and organic resources vary widely in their ability to provide nutrients directly for crop growth.; The option of feeding the plant materials to ruminant livestock and then adding the faeces to the soil did increase the rate of N mineralisation .. and produced larger N uptake in maize grown in pots .. the lower the quality of the feed material, the more beneficial the application of faeces is over direct application of the plant material to the soil. |
| 636 | Denef, K. & Six, J. | Clay mineralogy determines the importance of biological versus abiotic processes for macroaggregate formation and stabilization | 2005 | Soil (General) | Journal | Eur. J. Soil Sci.; 56 (4); 469-479 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the factors affecting macroaggregate formation in soils of differing mineralogy | Control macroaggregates in the kaolinitic soil were formed out of silt and clay particles without accumulating C. Residue input and plant growth had a greater positive effect on macroaggregate formation in the illitic than in the kaolinitic soil. ... kaolinitic soils can rapidly form macroaggregates independent of biological processes due to physical or electrostatic interactions between the 1:1 clay minerals and oxides. ... biological processes led to stronger organic bonds between the illite compared with the kaolinite clay, resulting in more macroaggregates with long-term stability in the illitic ... soil. |
| 637 | Denef, K. & Six, J. | Contributions of incorporated residue and living roots to aggregate-associated and microbial carbon in two soils with different clay mineralogy | 2006 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 774-786 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of clay mineralogy on the protection of organic matter in soils | ... the ratio of residue-derived over root-derived C decreased in most size fractions over time, indicating a greater potential for longer-term root-C than residue-C stabilisation by aggregates in both soils.; .. all aggregates >53 m had greater residue-C concentrations in the illitic soil than in the kaolinitic soil and this difference increased with increasing aggregate size. This suggested a greater affinity of illite clay than kaolinite clay to bind with fresh residue-derived cpds into larger aggregates and hence a greater importance of aggregates in stabilising residue-C in illitic compared with kaolinitic soils. |
| 1030 | Denef, K., Six, J., Merckx, R. & Paustian, K. | Short-term effects of biological & physical forces on aggregate formation in soils with different clay mineralogy | 2002 | Soil (General) | Journal | Plant Soil; 246; 185-200 | English | Hardcopy:Partial | Lab. expt. to study the effects of nutrient and OM addition, root growth and drying-wetting cycles on macroaggregate formation. Compared to 2:1-claydominated soils, 1:1 soils were less dependent on SOM for macroaggregate formation, showing a lower increase in macroaggregation on OM addition, but, under low OM levels, they had a larger capacity to form macroaggregates. At high OM levels mixed 1:1 and 2:1 soils, which had the highest CEC, showed the greatest macroaggregation and the greatest response to OM inputs. | .. In control treatments i.e. without nutrient or OM addition ..) the formation of .. macroaggregates (>250 m) increased in the order: 2:1 clay soil > mixed clay soil > 1:1 clay soil. |
| 1415 | Denef, K., Six, J., Merckx, R. & Paustian, K. | Carbon sequestration in microaggregates of no-tillage soils with different clay mineralogy | 2004 | Soil (General); Tillage | Journal | Soil Sci. Soc. Am. J.; 68 (6); 1935-1944 | English | Hardcopy:Partial | Lab. expt. to evaluate the contribution of macroaggregate-protected microaggregates in the sequestration of carbon in 3 very different soils under conventional (CT) and zero (NT) tillage | In all three soils total SOC as well as microaggregate-associated C was greater with NT compared with CT. Although less than half of the total SOC under NT was associated with the microaggregate fraction, more than 90% of the total difference in SOC between NT and CT was explained by the difference in microaggregate-associated C in all three soils. |
| 1207 | Denef, K., Six, J., Paustian, K. & Merckx, R. | Importance of macroaggregate dynamics in controlling soil carbon stabilisation: short-term effects of physical disturbances induced by dry-wet cycles | 2001 | Soil Organic Carbon; Soil (General) | Journal | Soil Biol. Biochem.; 33 (15); 2145-2153 | English | Hardcopy:Partial | Expt. to determine the effect of drying and wetting on macroaggregate turnover, microaggregate formation within macroaggregates and aggregate-assoc'd C dynamics | .. POM-C in new microaggregates within macroaggregates is inhibited by an enhanced macroaggregate turnover, which is only in the short term enhanced by drying and wetting. .. besides a release of total (i.e. native and wheatderived) POM upon macroaggregate breakdown, drying and wetting induced a fast reformation of macroaggregates with preferential incorporation of wheat-derived POM, resulting in a relative decline of native POM-C in DW macroaggregates. |
| 973 | Derenne, S. & Knicker, H. | Chemical structure and preservation processes of organic matter in soils and sediments | 2000 | Soil Organic Carbon | Journal | Org. Geochem.; 31; 607-608 | English | Hardcopy:Full; PDF:Full | Review (v. brief) of current state of humus research | Among the various reasons for the stability of OM in soils is the occurrence of black carbon ..; The role of the mineral phase in OM preservation is increasingly considered ..; .. aromatic structures and polysaccharides can be stabilised by organo-mineral associations. |
| 1383 | Derenne, S. & Largeau, C. | A review of some important families of refractory macro-molecules: composition, origin and fate in soils and sediments | 2001 | Lignin and CBW | Journal | Soil Sci.; 166 (11); 833-847 | English | Hardcopy:Partial | Review of lignin and other refractory substances in soil | Lignins are the second most abundant constituent of vascular plants after polysaccharides. They account for 5 to 10% by weight of leaves .. and for up to 30% of wood.; .. lignin exhibits a higher resistance to microbial degradation than cellulose. It is considered an important precursor of humic substances ..; Lignin is quite resistant under anaerobic conditions .. but it can be degraded aerobically by white-rot and brown-rot fungi, the former being more efficient.; The mineral matrix plays an important role in lignin degradation through its control of the microbial availability of OM. |
| 115 | Derpsch, R. [3 pp. only] | Historical review of no-tillage cultivation of crops | 1998 | Tillage | Book | ; Proc. 1st JIRACS Seminar on Soya-bean Research: No-tillage Cultivation and Future Research Needs; | English | Hardcopy:Partial | The development of zero tillage in Europe is described. Figures are given for the area under zero tillage in various countries. For the U.K. the figure in 1983/84 was 275,000 ha and for 'Others' (including the U.K.) in 1996/97, was 460,000 ha. [paper also on the website: www.rolf-derpsch.com/notill] | The invention of the herbicide Paraquat in 1955 in the United Kingdom was the start of modern no-tillage development in Europe and also world-wide. This discovery led .. I.C.I. to initiate research without soil tillage. In 1973/74 the area under no-tillage in Great Britain increased to 200,000 ha and ten years later to 275,000 ha. Thus the U.K. had the second largest area under no-tillage in the world after the U.S.A. |
| 726 | Desjardins, T., Andreux, F., Volkoff, B. & Cerri, C.C. | Organic carbon and 13C contents in soil size-fractions and their changes due to deforestation and pasture installation in eastern Amazonia | 1994 | Soil Organic Carbon | Journal | Geoderma; 61 (1/2); 103-118 | English | Hardcopy:Partial | Expt. to compare the soil under the native evergreen rainforest and the soil from 10-yr-old grassland on @deforested land. The forest soil had a C content of 81 t ha-1. | The decrease in soil C content which was observed after ten years of pasture appeared to be relatively low when compared with the results often reported about the effects of deforestation .. in the tropics.; .. the oldest SOM pool is considered to be present at the same concentration in any layer of the soil (profile. .. the amount of 2.8 mg g-1 in the 100-200 cm layer represents 42 t ha-1. If this amount is regarded as the stable pool and is converted into t ha-1 in each horizon of the 0-100 cm soil layer, it would represent about 45.2 t ha-1, that is, about 59% of the total C. Since the age decreases linearly toward the soil surface, the proportion of the stable C pool also decreases with the increasing proportion of the labile C pool. Thus, in the upper 20 cm layer the stable pool would represent about 26% of the total and the labile one about 74%. Similarly in the upper 10 cm layer the calculation yields 16% and 84% for the stable and labile fractions respectively. |
| 176 | Devendra, C. & Thomas, D. | Crop-animal systems in Asia: importance of livestock and characterisation of agro-ecological zone | 2002 | Stockless Farming | Journal | Agric. Sys.; 71 (1/2); 5-15 | English | Hardcopy:Full | The significance of animals in the agriculture of South and South-east Asia is explained. Although crops and animals are closely integrated in the mixed farming systems, crop production tends to predominate, especially in the irrigated areas. To meet increasing food requirements production of animal products needs to be developed, especially in the rain-fed areas, which already have greater stocks of animals. Animals increase both financial and food security, as well as providing transport, manure and power on the farm. | Animal production is a major component of the agricultural economy in Asia and its importance exceeds food production alone. Often official statistics underestimate the overall contribution of animals, as they ignore the multipurpose role that livestock play in agricultural production.; Livestock convert plant resources of low nutritive value to high quality products such as meat and milk ..; .. livestock are linked closely to the social, cultural and religious lives of millions of resource-poor farmers ..; Between 43 and 88% of the human population in these countries [of South-east Asia] depend on the agricultural sector for their livelihoods. Small-scale resource-poor farmers own about 95% of the livestock.; [in South Asia] agriculture is a major activity contributing 25-43% to the GDP, with animals contributing 10-45% to the agricultural GDP. This proportion is even higher if values for manure and draught power are included.; In Nepal increasing animal populations and uncontrolled utilisation have resulted in overgrazing, soil erosion (up to about 40 t/ha/year) and forest degradation. |
| 1531 | Dexter, A.R. & Bird, N.R.A. | Methods for predicting the optimum and the range of soil water contents for tillage based on the water retention curve | 2001 | Soil (General); Tillage | Journal | Soil Tillage Res.; 57 (4); 203-212 | English | Hardcopy:Partial | Review of published exptal results on soil water contents with a view to developing methods for the prediction of the soil water content at which tillage may satisfactorily be carried out. | Three water contents are considered: the lower (dry) limit, the optimum water content and the upper (wet) limit.; The effects of tillage are considered in relation to some fixed points, including the lower plastic limit, field capacity and a new fixed point 'the inflection point'. |
| 897 | Diamond, J.M. | Human use of world resources | 1987 | Greenhouse Gases; Sustainability | Journal | Nature (Lond.); 328; 479-80 | English | Hardcopy:Full | A review of the work of Vitousek et al. on the human appropriation of the global net primary product. A table is given, showing the ways in which humans use, divert and reduce the product of photosynthesis. | The resulting estimate [from Vitousek's work] is a global NPP of about 225 Pg [of OM per year].; The total NPP that humans command is 42.6 Pg, of which 7.2 Pg are used directly and 35.4 Pg diverted. This represents 19% of the earth's total NPP: 31% of that on land and 2% of that in the sea.; These reductions in NPP [resulting from human activity] by 17.5 Pg are in addition to the 42.6 Pg .. Hence out total appropriation in .. 60.1 Pg .. This appropriation falls more heavily on the terrestrial NPP (17.5 + 40.6 = 58.1, out of a potential terrestrial NPP of 132.1 + 17.5 = 149.6, or 39%) than on marine NPP (2.0/91.6 = 2%). |
| 1532 | Dick, W.A., Blevins, R.L., Frye, W.W., Peters, S.E., Christenson, D.R., Pierce, F.J. & Vitosh, M.L. | Impacts of agricultural management practices on C sequestration in forest- derived soils of the eastern Corn Belt | 1998 | Organic Farming; Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 47 (3-4); 235-244 | English | Hardcopy:Full; PDF:Full | Long-term field studies of tillage and rotation effects on SOC | One of the most important agricultural management practices controlling C concentrations and amounts in soil in managed agroecosystems is tillage intensity. Amount of organic C in the 0 to 30 cm soil layer .. was 17 Mg ha-1 greater when continuously managed (i.e. for 30 consecutive years) by NT as compared to plough tillage.; .. SOC concentrations (0 to 25 cm soil layer) in the manured plots .. were higher than in non-manured plots ..; Annual manure input ranged from 22 to 67 Mg ha-1 ..; Annual residue inputs to soil were estimated as 10, 6.0, 3.0, 5.5 and 8.0 Mg ha-1 for corn, sugar beet, navy bean, oat and alfalfa respectively . |
| 1208 | Diels, J., Vanlauwe, B., Sanginga, N., Coolen, E. & Merckx, R. | Temporal variations in plant 13C values and implications for using the 13C technique in long-term soil organic matter studies | 2001 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 33 (9); 1245-1251 | English | Hardcopy:Partial | Expt. to test the reliablity of the 13C technique in long-term SOM studies | |
| 689 | Diepenbrock, W. | Yield analysis of winter oilseed rape (Brassica napus L.): a review | 2000 | Rape and Biodiesel | Journal | Field Crops Res.; 67 (1); 35-49 | English | Hardcopy:Partial | Review of research into the yield and yield potential of winter oilseed rape | Analysing the yield of winter oilseed rape revealed considerable potential for further improvement of yield. Duration of growth, rate of production and harvest index are crucial for enhancing biomass and seed yield. During the growth cycle, establishment of the stand, flower initiation, use of radiation and availability of assimilates for pod set and seed filling are decisive factors influencing yield. For breeding purposes physiologically based selection criteria should include light absorption, the LAID until flowering, synchronisation of source and sink capacity and average productivity of pods. |
| 340 | Diepeningen, A.D. van, Vos, O.J. de, Korthals, G.W. & Bruggen, A.H.C. van | Effects of organic versus conventional management on chemical and biological parameters in agricultural soils | 2006 | Organic Farming; Soil (General) | Journal | Appl. Soil Ecol.; 31; 120-135 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare soils on organic and conventional farms | The main differences between the two mgmnt types are the significantly lower levels of both nitrate & total soluble N and the larger species richness in both bacteria and nematodes and higher numbers of bacteria in organic soils.; .. organic farmers plough their fields less deeply and tend to apply more OC to their fields, but this did not result in a significantly higher OC content ..; Soil type - clayey or sandy soil - .. had a much stronger effect on the soil characteristics than management type. |
| 727 | Dignac, M.F., Bahri, H., Rumpel, C., Rasse, D.P., Bardoux, G., Balesdent, J., Girardin, C., Chenu, C. & Mariotti, A. | Carbon-13 natural abundance as a tool to study the dynamics of lignin monomers in soil: an appraisal at the Closeaux experimental field (France) | 2005 | Lignin and CBW; Soil Organic Carbon | Journal | Geoderma; 128; 3-17 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the fate of lignin in soil | .. the proportion of newly derived OC after 9 years of maize cropping .. was 9% for total SOM and 47% for lignin, which displayed faster dynamics in this soil than total OC. This study confirms .. that lignin macromolecules are not stabilised as such in these soils. |
| 1719 | Dignac, M.F., Knicker, H. & Kögel-Knabner, I. | Effect of N content and soil texture on the decomposition of organic matter in forest soils as revealed by solid-state CPMAS NMR spectroscopy | 2002 | Uncategorised | Journal | Org. Geochem.; 33; 1715-1726 | English | PDF:Full | ||
| 1019 | Dilkes, N.B., Jones, D.L. & Farrar, J.F. | Temporal dynamics of carbon partitioning and rhizodeposition in wheat | 2004 | Plant C&N Allocation; Roots & Rhizodeposition | Journal | Plant Physiol. (Rockv.); 134; 706-715 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the exudation of recent photosynthate from plant roots | .. exudation [from roots] is maximal 2 to 3 h after fixation in photosynthesis, xthat exudation is, after 20 h, around 3% of the 14C fixed in photosynthesis and that exudation depends more on the rate of carbon import into the root than on the rate of photosynthesis. |
| 880 | Dill, I., Kraepelin, U., Schultze, U., Reh, U. & Weissleder, I. | The role of nitrogen in white- and brown-rot decay: presentation of an ecological model | 1987 | Lignin and CBW | Journal | Les colloques de l'INRA; 40; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the hypothesis that white- and brown-rot fungi are able to mobilise N from wood and that N availability in wood is the main cause of lignin degradation by white-rot fungi. Wood normally contains less than 3% of N and about half of that is firmly bound in ligno-protein complexes, so it is not freely available to microorganisms. In the case of n-sensitive white-rot fungi N limitation stimulates preferential or selective ligninolysis, which mobilises lignin-bound N. The consequent fungal growth re-establishes N limitation. | |
| 832 | Dilly, O. | Effects of glucose, cellulose and humic acids on soil microbial eco-physiology | 2004 | Soil Microorganisms | Journal | J. Plant Nutr. Soil Sci.; 167 (3); 261-266 | English | Hardcopy:Partial | 20-day lab. expt. to study the effect of substrate quality on microbial activity | Soil respiration was stimulated by the substrate quality in the order: humic acid < cellulose < glucose .. |
| 1209 | Dilly, O. | Microbial respiratory quotient during basal metabolism and after glucose amendment in soils and litter | 2001 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 33 (1); 117-127 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the relationship between CO2 evolved and O2 consumed by the SMB in various soils | @; The microbial respiratory quotient (RQ), defined as the ratio of mol CO2 evolution per mol O2 uptake, ... was frequently <1 during basal metabolism when no substrate was added. This indicates relatively high O2 consumption during the current microbial |
| 530 | Dilly, O., Blume, H.P., Sehy, U., Jimenez, M. & Munch, J.C. | Variation of stabilised, microbial and biologically active carbon and nitrogen in soil under contrasting land use and agricultural management practices | 2003 | Organic Farming; Soil Organic Carbon; Soil N Dynamics | Journal | Chemosphere; 52; 557-569 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the C/N ratios of whole soil, microbial biomass and biologically active C & N (measured by the C & N mineralisation rates) in soils from native forest and grassland and from conventional and organic arable land | .. the mineralisation activity rate .. ranged between 0.11 and 17.67 %g CO2-C g-1 soil h-1 & -0.12 and 3.81 %g (dNH4+ + dNO3-)-N g-1 soil h-1. Negative N data may be derived from both N immobilisation & N volatilisation during the expts. The ratio between C & N mineralisation rates differed significantly between the soils, ranging from 5 [?] to 37, and was not correlated with the soil C/N ratio and Cmic/Nmic ratio. The C/N ratio in the biologically active pool was .. smaller in soils under conventional farming than those under organic farming systems.; .. short-term available C & N compounds control N mineralis'n and the current microbial ecophysiology. In agricultural systems soil C/N ratios frequently ranged between 10 and 12, the microbial C/N ratio was lower and C/N ratio in the biologically active pool varied between -15 [?] and 37.; .. microbial C- and N-use efficiency was frequently higher in soils under conventional and precision farming systems than in those under organic farming systems. |
| 797 | Dinesh, R., Suryanarayana, M.A., Nair, A.K. & Ghoshal Chaudhuri, S. | Leguminous cover crop effects on nitrogen mineralisation rates and kinetics in soils | 2001 | Green Manure; Mineralisation; Soil N Dynamics | Journal | J. Agron. Crop Sci.; 187 (3); 161-166 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to study the N mineralisation rate in soil from a 7-year leguminous green manure, which was ploughed in and re-sown every year | The study .. revealed .. high [N] mineralisation rates during the first week .. thereafter they were below detection limits.; As the more labile org. N disappears & the more recalcitrant org. N predominates in the org. N pool, the mineralisation rate would be expected to slow down.; .. the lignin+polyphenol/ N ratio accounted for maximum variation in the rate of N mineralisation from the cover crops incorporated into the soil.; .. lignin reduces the rate of N mineralisation from decomposing plant materials by forming ligno-protein complexes. .. Soluble phenols may precipitate proteins, thereby inhibiting microbial/enzyme activities essential for N mineralisation. |
| 289 | Dobermann, A., Dawe, D., Roetter, R. & Cassman, K.G. | Reversal of rice yield decline in a long-term continuous cropping experiment | 2000 | Miscellaneous; Soil N Dynamics | Journal | Agron. J.; 92; 633-643 | English | Hardcopy:Partial; PDF:Full | Review of results of 35-year field expt. to study the yields of triple-crop rice | From 1968 to 1991 grain yields declined at an annual rate of 1.4-2.0%. From 1991 to 1995, dry-season yields in the highest N treatment increased to within 80 to 100% of the simulated yield potential; yields in the unfertilised control did not increase.; N deficiency caused the yield decline before 1991. |
| 833 | Domanski, G., Kuzyakov, Y., Siniakina, S. & Stahr, K. | Carbon flows in the rhizosphere of ryegrass (Lolium perenne) | 2001 | Plant C&N Allocation; Roots & Rhizodeposition | Journal | J. Plant Nutr. Soil Sci.; 164 (4); 381-387 | English | Hardcopy:Partial | Lab. expt. to study the carbon allocation and soil respiration of ryegrass | 14C in CO2 efflux from soil was detected as early as 30 min after labelling.; The partitioning of assimilated C was completed .. 5 days after assimilation. .. we calculated the amount of assimilated C during 47 days of growth at 256 g C m-2. Of this amount 122 g C m-2 were allocated to below ground, shoots retained 64 g C m-2 and 70 g C m-2 were lost from the shoots due to respiration. Roots were the main sink for belowground C.. they accounted for 74 g C m-2, while 28 g C m-2 `were respired & 19 g C m-2 were found as residual 14C in soil & microorganisms.; [100%, 48%, 25%, 27%, 29%, 11% and 7% of gross assimilated C respectively] |
| 1533 | Domzal, H., Hodara, J., Slowinska-Jurkiewicz, A. & Turski, R. | The effects of agricultural use on the structure and physical properties of three soil types | 1993 | Soil (General); Tillage | Journal | Soil Tillage Res.; 27; 365-382 | English | Hardcopy:Partial | Comparison of the properties of soils from natural forest and from agricultural systems with low and high levels of mechanisation. The agricultural use of forest soils results in an increase in BD and a reduction in water capacity and air permeability. | Full mechanisation of field operations over many years leads to additional increase of compaction .. as well as to further deterioration of the structure and physical properties of soils. This effect is stronger in soil with a small content of humic compounds .. |
| 394 | Donaldson, J.V.G., Hughes, J. & Leake, A.R. | The influence of cropping sequences and rotational management on energy use for machinery operations and crop production | 1996 | Energy in Agriculture; Organic Farming; Tillage | Journal | Aspect. Appl. Biol.; 47; 383386 | English | Hardcopy:Full | Calculation of energy used for grain production in organic, integrated (reduced tillage) and conventional (plough tillage) farming systems. Average energy use for winter wheat was 72.46, 39.84 and 51.16 kWh/ton | ... the mechanical energy use per hectare is far less under IFS than in crops grown conventionally. This is mainly due to savings ... through non-inversion tillage ...; The organic system at Stoughton compared unfavourable, although there are obviously large savings in outside energy inputs, as no pesticides or mineral fertilisers are used. There are also some savings in machinery energy, but the low level of output, <50% of conventional or IFS regime, means that a lot more machinery energy goes into each ton produced. |
| 395 | Donaldson, J.V.G., Hutcheon, J.A. & Jordan, V.W.L. | Evaluation of energy usage for machinery operations in the development of more environmentally benign farming systems | 1994 | Energy in Agriculture; Organic Farming; Tillage | Journal | Aspect. Appl. Biol.; 40; 87-91 | English | Hardcopy:Full | Calculation of energy use in conventional and integrated cereal production | ... savings in energy have been obtained in less intensive and integrated farming systems that use minimum tillage techniques for crop establishment compared with conventional production systems that are ploughed.; Low input systems for both rotations show considerable reductions in energy inputs over the standard farm practice: 19% on the conventional and 13% on the integrated ... |
| 341 | Donegan, K.K., Palm, C.J., Fieland, V.J., Porteous, L.A., Ganio, L.M., Schaller, D.L., Bucao, L.Q. & Seidler, R.J. | Changes in levels, species and DNA fingerprints of soil microorganisms associated with cotton expressing the Bacillus thuringiensis var. kurstaki endotoxin | 1995 | Miscellaneous | Journal | Appl. Soil Ecol.; 2 (2); 111-124 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of cotton plants, genetically engineered to produce Bacillus thuringinesis var. kurstaki endotoxin, on soil microorganisms | Although the generally transitory stimulation in microbial populations that was observed from the transgenic 247 and 249 cotton plants may not be of environmental concern, the accompanying change in the microbial species composition, with a potential impact on soil processes, may be of ecological significance.; Our results emphasise the importance of performing risk assessment studies for transgenic plants under a variety of environmental conditions. |
| 887 | Donnelly, P.K., Entry, J.A., Crawford, D.L. & Cromack, K. | Cellulose and lignin degradation in forest soils: response to moisture, temperature and acidity | 1990 | Lignin and CBW; Soil Organic Carbon | Journal | Microb. Ecol.; 20; 289-295 | English | Hardcopy:Partial | Expt. to study the factors affecting the rate of degradation of cellulose and lignin. There was a significant correlation between soil moisture, microbial biomass and the rates of cellulose and lignin degradation. | The concentration of lignin in plant tissue is a major factor controlling OM degradation rates in forest ecosystems.; .. cellulose decomposition was substantially higher than lignin decomposition.; Lignin degradation by wood decay fungi is known to be dependent on an additional source of C. As the additional C source is decomposed, both cellulose and lignin degradation rates should decrease. .. formation of humic compounds during decomposition will result in a residual C matrix more resistant to decomposition. |
| 212 | Doran, J.W. | Soil health and global sustainability: translating science into practice | 2002 | Soil (General); Sustainability | Journal | Agric. Ecosyst. Environ.; 88; 119-127 | English | Hardcopy:Full | The case is made for the importance of soil quality/health in the sustainability of agricultural systems and the need for simple indicators of soil quality/health that can be used by farmers to assess the sustainability of their practices. Some proposed indicators are: SOM changes with time, depth of topsoil and rooting, percentage of soil that has a protective cover and soil electrical conductivity as an index of leachable salts like nitrates. | .. SOM serves as a primary indicator of soil quality and health for both scientists and farmers.; Research is needed to help [farmers] assess the sustainability of agricultural management using indicators of soil quality and health to which they have access. |
| 1534 | Doran, J.W., Elliott, E.T. & Paustian, K. | Soil microbial activity, nitrogen cycling and long-term changes in organic carbon pools as related to fallow tillage management | 1998 | Soil Organic Carbon; Soil Microorganisms; Tillage | Journal | Soil Tillage Res.; 49 (1-2); 3-18 | English | Hardcopy:Full; PDF:Full | Long-term study of the microbial, C and N content of two soils (one that was broken from sod immediately before the start of the expt. and the other that had been under cultivation for 30 years) under a wheat-fallow rotation and various tillage treatments. | No-till management resulted in a different environment for biological activity near the soil surface, which was often cooler and wetter than that with conventional tillage .. Consequently biological activity and org. C reserves were also concentrated near the soil surface with no-tillage and there was greater potential for immobilisation of plant available N in organic forms. |
| 728 | Dorioz, J.M., Robert, M. & Chenu, C. | The role of roots, fungi and bacteria on clay particle organisation. An experimental approach | 1993 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Geoderma; 56 (1/4); 179194 | English | Hardcopy:Partial | Expt. to study the effects of living organisms on the structure of clay. The initiation & stabilis'n of microaggregates was favoured by the secretion of polysaccharides from roots, fungi & bacteria, as well as by mycelia networks entangling the clay and roots and hyphae causing compaction of the clay particles | |
| 213 | Douds, D.D., Galvez, L., Franke-Snyder, M., Reider, C. & Drinkwater, L.E. | Effect of compost addition and crop rotation point upon VAM fungi | 1997 | Compost & Biocontrol; Organic Farming; Soil Microorganisms | Journal | Agric. Ecosyst. Environ.; 65; 257-266 | English | Hardcopy:Partial | An expt. comparing the development of VAM fungus on three plots fertilised solely with conventional fertiliser, raw FYM and compost respectively. The compost was made from animal manure and leaves. The application of compost significantly increased the spore populations of two VAM fungus species groups, but populations of other groups were not affected. If the rate of compost application is calculated on the basis of the N requirement of the crop, other nutrients may be in excess, especially P. As this accumulates in the soil from year to year, it depresses the levels of VAM fungi, as does the inclusion of non-mycorrhizal plants in a rotation (e.g. spinach or peppers). | |
| 214 | Douds, D.D., Galvez, L., Janke, R.R. & Wagoner, P. | Effect of tillage and farming system upon populations and distribution of vesicular-arbuscular mycorrhizal fungi | 1995 | Soil Microorganisms; Tillage | Journal | Agric. Ecosyst. Environ.; 52 (2-3); 111-118 | English | Hardcopy:Partial | Inconclusive expt. in which V.A.M. fungi on maize roots were examined under various treatments ranging from ploughing to zero tillage in both conventional and low-input systems. Populations of some fungal species were higher and others lower under all treatments and in both systems. | |
| 898 | Downie, A. | Fixing a symbiotic circle | 1997 | Green Manure | Journal | Nature (Lond.); 387; 352-354 | English | Hardcopy:Partial; PDF:Full | Review of current research on bacterial plasmids in Rhizobium | ... rhizobia grow slowly for long periods in soil, but, if they infect a compatible legume, they can grow rapidly. Successful infection by a single bacterium can lead to the formation of a nitrogen-fixing nodule on the root of the legume, containing over 108 bacterial progeny. |
| 91 | Drinkwater, L.E. | Using plant species composition to restore soil quality and ecosystem function | 1999 | Green Manure; Organic Farming; Tillage | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Review of cropping system variations that can improve soil quality | Common short-comings of intensive cropping systems include: insufficient C additions to maintain SOM, the return of only low-quality high-C senescent organic residues to the soil, nutrient inputs that exceed harvested exports, excessive tillage or tillage at a time that exposes soil to wind and water erosion, rotations that include long fallow periods and use of temporal monocultures.; Although organically-managed systems routinely use many practices that are known to build soil fertility while reducing negative environmental impacts, tillage regimes in annual production systems remain intensive.; Small grains .. and legumes tend to promote aggregation to a greater extent than many cash crops. |
| 1031 | Drinkwater, L.E., Janke, R.R. & Rossoni-Longnecker, L. | Effects of tillage intensity on nitrogen dynamics and productivity in legume-based grain systems | 2000 | Green Manure; Organic Farming; Tillage | Journal | Plant Soil; 227 (1/2); 99-113 | English | Hardcopy:Full; PDF:Full | Long-term expt. to compare maize under org. & conv'l mgmt, & various tillage systems in respect of yield, N dynamics & weed control. With ploughing and chiselling similar yields of maize were obtained under org. & conv'l mgmnt. But the org. zero tillage plots did not give yields that were comparable with the conv'l ones. .. maize yields were 80% down. This may have been due to weed competition, as well as to low plant densities of both green manure and maize. | .. there is no doubt that annual legumes can provide adequate N for subsequent cash crops under conv'l tillage. However, the incorp'n of these low C/N residues frequently results in very rapid net release of min. N shortly after incorp'n, when plant uptake is still minimal.; .. large pools of nitrate resulting from rapid net mineralisation of [green manure] residues .. would be susceptible to leaching in years with rainy springs.; .. in green-manured systems without primary tillage, N limitations frequently occur and mineralisation of adequate N for uptake by the cash crop at the appropriate time is a major concern. |
| 545 | Drinkwater, L.E., Letourneau, D.K., Workneh, F., Bruggen, A.H.C. van & Shennan,C. | Fundamental differences between conventional and organic tomato agro-ecosystems in California | 1995 | Organic Farming | Journal | Ecol. Appl.; 5 (4); 1098-1112 | English | Hardcopy:Full | Expt. to compare organic and conventional agricultural systems | .. differences were demonstrated in many soil, plant, disease and diversity indicators, suggesting that the ecological processes determining yields and pest levels in these two management systems are distinct. .. N mineralisation potential and microbial and parasitoid abundance and diversity were higher in org. farms.; .. soil fertility management practices affected C & N dynamics and had cascading effects on plant-pathogen [and possibly plant-herbivore] interactions .. Increased labile C pools resulted in greater microbial activity in org. soils, contributing to root pathogen suppression through mechanisms such as microbial antagonism or competition. .. org. fertility regimes were associated with reduced tissue N levels and decreased susceptibility to root disease .. |
| 899 | Drinkwater, L.E., Wagoner, P. & Sarrantonio, M. | Legume-based cropping systems have reduced carbon and nitrogen losses | 1998 | Green Manure; Organic Farming; Stockless Farming | Journal | Nature (Lond.); 396; 262-265 | English | Hardcopy:Full | A comparison of three systems, fertilised with chemicals, FYM and leguminous green manure respectively, showed significant differences in the rate of accumulation of C and N in the soil over a fifteen-year period. The rate of C accumulation was highest in the animal manure system, about half as high in the legume system and insignificant in the conventional system. The soil N accumulation in the legume and animal manure systems was roughly equal when expressed as a proportion of the surplus of N input over export in each case. Soil N accumulation in the conventional system was negative. | Quantitative differences in net primary productivity and N balance across agroecosystems do not account for the observed changes in soil C and N. .. the use of low-C/N organic residues to maintain soil fertility ..increases the retention of soil C and N, which has important implications for regional and global C and N budgets.; Application of these practices in the major maize/soya bean growing region in the USA would increase soil C sequestration by 0.13 - 0.30 x 1014 g/yr. This is equal to 1-2% of the estimated annual C released into the atmosphere from fossil fuel combustion in the USA. .. The potential effects on the N cycle are much greater .. . |
| 1416 | Drury, C.F., Tan, C.S., Reynolds, W.D., Welacky, T.W., Weaver, S.E., Hamill, A.S. & Vyn, T.J. | Impacts of zone tillage and red clover on corn performance and soil physical quality | 2003 | Green Manure; Tillage | Journal | Soil Sci. Soc. Am. J.; 67 (3); 867-877 | English | Hardcopy:Partial | Expt. to study whether zone tillage could improve yields in comparison with zero tillage on fine-textured soil in cool humid climates. Zone tillage is a modification of zero tillage in which a narrow strip, 10-20 cm wide and 10-30 cm deep, is conventionally tilled in the crop row, leaving the rest of the soil untilled. | .. grain yield was the greatest under the zone-tillage treatment, .. intermediate under the conventional tillage treatments and lowest under the notillage treatments.; The optimal BD for root growth in fine-textured soils is .. 0.8 to 1.2 Mg m-3 and root growth often stops completely in clayey soils at about 1.5 Mg m-3. The [zone tillage] treatment had .. among the lowest BD in each .. year, while the two no-tillage treatments often had the greatest BD.; The air-filled porosities ranged from 0.14 to 0.20 m3 m-3 .. These values are .. near or above the suggested minimum of 0.15 m3 m-3 for adequate near-surface aeration in the root zone of clayey soils.; Saturated hydraulic conductivity values in hthe range 10-2 to 10-5 cm s-1 may provide an optimum between the competing needs for rapid sorption into the soil matrix of needed crop-available water and rapid drainage of excess water that could cause water-logging and associated aeration deficits. |
| 1599 | Duijn, C.M. van, Delasnerie-Lauprętre, N., Masullo, C., Zerr, I., de Silva, R., Wientjens, D.P., Brandel, J.P., Weber, T., Bonavita, V., Zeidler, M., Alpérovitch, A., Poser, S., Granieri, E., Hofman, A. & Will, R.G. | Case-control study of risk factors of Creutzfeld-Jakob disease in Europe during 1993-95 | 1998 | Miscellaneous | Journal | Lancet; 351(9109); 1081-1085 | English | Hardcopy:Full | A study of the factors increasing the risk of contracting CJD | .. a significant increase in risk of CJD was found for cases exposed to leather products and fertiliser containing hoofs and horns. .. the consumption of brain and raw meat were associated with an increased risk of CJD. No association was found with the consumption of beef, veal, lamb, cheese or milk .. |
| 1093 | Duncan, R.C. | World energy production, population growth and the road to the Olduvai Gorge | 2001 | Energy Resources | Journal | Popul. Environ.; 2 (5); | English | Hardcopy:Full; PDF:Full | Modelling the global human economy (based on a development of Forrester's 1972 World3 model) leads to almost the same results as Forrester's, namely, that industrial civilisation ([arbitrarily ?] defined as having started in 1930) will last just over 100 years and will peak in 2013. Per capita global oil production peaked in 1979. Global oil production, the growth rate of which has been decreasing since 1973, will peak in 2006. The proportion of oil produced by the OPEC nations is increasing and will pass the 50% mark in 2008. The Olduvai Theory asserts that the decline of industrial civilisation will take place in three stages: the slide (1979-2000), started by the decline of global per capita energy production, the slope, started by the end of cheap energy and the outbreak of violence in the Middle East, and the cliff, started by an epidemic of worldwide electricity blackouts, leading to the collapse of C3 (communication, computation and control) and eventually the expiry of the electric power networks. This will cause the decline of global per capita energy production, which, by 2030, will have fallen to 3.32 barrels of oil equivalent per year - the same value that it had in 1930. We are then back in the Dark Ages. | If God made the Earth for human habitation, then He made it for the Stone Age mode of habitation. |
| 267 | Dunin, F.X., Williams, J., Verburg, K. & Keating, B.A. | Can agricultural management emulate natural ecosystems in recharge control in south eastern Australia? | 1999 | Miscellaneous | Journal | Agrofor. Syst.; 45; 343-364 | English | Hardcopy:Partial; Wordperfect:Full | Review of the possibilities of designing agricultural systems that can restore the hydrological balance of natural ecosystems | Many of our current production systems are not ecologically sustainable because they leak water and nutrients which, in turn, may result in waterlogging, salinity and soil acidification.; Woody perennials offer a progressive mining of deep soil water over time to generate buffer sizes that may exceed lucerne by as much as 100 mm at a specific site.; Hydraulic lift is now a widely accepted phenomenon whereby deep soil water is uplifted along the translocation pathway during summer stress to be diverted into shallow roots to maintain turgor and function. |
| 173 | Durham, S. | Plastic mulch; harmful or helpful? | 2003 | Mulch | Journal | Agric. Res.; ; 14-16 | English | Hardcopy:Full | Exptal comparison between plastic mulch and hairy vetch in respect of the amount of pesticide in run-off, which was found to be less with living mulches than with plastic | |
| 8 | Ebertseder, T., Gutser, R. & Claassen, N. | Parameters to estimate the nitrogen effect of biogenic waste composts | 1996 | Compost & Biocontrol; Soil N Dynamics | Book | Bertoldi, M. de, Sequi, P., Lemmes, B., & Papi, T. (eds.); The science of composting; | English | Hardcopy:Full; Wordperfect:Full | Field and lab. expts to assess the effect of compost on nitrogen availability in compost-fertilised soils | @; The ratio of total organic C to total N of composts ... is relatively well correlated with their N effect in soil. However, [it] depends on the raw materials and management of composting. Therefore it cannot be used as the only parameter for calculatin |
| 215 | Edwards, L., Burney, J.R., Richter, G. & MacRae, A.H. | Evaluation of compost and straw mulching on soil-loss characteristics in erosion plots of potatoes in Prince Edward Island, Canada | 2000 | Compost & Biocontrol; Mulch; Tillage | Journal | Agric. Ecosyst. Environ.; 81 (3); 217-222 | English | Hardcopy:Partial; PDF:Full | Field trials were carried out for 3 years, using composted potato waste/ manure/sawdust and a mulch of barley straw in conventional potato growing. Compost application made no difference to soil shear strength, aggregate stability or soil loss. It reduced soil penetration resistance and increased soil moisture by 7% and, on sandy soils, increased potato yield by 7.5 Mg/ha. Mulch did not affect the potato yield or the aggregate stability or penetration resistance of the soil, but it increased soil moisture by 6% and decreased soil loss by 49%. | There seems to be little, arising from this study, to justify the use of compost as a soil amendment.; Spreading compost is tedious because of its bulk and its imposition on the farming schedule.; Not only is it tedious to spread the mulch post-planting, but just how much of it will stay on the surface under windy conditions before plant emergence or hilling is another matter.; .. while it takes reduced tillage to achieve maximum residue-cover effectiveness, for a row crop like potatoes reduced tillage is agronomically inimical to high tuber yields and wide acceptance is, therefore, unlikely. |
| 177 | Edwards-Jones, G. & Howells, O. | The origin & hazards of inputs to crop protection in organic farming systems: are they sustainable? | 2001 | Sustainability | Journal | Agric. Sys.; 67 (1); 31-47 | English | Hardcopy:Partial | Soil Association-approved pesticides and supplementary fertilisers are assessed for sustainability. Despite the high energy costs, the non-renewable inputs and the toxicity of some permitted pesticides and fertilisers, organic farming is probably more sustainable that conventional farming. | .. crop protection activities associated with organic farming are not sustainable in an absolute sense and organic farms are subject to the same class of non-sustainable characteristics as conventional farms. |
| 378 | Eggert, C., Temp, U. & Eriksson, K. | The ligninolytic system of the white rot fungus Pycnoporus cinnabarinus: purification and characterisation of the laccase | 1996 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 62 (4); 1151-1158 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the secretion of laccase by white-rot fungi, the ligninolytic activity of which is correlated with the secretion of three peroxidases: lignin peroxidase (LiP), manganese peroxidase and laccase | Laccase production by P. chrysosporium seems to be repressed by glucose, .. but laccase activity was detectable when the fungus was grown on cellulose. .. a great number of white rot fungi seem to efficiently degrade wood without the production of LiP .. The mechanism by which lignin is broken down in the absence of LiP, an enzyme with an exceptionally high oxidation potential, remains a mystery.; P. cinnabarinus represents a common type of white rot fungus, devoid of LiP but in possession of laccase in combination with a peroxidase of lower redox potential. Although P. cinnabarinus appears to lack enzymes having the high oxidation potential thought to be necessary for the depolymerisation of the major non-phenolic structures of lignin, it very efficiently degrades the lignin in wood.; Laccase production by P. cinnabarinus was less sensitive to high concentrations of N than is known for production of phenoloxidases in ligninolytic systems of most other white rot fungi. High concentrations of glucose in low-N cultures (C/N ratio 25) led to accumulation of an extracellular polysaccharide which strongly interfered with enzyme extraction from the medium. A similar effect has been demonstrated in P. chrysosporium, in which low-nitrogen high-glucose conditions trigger the synthesis of an extracellular b-1,3-glucan. |
| 33 | Ehaliotis, C. & Giller, K.E. | Nitrogen mineralisation induced by the disturbance of soils from adjacent old pastures and arable fields | 1995 | Mineralisation; Soil N Dynamics; Tillage | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; | English | Hardcopy:Full | Field expt. to compare the amount of N mineralisation resulting from soil disturbance in old pastures with that in adjacent arable fields | The mean amounts of nitrogen mineralised were from two-fold to three-fold greater in the old pastures ...; The difference was attributed to larger amounts of readily available organic substrates being physically protected in the old pasture soils and to greater microbial populations being sustained in old pasture oils, which were partly killed buy disturbance. |
| 1210 | Ehaliotis, C., Cadisch, G. & Giller, K.E. | Substrate amendments can alter microbial dynamics and N availability from maize residues to subsequent crops | 1998 | Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (10/11); 1281-1292 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of various amendments (bean residue; 4.4% N, KNO3 and cellulose) on the decomposition of maize (0.35% N) in soil over 5 cropping cycles. The bean residue treatment resulted in a 35% increase in maize-residue N recovery compared with the control, while the KNO3 treatment resulted in a 16% decrease. Cellulose application reduced availability of soil and residue to plants but the effect only lasted for one cropping cycle. Rather than a priming effect, the bean residue showed a pool-substitution effect, in which bean N substituted for maize N in the microbial metabolites being stabilised in the soil. | .. adding high quality plant residues can greatly enhance short- and long-term recovery of N from poor quality residues by plants without exploiting soil N. |
| 568 | Ehrenfeld, J., Parsons, W.F.J., Han, X.G., Parmelee, R.W. & Zhu, W.X. | Live and dead roots in forest soil horizons: contrasting effects on nitrogen dynamics | 1997 | Roots & Rhizodeposition; Soil N Dynamics | Journal | Ecology; 78 (2); 348-362 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of live and dead roots on the rates of ammonification and nitrification in the organic and mineral horizons of a podsol | In mineral soil live roots stimulated ammonification rates but had little effect on extractable N, and the stimulation occurred only if an organic surface horizon was present. In contrast, live roots in organic material reduced both ammonification rates and extractable N. Dead roots increased extractable N in the mineral material, but not the organic material. The presence or absence of an organic horizon had a dominating effect on all aspects of nitrogen dynamics in the mineral soil; not only extractable inorganic N, but also transformation rates, were higher in soils under OM.; Nitrate and nitrification were both extremely low ... In the organic material nitrification accounted for <5% of net mineralisation, but was a larger fraction (up to 70%) of total mineralisation in the mineral soil. |
| 1107 | Ehrlich, P.R. & Kennedy, D. | Millennium assessment of human behaviour | 2005 | Sustainability | Journal | Science; 309; 562-563 | English | Hardcopy:Full; Wordperfect:Full | Proposal for the establishment of an international forum (the MAHB) to discuss the problems of human behaviour as they affect the global ecosystem | A growing scientific consensus says that global society is under increasing threat from the impact of human activities .. Some of these problems require attention from governments and other social institutions. But it is the collective actions of individuals that lie at the heart of the dilemma. Analysis of individual motives and values should be critical to a solution.; The steps that most members of the relevant scientific community believe are necessary (e.g. reduction of .. greenhouse gas emissions, .. limiting human population growth and per capita consumption) are disconnected from those measures the rest of society, and especially politicians, are willing to undertake.; .. the MAHB courts criticism for naivety. |
| 888 | Eiland, F., Klamer, M., Lind. A.M. & Bĺĺth, E. | Influence of initial C/N ratio on chemical and microbial composition during long-term composting of straw | 2001 | Compost & Biocontrol | Journal | Microb. Ecol.; 41 (3); 272-280 | English | Hardcopy:Partial; PDF:Full | 1-year expt. to study the effect of C/N ratio on the composting of Miscanthus straw with varying amounts of added pig slurry. After 3 months the high-C/N lots showed a lesser degree of cellulose degradation (10-20%) than the low-C/N lots (40-69%), but after 12 months their microbial biomass and respiration rates were relatively high compared with the low-C/N lots and they had a higher F/B This could be because the low-C/N lots, which generated more heat in the initial stages of the composting, quickly exhausted the easily available carbon, which was therefore lacking at the stage of re-colonisation of the heap by fungi. | Lignin was not degraded in any of the treatments.; .. samples taken after 6 months .. were suitable for plant growth .. [hence] all composts were mature |
| 963 | Ekblad, A., Nyberg, G. & Högberg, P. | 13C-discrimination during microbial respiration of added C3-, C4- and 13C-labelled sugars to a C3-forest soil | 2002 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Oecologia; 131; 245-249 | English | Hardcopy:Full; PDF:Full | Field expt. to test whether 13C-discrimin'n takes place during microbial respir'n | x; .. our results confirm that any 13C-discrimin'n during microbial respiration of @glucose & sucrose is minor. This implies that 13C-discrimin'n due to factors such as isotopic exchange during CO2-diffusion in the soil atmosphere is also minor. |
| 1535 | Ekeberg, E. & Riley, H.C.F | Effects of mouldboard ploughing and direct planting on yield and nutrient uptake of potatoes in Norway | 1996 | Potato Growing; Tillage | Journal | Soil Tillage Res.; 39; 131-142 | English | Hardcopy:Partial | Field expt. to test the effects of zero tillage on potato yield. Potatoes were planted directly into barley stubble and ridged. | .. the same .. quality was achieved with no tillage ..; The nutrient uptake of the plants was increased by direct planting.; The yield curve to direct planting was steeper, crossing that of conventional tillage on approx. 10 September, thus predicting higher tuber yield for direct planting when harvesting occurred after this date .. |
| 774 | Ekman, S. | Tillage system selection: a mathematical programming model incorporating weather variability | 2000 | Tillage | Journal | J. Agr. Eng. Res.; 77 (3); 267-276 | English | Hardcopy:Partial | A farm-level mathematical programming model to analyse the economics of alternative tillage and cropping systems. The modelling technique used is discrete stochastic sequential programming. | .. a tillage system characterised by lower capital and labour requirements may be as profitable as a conventional system despite lower crop yields. |
| 729 | Ekschmitt, K., Liu, M.Q., Vetter, S., Fox, O. & Wolters, V. | Strategies used by soil biota to overcome soil organic matter stability - why is dead organic matter left over in the soil? | 2005 | Soil Organic Carbon; Soil Microorganisms | Journal | Geoderma; 128; 167-176 | English | Hardcopy:Full; PDF:Full | Review of factors determining the accessibility of SOM to microbial decomposers | .. we classify OM pools [into] passive v. active stabilisation & partial v. absolute refuge... in temperate soils a dominant quantity of org. material resides in the passive stabilisation/partial refuge status & persists in spite of being accessible & decomposable. .. SOM is stabilised by a complex of mechanisms that constrain decompos'n rates, several of which are not based on substrate quality or soil conditions, but on the biology of the decomposing soil organisms. |
| 342 | Elfstrand, S., Bĺth, B. & Mĺrtensson, A. | Influence of various forms of green manure amendment on soil microbial community composition, enzyme activity and nutrient levels in leek | 2007 | Green Manure; Soil Microorganisms | Journal | Appl. Soil Ecol.; 36; 70-82 | English | Hardcopy:Partial; PDF:Full | Field expt. to study how soil microorganisms and the activity of soil enzymes are influenced by different forms of green manure amendment (fresh or composted, incorporated or mulched) | .. fresh red clover residues, especially direct incorporation of a red clover crop, enhanced microbial biomass and soil enzyme activities more than processed green manure forms.; An initial increase in abundance of bacteria and fungi was observed after direct incorporation and amendment with red clover-derived slurry and compost, but amendment with fresh red clover sustained a higher bacterial and fungal biomass until the end of the cropping season. Mulching stimulated arbuscular mycorrhizal (AM) fungi at the end of the cropping season. |
| 1650 | Ellen, R. | Environment, Subsistence and System - the Ecology of Small-scale Social Formations | 1982 | Agricultural Ecology | Book | Ellen, R.; Environment, Subsistence and System - the Ecology of Small-scale Social Formations; 130-153 | English | Hardcopy:Full | Various mainly primitive societies are compared in respect of their food production and energy consumption | .. the functioning of culture as a whole rested on, and was determined by, the amount of energy produced and the ways in which it was put to work.; The total amount of energy produced by a population consists of the food yield and the calorific equivalent of other things produced or appropriated, such as crops produced for export and consumed as fuel.; .. total ecological effort .. must strictly speaking include all energy expended by a population.; A standard measure of efficiency is energy production divided by total human energy expenditure.; We are accustomed to associating economic development and cultural evolution with an increase in productive efficiency, but this is only the case if measured solely in terms of human energy expenditure.; .. efficiency is not to be measured in energy ratios alone. .. Nuaulu hunting .. provides a negative calorie return. The importance of the activity lies not in calories but in the provision of high-quality protein and nutrients .. |
| 513 | Ellert, B.H. & Bettany, J.R. | Calculations of organic matter and nutrients stored in soils under contrasting management regimes | 1995 | Soil Organic Carbon; Tillage | Journal | Can. J. Soil Sci.; 75 (4); 529-538 | English | Hardcopy:Partial | Expt. to study the effects of different crops (wheat and maize) and tillage (ploughed and zero tillage) on the storage of C and nutrients in the soil. Attention is drawn to the unreliability of figures for element (C, N, etc.) concentrations in the soil that do not take account of the varying BD of the soil. Examples are given from a paper by Doran. | .. ca. 15% of SOC originally present under forest vegetation was lost after 80 yr of annual cropping. |
| 1384 | Ellert, B.H. & Gregorich, E.G. | Storage of carbon, nitrogen and phosphorus in cultivated and adjacent forested soils of Ontario | 1996 | Phosphorus Cycling; Soil Organic Carbon; Soil (General) | Journal | Soil Sci.; 161 (9); 587-603 | English | Hardcopy:Partial | Field study of 15 arable sites and adjacent forest sites to compare their C, N and P stocks. On average the surface layer of the cultivated soils had 34% less C, 19% less N and 24% more P than the adjacent forest soils. Increase in P storage and narrowing of C/N ratios (12.4 against 16.2) in cultivated oils was a result of fertilisation. | .. from Eastern Qu)bec .. 30 to 35% of C originally present in the A and B horizons of native soils was lost after cultivation for 30 years or more .. soil C under perennial grasses was similar to or greater than that originally present under native forest vegetation. |
| 514 | Elliot, J.A. & Efetha, A.A. | Influence of tillage and cropping system on soil organic matter, structure and infiltration in a rolling landscape | 1999 | Tillage | Journal | Can. J. Soil Sci.; 79(3); 457463 | English | Hardcopy:Partial | A comparison of a continuously cropped zero tilled field (ZTCC) with a conventionally tilled field under a crop-summer fallow rotation (CTCF). Soil quality was better in many respects on the ZTCC field than on the CTCF. | SOC, aggregate size and aggregate stability were significantly greater on the ZTCC plot than the CTCF.; [There was] substantially more run-off from the CTCF plot than the ZTCC.; As a consequence the CTCF plot is more susceptible to wind and water erosion and has lower inherent fertility than the ZTCC plot. |
| 1417 | Elliott, E.T. | Aggregate structure and carbon, nitrogen and phosphorus in native and cultivated soils | 1986 | Soil Organic Carbon; Soil (General) | Journal | Soil Sci. Soc. Am. J.; 50 (3); 627-633 | English | Hardcopy:Partial | An expt. to examine the stability of soil aggregates and properties of occluded OM | The structure of soil protects SOM & influences OM turnover & soil fertility.; three types of physical units .. exist in mineral soil: free primary particles (i.e. sand, silt & clay), microaggregates & macroaggregates. .. three types of cementing agents [are] responsible for soil aggregation: (i) transient, composed of microbial- and plant-derived polysaccharides, which are rapidly decomposed by microbes; (ii) temporary, including roots and hyphae, especially mycorrhizal, and (iii) persistent: aromatic humic material in association with amorphous Fe & Al compounds.. Persistent binding agents are .. mainly responsible for microaggregates, which range in size from 50 to 250 m [and which] can become united to form macroaggregates through the action of temporary and transient binding agents and are generally 250 m to 2 mm in size.; The loss of OM resulting from cultivation comes chiefly from the organic material that binds individual microaggregates into macroaggregates, not from OM within microaggregates, a high proportion [of which is] more highly processed, humified old, passive or recalcitrant fractions.; There was more OM associated with macroaggregates and it was more labile than that associated with microaggregates. |
| 1676 | Ellis, F. | Peasant Economics: Farm Households in Agrarian Development | 1988 | Agricultural Ecology | Book | Ellis, F.; Peasant Economics: Farm Households in Agrarian Development; | English | Hardcopy:Partial | farming systems of various types are examined from an economic viewpoint | |
| 92 | Eltun, R. & Nordheim, O. | Yield results during the first eight years crop rotation of the Apelsvoll cropping system experiment | 1999 | Organic Farming | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | 8-year field expt. to compare organic and conventional farming systems | The average grain yields of barley in the [organic] systems .. were .. 67% of the [conv'l] system .. Wheat grain yields showed an even greater yield reduction than barley with ecological as compared to conv'l cropping, while a mixture of oats & peas gave higher yield than barley in ecological cropping. The grain protein content & grain size in ecologically grown wheat were lower than in conventionally grown wheat. For potatoes, root and forage crops the yield reduction incurred by .. ecological cropping was smaller than for cereals .. a change from conv'l to .. ecological cropping is easier to achieve in mixed farming systems with livestock than in arable farming systems without livestock. |
| 216 | Eltun, R., Korsaeth, A. & Nordheim, O. | A comparison of environmental, soil fertility, yield and economical effects in six cropping systems based on an 8-year experiment in Norway | 2002 | Organic Farming; Sustainability | Journal | Agric. Ecosyst. Environ.; 90; 155-168 | English | Hardcopy:Partial; PDF:Full | Comparison of conventional, integrated and organic arable and livestock farms (CON-A & -F, INT-A & -F, ECO-A & -F) in an 8-year expt.. On the arable farms the organic cereal and potato yields were 65% and 85% of the conventional yields respectively. | On the basis of nutrient run-off, soil erosion and pesticide contamination, the following ranking from the most to the least favourable was made for environmental effects: INT-F > ECO-F > ECO-A > INT-A > CON-F > CON-A.; .. biological activity seems to be a key explanation of the fact that ecological farming is easier to achieve in a mixed farming system than in an arable one.; Under most Norwegian growing conditions the nutrient mineralisation early in the growing season is limited resulting in insufficient nutrient supply in ecological cereal cropping; .. the yields in ecological farming will stabilise at a significantly lower level than the yields obtained formerly with conventional farming. |
| 1685 | Engle, T.E., Ames, D.R. & Enns, M. | Stress factors of farm animals and their effects on performance | 2002 | Greenhouse Gases | Website | www.colostate.edu/depts/aes (Colorado State University) | English | Hardcopy:Partial | An assessment, based on figures from the literature, of greenhouse gas emissions from cattle farms (beef and dairy). Enteric and manure CH4 emissions from dairy xcows are about 3500 and 1800 kg CO2 equiv. per year per cow respectively. Manure @CH4 emission could be as high as 2600 kg CO2 equiv. per year per cow if anaerobic slurry tanks are used. Total GHG emissions from beef cattle units average 4140 kg CO2 equiv. per cow over the lifetime of the animal (say, 2 years). Of this 50% is CH4 and 40% is N2O. | .. calves .. weighing approximately 230 kg .. fed .. for 56 days or until they reach an approximate weight of 360 kg.; The GHG emissions to produce milk .. are estimated at 1590 g of CO2 equivalent per kg of milk. Enterically produced CH4 is 33% and manure CH4 17% of this total, leaving 50% from other sources, e.g. fertiliser, fuel, soil-C, etc. .. best management practices for crop production could reduce the total by an estimated 14% through increased soil-C sequestration. |
| 1211 | Enwall, K., Nyberg, K., Bertilsson, S., Cederlund, H., Stenström, J. & Hallin,S. | Long-term impact of fertilisation on activity and composition of bacterial communities and metabolic guilds in agricultural soil | 2007 | Organic Farming; Soil Microorganisms | Journal | Soil Biol. Biochem.; 39; 106-115 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of different fertilisers on soil microorganisms | The fertilisation regimes had clear effects on both activity and composition of the soil communities. Basal respiration and r, which was kinetically derived as the exponentially growing fraction of the SIR-response, correlated well with the SOC content. Soil pH ... was found to be an important factor influencing all `microbial activities. pH correlated negatively with the [qCO2], indicating a decreased efficiency of heterotrophic microorganisms to convert org. C into microbial biomass in the most acid soils with pH 3.97 & 4.68 ((NH4)2SO4 & sewage sludge fertilised plots respectively).; The F/B biomass ratio has been suggested to affect the qCO2 and an increasing F/B ratio with decreasing pH has been H observed .. We found a clear correlation between the F/B ratio ... and the qCO2 measured in our study. ... a switch towards a more fungal-dominated microbial biomass could constitute part of the observed effect of pH on the qCO2. |
| 569 | Epstein, H.E., Lauenroth, W.K., Burke, I.C. & Coffin, D.P. | Productivity patterns of C3 and C4 functional types in the U.S. Great Plains | 1997 | Plant C&N Allocation; Miscellaneous | Journal | Ecology; 78 (3); 722-731 | English | Hardcopy:Partial | Study of the climatic and soil factors determining the ranges of C3 and C4 grasses in the U.S.A. 67-85% of the variation in relative and absolute production of C3 and C4 grasses could be explained by temperature, precipitation and soil texture. Production of C4 grasses was positively related to temperature, precipitation and soil sand content and negatively to clay content. Relative production of C3 reaches zero in the range from 17.5$C at 40 cm to 12$C at 110 cm mean annual temperature and precipitation respectively. Relative production of C4 grasses does not reach zero within the U.S.A. (but does in Canada, close to the boundary between grassland and boreal forest). | |
| 126 | Eriksen, J., Askegaard, M. & Vinther, F.P. | Nitrogen cycling in an organic dairy crop rotation: effects of organic manure type and livestock density | 1996 | Soil N Dynamics | Book | Raupp, J. (ed.); Symbiotic nitrogen fixation in crop rotations with manure fertilisation, Proc. 3rd mtg (concerted action AIR3-CT94-1940); | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to measure the N flows on an organic dairy farm | @; Nitrate leaching ranged from 12 to 100 kg ha-1 and was highest in the first years after ploughing-in the grass-clover pasture .. N balances not including atmospheric N fixation showed a deficit in legume-containing crops... it was estimated that this d |
| 1418 | Eswaran, H., Berg, E. van den & Reich, P. | Organic carbon in soils of the world | 1993 | Greenhouse Gases; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 57 (1); 192-194 | English | Hardcopy:Full | An estimate of the total weight of organic C in the world's soils. Other figures are quoted to give a breakdown of the global reserves of C: vegetation - 550 Pg C, soil - 1500, atmosphere - 750, oceans - 38,000, fossil fuels - 4000, giving a total of 44,800 Pg C. | Globally 1576 Pg of C is stored in soils, with 506 Pg (32%) of this in soils in the tropics. .. 40% of the C in the soils of the tropics is in forest soils. .. deforestation can result in 20 to 50% loss of this stored C, largely through erosion. |
| 1536 | Etana, A., Hĺkansson, I., Zagal, E. & Bucas, S. | Effects of tillage depth on organic carbon content and physical properties in five Swedish soils | 1999 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 52 (3-4); 129-139 | English | Hardcopy:Partial; PDF:Full | Study of the effect on the SOC content under different depths of mouldboard ploughing in five long-term tillage expts. | Increased depth of primary tillage reduced the concentration of SOM in the tilled layer .. Within the range of tillage depths studied (12-29 cm) the depth in itself did not affect the total content of organic C in the soil. .. Tillage depth did not affect the C/N ratio. |
| 974 | Eusterhues, K., Rumpel, C., Kleber, M., Kögel-Knabner, I. | Stabilisation of soil organic matter by interactions with minerals as revealed by mineral dissolution and oxidative degradation | 2003 | Soil Organic Carbon | Journal | Org. Geochem.; 34 (12); 1591-1600 | English | Hardcopy:Full; PDF:Full | Chemical treatment of soils to determine the amount and concentration of stabilised OM | @; .. soil samples were exposed to oxidation with Na2S2O8 .. young C is removed preferentially by this treatment. The fraction remaining after oxidation represents a certain stabilised long-residence-time C pool. [which] comprises between 1 and 30% of the |
| 858 | Eve, M.D., Sperow, M., Howerton, K., Paustian, K. & Follett, R.F. | Predicted impact of management changes on soil carbon storage for each cropland region of the conterminous United States | 2002 | Greenhouse Gases; Tillage | Journal | J. Soil Water Conserv.; 57 (4); 196-204 | English | Hardcopy:Partial | Estimating the effect on soil C storage of various changes in agricultural practices, including adoption of zero tillage, increased crop residue inputs, eliminating bare fallow, putting into set-aside and conversion to permanent grassland. Averaged over all regions of the U.S. the estimated rate of soil C accumulation was 1.141, 0.462, 0.325, 0.325 and 0.678 Mg C ha-1 yr-1 for conversion to permanent grassland, putting into set-aside, increasing crop residue input, adoption of zero tillage and a combination of increasing residue input and zero tillage respectively. | The IPCC method uses a tillage factor to account for the effects of tillage management on agricultural soils. The use of no-till is assumed to increase soil C by 10% (a tillage factor of 1.1) over conventional tillage systems ..; Through intensive cultiv'n for crop production 30% to 70% of the soil C that occurred in these soils under native veg'n has been lost to the atmosphere. |
| 268 | Ewel, J.J. | Natural systems as models for the design of sustainable systems of land use | 1999 | Sustainability | Journal | Agrofor. Syst.; 45 (1/3); 1-21 | English | Hardcopy:Partial; PDF:Full | Review of reasons for using natural ecosystems as models for the design of sustainable agriculture to mimic nature | Natural ecosystems, whose components are the results of natural selection, are sustainable .. Thus, they are appropriate models on which to base the design of new systems of land use.; .. it pays to imitate natural systems rather than struggle to impose simplicity on ecosystems that are inherently complex. The keys to success are to (i) channel productivity into outputs of nutritional and economic importance, (ii) maintain adequate diversity to compensate for losses in a system simple enough to be horticulturally manageable, (iii) manage plants and herbivores to facilitate associational resistance and not associational susceptibility and (iv) use perennial plants to maintain soil fertility, guard against erosion and make full use of resources.; .. much high-yield agriculture is not sustainable because its practice consumes non-renewable environmental capital, especially soil and ancient groundwater. .. Native ecosystems are timeproven survivors and it is logical to learn from them and imitate their useful traits. .. [they] are long-term products of evolution and the accommodation of organisms to environment: they change with time, as both environment and biota change, and they run on solar power, thus making them self-sustaining. |
| 9 | Ezelin, K., Brun, G., Kaemmerer, M. & Revel, J.C. | Glucose influence on the asymbiotic nitrogen fixation during lignocellulosic waste composting | 1996 | Compost & Biocontrol; Soil N Dynamics | Book | Bertoldi, M. de, Sequi, P., Lemmes, B., & Papi, T. (eds.); The science of composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the effect of addition of glucose on nitrogen fixation during the composting of woody waste | The main limiting factor [to N-fixing] was then the absence of C sources adapted to the requirements of the various microbial populations ... an easily degradable compound such as glucose promotes the activity of the N2-fixers, which `include also cellulolytic microorganisms.; .. without glucose no N2-fixation phase was observed.; .. no effect of phosphorus deficiency was observed in the free-living N2-fixers. |
| 1108 | Falkowski, P., Scholes, R.J., Boyle, E., Canadell, J., Caneld, D., Elser, J., Gruber, N., Hibbard, K., Högberg, P., Linder, S., Mackenzie, F.T., Moore III, B., Pedersen, T., Rosenthal, Y., Seitzinger, S., Smetacek, V. & Steffen, W. | The global carbon cycle: a test of our knowledge of earth as a system | 2000 | Greenhouse Gases; Soil Organic Carbon | Journal | Science; 290; 291-296 | English | Hardcopy:Partial; PDF:Full | Review of the mechanisms of the oceanic and terrestrial C cycles | x; Terrestrial net primary production is not saturated by present atmospheric CO2 @concentrations. Consequently, as atmospheric CO2 increases, terrestrial plants are a potential sink for anthropogenic carbon. The principal carbon-fixing enzyme in plants is ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco). In C3 plants the activity of rubisco increases with increasing CO2 concentrations, `saturating between 800 and 1000 ppmv CO2, a concentration that will probably be reached early in the next century at the present emissions rate.; ... increased temperature will probably lead to higher microbial heterotrophic respiration, which may counteract and even exceed the enhancement of NPP.; ... the feedbacks between C and other biogeochemical & climatological processes will lead to weakened sink strengths in the foreseeable future and the prospects of retrieving anthropogenic CO2 from the atmosphere by enhancing natural sinks are small. |
| 457 | Falloon, P.D. & Smith, P. | Modelling refractory soil organic matter | 2000 | Soil Organic Carbon | Journal | Biol. Fertil. Soils; 30 (5-6); 388-398 | English | Hardcopy:Full; PDF:Full | Review of current SOM models, particularly in relation to recalcitrant fractions. Estimates of their size and age from various authors average 2500 years and 30% of total SOC. | Most models for the turnover of SOM include a compartment that is either considered inert or has a very slow turnover time (refractory SOM).; True IOM [inert OM] is not biologically decomposable and therefore has no decomposition rate. .. IOM is a pool uncoupled from the other SOM pools and is effectively a constant. .. IOM remains unaffected by changes in climate, land use or management and, whilst its size is of importance, it cannot, by definition, act as a sink for atmospheric CO2.; A wide range of compounds (e.g. acid-hydrolysis residues, humin, humic acids, and interlayer organic complexes) .. have been identified as highly resistant components of SOM ..; .. attempts to relate physical and chemical fractionations to SOM model pools have had mixed success. Problems related to fractionation of SOM are illustrated by the .. light fraction OM [which] is generally considered labile, but may include charcoal (which is considered refractory), due to its low density. |
| 1212 | Falloon, P.D., Smith, P., Coleman, K. & Marshall, S. | Estimating the size of the inert organic matter pool from total soil organic carbon content for use in the Rothamsted carbon model | 1998 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 30 (8/9); 1207-1211 | English | Hardcopy:Full; PDF:Full | Estimating the quantity of inert OM (IOM) in soils on the basis of data from 28 long-term expt'l sites. The average IOM content was 6.4 t C/ha (4.2 and 9.4 for arable & forest soils respectively). The average age and size of the recalcitrant fraction from figures reported in the literature was 2400 years and 30% of total SOC. | In RothC IOM represents a small, stable and biologically inert fraction of soil C, which has a high radiocarbon age .. of more than 50,000 yr.; Chemically it is .. a mixture .. of charcoal .., coal and OM trapped irreversibly in the soil.; It may be that a substantial part of IOM is not truly inert, but of a very great turnover time. |
| 1213 | Fang, C. & Moncrieff, J.B. | The dependence of soil CO2 efflux on temperature | 2001 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 33 (2); 155-165 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the temperature & moisture dependence of soil respiration | .. soils showed an exponential increase in respiration rate with temp. No optimal temp for soil respiration was found with soil temp up to 32$C. The influence of soil moisture content .. was not obvious. |
| 1109 | Fang, J., Chen, A., Peng, C., Zhao, S. & Ci, L. | Changes in forest biomass carbon storage in China between 1949 and 1998 | 2001 | Energy Resources; Greenhouse Gases | Journal | Science; 292; 2320-2322 | English | Hardcopy:Full | Estimating the C storage in Chinese forests. The C content of tree biomass is taken as 50%. A formula is given for the conversion of volume of timber to biomass. The C density of natural forests averaged 48 Mg/ha. That of planted forest increased from 15 to 31 Mg/ha in about 20-25 yrs. | |
| 546 | Fang, J., Wang, G.G., Liu, G. & Xu, S. | Forest biomass of China: an estimate based on the biomass-volume relationship | 1998 | Energy Resources; Greenhouse Gases | Journal | Ecol. Appl.; 8 (4); 1084-1091 | English | Hardcopy:Full | Estimating the total (above- and belowground) biomass of China's forest. A C content in the biomass of 50% was assumed. The ratio of aboveground to belowground biomass averaged 4.6, ranging from 2.9 for oak to 7.5 for eucalyptus @plantation. The density of timber averaged 0.9 Mg/cm3. The average area-weighted biomass density was 84 Mg/ha, including 91 and 145 Mg/ha for oak and tropical forest respectively. The corresponding average figures for Europe and the U.S.A. were 64 and 122 Mg/ha respectively. | |
| 934 | Farrar, J.F. & Jones, D.L. | The control of carbon acquisition by roots | 2000 | Plant C&N Allocation; Roots & Rhizodeposition | Journal | New Phytol.; 147 (1); 43-53 | English | Hardcopy:Full; PDF:Full | Review of factors controlling the transport of carbon from shoot to root | The .. hypothesis that acquisition of C by roots is controlled by a range of variables distributed between root & shoot accords with both expt. & theory .. 2 levels of mechanistic control, short-term regul'n of phloem transport & control of gene-expression by cpds such as sugars, underlie distributed control. |
| 570 | Farrar, J.F., Hawes, M., Jones, D.L. & Lindow, S. | How roots control the flux of carbon to the rhizosphere | 2003 | Plant C&N Allocation; Roots & Rhizodeposition | Journal | Ecology; 84 (4); 827-837 | English | Hardcopy:Full; PDF:Full | Review of the factors controlling the flow of C from the roots into the soil | Roots lose metabolites & signal molecules to the soil at rates of significance to soil organisms ..; .. carbon flow to the rhizosphere is a function of root growth. .. the control over the rate at which roots grow is shared between root and shoot, with most control being in the shoot. |
| 217 | Feber, R.E., Firbank, L.G., Johnson, P.J. & MacDonald, D.W. | The effects of organic farming on pest and non-pest butterfly abundance | 1997 | Miscellaneous; Organic Farming | Journal | Agric. Ecosyst. Environ.; 64 (2); 133-139 | English | Hardcopy:Partial | Field expt. to compare the abundance of butterflies on organic and conventional farms | ... more non-pest butterflies were recorded on organic than on conventional farmland ... more non-[pest butterflies were recorded over the uncropped boundary habitat than over the crop edge habitat in both systems ... there was no significant difference ... in the abundance of two pest species ... between the two systems. |
| 730 | Feller, C. & Beare, M.H. | Physical control of soil organic matter dynamics in the tropics | 1997 | Soil Organic Carbon | Journal | Geoderma; 79; 69-116 | English | Hardcopy:Partial | Review of the literature on OM dynamics in tropical soils | Three primary groups of tropical soils can be distinguished, based on mineralogy: (1) kaolinitic/halloyistic or low-activity clay soils .. , (2) smectitic or high-activity clay soils .. , and (3) more or less allophanic soils .. with large amounts of amorphous or crypto-crystalline minerals.; .. in tropical soils .. 20-40% of the SOC is associated with the sand-size (POM) fraction as compared with 2-14% for many temperate examples.; .. greater than 50% of SOC associated with the clay fraction and derived from native vegetation may be lost after clearing and cultivation over a period of 10-20 years. |
| 343 | Feng, G., Song, Y.C., Li, X.L. & Christie, P. | Contribution of arbuscular mycorrhizal fungi to utilisation of organic sources of phosphorus by red clover in a calcareous soil | 2003 | Phosphorus Cycling; Soil Microorganisms | Journal | Appl. Soil Ecol.; 22 (2); 139-148 | English | Hardcopy:Partial | The results of an expt. to test the P uptake of plants with and without AM fungi when the soil outside the root zone was treated with one inorganic and three different inorganic sources of P. Non-mycorrhizal plants showed no difference between the four P sources, but mycorrhizal plants did differ. | At the third harvest, the contribution from KH2PO4 was 23%, while those from lecithin, RNA and sodium phytate [organic sources] were 23, 17 and 31%, respectively. |
| 1214 | Fierer, N. & Schimel, J.P. | Effects of drying-re-wetting frequency on soil carbon and nitrogen transformations | 2002 | Soil Microorganisms; Soil (General) | Journal | Soil Biol. Biochem.; 34 (6); 777-787 | English | Hardcopy:Partial | Expt. to test the effect of wetting and re-wetting on soil microbial communities in soils taken from oak forest and annual grassland | @; Exposure to frequent drying-re-wetting events decreased the amount of CO2 released upon re-wetting and dramatically increased the activity of autotrophic nitrifier populations. For up to 6 weeks after the last drying-re-wetting cycle, respiration rates |
| 218 | Filip, Z. | International approach to assessing soil quality by ecologically related biological parameters | 2002 | Soil (General) | Journal | Agric. Ecosyst. Environ.; 88; 169-174 | English | Hardcopy:Full | A summary of results of a project to test an approach to assessing soil quality, using biol. & biochem. criteria. The sensitivity of some criteria to anthropogenic effects on the soil was tested. The population of N-fixing bacteria, dehydrogenase activity & the processes of nitrification/denitrification & respiration (CO2 release) were found to be the most sensitive. A catalogue of soil organisms and their ecologically important activities is presented. | Soil quality is understood as an integral value of compositional structures and natural functions of soil in relation to soil use & environmental conditions .. |
| 834 | Filip, Z., Pecher, W. & Berthelin, J. | Microbial utilisation and transformation of humic acids extracted from different soils | 1999 | Soil Organic Carbon; Soil Microorganisms | Journal | J. Plant Nutr. Soil Sci.; 162 (2); 215-222 | English | Hardcopy:Partial | Lab. expt. to study the consumption of humic acid (HA) by aerobic cultures of soil microorganisms | .. between 14% & 86% of the added HA was utilised. The formation of microbial biomass was enhanced up to 6-fold in the full-strength nutrient media supplemented with HA, but was strongly inhibited if HA served as the sole C source. HA preparations re-isolated from the microbial cultures exhibited elemental and structural changes characteristic of early diagenetic transformations of humic substances. These included an increase in carbon content, C/N ratio and infrared absorption typical of aromatics and a decrease in infra-red absorption associated with aliphatic acids, nitrogenous and carbohydrate-like substances. |
| 1032 | Filser, J., Fromm, H., Nagel, R.F. & Winter, K. | Effects of previous intensive agricultural management on microorganisms and the biodiversity of soil fauna | 1995 | Soil Microorganisms | Journal | Plant Soil; 170 (1); 123-129 | English | Hardcopy:Partial | Field expt. to compare two plots under cereal crops, one of which had been under rotation and the other under a monoculture of hops, which involved spraying with copper. Populations of meso- and microfauna and of microorganisms were much lower in the hop field than in the rotation one in the first year of cereals (although specific respiration rate, which is a stress indicator, was higher), but by the second year all populations had recovered except the earthworms, which are very sensitive to copper contamination. There is conflicting evidence suggesting that earthworm activity may reduce the net N mineralisation rate because of the immobilisation of N by microorganisms that increase dramatically in the earthworm gut. | |
| 34 | Fisher, A., Bailey, R.J. & Williams, D.J. | Growing potatoes using a bed-planting technique | 1995 | Potato Growing | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 561-568 | English | Hardcopy:Full | Field expt. to test the growing of potatoes on flat beds | .. there is a yield advantage to be gained from growing potatoes in beds in certain situations. .. beds can be advantageous on light soils. ..improved water retention or efficiency of use is at least partly responsible. |
| 818 | Flavel, T.C. & Murphy, D.V. | Carbon and nitrogen mineralisation rates after application of organic amendments to soil | 2006 | Compost & Biocontrol; Soil Organic Carbon; Soil N Dynamics | Journal | J. Environ. Qual.; 35; 183-193 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the rates of C & N mineralisation in soil amended with various composts | @; There was a highly significant relationship between CO2-C evolution and gross N mineralisation.; The amount of gross N mineralised was .. significantly related to the total C and N, cellulose, lignin, ash and NO3--N contents of the amendments.; .. appl |
| 835 | Flessa, H., Ludwig, B., Heil, B. & Merbach, W. | The origin of soil organic carbon, dissolved organic carbon and respiration in a long-term maize experiment at Halle, Germany, determined by 13C natural abundance | 2000 | Soil Organic Carbon | Journal | J. Plant Nutr. Soil Sci.; 163 (2); 157-163 | English | Hardcopy:Partial | Field expt. to study the accumulation & mineralication of C in a maize field | After 37 years of continuous maize cropping, 15% of the total SOC in the topsoil originated from maize C. The fraction of maize-derived C below the ploughed horizon was only 3%-5%. The total amount of maize C stored in the profile was 9080 kg ha-1, which was .. about 31% of the estimated total C input via maize `residues (roots & stubble). The total CO2-C emission for 16 weeks was 18 g m-2. (58% of the soil respiration originated from maize C. The specific CO2 formation from maize-derived SOC was 8 times higher than that from the older SOC formed by C3 plants. |
| 1215 | Flessa, H., Potthoff, M. & Loftfield, N. | Greenhouse estimates of CO2 and N2O emissions following surface application of grass mulch: importance of indigenous microflora of mulch | 2002 | Greenhouse Gases; Mulch; Soil Microorganisms | Journal | Soil Biol. Biochem.; 34 (6); 875-879 | English | Hardcopy:Full; PDF:Full | 7-week lab.expt. to study the decomposition of a grass mulch on soil. Unless water stress or nutrient deficiency strongly reduces the activity of phyllosphere microflora, they predominate in the decomposition of surface-applied easily biodegradable N-rich mulches and autochthonous soil microbes have no effect. Substantial NH3 loss from N-rich mulches has been reported but evidence for increase N2O emis`sions is conflicting. In this expt only 0.3% of the applied N was lost as N2O. | |
| 219 | Flessa, H., Ruser, R., Dörsch, P., Kamp, T., Jimenez, M.A., Munch, J.C. & Beese, F. | Integrated evaluation of greenhouse gas emissions (CO2, CH4, N2O) from two farming systems in southern Germany | 2002 | Greenhouse Gases; Organic Farming | Journal | Agric. Ecosyst. Environ.; 91; 175-189 | English | Hardcopy:Partial; PDF:Full | Calculating the total greenhouse gas emissions from two farms - one conventional @and one organic. The aggregate emissions from the farms were 4.2 and 3.0 Mg CO2 equiv. per ha. respectively. Because of different crop rotations a strict comparison between the two farms was not possible, but, taking into account the lower yields from the organic farm, the emissions per unit yield were probably about equal. | (; N2O emissions from agriculture are estimated to account for more than 75% of the total global anthropogenic emission, the major part being produced in soils as an intermediate during nitrific'n & denitrific'n.; Agriculture and related activities account for about two-thirds of all anthropogenic CH4 emissions.; .. in systems with more intensive cattle production (2-3 animal units per hectare) .. CH4 emission from enteric fermentation & waste mgmt is the major contribution to the total emission of greenhouse gases.; .. livestock husbandry is a key factor determining GHG emission related to food production. This is due to the direct emissions from animals and animal wastes and, more importantly, to the low N efficiency of meat production, since about 80-95% of the N intake with feed is excreted as dung and urine. Therefore, the reduction of crop production for animal husbandry in favour of human nutrition represents one of the most efficient measures for mitigating greenhouse gas emissions from agriculture. |
| 638 | Flessa, H., Wild, U., Klemisch, M. & Pfadenhauer, J. | Nitrous oxide and methane fluxes from organic soils under agriculture | 1998 | Greenhouse Gases | Journal | Eur. J. Soil Sci.; 49; 327-335 | English | Hardcopy:Partial | Expt. to study the gas fluxes from cultivated drained peatland | .. peatlands are converted from sinks to sources of C and N by a lowering of xthe water table. .. Emissions of CH4 are much reduced after drainage. .. The @release of N2O generally increases after drainage. N2O is produced as an intermediate in denitrification and it is a by-product of nitrification.; .. large losses of N2O can occur from acid fen soils. The major part of the total annual emission occurred in the winter. .. Maximum emission rates occurred when temperatures fell below freezing point.; Due to intensive drainage all sites (were a net sink for atmospheric CH4. CH4 consumption was significantly affected by the kind of land use, with 4-5 times larger uptake on the intensively rooted meadows than on the arable sites. |
| 1002 | Fließbach, A., Dubois, D., Esperschütz, J., Gunst, L., Mäder, P., Oberholzer, H.R., Schloter, M., Gattinger, A. | Soil microbial community structure & OM transformation processes in org. & conv. farming systems | 2005 | Biodynamic Farming; Soil Organic Carbon; Soil Microorganisms | Website | Paper presented at Int. Sci. Conf. on Organic Agriculture, Adelaide | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the SOM accumulation and microbial biomass in soils under differing agricultural management | Roughly 20% of the initial SOM was lost when no manure was applied for 21 years as in the CONMIN and the NOFERT system, whereas SOM increased slightly by 4% in the BIODYN system, which used composted farmyard manure .. The BIOORG and the CONFYM systems lost about 7%. Soil microbial biomass .. revealed higher values in organically fertilised plots. Bacterial and eukaryotic biomasses followed the order: CONMIN < CONFYM = BIOORG = BIODYN. |
| 134 | Fließbach, A., Eyhorn, F., Mäder, P., Rentsch, D.I. & Hany, R. | DOK long-term farming systems trial: microbial biomass, activity and diversity affect the decomposition of plant residues | 2001 | Biodynamic Farming; Organic Farming; Soil Microorganisms | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Long-term field expt. to study the composition and degradation of OM in different farming systems | Crop yields were lower in the org. as compared with the conv'l farming systems: by 20% for winter wheat & up to 40% for potatoes. SOM & pH were markedly higher in the BIODYN system compared with the conventional and the unmanured systems; Even though total SOM differs between org. & conv'l agricultural systems, no substantial changes in the chemical compos'n ... were detectable. .. Labile SOM pools (SMB, light-fraction POM) indicated distinct changes in SOM dynamics. |
| 1216 | Fließbach, A., Mäder, P. | Microbial biomass and size-density fractions differ between soils of organic and conventional agricultural systems | 2000 | Biodynamic Farming; Organic Farming; Soil Microorganisms | Journal | Soil Biol. Biochem.; 32; 757-768 | English | Hardcopy:Full; PDF:Full | Expt. to compare the microbial activity and aggregation in soils under conventional and organic management | .. the amount of macro-OM (>150 m) is controlled by soil management, while the amount of C associated with clay and silt particles is controlled by soil texture. .. light fraction OM is sensitive to changes in C-input and can be used as an early indicator of management changes.; Among all the fractions, C/N ratios were smallest in the biodynamic soils.; Microbial biomass C & N as well as their ratios to the total and light fraction C & N pools in soils of the org. systems were higher than in conventional systems.; The metabolic efficiency of a microbial community is supposed to be reflected by their specific respiration rate. For the current study, qCO2 was lower in organic compared to conventional soils and since the substrate use diversity in organic soils has been found to be higher than in conventional ones, the hypothesis that a more diverse community has a higher metabolic efficiency is supported by our data. |
| 1217 | Fließbach, A., Mäder, P. & Niggli, U. | Mineralisation and microbial assimilation of 14C-labelled straw in soils of organic and conventional agricultural systems | 2000 | Biodynamic Farming; Organic Farming; Soil Microorganisms | Journal | Soil Biol. Biochem.; 32; 1131-1139 | English | Hardcopy:Partial; PDF:Full | Expt. to study the decomposition of straw in soil from org. & conv. systems. 4 treatments were used: untreated, chemical fertilisers only, FYM plus chemical fertilisers & biodynamic. The 2 latter treatments received FYM at the same rate based on 1.4 LU ha-1. The substrate-use efficiency (14Cmic/[14Cmic+14CO2-C]) was 0.30, 0.27, 0.30 and 0.34 for the four treatments respectively. Their Cmic/Corg ratios were 1.7%, 1.3%, 1.7% and 2.1% by weight respectively. | `The microbial respiration to microbial biomass ratio (qCO2 ) .. indicates the (energy needed for maintenance of microbial biomass. .. A high qCO2 .. indicates that nutrients are recycled quickly.; Microbial biomass C of the conventional soil was only 64% that of the biodynamic soils. .. crop yields in the BIODYN system were about 18% lower than in CONFYM. |
| 56 | Fluck, R.C. | Energy of human labour | 1992 | Energy in Agriculture | Book | Fluck, R.C. (ed.); Energy in Farm Production, vol. 6 of: Stout, B.A. (ed.), Energy in World Agriculture; 31-37 | English | Hardcopy:Full | The energy cost of human labour is calculated in two different ways - one, in the case of agriculture using no fossil fuels, is based on the energy of metabolised food, and the other, in the case of agriculture where fossil fuels are used, is based on the energy embodied in labour. | For primitive agricultural systems which [that?] consume no fossil fuel inputs it appears that a method based upon the energy of metabolised food is justifiable. .. the energy produced as a result of our work must suffice for all our .. activities. .. the total energy content of all food .. should be used under these circumstances. Where use of fossil fuels is prevalent, that energy subsidises all activities, including agricultural labour. Therefore the energy of human labour is the energy sequestered in labour. It appears that the netenergy analysis method is preferable since it includes only the energy sequestered in labour and excludes the remainder of energy which is instead sequestered in other goods and services of final consumption. |
| 178 | Fluck, R.C. | Energy productivity: a measure of energy utilisation in agricultural systems | 1979 | Energy in Agriculture | Journal | Agric. Sys.; 4; 29-37 | English | Hardcopy:Full | Energy productivity is defined and is advocated as a better measurement of agricultural efficiency than the energy ratio. The energy ratio (the ratio of energy output to energy input) is criticised for being inappropriate in the production of food, which is not only for energy, but even more so in the production of fibre and 'ornamentals'. Energy productivity (the ratio of the weight of agricultural product to the energy required to produce it) is more appropriate, although it is limited by being specific to each product. | .. foods are consumed for other reasons than their energy content only. .. In developed countries food is a form of entertainment, business function, a social amenity, a psychological escape or a form of peer acceptance. Only rarely is it used primarily as a source of nourishment ..; [it is wrong to infer] that in industrialised agriculture a ratio of less than unity is unacceptable .. farming for energy must be energetically sound, but there is no reason why farming for other products should cost less energy than is produced.; Comparisons have been made of the energy ratio of different agricultural products and of different cultures or agricultural systems. Such comparisons are meaningless and misleading.; Energy productivity is specific to each agricultural product, location and time. .. energy productivity can be used only to compare alternative production systems .. which result in the same product, at the same place, at the same time. |
| 1651 | Fluck, R.C. & Baird, C.D. | Agricultural Energetics | 1980 | Energy in Agriculture; Labour and Animal Power | Book | Fluck, R.C., & Baird, C.D.; Agricultural Energetics; | English | Hardcopy:Full | The energy inputs and the application of energy analysis to agriculture are examined (general review). The energy expended by labour is evaluated from different points of view (pp. 98-105). The energetics of greenhouse growing and transport from warmer climates, of mechanisation and manual labour and of crops and livestock are all compared. | Lifestyle support energy .. is the total energy sequestered in the services consumed by the farm worker and .. family.; Net energy analysis .. involves a dis-aggregation of the GNP into its components and estimation of the energy content and portion of each consumed as feed back to provide labour.; .. the energy sequestered in all United States agricultural labour in 1974 is estimated to be 594 MJ.d-1 [which] is approximately 45 times the value heretofore most widely used, 13 MJ.d-1, based on food caloric energy consumption.; .. 10 to 25 times as much energy is required for heating greenhouses as for trucking .. a given quantity of tomatoes [from Florida or Mexico to New York].; Greenhouse tomatoes required 50.3 MJ.kg-1 whereas field-grown required 0.9 MJ.kg-1.; Man is not competitive on an energetics basis with machinery .. |
| 443 | Fog, K. | The effect of added nitrogen on the rate of decomposition of organic matter | 1988 | Lignin and CBW; Soil Organic Carbon | Journal | Biol. Rev. (Camb.); 63; 433-462 | English | Hardcopy:Partial | Review of research on the effect of added N on the decompos'n rate of OM. In a survey of various substrates the effect of N addition was to retard decompos'n in all cases except deciduous leaf litter and FYM (slight). With cellulose the effect is always to accelerate decomposition and with lignin to slow it down. | .. the negative effect of addition of N can last for several years.; .. some data indicate that not all N immobilised is actually necessary for the decomposers.; .. for decomposition of straw at two different levels of added N .. at both levels nearly all N supplied was immobilised .. at the high N level the rate of decomposition was slightly lower than at the low level i.e. the extra N was not necessary for microbial activity - it was a luxury uptake. |
| 1110 | Foley, J.A., Fries, R. de, Asner, G.P., Barford, C., Bonan, G., Carpenter, S.R., Chapin, F.S., Coe, M.T., Daily, G.C., Gibbs, H.K., Helkowski, J.H., Holloway, T., Howard, E.A., Kucharik, C.J., Monfreda, C., Patz, J.A., Prentice, I.C., Ramankutty, N. & Snyder, P.K. | Global consequences of land use | 2005 | Sustainability | Journal | Science; 309; 570-574 | English | Hardcopy:Full; PDF:Full | Review of ecological consequence of human land use and how it can be improved | We face the challenge of managing trade-offs between immediate human needs and maintaining the capacity of the biosphere to provide goods and services in the long term.; Since 1850 roughly 35% of anthropogenic CO2 emissions resulted directly from land use.; .. anthropogenic nutrient inputs to the biosphere from fertilisers and atmospheric pollutants now exceed natural sources .. Human activities now appropriate nearly one third to one half of global ecosystem (production.; Global water withdrawals now total 3900 km3 yr-1 or 10% of the total global renewable resource and the consumptive use of water (not returned to the watershed) is estimated to be 1800 to 2300 km3 yr-1. Agriculture alone accounts for 85% of global consumptive use. |
| 1537 | Follett, R.F. | Soil management concepts and carbon sequestration in cropland soils | 2001 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 61 (1-2); 77-92 | English | Hardcopy:Partial | Review of the use of management techniques to increase SOM accumulation in the U.S.A. | |
| 859 | Follett, R.F. & Delgado, J.A. | Nitrogen fate and transport in agricultural systems | 2002 | Mineralisation; Soil N Dynamics | Journal | J. Soil Water Conserv.; 57 (6); 402-408 | English | Hardcopy:Full | Review of current knowledge about the N cycle. The active pool, slow pool and passive pool of SOM are defined. Figures are given on the recycling of forage N by livestock and the fate of fertiliser N. | Soil bacteria are integral to the immobilisation and mineralisation of SON .. Heterotrophic organisms use SOC as a source of energy, driving the aminisation and ammonification processes. Autotrophic nitrosomonas transform the ammonium to nitrite and nitrobacter transform the nitrite to nitrate. Bacteria obtain energy through the oxidation of these compounds.; Global N fixation from the use of legumes in agriculture [is estimated] at 40,000 Gg N/year.; Nitrate is a negatively charged ion repelled by the negatively charged clay mineral surfaces in soil.; .. over 50 years more than 80% of the N applied to a field will eventually return to the atmosphere through denitrification .. greater than H 95% .. as N2 gas but some unknown amount as N2O. |
| 1419 | Follett, R.F., Paul, E.A., Leavitt, S.W., Halvorson, A.D., Lyon, D. & Peterson, G.A. | Carbon isotope ratios of great plains soils and in wheat-fallow systems | 1997 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 61 (4); 1068-1077 | English | Hardcopy:Partial | Natural C isotope abundance methods were used to compare the SOM in samples taken from various sites, including two long-term field expt.s, which had been cultivated since 1909 and 1970 respectively. On the former site, by 1993, in the 0 to 15 cm depth, the total SOC and the native-vegetation-derived SOC had decreased to 61% and 46% of their original 1909 values respectively and about 24% of the SOC was from winter wheat. | .. continuous cultivation initially depletes near-surface soil-C stocks and, with increasing time of cultivation deeper soil-C stocks are depleted.; .. the 13C in the SOC in native grassland surface and sub-surface soils from the Great Plains in North America becomes less negative from north to south as the result of a broad regional shift from predominantly C3 to C4 vegetation.; Regional H patterns of 13C in the Great Plains show consistent trends of more negative 13C in younger surface soils than in older sub-surface soils (based on 14C dating). |
| 584 | Fontaine, S. & Barot, S. | Size and functional diversity of microbe populations control plant persistence and long-term soil carbon accumulation | 2005 | Priming Effect; Soil Organic Carbon; Soil Microorganisms | Journal | Ecol. Lett.; 8; 1075-1087 | English | Hardcopy:Partial; PDF:Full | Modelling the decomposition of SOM with the inclusion of the priming effect | We present an alternative theory of SOM dynamics, in which SOM decay rate is controlled by the size & the diversity of microbe popul'ns & by the supply of energy-rich litter cpds.; .. the priming effect has important consequences on SOM dynamics. The supply of fresh OM can increase the mineralis'n of SOM by 12%400% .. Increased rates of SOM mineralis'n persist in soil for several months after the complete decomposition of fresh OM, which leads to important C losses. Such priming may even induce a negative C balance, i.e. the supply of C decreases the total soil C content. |
| 583 | Fontaine, S., Bardoux, G., Abbadie, L. & Mariotti, A. | Carbon input to soil may decrease soil carbon content | 2004 | Priming Effect; Soil Organic Carbon | Journal | Ecol. Lett.; 7 (4); 314-320 | English | Hardcopy:Full; PDF:Full | Expt. to study the relationship between plant residue input and SOM content | It is commonly predicted that the intensity of primary production and soil C content are positively linked. Paradoxically many long-term field observations show that, although plant litter is incorporated to soil in large quantities, soil C content does not necessarily increase. These results suggest that a negative relationship between C input and soil C conservation exists.; .. the supply of fresh C may accelerate the decomposition of soil C and induce a negative C balance. .. soil C losses increase when soil microbes are nutrient limited.; .. energy available to soil microbes and microbial competition are important determinants of soil C decomposition. |
| 1420 | Fontaine, S., Bardoux, G., Benest, D., Verdier, B., Mariotti, A. & Abbadie, L. | Mechanisms of the priming effect in a savanna soil amended with cellulose | 2004 | Priming Effect; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 68; 125-131 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effect of priming a soil with cellulose | Two mechanisms have been hypothesised to explain the priming effect .. extracellular enzymes that are produced to decompose fresh C by fresh-C-specialised microbes may be partly efficient in degrading soil C .. [or] depending on the competition with fresh-C-specialised microbes, part of the fresh C may be absorbed by soil-C-decomposing microbes .. [which] increases the populations of soil-C-decomposing microbes and hence the decomposition rate of soil C.; The rate of soil C decomposition increased by 55% with cellulose addition .. |
| 1218 | Fontaine, S., Mariotti, A. & Abbadie, L. | The priming effect of organic matter: a question of microbial competition? | 2003 | Priming Effect; Soil Microorganisms | Journal | Soil Biol. Biochem.; 35 (6); 837-843 | English | Hardcopy:Full; PDF:Full | Review of work done to date on the priming effect, the increase in SOM decomposition rate after fresh OM input to soil, which had been supposed to result from a general increase in microbial activity due to the higher availability of energy released by the decomposition of fresh OM | Work to date .. suggests that supply of available energy induces no effect on SOM mineralisation.; After fresh OM input to soils, many specialised microorganisms grow quickly and only decompose the fresh OM. .. the priming effect results from the competition for energy and nutrient acquisition between the microorganisms specialised in the decomposition of fresh OM [r-strategists] and those feeding on polymerised SOM [K-strategists]. |
| 1219 | Fonte, S., Kong, A.Y., Kessel, C. van, Hendrix, P.F. & Six, J. | Influence of earthworm activity on aggregate-associated carbon and nitrogen dynamics differs with agroecosystem management | 2007 | Organic Farming; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 39; 1014-1022 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of eaarthworms on C & N cycling in diffrent farming systems | .. earthworms have important effects on C & N cycling processes ... their influence depends greatly on differences in management. We found earthworms to increase the incorporation of cover-crop-derived C into macroaggregates and more importantly into microaggregates formed within macroaggregates ... [which] indicates the potential for earthworms to facilitate SOM stabilisation and accumulation in agricultural systems. The influence of earthworms on N cycling, however, appears to be largely determined by cropping system and the form of fertiliser applied (mineral vs. organic).; .. earthworms have potentially negative consequences on fertiliser-N retention. |
| 540 | Forrer, H.R., Musa, T., Krebs, H. & Dorn, B. | Control of Phytophthora infestans in organic potato production | 2006? | Potato Growing | Book | Forrer, H.R., Musa, T., Krebs, H., & Dorn, B. ; E.U. project no.: QLK5-CT-2000-01065; | English | Hardcopy:Full; PDF:Full | Field expt. to test 26 different CFPs (copper-free preparations) for the biocontrol of LB (late blight) on potatoes | .. no commercial or experimental CFP with a reliable activity for LB control could be found.; Though all CFP treatments reduced LB significantly, none of them reached the 25% efficacy level.; [i.e. 25% reduction in foliar blight]; .. a main cause of failure could be a low stability towards rain or dew. |
| 290 | Fortin, M.C. & Pierce, F.J. | Developmental and growth effects of crop residues on maize | 1990 | Mulch; Soil Organic Carbon | Journal | Agron. J.; 82; 710-715 | English | Hardcopy:Full | Field expt. to test the effect on maize growth of a straw mulch compared with bare soil. | .. no consistent difference was found in aboveground phytomass when comparisons were done at similar vegetative stages.; .. when aboveground phytomass data were examined at various dates [instead of at vegetative stages] the residue treatment had consistently lower values than the bare treatment. |
| 291 | Fortin, M.C. & Pierce, F.J. | Timing and nature of mulch retardation of maize vegetative development | 1991 | Allelopathy; Mulch; Soil Organic Carbon | Journal | Agron. J.; 83; 258-263 | English | Hardcopy:Full | Field expt. to compare the vegetative development of maize under two treatments - bare soil and oat straw mulch | .. complete residue cover applied at LTE2 [second leaf tip emergence] on a notill loam soil resulted in delays of 5 to 7.5 days in vegetative .. development of maize. .. in addition to the soil temperature effect, other factors contributed to the delay in maize development .. allelopathy may be the source of unexplained delay. |
| 135 | Fortune, S., Conway, J.S., Philipps, L., Robinson, J.S., Stockdale, E.A. & Watson, C.A. | N, P and K budgets for some U.K. organic farming systems: implications for sustainability | 2001 | Organic Farming | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Review of the use of nutrient budgets in organic farming | '.. organic systems are inherently liable to nitrogen leaching'. The often reduced inputs of P & K to org. farming systems are believed to lead to negative P & K balances. Johnston (1991) suggested that organic systems are not inherently more sustainable than conventional farming, especially with regard to the long-term availability of P and K. |
| 1720 | Fox, O., Vetter, S., Ekschmitt, K. & Wolters, V. | Soil fauna modifies the recalcitrance-persistence relationship of soil carbon pools | 2006 | Uncategorised | Journal | Soil Biol. Biochem.; 38; 1353-1363 | English | PDF:Full | ||
| 159 | Fragstein, P. von | Organic arable farming - a contradiction? | 1996 | Stockless Farming | Book | van Ittersum, M. K., Venner, G. E. G. T., van de Geijn, S. C. & Jetten, T. H. (eds.); Fourth Congress of the ESA - Book of Abstracts, Vol. 2. European Society for Agronomy; 438-439 | English | Hardcopy:Full | A review of the pros and cons of stockless organic farming and of the literature published on it. [The very poor English makes most of this paper difficult to understand.] | |
| 93 | Fragstein, P. von & Schmidt, H. | External N sources in an organic stockless crop rotation: useful or useless additives? | 1999 | Compost & Biocontrol; Stockless Farming | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | 3-year field expt. to test stockless organic rotations with various amendments | From the perspective of sustainability the .. rotation has a need for further N-inputs apart from green manure crops. In stockless systems source-separated composts are suitable for the compensation of nutrient balances & the long-term improvement of SOM. Vinasse suits for the input of N & K and makes possible a direct manipulation of plant growth due to its high availability of N.; The short-term effect of source separated composts can be graded as very small. Quick responses of plant growth to compost application cannot be expected .. |
| 57 | Francis, C.A., Flora, C.B. & King | What is sustainable agriculture? | 1990 | Sustainability | Book | Francis, C.A., Flora C.B. & King (ed.); Sustainable Agriculture in Temperate Zones; 3-11 | English | Hardcopy:Full | Sustainable agriculture is defined. Common misconceptions about it are dispelled. | A sustainable agriculture is one that, over the long term, enhances environmental quality and the resource base on which agriculture depends; provides for basic human food and fibre needs; is economically viable; and enhances the quality of life for farmers and society as a whole.; .. most current definitions of sustainable agriculture allow for some use of synthetic inputs. |
| 344 | Franke-Snyder, M., Douds, D.D., Galvez, L., Phillips, J.G., Wagoner, P., Drinkwater, L.E. & Morton, J.B. | Diversity of communities of arbuscular mycorrhizal (AM) fungi present in conventional versus low-input agricultural sites in eastern Pennsylvania | 2001 | Green Manure; Organic Farming; Stockless Farming | Journal | Appl. Soil Ecol.; 16; 35-48 | English | Hardcopy:Partial | Comparison of AM fungal communities in soils from a conventional rotation and two organic rotations - one using FYM and the other - green manure. Little difference was found in the fungal diversity between the three treatments. | .. microbial communities [including AM fungi] .. are involved in processes such as acquisition and recycling of nutrients .., antagonism of detrimental organisms and participation in the formation and maintenance of soil structure. |
| 345 | Franzluebbers, A.J. | Microbial activity in response to water-filled pore space of variably eroded southern Piedmont soils | 1999 | Soil Microorganisms | Journal | Appl. Soil Ecol.; 11; 91-101 | English | Hardcopy:Partial; PDF:Full | Expt. to test water-filled pore space as an alternative to matric potential as a measure of of the effect of soil water content on soil microorganisms | Soil microbial activity is known to be strongly influenced by soil water content. Soil CO2 evolution increases with water additions above -5000 kPa up to a maximum near -15 kPa and subsequently declines near saturation due to O2 limitations. Net N mineralisation has been shown to follow a similar response to soil matric potential although a stronger decrease in net N mineralisation occurs near saturation compared with C mineralisation. Nitrate serves as an alternative electron acceptor when O2 becomes limiting, resulting in the conversion of NO3- to N2 or N2O via denitrification.; ..the matric potential to achieve maximum microbial activity ranged from -10 to -400 kPa for individual soils.; Matric potential is logarithmically related to gravimetric soil water content with the relationship depending mainly upon soil texture and OM content. The water retention curve of a soil can also be altered with changes in the BD. |
| 1538 | Franzluebbers, A.J. | Soil organic matter stratification ratio as an indicator of soil quality | 2002 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 66 (2); 95-106 | English | Hardcopy:Partial | The results of an expt. to test the hypothesis that the degree of stratification of SOC & -N pools with soil depth, expressed as a ratio, could be an indicator of soil quality. Because of the stratification of SOC in zero tillage soil the absolute quantity of SOC in a soil is not a good indicator of soil quality. | .. [on the three sites tested] stratification ratios of SOC were 1.1, 1.2 and 1.9 under conventional tillage (CT) and 3.4, 2.0 and 2.1 under no-tillage (NT) .. respectively.; Stratification of biologically active soil C & N pools (i.e. soil microbial biomass and potential activity) were equally or more sensitive to tillage, cropping intensity and soil textural variables than stratification of total C & N. High stratification ratios of soil C & N pools could be good indicators of dynamic soil quality, independent of soil type and climatic regime .. |
| 1539 | Franzluebbers, A.J. & Arshad, M.A. | Soil organic matter pools with conventional and zero tillage in a cold semi-arid climate | 1996 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 39; 1-11 | English | Hardcopy:Partial | In a field expt. the SOC depth distribution, soil microbial biomass, soil basal respiration and net N mineralisation were compared on plots subject to chiselploughing and zero tillage. On average soils were 4% denser and 24% wetter under zero tillage. The average basal soil respiration rates were 4.0 and 3.1 CO2C/m2/day and the net N mineralisation rates were 3.4 and 4.1 g/m2/24 days under chisel and zero tillage respectively. In this cold semi-arid climate the SOC and active C pools were not enriched by reduced tillage, as they are in more temperate and humid climates. | |
| 1540 | Franzluebbers, A.J. & Hons, F.M. | Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no-tillage | 1996 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 39; 229-239 | English | Hardcopy:Partial | Expt. to study the distribution of nutrients in the soil after different tillage methods | greater water-filled pore space under NT compared with CT may have contributed to the higher levels of extractable Fe, Mn and Cu under NT by providing a more reduced soil condition.; these nutrients under NT tended to be present in higher levels that under CT, especially near the soil surface .. due to surface placement of crop residues. .. [This] was beneficial .. by allowing accumulation near the soil surface where plant roots tend to be most active. |
| 1541 | Franzluebbers, A.J., Hons, F.M. & Zuberer, D.A. | Tillage-induced seasonal changes in soil physical properties affecting soil CO2 evolution under intensive cropping | 1995 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 34; 41-60 | English | Hardcopy:Partial | Field expt. to establish how tillage and soil CO2 evolution are related to soil temperature, BD and water-filled pore space and to the dynamics and distribution @of gravimetric soil water content. The mean rate of soil CO2 evolution was 1.98 g CO2-C/m2/day under chisel ploughing and 2.11 under zero tillage. | Tillage caused disruption and mixing of the soil, which allowed the soil to dry more rapidly, become more loosely aggregated, lose more heat during the night `and evolve less CO2 due to the reduced concentration of SOC. |
| 1619 | Franzluebbers, A.J., Hons, F.M. & Zuberer, D.A. | Seasonal dynamics of active soil C & N pools under intensive cropping in conventional and no tillage | 1996 | Soil Organic Carbon; Soil N Dynamics; Tillage | Journal | Z. Pflanz. Bodenkunde; 159; 343-349 | English | Hardcopy:Partial | Field expt. to determine the effect of tillage on the seasonal dynamics of potential C & N mineralisation, soil inorganic N and soil microbial biomass C and its specific respiratory activity. | .. the size and activity of the active soil C & N pools of SOM are seasonally dependent.; .. increased C input, rather than reduced microbial activity, led to conservation of SOM in this soil. |
| 1421 | Franzluebbers, A.J., Wright, S.F. & Stuedemann, J.A. | Soil aggregation and glomalin under pastures in the southern Piedmont USA | 2000 | Soil Microorganisms; Soil (General) | Journal | Soil Sci. Soc. Am. J.; 64; 1018-1026 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the relationship between glomalin and aggregation | Total glomalin .. was highly related to whole soil organic C content, but neither of these properties was particularly well related with water-stable macroaggregation, mean-weight diameter or their stabilities.; Although soil biological activity and deposition of glomalin by AM fungi, of carbohydrates by various microorganisms, of muramic acid by bacteria and of glucosamine by fungi may be essential in binding soil aggregates, other physical and chemical factors appear to be equally important in the development of strong aggregate distribution and stability properties of soils .. These factors may be: the extent of physical weathering of soils, high Al and Fe contents and intense drying-wetting cycles .. |
| 346 | Fraser, P.M. & Piercy, J.E. | The effects of cereal straw management practices on lumbricid earthworm populations | 1998 | Green Manure; Soil (General) | Journal | Appl. Soil Ecol.; 9 (1-3); 369-373 | English | Hardcopy:Partial; PDF:Full | 4-year field expt. to study the effect of straw residue management and green manures on earthworm populations on land that had been 4 yrs under grass | Overall ... there was a gradual decline in both the size of the total earthworm populations and earthworm biomass over the first 4 yr of the experiment in the continuous cereal treatments. Burning and removing straw had similar effects on earthworm numbers. However, by year 4 there were considerably more earthworms in the incorporation treatment plots, indicating that there may be some longterm effects of straw management on earthworm populations. In the treatment undersown with clover seed, the earthworm numbers, biomass and species diversity increased dramatically in the fourth year. This may be attributed to the clover plants providing a suitably moist and cool microclimate conducive for earthworm survival and the high protein content of the clover plants providing a rich food source for the earthworms and the microorganisms.; [or to the less cultivation?] |
| 950 | Freney, J.R. | Emission of nitrous oxide from soils used for agriculture | 1997 | Greenhouse Gases; Green Manure | Journal | Nutr. Cycl. Agroecosyst.; 49; 1-6 | English | Hardcopy:Full; PDF:Full | Review of N2O emissions from agricultural soils | N2O production is controlled by temperature, pH, water holding capacity of the soil, .. fertiliser rate, tillage practice, soil type, O2 concentration, availability of C, vegetation, land use practices and use of chemicals. .. emissions from agricultural soils are increased by the addition of fertiliser N and by the growth of legumes to fix atmospheric nitrogen.; .. predictions of N2O emissions associated with N applied are not reliable. Soil management and `cropping systems and variable rainfall have a greater effect on N2O emission than (the type of fertiliser nitrogen.; .. legumes may contribute to N2O emission in a number of ways. Atmospheric N fixed by the legumes can be nitrifed and denitrifed in the same way as fertiliser N, thus providing a source of N2O. .. symbiotically living Rhizobia in root nodules are able to denitrify and produce H N2O. .. legumes can increase N2O emissions from pastures by a factor of 2 to 3. |
| 1220 | Frey, B. & Schüepp, H. | A role of vesicular-arbuscular (VA) mycorrhizal fungi in facilitating interplant nitrogen transfer | 1993 | Green Manure; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 25 (6); 651-658 | English | Hardcopy:Partial | The transfer of N from a legume (berseem) to associated non-leguminous plants (maize and apple) was studied with and without innoculation of the legume roots with V.A.M. fungus. A significant quantity of N was transferred to the nonlegume in both cases, though the quantity was much smaller with the maize than with the apple. | |
| 1221 | Frey, S.D., Elliott. E.T. & Paustian, K. | Bacterial and fungal abundance and biomass in conventional and no-tillage agroecosystems along two climatic gradients | 1999 | Soil Microorganisms; Tillage | Journal | Soil Biol. Biochem.; 31 (4); 573-585 | English | Hardcopy:Full; PDF:Full | Expt. to determine the factors controlling absolute and relative microbial populations and biomass in soils taken from six long-term tillage expt.s. In the surface soil the F/B ratio was significantly higher under CT than under NT, although generally bacterial biomass was greater than fungal. | The proportion of the total biomass composed of fungi ranged from 10 to 60% and was significantly higher in NT compared to CT .. [It] was not strongly related to soil texture, pH, aggregation or organic C & N fractions, but was positively related to soil moisture.; Bacterial abundance and activity decline rapidly as soil water content falls below field capacity & bacterial respiration & .. transformations are negligible at potentials blow -1.5 MPa. Many fungi are active at considerably lower water potentials.; Expressed as a percentage of TOC, total microbial biomass (bacterial+fungal C) ranged from 0.3 to 0.8%. There were no differences between CT and NT soils for this variable.; .. previous studies have shown that fungi are the dominant decomposers of NT surface residues. |
| 1222 | Frey, S.D., Elliott. E.T., Paustian, K. & Peterson, G.A. | Fungal translocation as a mechanism for soil nitrogen inputs to surface residue decomposition in a no-tillage agroecosystem | 2000 | Mulch; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 32 (5); 689-698 | English | Hardcopy:Partial | Expt. to measure the rate of N flux from the mineral soil to surface-applied crop residues | @; We estimate a total annual fungal-mediated N flux of 2.4 g m-2, which is nearly equivalent to the N immobilization potential predicted, based on initial N and lignin content, for the wheat straw used in this study. We conclude that fungal N translocati |
| 704 | Frey, S.D., Knorr, M., Parrent, J.L. & Simpson, R.T. | Chronic nitrogen enrichment affects the structure and function of the soil microbial community in temperate hardwood and pine forests | 2004 | Soil Microorganisms; Soil N Dynamics | Journal | For. Ecol. Manag.; 196; 159-171 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of chronic nitrogen enrichment on the soil nmicrobial community | Active fungal biomass was 27-61% & 42-69% lower in the fertilised compared to control plots in the hardwood & pine stands respectively. Active bacterial biomass was not greatly affected by N additions, resulting in significantly lower F/B biomass ratios in the N-treated plots. This .. was accompanied by a significant reduction in the activity of phenol oxidase, a lignin-degrading enzyme produced by white-rot fungi. In the pine stand ectomycorrhizal fungal community diversity was lower in the low N-treated plot .. |
| 1223 | Frey, S.D., Six, J. & Elliott, E.T. | Reciprocal transfer of carbon and nitrogen by decomposer fungi at the soil-litter interface | 2003 | Mulch; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 35 (7); 1001-1004 | English | Hardcopy:Full; PDF:Full | Expt. to study the reciprocal translocation of C & N between litter and the soil by the action of decomposer fungi | .. C & N were reciprocally transferred by [saprophytic] fungi, with a significant quantity (121-151 g C g-1 whole soil) of litter-derived C being deposited into newly formed macroaggregates (>250 m sized aggregates). Fungal inhibition reduced fungal biomass and the bidirectional C & N flux by approximately 50%. The amount of litter-derived C found in macroaggregates was positively correlated with litter-associated fungal biomass. This fungalmediated litter-to-soil C transfer .. may represent an important mechanism by which litter C enters the soil and becomes stabilised as SOM within the macroaggregate structure. |
| 262 | Frissel, M.J. | Description and classification of agro-ecosystems | 1978 | Agricultural Ecology | Book | Frissel, M.J. (ed.); Cycling of Mineral Nutrients in Agricultural Ecosystems; 17-24 | English | Hardcopy:Partial | The various agricultural systems in the world are defined and compared, mainly in relation to their efficiency in the use of N. A table shows the N output (in kg/ha) of all the systems discussed. | For a part this system [extensive arable farming] depends on the decomposition of the organic soil fraction which was formed before agriculture was practised. .. The reclaimed Lake Kopais in Greece had lost its natural fertility within 15 years .. In Saskatchewan .., where the temperature is considerably lower, soils which have already been in production for about 100 years have lost only about one third of the N stored in the SOM. .. After the depletion period the soils are abandoned or use is also made of manure or fertilisers.; [i.e. transition to mixed or intensive farming] |
| 66 | Fuchs, J.G. | Practical use of quality compost for plant health and vitality improvement | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the effect of composts of varying maturity on the ability of the compost to suppress plant diseases | The composition and the maturity of the compost influence the potential for suppression of plant disease. The management of the composting processes, and the oxygen supply in particular, seem to affect compost quality strongly.; Whereas some composts showed no reaction to Pythium ultimum on cress plants, other composts showed full protection against this disease. After a heat treatment (1 day at 90$C) the suppressive composts lose their potential for disease suppression. This indicates that disease suppression is linked with the microbiological activity of the composts |
| 179 | Fujisaka, S., Harrington, L. & Hobbs, P.R. | Rice-wheat in South Asia: systems and long-term priorities established through diagnostic research | 1994 | Miscellaneous | Journal | Agric. Sys.; 46 (2); 169-187 | English | Hardcopy:Partial | Rice-wheat growing in South Asia is reviewed from the standpoint of agronomic and sustainability problems. | System problems include poor wheat populations caused by the poor soil structure and plough pan formed for puddled rice, late wheat planting resulting from late rice harvesting and losses to grassy weeds encouraged by continuous rice-wheat cultivation. Sustainability issues include soil nutrient depletion and possible build-up of insects, weeds and diseases. |
| 379 | Fustec, E., Chauvet, E. & Gas, G. | Lignin degradation and humus formation in alluvial soils and sediments | 1989 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 55 (4); 922-926 | English | Hardcopy:Full | 7-week field expt. to study the fate of lignin from different tree species (poplar, willow and alder) in silty alluvial soil taken from beneath the trees xand in its size fractions. 10-15% of the lignin-C was evolved as CO2 and 65-75% was found in the coarse fractions (>50 m) of the soil. 5.3%, 3.1% and 24% of the lignin-C was found in complex humic polymers (humic and fulvic acids), mainly in the coarse fractions. | Although the soil beneath willows was waterlogged and flooded each year, its lignin mineralisation potentialities seemed to be higher than that of other alluvial soils, but .. the humification process was much slower. .. In soil beneath alders [which is waterlogged but not flooded] the mineralisation of lignin was not very different, but humic and fulvic acid formation appeared to be more rapid. |
| 318 | Gadgil, M. & Solbrig, O.T. | The concept of r- and K-selection: evidence from wild flowers and some theoretical considerations | 1972 | Miscellaneous | Journal | Am. Nat.; 106 (947); 14-31 | English | Hardcopy:Partial | Review of the evidence for r- and K-strategies among herbaceous plants | The most important characteristic of an r-strategist is that it devotes a greater proportion of available resources to reproduction than a related Kstrategist. This implies a higher birth rate;; ... populations living in environments imposing high density-dependent regulation (K-strategists) will be selectively favoured to allocate a greater proportion of resources to nonreproductive activities, at the cost of their capabilities to propagate under conditions of high density-independent mortality. |
| 609 | Gahoonia, T.S. & Nielsen, N.E. | Variation in root hairs of barley cultivars doubled soil phosphorus uptake | 1997 | Phosphorus Cycling; Roots & Rhizodeposition | Journal | Euphytica; 98; 177-182 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the part played by root hairs in P uptake. One cultivar with longer and denser root hairs could exploit nearly 3 times more soil and was able to intercept more labile P (NaHCO3-P) diffusing towards the roots, but not dissolve more P from stable P fractions. | In soil diffusion of P to the root surface is rate limiting ..; A large part of plant-available P in soil may be located in small-diameter pores. Root hairs can penetrate these pores and act as an extension of effective root-soil contact. Curled root hairs .. indicated that root hairs grew into soil pores. |
| 1033 | Gahoonia, T.S. & Nielsen, N.E. | The effects of root-induced pH on the depletion of inorganic and organic phosphorus in the rhizosphere | 1992 | Phosphorus Cycling | Journal | Plant Soil; 143; 185-191 | English | Hardcopy:Partial | Study of the increased uptake of soil P as a result of a root-induced pH reduction in the rhizosphere of rape plants. P-starved rape plants may exude substantial amounts of organic acids, but the pH decrease seems to be mainly due to a higher net inflow of cations than anions. The root-induced pH reduction causes a 20% increase in the total P depletion in the rhizosphere. The depletion of certain P fractions is even greater - KHCO3-Pi and residual P are increased by 34% and 43% respectively. 11-15% of total P withdrawn originated from organic P fractions and this was not affected by the pH change. | .. 40-46% of the P withdrawn near the root mat of rape originated from nonmobile fractions normally not included in .. plant-available soil P.; Shortterm mineralisation of organic P in the rhizosphere thus seems to be of importance in plant nutrition.; About 15-18% of total P depletion .. originated from the residual P, thus showing that rather non-mobile P may become mobile if roots strongly deplete the mobile P pool in the rhizosphere. |
| 1034 | Gahoonia, T.S. & Nielsen, N.E. | Direct evidence on participation phosphorus of root hairs in phosphorus (32P) uptake from soil | 1998 | Phosphorus Cycling | Journal | Plant Soil; 198; 147-152 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to measure the proportion of P taken up via root hairs, which have a functional lifetime of 2-3 days and are the site of infection in Rhizobiumlegume symbiosis. | The presence of 32P in the shoot in just 2 days showed that the plants absorbed P via root hairs and that it was translocated to the shoot.; .. the presence of radioisotope P in the shoots shows a substantial participation of root hairs in uptake of P from soil.; .. when 70 percent of the root hairs grew into the labelled soil, they contributed to 63 percent of the total P uptake.; The abundance of root hairs increases when P supply is lowered. |
| 639 | Gaillard, V., Chenu, C., Recous, S. & Richard, G. | Carbon, nitrogen and microbial gradients induced by plant residues decomposing in soil | 1999 | Soil Organic Carbon; Soil Microorganisms | Journal | Eur. J. Soil Sci.; 50; 567-578 | English | Hardcopy:Partial; PDF:Full | 100-day lab. expt. to study the microbial activity close to incorporated straw residues. Up to 4 mm from the surface of the straw (named the detritussphere) there was a steep downward gradient in microbial activity, presumably because of diffusion of soluble organic matter from the straw. | .. microorganisms and organic materials are heterogeneously distributed in the soil matrix and often separated from each other by physical barriers such as clay particles, which presumably limit the physical access of organic substrates to microorganisms. Disrupting the soil structure by grinding .. leads to rapid mineralisation of organic matter.; We..define four distinct spatial compartments. The first was the straw or particulate fraction, densely colonised by microorganisms .. The second was the adhering soil, also densely colonised and containing high C and N contents. A third .. was the soil situated to about 4 mm from the straw surface, in which dehydrogenase activity was stimulated and in which the C and N derived from the straw accumulated. The last compartment was the soil situated further than 4 mm from the straw; it was not affected by the decomposing straw except for a little accumulation of N derived from the straw.; The decomposition and mineralisation of the straw residues was brought about by microorganisms either on the surfaces of residues or in the soil within 4 mm from the straw residues. |
| 1422 | Gale, W.J. & Cambardella, C.A. | Carbon dynamics of surface-residue- and root-derived organic matter under simulated no-till | 2000 | Roots & Rhizodeposition; Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 64 (1); 190-195 | English | Hardcopy:Partial | Expt. to subject a soil that had been under continuous maize and conventional tillage for 30 years to simulated zero tillage | .. C retention is increased in no-till because the surface residue is primarily decomposed by fungi, which have a higher assimilation efficiency than the bacteria that dominate the decomposition processes of residue mixed into the soil.; POM consists of partially decomposed plant residues and is considered to be the first intermediate pool in the decay continuum between crop residue (and humified stable OM.; After 360 days 66% of the 14C contained in the surface residue .. had been respired as CO2, 11% remained in the residue on the soil surface and 16% was in the soil. Most of [it] .. was associated with the silt+ clay fraction. Only a small amount .. accrued in the POM ..; In comparison, 56% H of the root-derived 14C in the soil was evolved as CO2 and 42% remained in the soil. .. the beneficial effects of no-till on SOC accrual are primarily due to the increased retention of root-derived C in the soil. |
| 1423 | Gale, W.J., Cambardella, C.A. & Bailey, T.B. | Surface-residue- and root-derived carbon in stable and unstable aggregates | 2000 | Roots & Rhizodeposition; Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 64 (1); 196-201 | English | Hardcopy:Partial | Expt. to subject a soil that had been under continuous maize and conventional tillage for 30 years to simulated zero tillage | x; We observed a rapid loss of 14C from both the surface residue and coarse roots .. and an increase in aggregate stability until day 180 [followed by a decline]. This suggests that microbial binding agents produced during the decomposition of the surface residue and/or roots will result in increased aggregate stability under no-till. This increase is temporary, ostensibly because the microbial `products are labile and subject to further decomposition.; The 14C concentrations in .. microaggregates .. generally increased throughout the incubation.; .. root-derived C has an important role in the stabilisation of small macroaggregates, whereas new C inputs from surface residue do not contribute significantly to macroaggregate stability under simulated no-till. |
| 1424 | Gale, W.J., Cambardella, C.A. & Bailey, T.B. | Root-derived carbon and the formation and stabilisation of aggregates | 2000 | Roots & Rhizodeposition; Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 64 (1); 201-207 | English | Hardcopy:Partial | Expt. to subject a soil that had been under continuous maize and conventional tillage for 30 years to simulated zero tillage | .. new micro aggregates form around decomposing pieces of root-derived POM inside existing macroaggregates ..; After day 180 .. the stability of the macroaggregates begins to decline, as evidenced by the release of large microaggregates that contain cores of new root-derived POM. Some of the microaggregates .. become unstable after about 1 year and release labile POM C that is now available for further decomposition. |
| 1035 | Galvez, L., Douds, D.D., Drinkwater, L.E. & Wagoner, P. | Effect of tillage and farming systems on VAM fungus populations and mycorrhizas and nutrient uptake of maize | 2001 | Organic Farming; Soil Microorganisms; Tillage | Journal | Plant Soil; 228 (2); 299-308 | English | Hardcopy:Partial | The effect of tillage and low-input v. conventional farming on vesiculararbuscular mycorrhizal fungi in maize is examined. Fungal spore populations, mycorrhiza formation and nutrient utilisation by the maize were studied in ploughed, chisel-disced and no-tilled soil in conventional and low-input systems. | VAM fungi play a key role in the nutrition, water relations and pest resistance of host plants.; Damage to [their] hyphal network by tillage and soil disturbance may contribute to .. reduction of P uptake by plants.; Soils under low-input management had higher VAM fungus spore populations than soils under conventional management. Spore populations and colonisation of maize roots by VAM fungi were higher in no-tilled soil than in .. ploughed or chisel-disced soil. .. This benefit of enhanced VAM fungus colonisation, particularly in the low-input system in the absence of effective weed control and with likely lower soil temperatures, did not translate into enhanced growth and yield. |
| 458 | Gami, S.K., Ladha, J.K., Pathak, H., Shah, M.P., Hobbs, P.R., Pasuquin, E., Hobbs, P.R., Joshi, D. & Mishra, R. | Long-term changes in yield and soil fertility in a twenty-year rice-wheat expt. in Nepal | 2001 | Soil (General) | Journal | Biol. Fertil. Soils; 34; 73-78 | English | Hardcopy:Full | The results of an expt. with a rice-wheat rotation under various amendment regimes, namely, no fertiliser, FYM only, FYM plus inorganic N, chopped wheat straw plus inorganic N, and various combinations of inorganic N, P and K fertilisers. Owing to poor husbandry the yields generally were only about half what would normally be expected in the region. The poorest mean annual yields of rice were obtained with no fertiliser, followed by 50 kg/ha of inorganic N only, followed by 4 Mg/ha FYM only. The highest mean annual yield of rice was obtained with the highest application of inorganic fertiliser, namely, 100 N, 13.1 P and 25 K kg/ha. In the case of wheat, the lowest yield was again with no fertiliser, followed by the plot with FYM only. The highest yield was with the same NPK application as with the rice. Total soil C & N did not change significantly on any of the plots over the period of the expt. The treatment with FYM so the greatest annual accumulation of both C & N. There was no significant change in the soil BD and no significant difference in soil BD between the different amendments. | The production of both [rice and wheat] has increased markedly with the introduction of modern technologies based on early maturing, N-responsive, semidwarf cultivars. .. There are indications that the yields .. have declined. The depletion of soil nutrients, particularly K, is reported to be a possible cause of such a decline. |
| 1721 | Gamliel, A., Austerweil, M. & Kritzman, G. | Non-chemical approach to soilborne pest management - organic amendments | 2000 | Uncategorised | Journal | Crop Prot.; 19; 847-753 | English | PDF:Full | ||
| 380 | Garcia, S., Latge, J.P., Prevost, M.C. & Leisola, M. | Wood degradation by white-rot fungi: cytochemical studies using lignin peroxidase-immunoglobulin-gold complexes | 1987 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 53 (10); 2384-2387 | English | Hardcopy:Full | Lab. expt. to study the degradation of various wood and sawdust samples by 4 different white-rot fungi | Lignin peroxidase was located mainly intracellularly in naturally decayed wood ..; .. lignin peroxidase can oxidise lignin through one-electron transfer mediators .. no direct contact is necessary between the enzyme and the lignin. |
| 1224 | Garcia-Gil, J.C., Plaza, C., Soler-Rovira, P. & Polo, A. | Long-term effects of municipal solid waste compost application on soil enzyme activities and microbial biomass | 2000 | Compost & Biocontrol; Soil Microorganisms | Journal | Soil Biol. Biochem.; 32; 1907-1913 | English | Hardcopy:Partial; Wordperfect:Full | A 9-year field expt. to study the effects of four different treatments x(municipal solid waste compost at 20 or 80 t ha-1, FYM at 20 t ha-1 and chemical fertiliser) on soil enzyme activities and microbial biomass. These amendments increased soil microbial biomass in the order 80t MSW > FYM > 20t MSW > chemical. Oxidoreductase enzyme activity was greatly enhance by all organic amendments (FYM > MSW), but hydrolase enzymes showed varying response. | |
| 731 | Garcia-Oliva, F., Martinez Lugo, R. & Maass, J.M. | Long-term net soil erosion as determined by 137Cs redistribution in an undisturbed and perturbed tropical deciduous forest ecosystem | 1995 | Miscellaneous; Soil (General) | Journal | Geoderma; 68 (1/2); 135-147 | English | Hardcopy:Partial | Cs-137 was used to estimate the rate of soil erosion. On pasture, following slash-and-burn, the rates ranged from zero to 23 Mg/ha/yr, with an average of 9 Mg/ha/yr. | The half-life of 137Cs is relatively long (30.2 years) and its concentration in soil world-wide is the result of nuclear testing. The most important period of 137Cs fall-out occurred during 1962-1964. .. A significant amount of 137Cs was released .. following the accident at the Chernobyl nuclear power station in 1986. .. Radio-caesium is strongly adsorbed by fine soil particles and OM.; .. the first year after slash-and-burn is critical for susceptibility to soil erosion. Based on .. the present study, the top 5 cm. of soil could be removed in only 25 years. |
| 732 | Garcia-Oliva, F., Sanford, R.L. & Kelly, E. | Effects of slash-and-burn management on soil aggregate organic C & N in a tropical deciduous forest | 1999 | Soil Organic Carbon; Sustainability | Journal | Geoderma; 88 (1/2); 1-12 | English | Hardcopy:Partial | An expt. to test the effect on SOM of burning forest to convert it to pasture. | Fire did not destroy macroaggregates but their associated C was lost by combustion. This C reduction disrupted soil macroaggregate stabilisation .. large macroaggregates decreased by 53% during the first growing season [because of] three processes: .. large macroaggregates are preferentially removed by soil erosion, .. the breakdown of macroaggregates by raindrop impact .. the breakdown of aggregates by slaking .. periods of intense rainfall occur[ing] after soils have dried out.; .. the organic C content associated with large macroaggregates comprised approximately 50% of the total sand-free sol C content in forest soil. Large macroaggregates, however, had only 20% of the total C after the first growing season and the highest percentage of SOC was associated with microaggregates. |
| 640 | Garnier, P., Neel, C., Aita, C., Recous, S., Lafolie, F. & Mary, B. | Modelling carbon and nitrogen dynamics in a bare soil with and without straw incorporation | 2003 | Soil Organic Carbon; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 54; 555-568 | English | Hardcopy:Partial; PDF:Full | Expt. to compare the C & N dynamics in soils untreated and treated with straw | The microbial population is split into an autochthonous biomass that decomposes humified OM & a zymogenous biomass that decomposes fresh & soluble OM. |
| 641 | Garnier, P., Neel, C., Mary, B. & Lafolie, F. | Evaluation of a nitrogen transport and transformation in a bare soil | 2001 | Soil Organic Carbon; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 52 (2); 253-268 | English | Hardcopy:Partial | Modelling the transformation and transport of N in the soil | .. biological factors (the autochthonous biomass decomposition rate .. and the temperature factor coefficient of HOM decomposition ..) affected mostly N mineralisation and had very little effect on nitrate leaching. .. the initial boundary conditions (potential evapotranspiration and initial nitrate content in the first layer) and the ..hydraulic conductivity function had a great influence on nitrate leaching but had no influence on nitrate mineralisation. |
| 515 | Gasser, M.O., N'dayegamiye, A. & Laverdičre, M.R. | Short-term effects of crop rotations and wood-residue amendments on potato yields and soil properties of a sandy loam soil | 1995 | Lignin and CBW; Potato Growing | Journal | Can. J. Soil Sci.; 75 (3); 385-390 | English | Hardcopy:Partial | Field trials on the use of various organic soil amendments on a sandy loam soil xbefore a potato crop. Barley stubble gave the best yield and best quality potato crop. There was not much difference between the other amendments. | The .. size of the tree clippings .. varied from 6 to 14 mm, with only 13% of the material being <2 mm .. thereby resulting in a small soil interface, which can limit its attack by microorganisms.; .. wood residue materials with higher lignin contents than the crop residues should degrade more slowly and therefore contribute more to soil humus formation. .. [but] ligneous materials did not appear to significantly improve the structural stability of the soil. This .. contrasts with observations presented on other organic amendments such as manure. |
| 1225 | Gathumbi, S.M., Cadisch, G. & Giller, K.E. | 15N natural abundance as a tool for assessing N2-fixation of herbaceous, shrub and tree legumes in improved fallows | 2002 | Green Manure; Soil N Dynamics | Journal | Soil Biol. Biochem.; 34 (8); 1059-1071 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to test the effectiveness of 15N natural abundance methods for assessing N fixation of leguminous trees and shrubs | @; Most tested tree/shrub legumes showed no 15N discrimination during N2-fixation .. Significant 15N isotopic discrimination occurred during translocation of fixed N, which resulted in 15N depletion in shoots compared with roots and nodules, which were 15 |
| 424 | Gaudinski, J., Trumbore, S.E., Davidson, E. & Zheng, S. | Soil carbon cycling in a temperate forest: radio-carbon-based estimates of residence times, sequestration rates and partitioning of fluxes | 2000 | Energy Resources; Greenhouse Gases; Soil Organic Carbon | Journal | Biogeochemistry (Dordr.); 51; 33-69 | English | Hardcopy:Partial; PDF:Full | Estimating the rate of carbon accumulation in a temperate forest | @; Soil respiration was partitioned into two components ..: recent photosynthate which is metabolised by roots and microorganisms within a year of initial fixation (Recent-C) and C that is respired during microbial decomposition of SOM that resides in the |
| 329 | Gavett, E.E. | Agriculture and energy use | 1973 | Energy in Agriculture | Journal | Ann. Meet. Amer. Agric. Econ. Assoc.; ; | English | [cited in Fluck and Baird (1980), p.112] To emphasise the infeasibility of a return to draft animals Gavett stated that 61 million draft animals [horses or mules ?] would be required to power today's U.S. agriculture and that these draft animals would consume the feed produced from over 73 million hectares of arable land or almost half the U.S. arable land. This means that the average draft animal requires 1.2 ha of land to feed it. | ||
| 642 | Gerzabek, M.H., Antil, R.S., Koegel-Knabner, I., Knicker, H., Kirchman, H. & Haberhauer, G. | How are soil use and management reflected by soil organic matter characteristics: a spectroscopic approach | 2006 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 485-494 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the changes in SOM due to different land-uses (arable & grassland) and treatments (FYM & chemical fertiliser) | .. increasing OC contents of the silt-sized fractions were not matched by a linear increase of silt-sized aggregates. This indicated saturation of the aggregates with OC & a limited capacity of particles to protect OC physically. .. The silt-sized fractions contained the largest SOM pool & .. were qualitatively more influenced by the plant residue versus manure input than the clay fractions. |
| 1425 | Gerzabek, M.H., Haberhauer, G. & Kirchmann, H. | Soil organic matter pools and carbon-13 natural abundance in particle-size fractions of a long-term agricultural field expt. receiving organic amendments | 2001 | Green Manure; Organic Farming; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 65 (2); 352-358 | English | Hardcopy:Full | Expt. to study the distribution of native and amendment-derived C in plots from a 42-yr trial under four different treatments: green manure, FYM, sewage sludge and peat. Organic C in the silt-sized particles (2-63 m) is the main medium-term C sink, as it increased with increasing bulk-soil SOC, whereas the contribution of clay-sized particles (<2m) decreased. The proportion of SOC originating from amendments decreased (from 70% to 30%) with particle size, the sand fraction being the most sensitive to differing treatments. The C content went down in the unfertilised controls and up by 21%, 50%, 72% and 113% in the green manure, FYM, sewage sludge and peat treatments respectively. | The annual C turnover through the terrestrial biosphere amounts to 60 Gt, which is around 9% of the atmospheric C pool.; .. SOC content increased with diminishing particle size, whereas the C/N ratio decreased. .. OM recently introduced into soil is predominantly located in larger aggregates. .. macroaggregates (<250 m) can be destroyed by agricultural practices, whereas microaggregates cannot.; Microbial and chemical transformation during humification 0enriches 13C in silt and clay. Consequently, the introduction of organic manures whose 13C enrichment differs from that of the soil .. enables the C derived from amendments to be traced into the existing SOC pool. |
| 643 | Gerzabek, M.H., Pichlmayer, F., Kirchmann, H. & Haberhauer, G. | The response of soil organic matter to manure amendments in a long-term expt. at Ultuna, Sweden | 1997 | Green Manure; Organic Farming; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 48 (2); 273-282 | English | Hardcopy:Partial | 40-year field expt. to study the changes in OM as a result of manure amendments applied at a standard rate of 2000 kg C per ha per year: fallow, green manure, FYM, peat and chemical fertiliser with no N. | Fallow and mineral fertiliser without N led to a significant decrease in SOM, green manure maintained the SOM content and peat increased the SOM content significantly. The stable portion of the added organic materials .. was 12.8, 27.3 and 56.7% for green manure, animal manure and peat respectively. This was reflected [in the] half-lives of organic C originating from the amendments between 3.0 (green manure) and 14.6 years (peat).; Total losses of C were greatest from the green manure treatment .. |
| 860 | Ghidey, F. & Alberts, E.E. | Runoff and soil losses as affected by corn and soybean tillage systems | 1998 | Soil (General); Tillage | Journal | J. Soil Water Conserv.; 53 (1); 64-70 | English | Hardcopy:Full | A comparison of water run-off and soil erosion under conventional and zero tillage during maize and soya bean cultivation. Zero tillage performed better in respect of soil loss and worse in respect of water run-off compared with conventional tillage. Soil loss figures varied between 0.02 Mg/ha at the crop maturing stage under zero tillage and 7.33 Mg/ha for a seedbed under conventional tillage. The cumulative soil loss over the ten years of the expt. were: 170 Mg/ha for conventional tillage and 25 Mg/ha for zero tillage. | .. the study showed that (1) cropping had little effect on run-off and soil loss and (2) no-till significantly increased run-off and substantially reduced soil loss when compared to the conventional method. |
| 220 | Giampietro, M. | Socioeconomic constraints to farming with biodiversity | 1997 | Sustainability | Journal | Agric. Ecosyst. Environ.; 62; 145-167 | English | Hardcopy:Partial | The biodiversity of agricultural crops is reviewed. A radical reduction in the number of plant and animal species used as food has occurred as a result of the pressure for greater agricultural productivity, which is an inevitable consequence of the pattern of development adopted by western civilisation. | .. more than 90% of the world food supply is currently derived from only fifteen plant and eight animal species, and 60% of the world food supply from only rice, corn [maize] and wheat. .. also the genetic diversity within cultivated species .. in the next ten years 90% of the existing genetic diversity within the main crops (rice, wheat, corn [maize], sorghum, etc.) is at serious risk of disappearing.; .. a reduced diversity in the plants and animals used as our food base carries serious risks ..; Alternative agricultural techniques based on traditional solutions that use more biodiversity must .. be revisited ..; Agriculture .. cannot be defined only in terms of economic efficiency in food production.; .. most countries are moving toward high-energy-input and labour-saving technologies. Moving away from this path of technological development .. would be required to preserve and enhance biodiversity use in agriculture .. |
| 221 | Giampietro, M. & Pimentel, D. | Assessment of the energetics of human labour | 1990 | Energy in Agriculture; Labour and Animal Power | Journal | Agric. Ecosyst. Environ.; 32 (3-4); 257-272 | English | Hardcopy:Partial | The energy cost of human labour is considered on a societal level instead of the usual individual level. | The shift from the individual level to the societal level provides a new perspective when assessing the energetic efficiency of farming. For example, the power level of the system becomes a new and important parameter to consider. |
| 180 | Giampietro, M., Bukkens, S.G.F. & Pimentel, D. | Models of energy analysis to assess the performance of food systems | 1994 | Energy in Agriculture | Journal | Agric. Sys.; 45; 19-41 | English | Hardcopy:Partial | Energy analysis can be used as a tool to assess the impact of food system activities on society and the environment. It can be used (alongside economic indicators) to quantify the performance of a food system, including not only the direct costs of production and of post-harvest operations (processing and distribution), but also the indirect costs related to the economic efficiency of society and to the ecological efficiency of ecosystems. The cost to society is calculated on the basis of the opportunity cost of human labour. | 100,000 kcal [= 420 MJ] is the opportunity cost of one hour of US labour assessed at the level of society. .. For traditional pre-industrial societies the opportunity cost of human labour can be estimated in the range of 3000-3500 kcal/hour [12.5-15 MJ] .. |
| 1630 | Gibson, M. | Can stockless organic systems really be sustainable? | 2004 | Stockless Farming; Sustainability | Book | Gibson, M.; Can stockless organic systems really be sustainable?; | English | Hardcopy:Full | Review of stockless organic research and enterprises (Iain Tolhurst's) | .. a significant increase in stockless system would be the most economical, sustainable and least harmful use of the earth's increasingly pressured food producing resources. |
| 149 | Gifford, R.M. | Energy in different agricultural systems: renewable and non-renewable resources (part) | 1984 | Energy in Agriculture | Book | Stanhill, G. (ed.); Energy and Agriculture; 84-112 | English | Hardcopy:Partial | Solar energy use in agriculture - direct and indirect (in the form of biomass, fossil fuels, etc.). Energy shortages, caused (in the Third World) by lack of resources or (in the industrialised countries) by eventual scarcity of fossil fuels, can only to a limited degree be compensated by use of renewable resources like biomass and by improvements in the efficiency of use of existing fuels | The single most important energy objective in world agriculture is to maximise the amount of solar light intercepted by crop and pasture leaves. This requires skilled and timely management, crop breeding and support energy inputs. .. As crude petroleum runs out over the next century, liquid fuels derived from coal are likely to be the most abundant and inexpensive substitutes .. The urgency to diversify into [alternative] energy resources will be increased if the H climatic impact of rising atmospheric CO2 concentration is identified as being a serious concern. However, there is no general prospect of farms providing biomass for conversion to liquid fuels on sufficient scale to match the present level of petroleum consumption by the cities. Furthermore, there is risk that biomass fuel production will compete with food production and exacerbate soil erosion. |
| 587 | Gilland, B. | Energy for the 21st century: an engineer's view | 1990 | Energy Resources | Journal | Endeavour; 14 (2); 80-86 | English | Hardcopy:Partial | Energy consumption worldwide, CO2 flux and renewable energy sources are considered. Predictions are made of the magnitude of future alternative energy resources. If fully exploited, hydroelectric power could supply all the present world's energy consumption. All other renewable resources together would supply about the same amount again. | .. the fast reactor will be the only means of maintaining power production when the inevitable decline in fossil fuel production sets in. |
| 16 | Giller, K.E. & Cadisch, G. | Driven by nature: a sense of arrival or departure? | 1997 | Soil Organic Carbon | Book | Cadisch, G. & Giller, K.E. (eds.); Driven by Nature: Plant Litter Quality and Decomposition. C.A.B. International; | English | Hardcopy:Partial; Wordperfect:Full | Review of the part played by plant litter in regulating the SOM content and the rate and outcome of its decompostion | Are polyphenols a fast-route to SOM, due to their ability to complex proteins and carbohydrates? The stability of protein-polyphenol complexes formed during early decomposition ... have indicated that the protein N is not released over periods of several months, once it has been complexed by polyphenols. The degradative capacity of basidiomycetes in attacking polyphenol- and lignin-rich litter in forest systems is highlighted below, but such fungi are not abundant in many agricultural systems. |
| 1036 | Giller, K.E. & Cadisch, G. | Future benefits from biological nitrogen fixation: an ecological approach to agriculture | 1995 | Green Manure; Stockless Farming; Soil N Dynamics | Journal | Plant Soil; 174; 255-277 | English | Hardcopy:Partial | Review of the applications and possibilities of N-fixing leguminous plants | x; .. inoculation is the approach most likely to result in maximising N2-fixation.; Unfortunately in many Africa countries, where large potential benefits might be accrued from BNF [biological N fixation], the basic inputs such as P fertilisers necessary to allow N2-fixation to work are beyond the reach of the farmers. |
| 347 | Giller, K.E., Beare, M.H., Lavelle, P., Izac, A.M.N. & Swift, M.J. | Agricultural intensification, soil biodiversity and agroecosystem function | 1997 | Soil (General); Sustainability | Journal | Appl. Soil Ecol.; 6; 3-16 | English | Hardcopy:Partial; PDF:Full | Review of ideas relating to the possible connection between soil biodiversity and the productivity of agroecosystems | A popular assumption is that anthropogenic interference in nature results in a loss of biological diversity. .. Yet .. there is little detailed evidence for agricultural intensification resulting in loss of biodiversity in soil.; .. there no clear link between agricultural intensification and biodiversity ..; There is evidence that ecosystem function may be significantly impaired by loss of soil biodiversity ..; The use of broad-spectrum pesticides .. has both targeted and non-targeted effects on the composition and diversity of soil biological communities. While the targeted effects are often well characterised, the non-targeted effects, such as those reported for earthworms, microarthropods and certain beneficial (e.g. predatory) insects, are poorly known .. |
| 861 | Gilley, J.E. & Doran, J.W. | Tillage effects on soil erosion potential and soil quality of a former Conservation Reserve Program site | 1997 | Soil (General); Tillage | Journal | J. Soil Water Conserv.; 52 (3); 184-188 | English | Hardcopy:Full | Three CRP plots (one undisturbed, one 4 days after initial cultivation and one nine months after initial cultivation) were compared with a plot of long-term arable land in respect of erosion potential and soil quality. The indices of erosion potential were surface cover, run-off, sediment concentration in the run-off and soil loss. the indices of soil quality were SOM, BD, water content, mineralisable N content, electrical conductivity, pH and extractable phosphorus content. | A substantial reduction in the amount of SOC .. occurred nine months following tillage. .. no significant difference in run-off was found between the undisturbed CRP and tilled treatments. Soil loss values were minimal on the undisturbed CRP and the plots that had been recently tilled. .. soil loss on plots that had been tilled nine months previously were similar to values obtained when the area had been used as cropland. Soil physical, chemical and biological properties were also greatly influenced by tillage and fallowing of the former CRP site. |
| 862 | Gilley, J.E., Doran, J.W., Karlen, D.L. & Kaspar, T.C. | Run-off, erosion and soil quality characteristics of a former Conservation Reserve Program site | 1998 | Soil (General); Tillage | Journal | J. Soil Water Conserv.; 54 (1); 189-193 | English | Hardcopy:Full | A comparison of soil qualities between grassland that had been undisturbed for ten years and arable land under different tillage regimes. Zero tilled arable land showed better soil qualities in certain respects, comparable with those of the undisturbed grassland. The soil loss was much greater from the autumnploughed land than from the spring-ploughed. | Substantial soil loss was measured from the mouldboard plough treatments, but no significant difference in the erosion rates were found between the undisturbed [grassland] and no-till management systems. No-till management maintained levels of soil quality similar to those of [undisturbed grassland] by preserving soil structural integrity and reducing losses of SOM associated with tillage. |
| 819 | Ginting, D., Kessavalou, A., Eghball, B. & Doran, J.W. | Greenhouse gas emissions and soil indicators four years after manure and compost applications | 2003 | Compost & Biocontrol; Greenhouse Gases | Journal | J. Environ. Qual.; 32; 23-32 | English | Hardcopy:Partial; PDF:Full | Expt. to quantify the emission of greenhouse gases from soil four years after FYM and compost application had stopped | The average annual C input in the [control] and [chemically fertilised] plots were similar to soil CO2-C emission (4.4 and 5.1 Mg C ha-1 yr-1, respectively). Manure and compost resulted in positive C & N balances in the soil four years after application. Fluxes of CH4-C and N2O-N were nearly zero, which indicated that the residual effects of manure and compost four years after application had no negative influence on soil C & N storage and global warming. Residual effects of compost and manure resulted in 20 to 40% higher soil microbial biomass C, 42 to 74% higher potentially mineralisable N and 0.5 unit higher pH compared with the FRT treatment.; Most of the CO2-C fluxes were from soil microbial and invertebrate activities. .. contribution of root and root-induced respiration to the total CO2-C fluxes ranged from 10 to 50% of total CO2-C emitted.; The [chemically] fertilised plots had lower MBC [microbial biomass C], PMN [potentially mineralisable N] and soil pH compared with the manure and compost plots. |
| 1637 | Giri, G.S. | Surface/relay planting: an option for planting wheat on time in the lower wetlands of the Tarai, Nepal | 1997 | Miscellaneous; Mulch | Book | ; Proceedings of the RiceWheat Research End-of-Project Workshop 13 October 1997, Hotel Shangri-La, Kathmandu, Nepal; 57-62 | English | Hardcopy:Full | Field-scale and on-farm research to study various methods of growing wheat after rice, comparing relay sowing, surface seeding and farmers' current practice (ploughing after rice harvest). Various techniques were tested, including surface sowing, relay sowing, pre-soaking the seed, pre-irrigating the soil, sowing into various depths of rice stubble and covering the seed with harvested rice for a few days. | The wheat crop relayed into standing rice produced the highest yield, followed by surface seeding [after rice harvest ?] and farmers' practice.; Wheat seed was soaked .., treated with fresh cow dung [to repel birds] and broadcast into the standing rice crop .. three days before harvest. After the rice was harvested, the plots were uniformly covered with the harvested rice.; The farmers' practice consisted of four ploughings followed by two plankings.; Covering seeds with rice for 9 days produced more effective tillers than the rest of the covering treatments [0, 3 and 6 days]. .. an increase in the duration of seed cover increased yield.; Excess soil moisture is the most critical factor for the success of zero tillage wheat cultivation .. the effect of soaking the seed became negligible when [the] soil had sufficient moisture for crop establishment ..; .. wheat yield was positively correlated to rice stubble height: the higher the rice stubble, the higher the yield. |
| 1638 | Giri, G.S. | Effect of rice and wheat establishment techniques on wheat grain yield | 1997 | Miscellaneous | Book | ; Proceedings of the RiceWheat Research End-of-Project Workshop 13 October 1997, Hotel Shangri-La, Kathmandu, Nepal; 66-68 | English | Hardcopy:Full | Trial-plot research to test the effect of rice establishment techniques on the following wheat crop and to compare various wheat establishment techniques. Rice was broadcast into a dry seed bed and into a wet one, drilled with a machine and transplanted. The following wheat crop was better, in terms of tillering, yield, thousand-grain weight and total biomass, after the dry broadcast rice than after any of the other rice establishment methods. In the wheat trials the surfaceseeded wheat had the highest thousand-grain weight, but the machine-drilled crop was better in all other respects. Its yield exceeded by about 10% that of the surface-seeded wheat. | |
| 382 | Girvan, M., Bullimore, J., Ball, A., Pretty, J. & Osborn, M. | Responses of active bacterial and fungal communities in soils under winter wheat to different fertiliser and pesticide regimens | 2004 | Soil Microorganisms | Journal | Appl. Environ. Microbiol.; 70 (5); 2692-2701 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect on soil microbial communities of differing levels of fertiliser and pesticide application | Microbial community structure was primarily determined by season, and the seasonal trends were similar for the fungal and bacterial components.; .. the different fertilisation regimens had the greatest effects on bacterial & fungal community structure, causing short-term increases in total culturable bacterial counts. .. a decrease in the overall diversity & heterogeneity of the bacterial community, but not the fungal community, was observed. Pesticide application did not reduce the total bacterial numbers or the active bacterial diversity, but it did affect the community structure, possibly due to bacterial pesticide degradation. Smaller management effects were observed in the fungal population. |
| 381 | Girvan, M., Bullimore, J., Pretty, J., Osborn, M. & Ball, A. | Soil type is the primary determinant of the composition of the total and active bacterial communities in arable soils | 2003 | Organic Farming; Soil Microorganisms | Journal | Appl. Environ. Microbiol.; 69 (3); 1800-1809 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the factors affecting soil microbial communities in soils under different management systems | .. soil type is the overriding factor in community determin'ns at these sites, followed by the planting of specifically leguminous crops rather than other mgmt practices.; Org. farming did not necessarily result in elevated OM levels; instead a strong assoc'n with increased nitrate availability was apparent. |
| 308 | Glasby, G.P. | Entropy, pollution and environmental degradation | 1988 | Sustainability | Journal | Ambio; 17 (5); 330-335 | English | Hardcopy:Full | Energy consumption by human activity necessarily involves environmental degradation and increase in entropy. Humans use the energy of nature to produce order (lower entropy). In the process part of nature's energy is dissipated and its entropy increases. So environmental degradation is a necessary part of human activity. Thus our own success as a species is our biggest threat. | ..human development must pass into a state of ecological balance if its is not to end with the Pleistocene.; We live in a small bubble of order. .. This ordering constitutes the capital of low entropy with which our planet is endowed. .. man is living off this `capital' of low entropy.; The energy needed to drive the entropy reduction is supplied almost entirely by radiation from the sun.; .. activity per se necessarily leads to increased disorder ..; ..our massive assault against the biosphere, along with the availability of energy, [is] the main determinant of our potential rate of industrial expansion. |
| 975 | Glaser, B., Balashov, E., Haumaier, L., Guggenberger, G. & Zech, W. | Black carbon in density fractions of anthropogenic soils of the Brazilian Amazon region | 2000 | Soil Organic Carbon | Journal | Org. Geochem.; 31 (7-8); 669-678 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the concentration and distribution of black C in Brasilian Terra Preta soils | .. SOM of Terra Preta soils consists of up to 35% of black C throughout the deep A horizons. In the surrounding Oxisols black C occurs only in the first few centimetres of the soil profile with concentrations of up to 14% of the SOM. 14C ages of black C of about 1000-1500 years suggest a high stability ..; .. black C in soils can be found as particulate, unprotected, physically trapped and as oxidatively altered forms that are complexed with minerals.; The highest concentrations and absolute amounts of black C were identified in the light fraction, indicating the particulate nature of black C.; [hence]; .. a major part of black carbon is not chemically stabilised but intrinsically refractory. |
| 927 | Glaser, B., Haumaier, L., Guggenberger, G. & Zech, W. | The 'Terra Preta' phenomenon: a model for sustainable agriculture in the humid tropics | 2001 | Soil Organic Carbon | Journal | Naturwissenschaften; 88; 37-41 | English | Hardcopy:Full; PDF:Full | Study of a certain black-earth-like soil found in central Amazonia, known as Terra Preta | More likely than natural fires as a source of black C in Terra Preta soils are the low-heat smouldering domestic fires commonly used by the native population for cooking and heating.; In the Brazilian Amazon region dense populations once successfully farmed poor oxisols for at least 2,500 years, leaving behind the rich Terra Preta soils, before being displaced by Europeans; Terra Preta soils may be derived from oxisols by enrichment with black C from residues of incomplete burning produced by the early Amerindian population. Due to the highly aromatic structure of black C, it is assumed be chemically and microbially stable and persists in the environment over centuries or millennia. Thus, a part of the labile C pool in the biomass has been converted into a stable SOM pool.; .. in contrast with burning, charring not only prevents large amounts of CO2 from being released into the atmosphere but also provides the soil with a persistent SOM pool rich in nutrient-holding capacity .. |
| 976 | Gleixner, G., Poirier, N., Bol, R. & Balesdent, J. | Molecular dynamics of organic matter in a cultivated soil | 2002 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 33; 357-366 | English | Hardcopy:Partial; PDF:Full | Field expt. to assess the residence time of maize-derived OM in soil | Most pyrolysis products from the maize were derived from polysaccharides and lignins and were not detected in soils. However polysaccharide-derived products @were major pyrolysis products in soils.; *; .. the same 18 pyrolysis products were identified in both cultivated soils.. Most of them were related to polysaccharides, proteins or cpds from multiple sources. .. the majority of pyrolysis products in the maize soil originated from a slowly degrading C pool (between 10 and 100 years). Pyrolysis products from N-containing precursors, i.e. proteins, amino acid moieties or chitin, and polysaccharides had high residence times of about 50 yrs. The results confirm .. that N-containing moieties can be preserved during soil decompos'n & humification processes. Moreover, our results suggest that recycling of amino acids & carbohydrates plays a major role in this stabilisation. The virtual lack of lignin biomarkers demonstrates that lignin is severely biodegraded and is probably not present any more in its initial form. |
| 848 | Goicoechea, N., Merino, S., S1nchez-D1az, M. | Arbuscular mycorrhizal fungi can contribute to maintain antioxidant and carbon metabolism in nodules of Anthyllis cytisoides L. subjected to drought | 2004 | Green Manure; Soil Microorganisms | Journal | J. Plant Physiol.; 162; 27-35 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to test whether AM fungi could help a legume (a Mediterranean relative of kidney vetch) to maintain N fixation during drought | .. long periods of water deficit decrease the diffusion rate of P and consequently also decrease the BNF.; .. the limited diffusion rate of nutrients, particularly p, from the soil matrix to the absorbing surface when soil moisture declines, negatively affects nodulation and BNF.; .. a low soil water content .. accelerated the senescence of nodules in both non-mycorrhizal and mycorrhizal plants. However, while total soluble protein, leghaemoglobin (Lb) content, as well as carbon and antioxidant metabolism significantly decreased in nodules from non-mycorrhizal A. cytisoides subjected to drought, nodules from stressed mycorrhizal plants maintained Lb levels, showed greater rates of carbon metabolism, and exhibited higher enzymatic activities related to the removal of reactive oxygen species. |
| 1702 | Goklany, I.M. | The ins and outs of organic farming | 2002 | Uncategorised | Journal | Science; 298; 1889-1891 | English | PDF:Full | ||
| 733 | Golchin, A., Baldock, J.A., Clarke, P., Higashi, T. & Oades, J.M. | The effects of vegetation and burning on the chemical composition of soil organic matter of a volcanic ash soil as shown by 13C NMR spectroscopy: II. Density fractions | 1997 | Soil Organic Carbon | Journal | Geoderma; 76; 175-192 | English | Hardcopy:Partial | Study on three Japanese soils derived from volcanic ash | .. both free and occluded POM may include considerable amounts of charcoal and charred plant residues where vegetation burning was practised. Assuming no or a limited degradation of charcoal with time through microbial or inorganic reactions, the presence of charcoal in soils not only changes the chemistry of SOM (e.g. increase in aromaticity) .. but can also change its mean turnover times. |
| 734 | Golchin, A., Clarke, P., Baldock, J.A., Higashi, T., Skjemstad, J.O. & Oades, J.M. | The effects of vegetation and burning on the chemical composition of soil organic matter of a volcanic ash soil as shown by 13C NMR spectroscopy: I. Whole soil and humic acid fraction | 1997 | Soil Organic Carbon | Journal | Geoderma; 76; 155-174 | English | Hardcopy:Partial | Study on three Japanese soils derived from volcanic ash | On site I, where grasses were still burned annually, SOM and humic acid fraction contained a greater proportion of aromatic and carbonyl carbons compared to the other sites.; Invasion of grassland by forest resulted in a decrease in C aromaticity and an increase in alkyl C content of the soil and humic acid fraction. |
| 403 | Golchin, A., Clarke, P., Oades, J.M. & Skjemstad, J.O. | The effects of cultivation on the composition of organic matter and structural stability of soils | 1995 | Soil Organic Carbon; Tillage | Journal | Aust. J. Soil Res.; 33 (6); 975-993 | English | Hardcopy:Partial | Lab. expt. to compare the composition of tilled and untilled soils | Differences in the chemical composition of OC between cultivated and uncultivated soils resided mostly in organic materials occluded within aggregates.; .. the virgin sites and sites that had been under long-term pasture had a greater aggregate stability than the cultivated sites.; .. only part of soil C or carbohydrate is involved in aggregate stability. The fractions of C and O-alkyl C present in the form of POM occluded within aggregates were better correlated with aggregate stability. |
| 404 | Golchin, A., Oades, J.M., Skjemstad, J.O. & Clarke, P. | Soil structure and carbon cycling | 1994 | Soil Organic Carbon | Journal | Aust. J. Soil Res.; 32 (5); 1043-1068 | English | Hardcopy:Partial | Lab. study to investigate and model the changes undergone by OM during decomposition in various native soils | .. OM enters the soil, is enveloped in aggregates and eventually is incorporated into microbial biomass and metabolites and associated with clay minerals. .. This model indicates a major role for carbohydrate-rich plant debris in formation and stabilisation of microaggregates. |
| 1005 | Goldemberg, J. | One kilowatt per capita | 1990 | Energy Resources; Sustainability | Journal | Perspective; 46 (1); | English | Hardcopy:Partial | A review of the energy situation and requirements of developing countries | .. energy policy, like other policies, is biased toward the desires of the elites.; .. the vast majority of the rural population in developing countries still use mainly biomass sources - firewood, agricultural wastes and dung.; The results of one systematic computation of direct energy needs suggest that they can be met by an average of 0.3-0.8 kilowatt per capita per day. .. in the mid 1970s the per capita kilowatt usage of industrialised countries ranged from slightly under one kilowatt to slightly over two kilowatts. It is more difficult to quantify the amount of energy consumed indirectly in the form of basic goods and services. One approach is to compare national per capita energy consumption with measures of quality of life. Such comparisons have indicated that above the range of 1.1-1.3 kilowatts per capita improvements in the quality of life are only marginal.This suggests that with current energy technologies an energy consumption rate of 1.1-1.3 kilowatts per capita can satisfy basic human needs .. |
| 555 | Goodland, R. | Environmental sustainability in agriculture: diet matters | 1997 | Stockless Farming; Sustainability | Journal | Ecol. Econ.; 23; 189-200 | English | Hardcopy:Full; PDF:Full | Agricultural sustainability requires us to eat lower on the food chain, eating less or not meat and more grains. Taxing food according to the efficiency and the pollution involved in its production is advocated to induce people to change their diet. | Cattle raising is one of the most damaging components of agriculture. Livestock now eat about half of global grain production.; .. livestock now outnumber humans 3:1.; Most nations were .. self-sufficient in food until the early 1960s; now only a few are. .. Now only Canada and the U.S. are major grain exporters.; The production of one pound of beef consumes over 2700 gallons of water, whereas one pound of grain production consumes less than 200 gallons and vegetables about half that.; .. methane from cattle contributes 2.5% of global greenhouse gas production.; One acre of cereals can produce twice to ten times .. [and] one acre of legumes .. ten to twenty times more protein than an acre in beef production. |
| 109 | Goodland, R. & Pimentel, D. | Environmental sustainability and integrity in the agriculture sector | 2000 | Sustainability | Book | Pimentel, D., Westra, L. & Noss, R.F. (eds.); Ecological Integrity: Integrating Environment, Conservation & Health; | English | Hardcopy:Partial; Wordperfect:Full | Review of measures necessary to make agriculture sustainable | .. the rate of water extraction needs to be balanced with either replenishment rate or the rate of development of a substitute.Most (87 percent) of the world's fresh water is used by the agriculture sector. .. sustainable agriculture will often yield less per area than today's high-input and depleting agriculture in the short term, so demand management (involving such activities as controlling population and stabilising living standards) are essential to achieving sustainability.; .. in order to achieve long-term sustainability and integrity in agriculture, the following three circumstances are envisaged: (1) most people of the world .. would stay at the low end of the chain, but would diversify their diet; (2) affluent people now eating at the top of the food chain would pay full costs or elect to consume more efficiently lower down the food chain; and (3) people starting to move up the food chain (e.g. in China and India): would be encouraged to stop where they are ... |
| 613 | Goodlass, G., Halberg, N. & Verschuur, G. | Input-output accounting systems in the European community: an appraisal of their usefulness in raising awareness of environmental problems | 2003 | Sustainability | Journal | Eur. J. Agron.; 20 (1-2); 17-24 | English | Hardcopy:Partial | Survey of over fifty farm-level input output accounting systems from various European countries | The subjects covered by the IOAs included nutrients, pesticides, energy, soil/habitat, conservation, wastes (e.g. packaging and tyres) and other items such as veterinary products. Nearly half the IOAs covered more than one subject and nutrient budgets were the most commonly included (91% of the IOAs studied).; .. economic issues need to be considered, because, if the costs to the farmer outweigh the benefits, uptake will not be sustained.; .. more studies are needed to ensure that farmers in reality change their behaviour .. |
| 951 | Goossens, A., Visscher, A.D., Boeckx, P. & Cleemput, O. van | Two-year field study on the emission of N2O from coarse and middle-textured Belgian soils with different land use | 2001 | Greenhouse Gases | Journal | Nutr. Cycl. Agroecosyst.; 60 (1-3); 23-34 | English | Hardcopy:Partial | N2O emissions from forest, grass and arable land with various soil textures was measured over 2 years. | @; .. land use rather than soil properties influenced the N2O emission.; .. the N2O-N loss per unit of fertiliser N applied is larger for intensively managed and heavily fertilised (up to 500 kg N ha-1) grasslands than for arable lands and is substantiall |
| 644 | Goss, M.J., Howse, K.R., Christian, D.G., Catt, J.A. & Pepper, T.J. | Nitrate leaching: modifying the loss from mineralised organic matter | 1998 | Cover Crops; Soil N Dynamics; Tillage | Journal | Eur. J. Soil Sci.; 49; 649-659 | English | Hardcopy:Partial | 4-year expt. to compare the effect of different winter treatments on nitrate leaching from the soil | .. reducing tillage depth, incorporating harvest residues, reducing fertiliser N by growing unfertilised grass or by spring-sown rather than autumn-sown crops .. were compared with a control treatment in which autumn crops were sown after burning harvest residues, mouldboard ploughing and seedbed preparation. Winter cover cropping [with white mustard and forage rape] was also compared with winter fallowing.; Only unfertilised grass resulted in a consistent and significant reduction in nitrate leaching during autumn and winter. .. Sowing a cover crop and winter fallowing both resulted in increased leaching of nitrate compared with the control. |
| 1652 | Goswami, D.Y. (ed.) | Alternative Energy in Agriculture | 1986 | Energy in Agriculture; Tillage | Book | Goswami, D.Y.; Alternative Energy in Agriculture; | English | Hardcopy:Partial | Fuel requirements for various farming operations. Also, possible use of solar energy in agriculture. Also, biomass resources of U.S.A. (as alcohol). Figures given show a 33.4 l/ha saving in diesel for zero tillage as compared with conventional cultivation, which requires a total of about 54 l/ha of diesel for cereal growing. | |
| 1111 | Goulden, M.L., Munger, J.W., Fan, S.M., Daube, B.C. & Wofsy, S.C. | Exchange of carbon dioxide by a deciduous forest: response to interannual climate variability | 1996 | Greenhouse Gases | Journal | Science; 271; 1576-1578 | English | Hardcopy:Full | Measurements of net CO2 by New England forest in relation to weather | .. the carbon balance .. of the earth's terrestrial biosphere varies by 1 gigaton of C per year or more from year to year.; The forest gained 30 to 60 kg C ha-1 day-1 in the growing season and lost 10 to 20 kg C ha-1 day-1 in the dormant periods. Annual net CO2 uptake ranged from 1.4 to 2.8 metric tons C ha-1 .. |
| 935 | Goulding, K.W.T., Bailey, N.J., Bradbury, N.J., Hargreaves, P., Howe, M., Murphy, D.V., Poulton, P.R. & Willison, T.W. | Nitrogen deposition and its contribution to nitrogen cycling and associated soil processes | 1998 | Greenhouse Gases; Soil N Dynamics | Journal | New Phytol.; 139 (1); 49-58 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of atmospheric N deposition on forest, grassland and arable soils | N depos'n to winter cereals at Rothamsted is c. 45 kg N ha-1 yr-1; deposition to woodland is likely to be 100 kg N ha-1 yr-1 or more. .. effects on arable land are minimal, but .. the unfertilised plot .. receives enough N to maintain a yield `of 1-2 t wheat ha-1 yr-1.. Such an amount of free N would greatly benefit organic .. farming systems, but will significantly change semi-natural habitats. |
| 136 | Goulding, K.W.T., Murphy, D.V., MacDonald, A., Stockdale, E.A., Gaunt, J.L., Blake, L., Ayaga, G. & Brookes, P.C. | The role of soil organic matter and manures in sustainable nutrient cycling | 2001 | Soil Organic Carbon; Stockless Farming; Soil N Dynamics | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Review of recent research into the quantification of gross N transformations, into the size and significance of the soil soluble N pool and into the comparative effectivness of FYM and chemical fertilisers in the supply of nutrients | Generally, for immobilisation to dominate over nitrification and for N to be conserved, sufficient C is needed to drive the heterotrophic organisms that immobilise ammonium. Thus C & N availability determine the rate & balance of MIT and the supply of nitrate available for plant uptake or loss to the environment. Exudates from the .. root mass .. could be the source of the C needed to cause immobilisation to dominate.; .. as much soluble org. N as mineral N can exist in soil under agricultural cropping systems.; Under continuous arable cultivaH tion the size of the soluble org. N pool is relatively constant at 15-20 kg N/ha ... Under ploughed-out grass the .. pool size is larger at 20-25 kg N/ha. |
| 873 | Goulding, K.W.T., Stockdale, E.A., Fortune, S. & Watson, C.A. | Nutrient cycling on organic farms | 2000 | Organic Farming | Journal | J. R. Agric. Soc. Engl.; 161; 65-74 | English | Hardcopy:Partial | Review of the possible sustainability of organic farming, given its dependence on feedstuffs and bedding for inputs of P and K and on the very variable fixation by legumes or imports of manure or compost for N. | Stockless systems are possible. .. Most common is a 2-year grass-red clover ley, which can accumulate 250-370 kg N/ha and is cut and mulched .. The transition from ley to arable cropping in an organic rotation is generally associated with the highest loss, with up to 180 kg N/ha leached in the winter after ploughing.; Losses of N from organic systems can be as large as those from conventional systems .. they are even more difficult to limit than those from fertilisers applied to conventional farms. There is some evidence of P deficiency in soils under organic production. |
| 977 | Gońi, M.A. & Eglinton, T.I. | Stable carbon isotopic analyses of lignin-derived CuO oxidation products by isotope ratio monitoring-gas chromatography-mass spectrometry (irm-GC-MS) | 1996 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 24 (6/7); 601-615 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to test the efficacy of stable carbon isotope analysis as a means of differentiating between cupric oxide oxidation products of lignin | Most lignin-derived CuO reaction products retain the isotopic signature of their biopolymeric precursor and therefore can be used to characterise the isotopic composition of parent lignins in natural samples. Vascular plant tissues yield lignin reaction products with distinctive isotopic signatures which reflect their major biosynthetic pathways and differentiate between C3 and C4 sources.; .. it is possible to characterise directly the isotopic compos'n of .. lignins by combined application of alkaline CuO oxidation and irm-GC-MS without the need for prior demineralisation. |
| 1722 | Grandy, A.S. & Robertson, G.P. | Aggregation and Organic Matter Protection Following Tillage of a Previously Uncultivated Soil | 2006 | Uncategorised | Journal | Soil Sci. Soc. Am. J.; 70; 1398-1406 | English | PDF:Full | ||
| 820 | Grandy, A.S., Loecke, T.D., Parr, S. & Robertson, G.P. | Long-term trends in nitrous oxide emissions, soil nitrogen and crop yields of till and no-till cropping systems | 2006 | Greenhouse Gases; Soil N Dynamics; Tillage | Journal | J. Environ. Qual.; 35; 1487-1495 | English | Hardcopy:Partial; PDF:Full | 12-yr field expt. to study the effect of tillage on N2O emissions, N availability and crop yields | .. no-till increased soil C in the top 5 cm .. and increased aggregate MWD ..; Average N2O emissions were similar in till & no-till.; Mean annual NO3- concentrations in no-till were significantly less than in conventional till ..; .. lower soil NO3- concentrations did not result in lower yields. |
| 35 | Granstedt, A.G. | The mobilisation and immobilisation of soil nitrogen after green-manure crops at three locations in Sweden | 1995 | Soil N Dynamics | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 265-275 | English | Hardcopy:Full | Field expt. to investigate the possibility of predicting the quantity of soil inorganic nitrogen after the ploughing in of a green-manure crop | ... it is possible to predict the crop value of green manure, in the form of the quantity of mineralised nitrogen, if the amount of ploughed-under nitrogen and the carbon/nitrogen ratio are known for a given humification coefficient. The best agreement between measured and simulated values was obtained when a humification coefficient of 35% was assumed, meaning that 65% of the crop carbon (was released as CO2 within about a year of being ploughed under ... At an average N content of 2.4% and a C/N ratio of 19, 34% of the ploughed-under N was released ... while the rest of the N was bound in the humus... |
| 124 | Granstedt, A.G. & Kjellenberg, L. | Quality investigations with the K-trial, Jarna and other Scandinavian fertilisation experiments | 1996 | Biodynamic Farming; Miscellaneous; Organic Farming | Book | Raupp, J. (ed.); Quality of plant products grown with manure fertilisation, Proc. 4th mtg (concerted action AIR3-CT94-1940); | English | Hardcopy:Partial; Wordperfect:Full | Review of yield and quality of produce from conventional and biodynamic farming systems in some long-term field expts | Compared with the conv'l treatments the content of crude protein in the organic treatments was lower but the relative pure protein and the content of essential amino acids were higher in potatoes and wheat.; The average tuber yield .. was the same in the organic & conv'l treatments.; The average [wheat] yield levels in [biodynamic] and [conv'l treatments] were nearly the same. For [the organic treatment], in which there was no application of biodynamic field prep'ns, the yield level was significantly lower. |
| 1112 | Grant, L. | When will the oil run out? | 2005 | Energy Resources | Journal | Science; 309; 52-54 | English | Hardcopy:Partial | Reply to a previous article alleging that there were still 3x109 barrels of recoverable oil resources in the world | the remaining oil totals 2311 billion barrels, a figure closer to other estimates.; .. although the experts may quibble over their differences, they are in broad agreement: all the estimates I have seen agree within a factor of about two as to how much oil remains.; With a projected annual growth worldwide of 1.9% from 2001 to 2025, the 32 years' supply [of oil] would decline to about 26 years. |
| 978 | Grasset, L. & Amblčs, A. | Structure of humin and humic acid from an acid soil as revealed by phase transfer catalysed hydrolysis | 1998 | Soil Organic Carbon | Journal | Org. Geochem.; 29 (4); 881-891 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the composition of humus (humin and humic acid) | .. the OM of the initially insoluble humin .. can be almost completely solubilised (87%) when submitted to step-wise hydrolysis under phase-catalysis transfer conditions.; .. significant structural differences do exist between humin & humic acid.; .. fatty acid and alkanol moieties indicates a bacterial input. .. A higher plant input for some lipids is indicated by the presence of ligninderived aromatic acids. Lipids such as hydrocarbons can be present as trapped molecules in the macromolecular network of humin and humic acid. These hydrocarbons are predominantly of bacterial origin. |
| 645 | Greenfield, L.G. | The origin and nature of organic nitrogen in soil as assessed by acidic and alkaline hydrolysis | 2001 | Soil N Dynamics | Journal | Eur. J. Soil Sci.; 52 (4); 575-583 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the nature of org. N cpds in soil using acid & alkaline hydrolysis | .. the identity of about 35% of the org. N in the soil & the origin of approx. 50% of hydrolysable ammonium is not known or at least is debatable.; Alkaliinsoluble residues from a wide variety of soils contained largely fixed ammonium or chitin or both. Acid hydrolysis of alkali-insoluble residues from soils, microbes, insects & well-rotted plant litter confirmed the presence of hexosamineN.; .. much of this N is in the form of polymeric hexosamines derived largely from fungi and insects. Chitin .. [is] widely distributed in the soil ecosystem, particularly in microbes & insects, but not in plants. Low MW hexosamines, e.g. glucosamine, galactosamine & muramic acid, occur in bacteria & plants, but these will be largely destroyed during alkali hydrolysis, leaving chitin & chitosan residues which are largely insoluble following alkali hydrolysis. |
| 320 | Greenhalgh, J.F.D. | The dilemma of animal feeds and nutrition | 1976 | Stockless Farming | Journal | Anim. Feed Sci. Technol.; 1 (1); 1-7 | English | Hardcopy:Full | Animals are fed on cereals that could be consumed by humans. It is immoral that people starve in poor countries, while cereals that could save them are used to feed livestock in richer countries. The counter argument is an economic one - that the people in the poor countries cannot afford to buy that grain, while the livestock farmer in the richer countries can. | In Britain today the feed requirements of the nation's domestic animals, when expressed in metabolisable energy, are three times those of the country's human population. .. [But] they provide only one third of the energy intake of their consumers.; Most domestic animals are kept to provide food for man, which they do with a woefully poor energetic efficiency.; The food deficit in the developing countries is still small in relation to the food `surplus' that is used for animal feed in the develop[ed countries.; .. the resources of land, labour and capital needed to grow forages [animal feed] could often be used to produce plant foods for direct human consumption. |
| 1482 | Greenland, D.J. | Soil conditions and plant growth | 1997 | Soil (General) | Journal | Soil Use Manag.; 13; 169-177 | English | Hardcopy:Full | Review of existing knowledge of soil conditions and how they influence plant growth (inaugural Russell memorial lecture) | .. to yield gains of wheat in Mexico from 1968 to 1990 .. genetic improvement contributed 28% .., N supply 48% & changes in the resource base & pest & disease incidence the remaining 24%.; .. as the nat'l average wheat yield .. approaches 9 t/ha, the return from the use of high levels of inorg.fertilisers .. will only be fully realised if higher levels of OM can be .. maintained.; The All-India long-term trials.. showed a consistent advantage to the integrated use of inorg. fertilisers & manure ..; on the global extent of degradation .. more than 40% of agric. soils had been degraded ..; If all resources are harnessed & adequate measures are taken to minimise soil degradation, sufficient food can be produced to sustain a population several times more than the present population. |
| 1426 | Gregorich, E.G., Beare, M.H., McKim, U.F. & Skjemstad, J.O. | Chemical and biological characteristics of physically uncomplexed organic matter | 2006 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 70; 975-985 | English | Hardcopy:Full; PDF:Full | Review of current knowledge of so-called physically uncomplexed SOM (the SOM fractions that are not bound to mineral particles, including LF & POM) | Physically uncomplexed OM .., compared with the whole soil or heavy fraction, has a wide C/N ratio and high O-alkyl (i.e. carbohydrate) and low carbonyl (i.e. protein) C contents. The response of [it] to changes in land use and management practices is greater than that of other labile OM fractions or the whole soil C and N. .. it is not an immediate source of nutrients. .. the quantity and the biol. & chem. props of phys. uncomplexed OM are affected by the amount, compos'n & accessibility of plant residues entering the soil; env'mtal conditions that may enhance or constrain decomposition; and the fractionation technique used. |
| 516 | Gregorich, E.G., Carter, M.R., Angers, D.A., Monreal, C.M. & Ellert, B.H. | Towards a minimum data set to assess soil organic matter quality in agricultural soils | 1994 | Soil Organic Carbon | Journal | Can. J. Soil Sci.; 74 (4); 367-385 | English | Hardcopy:Partial | Review of the various attributes of soil quality | Soil quality is a composite measure of both a soil's ability to function and how well it functions relative to a specific use.; .. non-humic substance that contribute to the organic C & N contents in soil consist of low-molecular-weight aliphatic and aromatic acids, carbohydrates, amino-acids and their polymeric derivatives such as polypeptides, proteins, polysaccharides and waxes. These compounds have a relatively rapid turnover in soil and are used readily as substrates by soil microorganisms. Humic substances .. consist of complex polymeric organic compounds with high molecular weight and are intimately associated with inorganic constituents [which] make them more resistant to decomposition than the non-humic materials. |
| 517 | Gregorich, E.G., Drury, C.F. & Baldock, J.A. | Changes in soil carbon under long-term maize in monoculture and legume-based rotation | 2001 | Green Manure; Soil Organic Carbon | Journal | Can. J. Soil Sci.; 81; 21-31 | English | Hardcopy:Full | Legume-based cropping systems could help to increase crop productivity and SOM levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. Organic C abundance was measured in soils under forest, under fertilised and unfertilised continuous grass and under fertilised and unfertilised maize, both in monoculture and in legume-based rotations. | .. the quantity of C inputs was not the primary factor affecting soil C storage. .. residue quality is an important factor in increasing the retention of soil C in agro-eco-systems. .. the quantity of soil C was smaller in the maize monoculture systems than in the rotation systems, even though C inputs were about the same or higher in the monoculture systems. ..; .. soils under legume-based rotation tend to be more `preservative' of residue C inputs .. than soils under monoculture.; .. substantial amounts of C can be mineralised and lost from below the plough layer after the conversion of forest to arable agriculture. |
| 518 | Gregorich, E.G., Ellert, B.H. & Monreal, C.M. | Turnover of soil organic matter and storage of corn residue carbon estimated from natural 13C abundance | 1995 | Mineralisation; Soil Organic Carbon | Journal | Can. J. Soil Sci.; 75 (2); 161-167 | English | Hardcopy:Partial | Expt. to compare the quantity and initial source of OM in a forest soil and a soil under continuous maize for 25 years | The total mass of organic C in the cultivated oils was 19% lower than in the forest soil .. after 25 yr of continuous corn.; [and]; more than 75% of the residue C added to the soil was lost by mineralisation and returned to the atmosphere as CO2. Between 25 and 35% of the organic C in the plough layer was derived from corn residues. .. The turnover was fastest in the LF [which] appeared mainly to comprise recently added residues, about 70% [of which] was derived from corn. |
| 1427 | Gregorich, E.G., Ellert, B.H., Drury, C.F. & Liang, B.C. | Fertilisation effects on soil organic matter turnover and corn residue C storage | 1996 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 60; 472-476 | English | Hardcopy:Partial | A comparison of SOM residue and turnover in fertilised and unfertilised soils. Soils under continuous maize cropping and fertilised with nitrogenous chemical fertilisers showed a greater accumulation of organic C than unfertilised soils. @13C measurements showed that the amount of C3-derived C is about the same in both fertilised and unfertilised soils. The difference is accounted for by the greater amount of C4-derived (maize-derived) C in the fertilised soils. | .. adequate fertilisation increases crop yields, in turn leading to greater [crop-derived] C storage .. fertilisation does not significantly alter the rate of turnover of native [C3-derived] SOM.; Larson et al. (1972) found that changes in SOC were linearly related to the amount of residue applied to soil under continuous corn. Rasmussen et al. (1980) .. noted that the changes were independent of the type of residue applied. |
| 1542 | Gregorich, E.G., Greer, K.J., Anderson, D.W. & Liang, B.C. | Carbon distribution and losses: erosion and deposition effects | 1998 | Greenhouse Gases; Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 47 (3/4); 291-302 | English | Hardcopy:Full; PDF:Full | Review of research into the effects of erosion and deposition on the storage of C in soils | .. the rate of soil loss on shoulder slope positions after primary and @secondary tillage was greater than 54 Mg ha-1 yr-1 and concluded that this tillage erosion accounted for at least 70% of the soil loss.; .. net mineralisation is the dominant process in the decline of organic C when native grassland soils are first cultivated, and that erosion becomes a major factor in later years. |
| 1543 | Gregorich, E.G., Rochette, P., Bygaart, A.J. van den & Angers, D.A. | Greenhouse gas contributions of agricultural soils and potential mitigation practices in Eastern Canada | 2005 | Greenhouse Gases; Green Manure; Tillage | Journal | Soil Tillage Res.; 83 (1); 53-72 | English | Hardcopy:Partial; Wordperfect:Full | Review of research into the production and mitigation of greenhouse gases in agriculture in eastern Canada | @; In cool temperate regions N2O emission comprises the majority of greenhouse gas emission associated with crop production. Manure is an important source of N2O emission.. Most of the CH4 produced in the agriculture sector is associated with animal produ |
| 1226 | Gregorich, E.G., Voroney, R.P. & Kachanowski, R.G. | Turnover of carbon through the microbial biomass in soils with different textures | 1991 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 23 (8); 799-805 | English | Hardcopy:Full | Lab. expt. to study the effect of labelled glucose on ten soils with different clay contents | Total biomass C (labelled + unlabelled C) contents reached maximal amounts after 1.25 days .. Biomass 14C was maintained at higher amounts in soils with more clay .. until 45 days. The [proportion of C derived from labelled glucose and incorporated in the biomass ranged from 59% to 73% after 1.25 days and from 16% to 20% after 90 days. The labelled biomass was .. correlated with the amount of clay at all sampling dates .. |
| 1723 | Gregory, P.J. | Roots, rhizosphere and soil: the route to a better understanding of soil science? | 2006 | Uncategorised | Journal | Eur. J. Soil Sci.; 57; 2-12 | English | PDF:Full | ||
| 222 | Gregory, P.J., Ingram, J.S.I., Andersson, R., Betts, R.A., Brovkin, V., Chase, T.N., Grace, P.R., Gray, A.J., Hamilton, N., Hardy, T.B., Howdena, S.M., Jenkins, A., Meybeck, M., Olsson, M., Ortiz-Monasterio, I., Palm, C.A., Payne, T., Rummukainena M., Schulze, R.E., Thiema, M., Valentin C. & Wilkinson, M.J. | Environmental consequences of alternative practices for intensifying crop production | 2002 | Agricultural Ecology; Miscellaneous | Journal | Agric. Ecosyst. Environ.; 88; 1-12 | English | Hardcopy:Partial; PDF:Full | Review of possible apporaches to increase world food production | The use of low amounts of external inputs is generally regarded as being the most environmentally benign, although this advantage over systems with higher inputs may disappear if the consequences are expressed per unit of product rather than per unit area. The adverse effects of production systems with high external inputs, especially losses of nutrients from fertilisers and manures to water courses and contributions of gases to climate forcing, have been quantified. Future intensification, including the use of improved germ-plasm via genetic modification, will seek to increase the efficiency of use of added inputs while minimising adverse effects on the environment. However, reducing the loss of nutrients from fertilisers and manures and increasing the efficiency of water utilisation in crop production remain considerable challenges. |
| 17 | Gressel, N. & McColl, J.G. | Phosphorus mineralisation and organic matter decomposition: a critical review | 1997 | Phosphorus Cycling | Book | Cadisch, G. & Giller, K.E. (eds.); Driven by Nature: Plant Litter Quality and Decomposition. C.A.B. International; | English | Hardcopy:Partial; Wordperfect:Full | Review of soil P research up to the present. Scientific opinion differs on whether or not phosphatase activity is the rate-limiting step for organic P mineralisation. | The global P cycle consists of weathering processes, including mineral dissolution, erosion and leaching, which transfer P from the terrestrial environment to oceanic deposits, and of volcanism and uplifting of marine sediments which replenish terrestrial P and complete the cycle.; Concentrations (of total P are low in soils (usually 0.2-5.0 g kg-1) and soil solutions (<1 mg l-1) ..; In agricultural soils most Po is in forms that are .. poor nutrient sources on a time-scale appropriate for agricultural production .. However, forests and other non-agricultural ecosystems rely more heavily on H mineralisation of Po, which typically comprises 30-80% of total P in litter and soil.; On a biological time-scale .. P mineralisation is associated with decomposition of litter and soil OM, although availability of P on a pedogenic time-scale is ultimately controlled by the release of P from primary minerals and subsequent leaching. |
| 269 | Grierson, P.F. & Adams, M.A. | Nutrient cycling and growth in forest ecosystems of south western Australia: relevance to agricultural landscapes | 1999 | Miscellaneous; Sustainability | Journal | Agrofor. Syst.; 45 (1/3); 215-244 | English | Hardcopy:Partial; PDF:Full | Review of the qualities desirable in an agricultural system designed to mimic nature | .. application of such a mimic concept to systems of low natural productivity is limited when agricultural systems require continued high productivity. Nonetheless, the mimic concept may help in developing sustainable management of agriculture on marginal lands and contribute to the nutritional resilience of agroecosystems. Relevant characteristics for mimic agroecosystems .. include: high species diversity, diversity of rooting attributes, utilisation of different forms of nutrients (especially of N and P) in space and time, and the promotion of practices which increase soil organic matter content.; Improving SOM content is crucial .. to the maintenance of soil fertility .. The inclusion of shade trees, mixed cropping of species that differ in phenology (both above- and belowground), controlling weeds and pests through crop rotation, dense spacing, mulching and application of manure rather than through cultivation, are all likely to result in an increase in soil organic matter. |
| 1227 | Grierson, P.F., Comerford, N.B. & Jokela, E.J. | Phosphorus mineralisation kinetics and response of microbial phosphorus to dying and rewetting in a Florida spodosol | 1998 | Phosphorus Cycling | Journal | Soil Biol. Biochem.; 30 (10/11); 1323-1331 | English | Hardcopy:Partial; PDF:Full | Net mineralisation of P in undried soils was best described by zero-order kinetics and in dried and re-wetted soils by a 2-pool model with one pool zeroorder and the other first-order. Net mineralisation in re-wetted soils went in three stages: (1) an initial flush due to turnover of the microbial biomass from the drying period and mineralisation of organic substrates; (2) a lag of a few days with no net release of P; and (3) a period of zero-order kinetics, where the microbial biomass had recovered sufficiently to mineralise P from SOM. | |
| 1653 | Grigg, D.B. | The Agricultural Systems of the World: An Evolutionary Approach | 1974 | Agricultural Ecology | Book | Grigg, D.B.; The Agricultural Systems of the World: An Evolutionary Approach; | English | Hardcopy:Partial | Agricultural systems are reviewed geographically and historically, including, in the pp. photocopied, the characteristics of Mediterranean farming such as transhumance and the development of agriculture, especially mixed farming, in the Middle Ages. | In traditional Mediterranean agriculture every village, if not every farm, would grow cereals, keep sheep and goats and have grapes for wine and olives for cooking oil and lighting.; Both fruits and vegetables have been an important part of Mediterranean farming since at least Roman times ..; .. in northern Europe in Roman times .. oats, barley, wheat and rye were all grown, as was spelt, which remained a major crop until the late Middle Ages .. but vegetables and fruits .. were of little significance. .. There was still much shifting agriculture .. The plough [was] made of wood. .. Most farmers kept livestock as well as growing cereals; pigs probably provided most of the meat .. cropping was unimportant compared with pastoralism.; The date of the introduction of the heavy [steel] plough is still unknown; it seems to have spread slowly .. after the sixth century A.D. Later horses began to be used instead of oxen, .. but horses did not immediately replace oxen; they cost more to feed and could not be sold for meat.; Thus by 1300 .. the main aim of the farmer was to raise cereals .. other crops were rare, although some pulses were grown. |
| 36 | Grimal, J.Y., Frossard, E. & Morel, J.L. | The acquisition of phosphorus sorbed on a goethite by maize | 1995 | Phosphorus Cycling | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 235-239 | English | Hardcopy:Full | Lab. expt. to determine to what extent maize roots could mobilise phosphorus absorbed on goethite in the absence of microorganisms | After ten days of growth in the presence of phosphated goethite, ... 23.5% of the sorbed P was removed from the goethite, whereas less than 1% was extractable by an anionic resin. |
| 775 | Groenestein, C.M. & Faassen, H.G. van | Volatilisation of ammonia, N2O and nitric oxide in deep-litter systems for fattening pigs | 1996 | Greenhouse Gases | Journal | J. Agr. Eng. Res.; 65 (4); 269-274 | English | Hardcopy:Partial | Expt. to compare the gas emissions from pigs kept on slatted floors and on deep litter | @; The N emitted as NH3, NO and N2O measured with System 1 was 0.24, 0.04 and 0.3 g N/h per pig respectively. For System 2 emissions were 0.12, 0.01 and 0.2 g N/h per pig respectively.; .. deep-litter systems for fattening pigs may reduce NH3- emission co |
| 1724 | Gryze, S. de, Jassogne, L., Six, J. & Merckz, R. | Water repellence and soil aggregate dynamics in a loamy grassland soil as affected by texture | 2006 | Uncategorised | Journal | Eur. J. Soil Sci.; 57; 235-246 | English | PDF:Full | ||
| 1725 | Gryze, S. de, Six, J. & Merckx, R. | Quantifying water-stable soil aggregate turnover and its implication for soil organic matter dynamics in a model study | 2006 | Uncategorised | Journal | Eur. J. Soil Sci.; 57; 693-707 | English | PDF:Full | ||
| 1228 | Gryze, S. de, Six, J., Brits, C. & Merckx, R. | A quantification of short-term macroaggregate dynamics: influences of wheat residue input and texture | 2005 | Soil Organic Carbon; Soil (General) | Journal | Soil Biol. Biochem.; 37 (1); 55-66 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of wheat residue decomposition on the macroaggregate dynamics of three fertilised grassland soils of differing textures | Aggregate formation increased linearly with increasing amounts of residue ..; While amounts of water-stable macroaggregates in the sandy loam & the silt loam soil corresponded well with fungal lengths, this was not the case for the silty clay loam soil. This suggests that fungi are less important in aggregate formation in more clayey soils.; .. a macroaggregate turnover time of 40-60 days. |
| 1230 | Guggenberger, G. & Zech, W. | Composition and dynamics of dissolved carbohydrates and lignin degradation products in two coniferous forests, N.E. Bavaria, Germany | 1994 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 26 (1); 19-27 | English | Hardcopy:Partial | Expt. to study the flux of carbohydrates and lignin-derived substances through the soil. The input was much greater than the output and this was more due to adsorption of the substances on the soil matrix than to their biodegradation. | |
| 646 | Guggenberger, G., Christensen, B.T. & Zech, W. | Land-use effects on the composition of organic matter in particle-size separates of soil: I. Lignin and carbohydrate signature | 1994 | Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 45 (4); 449-458 | English | Hardcopy:Partial | Expts. to compare the quality (including lignin and carbohydrates) and quantity of the OM in soils under forest, arable rotation and grassland (converted from arable rotation in 1956). | Whole soil from spruce forest, deciduous forest, permanent grassland and arable rotation contained 84, 59, 73 and 25 g C per kg. soil respectively. For all sites the C content declined .. in the order: clay (< 2 m), silt (2-20 m), sand (20-2000 m).; [This] is indicative of an increasing degree of humification.; SOM associated with silt has the slowest turnover. |
| 1229 | Guggenberger, G., Elliott, E.T., Frey, S.D., Six, J. & Paustian, K. | Microbial contributions to the aggregation of a cultivated grassland soil amended with starch | 1999 | Soil Microorganisms; Soil (General) | Journal | Soil Biol. Biochem.; 31 (3); 407-419 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of microorganisms on the formation of macroaggregates from microaggregates in soil amended with starch | .. we observed no formation of macroaggregates in the control samples (incubated without starch amendment) & the undecomposed starch did not glue microaggregates into macroaggregates either. We suggest that microhabitats enriched in substrate acted as hot-spots for fungal growth .. However, the stabilisation of the macroaggregates throughout the expt may be attributed to other factors that persist after cell death of the microorganisms. In-situ mineralis'n rate constants of [starch-derived] C were much lower for the microaggregates compared with .. macroaggregates, indicating a better stabilis'n of starch-derived C within the microaggregates & .. supporting the macro- [&] microaggregate conceptual model. |
| 1428 | Guggenberger, G., Frey, S.D., Six, J., Paustian, K. & Elliott, E.T. | Bacterial and fungal cell-wall residues in conventional and no-tillage agroecosystems | 1999 | Soil Microorganisms; Tillage | Journal | Soil Sci. Soc. Am. J.; 63 (5); 1188-1198 | English | Hardcopy:Partial; PDF:Full | In soil samples from long-term conventional v. zero tillage trials microbial necromass (mass of dead cells) is estimated by determining the concentration of glucosamine, a product of the hydrolysis of chitin (poly-N-acetyl glucosamine) that is commonly found in the cell walls of fungi, and muramic acid, which is exclusively found in the cell walls of bacteria. Glucosamine is not a suitable indicator, however, for fungal biomass (mass of living cells) - the cell-wall residues have a much longer turn-over time in the soil than the living microorganisms, are physically protected from microbial decomposition inside soil aggregates and may represent a microbially derived intermediate SOM pool that accumulates in NT systems. | Beare (1997) showed that litter placement exerts a profound influence on the composition of decomposer communities. CT systems, where litter is buried, favour a bacterial-dominated community, whereas in surface litter .. of NT systems filamentous fungi are relatively more abundant.; .. hyphae are important in the formation and stabilisation of macroaggregates .. During .. the expt. fungal and bacterial biomass declined rapidly [but] macroaggregates remained stable. This suggests that more recalcitrant compounds like cell-wall residues were involved in the aggregate stabilisation. .. However, a clear cause-and-effect relationship between aggregation and accumulation of cell-wall residues still needs to be [established]. |
| 1231 | Guggenberger, G., Zech, W. & Thomas, R.J. | Lignin and carbohydrate alteration in particle-size separates of an oxisol under tropical pastures following native savanna | 1995 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 27 (12); 1629-1638 | English | Hardcopy:Partial | Expt. to study the changes in SOM following the establishment of pastures following native grassland | .. [the results] indicated progressive lignin alteration with decreasing particle size.; Clay-bound SOM was rich in microbially-derived sugars ..; Earthworm casts were characterised by a tremendous enrichment of C, intact lignin and plant-derived sugars .. compared with the surrounding soil. |
| 647 | Guggenberger, G., Zech, W., Haumaier, L. & Christensen, B.T. | Land-use effects on the composition of organic matter in particle-size separates of soils: II. CPMAS and solution 13c NMR analysis | 1995 | Soil Organic Carbon; Tillage | Journal | Eur. J. Soil Sci.; 46 (1); 147-158 | English | Hardcopy:Partial | Lab. expt. to study the composition of SOM in different fractions of forest, grassland and arable soils | .. sand-sized separates were enriched in plant residues .. whereas clay-sized separates were dominated by products of microbial re-synthesis. Silt was rich in selectively preserved & microbially transformed primary resources.; ..arable rotation decreased SOM .. in all size separates, but the proportion of wholesoil SOM in clay increased .. probably due to loss of stabilisation of POM after disintegration of soil aggregates upon cultivation.; Perm. grassland resulted in a high proportion of lignin and plant-derived carbohydrates in the sand-sized separates .. probably due to a high rate of rhizodeposition and occlusion of plant residues within aggregates. |
| 37 | Guiking, F.C.T. & Stomph, T.J. | The modification of soil processes by mulching in the humid tropics | 1995 | Mulch | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 383-386 | English | Hardcopy:Full | Review of the effects of mulch on the soil in the humid tropics | Improved crop performance in mulched fields is generally ascribed to one or a combination of the following changes in growth conditions: reduced water loss by evaporation, increased infiltration, reduced temperature fluctuations and improved nutrient status.; The main positive effect of mulch in the humid tropics is likely to be the build-up and maintenance of a flourishing soil (micro)fauna and flora. |
| 1385 | Guimarăes, M.F., Nascimento Filho, V.F. & Ritchie, J.C. | Application of Cesium-137 in a study of soil erosion and deposition in southeastern Brazil | 2003 | Soil (General) | Journal | Soil Sci.; 168 (1); 45-53 | English | Hardcopy:Partial | The cesium-137 concentrations in soil samples from a valley in Brasil were measured and used to assess the relative rate of soil loss in that locality. | @; One of the most abundant radionuclides, 137Cs has a relatively long half-life (30.2 years). Once in contact with the soil, 137Cs is quickly adsorbed to fine particles and .. is not easily removed.; The vertical distribution of 137Cs in the soil profile |
| 1232 | Gunapala, N. & Scow, K.M. | Dynamics of soil microbial biomass and activity in conventional and organic farming systems | 1998 | Organic Farming; Soil Microorganisms | Journal | Soil Biol. Biochem.; 30 (6); 805-816 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the quantity and activity of microorganisms in conventionally and organically farmed soils | After one 4-y rotation cycle, total OM content had increased in the organic system by 8-15% in comparison to the conventional systems and since then OM contents have been consistently and significantly higher in ... organic than conventional systems. More significant was the increase in the amount of C associated with microbial biomass in the organic ... relative to the conventional system, ... |
| 1233 | Gunapala, N., Venette, R.C., Ferris, H. & Scow, K.M. | Effects of soil management history on the rate of organic matter decomposition | 1998 | Organic Farming; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 30 (14); 1917-1927 | English | Hardcopy:Partial; PDF:Full | Long-term field expt. comparing the rate of organic matter decomposition in organically and conventionally managed soils | .. soils managed under org. farming practices had greater microbial abundance & activity .. during crop growth than those managed under conv'l .. We tested rates of organic matter decompos'n in the two soils and monitored the abundance and activity of soil biota during the decomposition process. Differences in soil biology between soils from org. & conv'l farming systems did not persist when soils were amended with OM & maintained under similar conditions. Microbial communities in soil from the conv'l system were sufficient and active enough to respond to org. inputs. There were minimal differences in the ability of the microbial communities of the two soils to decompose organic residues. |
| 1429 | Guo, F., Yost, R.S., Hue, N.V., Evensen, C.I. & Silva, J.A. | Changes in phosphorus fractions in soils under intensive plant growth | 2000 | Phosphorus Cycling | Journal | Soil Sci. Soc. Am. J.; 64 (5); 1681-1689 | English | Hardcopy:Partial; PDF:Full | Study of the changes in the various P fractions in eight soils during a 14-year cropping with maize and soya beans. NaOH-Pi was a buffer for available P (strip-P xand NaHCO3-Pi) in highly weathered soils, HCl-P and residual P only in slightly weathered soils. | Organic P may be important in P fertility in unfertilised soils or soils with high OM, but it does not appear to affect P availability significantly in high-P mineral soils. |
| 980 | Gupta, N.S., Briggs, D.E.G., Collinson, M., Evershed, R.P., Michels, R. & Pancost, R.D. | Reply to de Leeuw's comment 'On the origin of sedimentary aliphatic macromolecules' | 2007 | Soil Organic Carbon | Journal | Org. Geochem.; 38; 1588-1591 | English | Hardcopy:Full; PDF:Full | Review of the research on aliphatic macromolules in fossilised plants | Examination of the fossil organisms' extant analogues fails to reveal direct biological precursors... research indicates that aliphatic geomacromolecules in fossils derive from the in-situ incorporation and polymerisation of labile aliphatic compounds (including both high and low molecular weight compounds) from the organism. Other workers .. have suggested that the process of oxidative cross-linking accounts for the fossilisation of some algae and Archaea which likewise lack resistant aliphatic biopolymers in the living organism. |
| 979 | Gupta, N.S., Briggs, D.E.G., Collinson, M., Evershed, R.P., Michels, R., Jack, K.S. & Pancost, R.D. | Evidence for the in-situ polymerisation of labile aliphatic organic compounds during the preservation of fossil leaves: implications for organic matter preservation | 2007 | Soil Organic Carbon | Journal | Org. Geochem.; 38; 499-522 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the aliphatic content of fossil leaves and leaves from analogous modern plants | Chemical degradation of the modern plants failed to reveal the presence of the aliphatic biomacromolecule cutan, thereby precluding selective preservation of this cpd as the source of the aliphatic component of the fossil leaves. ..investigations of the fossils revealed no evidence for cuticle preservation and, while a contribution from cutin cannot be excluded, the aliphatic component of the fossil polymer is possibly derived instead from the in-situ polymerisation of labile cell membrane lipids and free fatty acids. |
| 1234 | Gupta, V.V.S.R. & Germida, J.J. | Distribution of microbial biomass and its activity in different soil aggregate size classes as affected by cultivation | 1988 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 20 (6); 777-786 | English | Hardcopy:Partial | Study of the microbial biomass in different aggregate size classes in native soil and soil cultivated for 69 years | Cultivation decreased microbial biomass content, its activity and enzyme activity .. Microaggregate (<250 m) .. in both native and cultivated soils contained lower organic C, microbial biomass C, fungal biomass .. and respiratory activities as compared to macroaggregates. .. the negative effects of cultivation were more pronounced on macroaggregate .. |
| 120 | Guy, S.O. | Crop rotation and residue durability effects of brassicas and other crops on winter wheat | 1999 | Miscellaneous; Rape and Biodiesel | Book | ; Proceedings of the Tenth International Rapeseed Conference; | English | Hardcopy:Full | 2-year field expt. to determine the effect of previous crops on the yield of winter wheat. The results are generally rather inconclusive, but in on year there is a significant increase in wheat yield following peas and lentils as previous crop. | |
| 1544 | Guérif, J., Richard, G., Dürr, C., Machet, J.M., Recous, S. & Roger-Estrade,J. | A review of tillage effects on crop residue management, seedbed conditions and seedling establishment | 2001 | Tillage | Journal | Soil Tillage Res.; 61; 13-32 | English | Hardcopy:Partial; PDF:Full | Review of tillage effects on crops | .. crop residues left on the soil surface .. limit evaporation, soil sealing and soil crusting .. thus increase infiltration and limit soil erosion .. [but] may affect soil thermal regime and reduce grain yield .. can impede crop establishment and provide a favourable habitat for slugs. |
| 759 | Gómez-Ibáńez, D.A. | Energy, economics and the decline of transhumance | 1977 | Energy in Agriculture | Journal | Geogr. Rev.; 67; 284-298 | English | Hardcopy:Partial | Energy flows are compared in transhumance and in modern systems that have succeeded it in the western United States. The energy efficiency of transhumance is shown to be greater than that of more modern systems | Agriculture in industrialised societies (and 'Green Revolution' agriculture) depends on large inputs of energy in the form of petroleum.; In the U.S. an average of 10 joules is required to put one joule's worth of food on the table.; It is profitable only because we still measure efficiency in terms of dollars rather than energy or work and because fossil fuels are still available. As these sources of energy become scarcer and more expensive, energy-subsidised agricultural systems must evolve toward energy efficiency. A reversal in the trends of the last two centuries might be realised by a shift from fossil fuels to solar energy sources, including an increasing use of human labour and animal traction ..; The quest to improve the energy efficiency of modern agriculture will benefit greatly from investigations of traditional agricultural systems in which there is no energy subsidy. .. In traditional systems each joule of work expended .. obtains more than one joule's worth of food. Any other result leads to starvation. .. |
| 690 | Gómez-Rodríguez, O., Zavaleta-Mejía, E., González-Hernández, V.A., Livera-Muńoz, M. & Cárdenas-Soriano, E. | Allelopathy and microclimatic modification of intercropping with marigold on tomato early blight disease development | 2003 | Allelopathy | Journal | Field Crops Res.; 83 (1); 27-34 | English | Hardcopy:Partial | Expt. to test the effect of marigolds on the disease resistance of tomato plants | .. intercropping [tomato] with marigold induced a significant reduction in tomato early blight caused by A. solani ..; .. marigold helped tomato plants in 3 different ways: .. by the allelopathic effect on A. solani development; .. by reducing maximal RH [relative humidity] to levels lower than 92%, since this pathogen requires high humidity ... [and by] act[ing] as a physical barrier against spore dispersion.; Our results show a clear allelopathic effect of marigold leaves on A. solani development .. this allelopathic effect is due to the ability of marigold leaves to produce and liberate volatile tiophenes. |
| 1037 | Görres, J.H., Savin, M.C., Neher, D.A., Weicht, T.R. & Amador, J.A. | Grazing in a porous environment: 1. The effect of soil pore structure on C and N mineralization | 1999 | Soil Organic Carbon; Soil Microorganisms; Soil N Dynamics | Journal | Plant Soil; 212 (1); 75-83 | English | Hardcopy:Partial; PDF:Full | Review of the effect of grazing on microbial abundance and activity and on C & N mineralisation | Grazing of microorganisms by soil microfauna accelerates nutrient mineralisation, contributing up to 30% to N mineralisation. Microbivorous soil animals contribute directly to nutrient mineralisation by egesting mineral nutrients derived from their forage and indirectly by affecting microbial growth rates and changing the structure of the microbial communities. |
| 1 | Haas, G., Berg, M. & Köpke, U. | Nitrate leaching: comparing conventional, integrated and organic agricultural production systems | 2001 | Organic Farming; Soil N Dynamics | Book | Steenvorden, J., Claessen, F. & Willems, J. (eds.); Agricultural Effects on Ground and Surface Waters; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the extent of nitrate leaching under conventional, integrated and organic farms | Shifting from conventional to an integrated practice only 15% less nitrate leached and lower nitrate concentration was found. By converting to organic farming a reduction in N leaching losses of more than 50% ... Yields of the organic field plots were lower [But] Comparing the dry matter yield of the cash crops sugar beets, potatoes, winter wheat and rye in relation to the amount of leached nitrate on average of both sites, the production efficiency (kg nitrateN ha-1 yr-1 leached related to dm yield ha-1 yr-1) of the organic farming system was clearly higher (relatively 100% conventional compared to 80% integrated and 57% organic). |
| 413 | Haas, G., Geier, U., Schulz, D.G. & Köpke, U. | Vergleich konventioneller und organischer Landbau, Teil I: klimarelevante Kohlendioxid-Emission durch den Verbrauch fossiler Energie | 1995 | Energy in Agriculture; Greenhouse Gases; Organic Farming | Journal | Ber. Landwirtsch.; 73; 401-415 | German | Hardcopy:Full; Wordperfect:Full | Calculation of the energy use and amount of CO2 emission in organic and convenxtional farming. The gross CO2 emissions in organic and conventional farming are @reckoned to be 0.503 and 1.196 tons CO2 per hectare respectively. The corresponding figures for energy use are 6.8 and 18.9 GJ per hectare. So organic farming is significantly better than conventional in these respects. | n/a [title contd.: durch den Verbrauch fossiler Energie] |
| 772 | Haas, G., Wetterich, F. & Geier, U. | LCA methodology: framework in agriculture on the farm level | 2000 | Miscellaneous | Journal | Int. J. Life Cycle Assess.; 5 (6); | English | Hardcopy:Partial; Wordperfect:Full | Methodological study of a survey designed to compare the enviromental impact of 18 farms (6 each under intensive, extensive and organic systems), using LCA | |
| 223 | Haas, G., Wetterich, F. & Köpke, U. | Comparing intensive, extensified and organic grassland farming in southern Germany by process life-cycle assessment | 2001 | Energy in Agriculture; Greenhouse Gases; Organic Farming | Journal | Agric. Ecosyst. Environ.; 83 (1/2); 43-53 | English | Hardcopy:Partial | Field expt. to compare conventional and organic farming in respect of the energy xconsumed, the CO2 emitted and other environmental impacts | Energy consumption of intensive farms was 19.1 GJ/ha ..., of ... organic farms ... 5.9 GJ/ha. Global warming potential was 9.4 ... and 6.3 CO2 equivalents/ha.; Farm-gate balances for N (80.1 ... and 31.1 kg/ha) and P (5.3 ... and -2.3 kg/ha) ... indicate the different impacts on ground and surface water quality. |
| 614 | Habekotté, B. | Identification of strong and weak yield-determining components of winter oilseed rape compared with winter wheat | 1997 | Rape and Biodiesel | Journal | Eur. J. Agron.; 7; 315-321 | English | Hardcopy:Partial | Field expt. to determine the main factors determining the lower yield of rape as compared with wheat. Wheat yield averaged 8.1 t/ha as compared with 4.7 t/ha for rape. The difference was mainly due to the 12% higher cumulative absorption of photosynthetically active radiation, the 35% higher radiation use efficiency and the 35% higher harvest index of wheat, as compared with rape. | |
| 691 | Habekotté, B. | Options for increasing seed yield of winter oilseed rape (Brassica napus): a simulation study | 1997 | Rape and Biodiesel | Journal | Field Crops Res.; 54 (2-3); 109-126 | English | Hardcopy:Partial | Expt. to determine how plant breeding could best improve the yield of winter oilseed rape | .. higher seed yields may be obtained through (in descending order of importance): (a) delayed maturity; (b) improved seed set: (c) smaller petals or apetalous flowers; (d) increased potential growth rate of individual seeds; (e) earlier flowering with retention of the duration of total growth period and (f) erect clustered pods.; The most promising crop type for high seed yield matures late, combines early flowering with a maximum LAI of about 3 for almost maximum light absorption and has erect clustered pods for source improvement. To take full advantage of the source the sink has to be increased through a high rate of seed set, a large sink capacity of individual seeds, apetalous flowers or a combination of these characteristics. |
| 648 | Hadas, A., Doane, T.A., Kramer, A.W., Kessel, C. van & Horwath, W.R. | Modelling the turnover of 15N-labelled fertiliser and cover crop in soil and its recovery by maize | 2002 | Green Manure; Organic Farming; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 53; 541-552 | English | Hardcopy:Partial; PDF:Full | Field expt. in which the recovery of labelled N-fertiliser by maize was measured in soils under three mgmnt systems: conventional, low-input (vetch+chemical fertiliser) & organic (vetch+composted FYM), in order to test the synchronisation between N release and the requirements of the crop. The vetch and FYM were incorporated into the soil 1 week prior to planting the maize. | .. in the ORG system .. the maximal availability of N was reached at about the same time as the fertiliser was applied in the LI and CONV systems. .. may therefore be made to coincide with maximum demand by the crop .. |
| 1235 | Hadas, A., Kautsky, L., Goek, M. & Kara, E.E. | Rates of decomposition of plant residues & available N in soil related to residue composition through simulation of carbon and nitrogen turnover | 2004 | Mineralisation; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 36 (2); 255-266 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to study the decomposition in the soil of plant residues with various C/N ratios, including wheat straw and tobacco, rape, rice and maize residues. Tobacco, rape and maize decomposed equally rapidly (14-18% of their C in the first week), even though maize had a C/N ratio 2.5-3 times greater than the others. This was probably because of the large proportion of the maize C (30-35%) in soluble form. The decomposability of residue fractions is more important in determining decomposition rates than C/N ratio. | Vigil & Kissel (1991) .. showed that the break-even point between net N immobilisation and mineralisation of residues was at a C/N ratio of 41. This corresponds to an N content of ca. 1%, meaning that 1 g of N is retained in soil per 100 g of decomposing residue, a value commonly accepted as the amount of fertiliser-N needed to compensate for N immobilisation when straw is incorporated in soil.; Large quantities of available C added to the soil, e.g. in the form of residues with large C/N ratios, will stimulate microbial growth and N immobilisation, as well as microbial activity and oxygen consumption that may cause temporary conditions for denitrification. |
| 649 | Hadas, A., Parkin, T.B. & Stahl, P.D. | Reduced CO2 release from decomposing wheat straw under N-limiting conditions: simulation of carbon turnover | 1998 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 49; 487-494 | English | Hardcopy:Partial; PDF:Full | Modifying the NCSOIL model to simulate the CO2 release from decomposing straw in conditions of restricted N supply. | .. the turnover of endogenous mineralisable SOM by soil microbial biomass and the turnover of added residues by a zymogenous microbial biomass.; .. when N is deficient microbial use efficiency (the fraction of decomposed C used for microbial growth) decreases ..; When N was not limiting microbial growth, microbial use efficiency was 0.6 and there was no accumulation of polysaccharides. In the C-N treatment [addition of chopped wheat straw] the microbial efficiency was considerably less, but increased with time because available C was continuously depleted by being partly released as CO2 and partly sequestered into a polysaccharide pool that was less decomposable than the residue ..; Long-term persistence of microbial polysaccharides has been demonstrated in a field expt., where significant differences in polysaccharide content of the soil were found 4 months after differential management treatments and even after a longer time ..; The rate of CO2 release from samples with straw and N .. was rapid for the first 50 days, in which 40% of added C was mineralised. .. The rate declined towards 150 days.. The total amount released in 460 days was 58% of added C. |
| 1236 | Hadas, A., Sofer, M., Molina, J.A.E., Barak, P. & Clapp, C.E. | Assimilation of nitrogen by soil microbial population: NH4 versus organic N | 1992 | Mineralisation; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 24 (2); 137-143 | English | Hardcopy:Full | Inconclusive lab. expt. to ascertain the pathway by which organic N enters microorganisms, directly or via the soil inorganic N pool | .. the decay of OM can follow two patterns: (1) microbes incorporate low MW organic N compounds .. This .. assumes that N transfer .. is mostly mediated through organic compounds and that N mineralisation or immobilisation occurs only when there is an excess or deficit of N with respect to biomass needs to maintain their C/N ratio ..; (2) microbial biomass immobilises N only from the inorganic pool, while decay always results in N mineralisation and release of (NH4+ into the inorganic pool (the mineralisation-immobilisation turnover, MIT, hypothesis).; .. a zymogenous population developed on the added organic substrate (alanine) and possibly directly assimilated the organic N for growth. But at the same time the native soil population developed ..,consuming the H available SOM and probably assimilated NH4+, as suggested by the MIT hypothesis. |
| 1237 | Hagedorn, F., Spinnler, D. & Siegwolf, R. | Increased N deposition retards mineralisation of old soil organic matter | 2003 | Mineralisation; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 35 (12); 1683-1692 | English | Hardcopy:Partial | An investigation of the effects of increased N deposition on new and old pools of SOM in a 4-yr expt. on spruce and beech growing on an acidic loam and a calcareous sand | Elevated N deposition for 4 yr increased significantly the contents of total SOM in 0-10 cm depth of the acidic loam (+9%) .. Down to 25 cm soil depth, C storage in the acidic loam was between 100 and 300 g C m-2 larger under high than under low N additions.; The amounts of new (less than 4-yr-old) SOM in the sand fractions of both soils were greater under high N deposition, showing that C inputs from trees into soils increased. Root biomass in the acidic loam was larger under N additions (+25%). Contents of old (more than 4-yr-old) C in the clay and silt fractions of both soils were significantly greater under high than under low N deposition. Since clay- and silt-bound SOM consists of humified compounds, this indicates that N addition retarded mineralisation of old and humified SOM, [which] accounted for 60-80 g C m-2 4yr-1, which corresponds to about 40% of the old SOM mineralised in these fractions. As a consequence, preservation of old and humified SOM under elevated N deposition might be a process that could lead to an increased soil C storage in the long-term. |
| 1006 | Hagmeier, H.U. | M?glichkeiten und Probleme der N-Akkumulation durch Leguminosen und der NVerwertung in einem nach biologischen Gesichtspunkten bewirtschafteten Betrieb | 1980 | Green Manure; Stockless Farming | Book | Hagmeier, H.U.; Möglichkeiten und Probleme der N-Akkumulation durch Leguminosen und der N-Verwertung in einem nach biologischen Gesichtspunkten bewirtschafteten Betrieb; | English | Hardcopy:Partial | The defining characteristics of organic cultivation are considered. Among them are: care of the living organisms in the soil, the maintenance of SOM content with materials originating within the holding, the maintenance of soil N content mainly through microbial fixing of atmospheric N and the production of healthy, high quality food. Careful consideration is necessary before all cultivation measures, especially of their long-term consequences. The soil should be kept covered at all times. | Im Mittelpunkt aller Betrachtungen steht bei diesem Landbausystem derBoden.; .. bei allen Kulturmanahmen [ist] eine wohlueberlegte Vorgehenweise erforderlich.; Die meisten acker- und pflanzenbaulichen Entscheidungen haben hier laengerfristige Bedeutung. Bei der Entscheidungsfindung sollte daher versucht werden, zu erwartende positive und negative Haupt- und Nebenwirkungen moeglichst weit vorauszusehen. |
| 1632 | Hagmeier, H.U. | Ueber die Stickstoffversorgung von Winterweizen und Winterroggen durch Leguminosenvorfruechte, dargestellt anhand von Expt.en auf einem viehlos bewirtschafteten organischbiologischen Ackerbaubetrieb auf der Schwbischen Alb | 1986 | Stockless Farming | Book | Hagmeier, H.U.; Ueber die Stickstoffversorgung von Winterweizen und Winterroggen durch Leguminosenvorfruechte, dargestellt anhand von Expt.en auf einem viehlos bewirtschafteten organischbiologischen Ackerbaubetrieb auf der Schwbischen Alb; | German | Hardcopy:Partial | Expt. to test whether preceding leguminous green crops could supply the N requirements of a following winter wheat crop. Three different green crops were tried: lucerne (undersown into the preceding year's rye crop), field beans undersown with a grass/clover and two successive crops of field beans in the same season. The green crops were cut three times in the season and either removed from the field or mulched on it. The lucerne and the double bean crop gave rise to equally high N accumulation (reflected in the following cereal yields), while the single bean crop was somewhat lower. There was a higher total N accumulation when the cut material from the green crop was removed than when it was cut-and-mulched. | |
| 536 | Haidar, M.A., Bibi, W. & Sidahmed, M.M. | Response of branched broomrape (Orobanche ramosa) growth and development to various soil amendments in potato | 2003 | Lignin and CBW; Potato Growing | Journal | Crop Prot.; 22; 291-294 | English | Hardcopy:Full; PDF:Full | Field expt. to test the capacity of various fertilisers to suppress the growth of broomrape - a weed in potato fields in Lebanon. The control (unamended) plot gave a potato yield of 22,220 kg/ha. The other treatments gave similar yields except the wood chips, which yielded only about half that. | The treatments were broiler, cattle, goat, layer [and] sheep manure and wood chips.; None of the treatments except wood chips were phytotoxic to potato plants. |
| 1620 | Haider, K. | Von der toten organischen Substanz zum Humus | 1999 | Lignin and CBW; Soil Organic Carbon | Journal | Z. Pflanz. Bodenkunde; 162; 363-371 | German | Hardcopy:Full | Review of current knowledge of plant residue decay in soil. Less humified residues can be stabilised by sorption, by complex'n with metal oxides or by spatial sequestration on the surfaces of or inside the inorganic particle fraction or in aggregates. In relation to the total global SOC, total atmospheric CO2-C is 50%, total plant biomass C is 40%, annual plant biomass incorporation into the soil is 4% & total microbial biomass is 2%. Within a year in temperate climates, 60-70% of leaves or straw are mineralised to CO2, but only 30% of lignin. The C/N ratio of SOM decreases with decreasing particle size. In a chernozem 60% of the org. N is in the clay fraction (<2m). Allophanic soils have a relatively higher SOM content, as the OM is bound to Al3+ ions. Mean residence times of SOM varies from 0.5 yr for coarse plant material to >1000 yr for SOM in fine clay. The SOM sorbed onto clay consists mainly of aliphatic compounds, especially those of protein origin. The tannins, phenolic and other lignin residues are found mainly in the silt fractions. Lignin degradation is aerobic and co-metabolic, requiring a supplementary labile C source. It is considered by some to take place rapidly, giving products that are re-polymerised into recalcitrant OM, and by others to take place slowly and continuously, giving intermediate products that are protected by attachment to mineral particles. | Die Huminstoffe des Bodens bestehen .. aus Produckten eines kontinuierlichen Fberganges von nur wenig vernderten aber rumlich stabilisierten pflanzlichen Inhaltsstoffen bis hin zu zunehmend inerten Strukturen, die aber ebenfalls zustzlich durch sorptive und komplexierende Reaktionen stabilisiert sein k?nnen. |
| 1545 | Hajabbasi, M.A. & Hemmat, A. | Tillage impacts on aggregate stability and crop productivity in a clay-loam soil in central Iran | 2000 | Soil (General); Tillage | Journal | Soil Tillage Res.; 56 (3-4); 205-212 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of different tillage treatments on the soil and crop yields. Initial SOC content of soil - 0.94% | After 4 years .. a decrease of 11% in SOC in the conventional tillage treatment (MD) was observed .. while an increase of 4 and 2% of organic C in the non-inversion .. and CR [chisel-ploughing + rotary tilling] tillage treatments were seen respectively.; Although direct drilling improved soil structural `stability, its lower yield (5608 and 4731 kg ha-1 for TP and NT respectively) potential would indicate that reduced tillage systems (i.e. CD [chisel-ploughing and discing]) appear to be the accepted alternative management compared to conventional practice. |
| 108 | Hall, C.W. | Mechanisation and Food Availability | 1989 | Energy in Agriculture | Book | Pimentel, D. & Hall, C.W. (eds.); Food and Natural Resources; | English | Hardcopy:Partial | Impact of mechanisation on agriculture. A table from Pimentel and Pimentel (1979) shows the energy input needed to till soil by hand, oxen and tractors. Two graphs from Steinhart and Steinhart (1975) relate the energy use on farms to the labour use and to the energy content of the food produced. | |
| 1663 | Hall, C.W. & Pimentel, D. | Food and Natural Resources | 1989 | Agricultural Ecology | Book | Hall, C.W. & Pimentel, D.; Food and Natural Resources; | English | Hardcopy:Partial | See under Hall, C.W. (1989) | |
| 735 | Hamer, U. & Marschner, B. | Priming effects in soils after combined and repeated substrate additions | 2005 | Priming Effect | Journal | Geoderma; 128; 38-51 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the primingeffect on soil after multiple substrate additions | .. the combined substrate addition induced stronger positive priming than the single additions. .. Since priming effects were not depressed after extended pre-incubation of a soil sample, it seems unlikely that only the labile SOC-pool is susceptible. Co-metabolism and the turnover of native microbial biomass are insufficient to explain the observed positive priming effects. |
| 1238 | Hamer, U. & Marschner, B. | Priming effects in different soil types induced by fructose, alanine, oxalic acid and catechol additions | 2005 | Priming Effect | Journal | Soil Biol. Biochem.; 37 (3); 445-454 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the primingeffect on soil after multiple substrate additions | The strongest positive priming effects were induced by fructose and alanine.. these substrates enhanced SOC mineralisation by +10% to [ca.90]%. Catechol additions generally reduced SOC mineralisation by -12% to -43%.; .. priming effects are ubiquitously occurring in surface and subsoil horizons of forest soils as well as in arable soils.; .. positive priming effects are most pronounced in forest soils that contain SOC of low biodegradability, where the added substrates may act asan important energy source for microbial metabolism. |
| 981 | Hamer, U., Marschner, B., Brodowski, S. & Amelung, W. | Interactive priming of black carbon and glucose mineralisation | 2004 | Priming Effect; Soil Organic Carbon | Journal | Org. Geochem.; 35; 823-830 | English | Hardcopy:Partial; PDF:Full | Expt. to study the biodegradation in soil of charred wood and crop residues and the effect of added glucose. Charred plant materials can constitute from 35-60% of the SOM in black soils (chernozems). | Black C (BC) is produced by incomplete combustion of fossil fuels and vegetation and occurs ubiquitously in soils and terrestrial sediments. It is relatively inert and thus contributes to refractory SOM; The charred materials in our study were as degradable as SOM ..; wood-decaying fungi that were able to degrade low-rank coals .. the presence of a second, easily available, C source was required to induce microbial degradation of brown coal. .. co-metabolism might be a major pathway of BC degradation. In general, organic substrates are considered to be degraded co- metabolically if another C source is required by microorganisms for their degradation.; Mineralisation of BC is stimulated by glucose addition. The second glucose additions exhibits a stronger priming effect on BC degradation than the first, because of a better adaptation of the microorganisms to BC decay. |
| 18 | Hammel, K.E. | Fungal degradation of lignin | 1997 | Lignin and CBW; Soil Microorganisms | Book | Cadisch, G. & Giller, K.E. (eds.); Driven by Nature: Plant Litter Quality and Decomposition. C.A.B. International; | English | Hardcopy:Partial; Wordperfect:Full | Review of the biodegradation of lignin | Fungi that degrade lignin are faced with several problems. Since the polymer is extremely large and highly branched, ligninolytic mechanisms must be extracellular. Since it is interconnected by stable ether and carbon-carbon bonds, these mechanisms must be oxidative rather than hydrolytic. Since lignin consists of a mixture of stereo-irregular units, fungal ligninolytic agents have to be much less specific than typical biological catalysts. |
| 1654 | Hammond, A.L., Metz, W.D. & Maugh, T.H. | Energy and the Future | 1973 | Energy Resources | Book | Hammond, A.L., Metz, W.D. & Maugh, T.H.; Energy and the Future; | English | Hardcopy:Partial | Alternative energy sources in the United States are reviewed. Estimates are made of the renewable and depletable energy resources of the United States, | The world's total hydroelectric power is estimated to be three billion kilowatts, of which only 8.5 per cent is developed. |
| 1038 | Handayanto, E., Cadisch, G. & Giller, K.E. | Nitrogen release from prunings of legume hedgerow trees in relation to quality of the prunings and incubation method | 1994 | Mineralisation; Mulch; Soil N Dynamics | Journal | Plant Soil; 160; 237-248 | English | Hardcopy:Partial | Lab. expt. to study the decomposition of residues from leguminous trees | Alley cropping is an agroforestry system in which food crops are grown between rows of .. preferably N-fixing trees, which are periodically pruned to prevent shading .. and to reduce competition with the food crops.; .. the synchronisation of N release from decomposing plant residues with crop demand for N is critical for the successful use of such approaches.; The critical N content .. for immediate net mineralisation of N to occur was .. 1.73% and the critical C/N ratio was 20.; .. the protein-binding capacity of the polyphenols played an important role in N release from the prunings ..; .. lignin is also capable of reducing the availability of both carbohydrates and protein by complexing them. |
| 1239 | Handayanto, E., Giller, K.E. & Cadisch, G. | Regulating N release from legume tree prunings by mixing residues of different quality | 1997 | Mineralisation; Mulch; Soil N Dynamics | Journal | Soil Biol. Biochem.; 29 (9/10); 1417-1426 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the rate of N mineralisation from a mixture of prunings from two tree species, one high and one low quality, showing that the rate can be manipulated by altering the proportion in the mixture. The effect was to reduce not only the rate of N release but also the total amount of N released from the prunings over a 3-month period. | .. the quality .. best related to N release under leaching conditions was the (lignin+polyphenol)/N ratio, whereas under non-leaching conditions the proteinbinding capacity gave the [best]; .. mixing residues that contained little polyphenols but had varying N & lignin contents have resulted in intermediate rates of decompos'n .. mixing of Gliricidia residues with rice straw led to delayed N release, but the total amount of N mineralised was not altered. |
| 309 | Hannah, L., Lohse, D., Hutchinson, C., Carr, J.L. & Lankerani, A. | A preliminary inventory of human disturbance of world ecosystems | 1994 | Sustainability | Journal | Ambio; 23 (4-5); 246-250 | English | Hardcopy:Full | The human impact on the biosphere is assessed. A mapping of human intervention in natural ecosystems is presented. | .. the study .. examine[s] all natural areas of potential importance for conservation ..; This study has not addressed diversity, endemism or rate of destruction .. |
| 224 | Hansen, B., Alrře, H.F. & Kristensen, E.S. | Approaches to assess the environmental impact of organic farming with particular regard to Denmark | 2001 | Energy in Agriculture; Organic Farming; Soil N Dynamics | Journal | Agric. Ecosyst. Environ.; 83; 11-26 | English | Hardcopy:Partial; PDF:Full | Review of energy use and effects on soil and environment in organic farming | .. the risk of harmful environmental effects is lower with organic than with conventional farming methods, though not necessarily so.; In most cases there is .. a lower surplus of nutrients & less leaching with organic than with conventional farming. However, poor mgmnt (e.g. the ploughing of grass and legumes at the wrong time of year with no subsequent crops to capture the mineralised nitrogen) .. can lead to a high level of leaching in some organic systems.; .. a transition to 100% organic farming would result in a 9-51% reduction in the net consumption of fossil energy... The decrease in (i) agricultural energy consumption, (ii) N turnover and (iii) animal production in a 100% organic Denmark would produce a corresponding decrease (13-38%) in the national emission of H greenhouse gases (CO2, CH4, N2O). |
| 615 | Hansen, B., Kristensen, E.S., Grant, R., Hřgh-Jensen, H., Simmelsgaard, S.E. & Olesen, J. | Nitrogen leaching from conventional versus organic farming systems - a systems modelling approach | 2000 | Soil N Dynamics | Journal | Eur. J. Agron.; 13; 65-82 | English | Hardcopy:Partial; PDF:Full | Modelling nitrate leaching in conventional and organic farming systems | |
| 181 | Hansen, J.W. | Is agricultural sustainability a useful concept? | 1996 | Sustainability | Journal | Agric. Sys.; 50; 117-143 | English | Hardcopy:Partial | Barriers to using sustainability as a criterion for guiding change in agriculture are examined. Sustainability is considered from four points of view - as an ideology, as a set of strategies for managing agricultural systems, as the ability to fulfil a set of goals - generally including environmental soundness and financial viability, and as the ability to continue indefinitely. | Literal interpretations of sustainability as an ability to continue into the future suggest measurable integrated criteria for its characterisation. However, applications of these criteria - time trends and resilience - have neglected or misinterpreted important aspects of system performance that influence sustainability. .. In order for sustainability to be a useful criterion for guiding change in agriculture, its characterisation should be literal, systemoriented, quantitative, predictive, stochastic and diagnostic. |
| 182 | Hansen, J.W. & Jones, J.W. | A systems framework for characterising farm sustainability | 1996 | Sustainability | Journal | Agric. Sys.; 51; 185-201 | English | Hardcopy:Partial | Sustainability in agriculture is compared with other dynamic stochastic processes. It can be expressed as the probability of continuation within specified threshold boundaries through a specified future period. It is defined and quantified using the proposed framework. | To sustain is literally to keep in existence; keep up; maintain or prolong .. Sustainability can therefore be defined as the ability of a system to continue into the future.; .. the concept of sustainability can be applied to any system that is dynamic, stochastic and purposeful. .. sustainability has no meaning unless some .. threshold condition exists which distinguishes a system that is sustaining from one that has failed.; .. the ability of a system to continue in the future is best expressed as a probability .. with a zero-to-one range that addresses the question, 'With what degree of certainty will the system sustain?' |
| 863 | Hansen, N.C., Daniel, T.C., Sharpley, A.N. & Lemunyon, J.L. | The fate and transport of phosphorus in agricultural systems | 2002 | Phosphorus Cycling | Journal | J. Soil Water Conserv.; 57 (6); 408-417 | English | Hardcopy:Full | Review of research into phosphorus cycling in agricultural ecosystems. There are three hypothetical pools of soil phosphorus: soluble P (orthophosphate anions); reactive P, consisting of organic P (fresh OM) and inorganic P (on anion exchange sites) in dynamic equilibrium with dissolved P; and stable P, consisting of organic and inorganic P that is occluded, insoluble or tightly sorbed. Soil test P (STP) includes soluble P and part of reactive P. When no P fertiliser is applied, total P and STP of soils averaged about 400 mg kg-1 and `12 mg kg-1 respectively, making STP around 3% of total P. Under annual cropping (removing about 8 kg ha-1 yr-1, STP declined at rates of only 1.6 and 2.9 mg kg-1 yr-1 when the initial STP level was 20 and 40 mg kg-1 respectively, showing that some P was being mineralised in the soil, but not enough to sustain cropping. | .. loss of BAP [bio-available phosphorus] from agricultural watersheds was approximately three times less with no tillage than with conventional tillage.; Soil have a finite P sorption capacity, which varies [with] clay content, clay type, OM content, concentration of exchangeable Al, Fe & Ca and soil pH.; The P saturation expresses the percent of the P sorption capacity that is filled.; When the P saturation is high, a larger percentage of the applied P remains in forms extracted by STP methods than for soils with a low percent of P saturation.; Addition of organic amendments to soils can reduce the P sorption capacity .. |
| 1240 | Hansen, S., Maehlum, J.E. & Bakken, L.R. | N2O and CH4 fluxes in soil influenced by fertilisation and tractor traffic | 1993 | Greenhouse Gases; Soil N Dynamics | Journal | Soil Biol. Biochem.; 25 (5); 621-630 | English | Hardcopy:Partial | Expt. to study the effect of fertiliser and tractor traffic on the soil N2O and CH4 fluxes | x; Concentrations of N2O in soil air were more than seven times higher in compacted @NPK-fertilised soil than in any other treatments. .. The accumulated N2O emissions from the NPK-fertilised treatment (4 June-8 July) corresponded to 5.3% of added NH4NO3-N in compacted soil and 3.9% in uncompacted soil. Fertilisation with cattle slurry equivalent to 81 kg total N ha-1 gave an N2O emission `corresponding to 3.1% of added NH4-N in uncompacted soil and 2.7% in compacted (soil. .. The accumulated CH4 uptake (4 June-8 July) in the soil was 9.7 mg CH4 m-2 in unfertilised and uncompacted soil. It was reduced by 52% by soil compaction, 50% on average by fertilisation and 78% by soil compaction and fertilisation combined. |
| 425 | Hanson, P.J., Edwards, N.T., Garten, C.T. & Andrews, J.A. | Separating root and soil microbial contributions to soil respiration: a review of methods and observations | 2000 | Roots & Rhizodeposition | Journal | Biogeochemistry (Dordr.); 48 (1); 115-146 | English | Hardcopy:Partial; PDF:Full | Review of experimental methods to measure root and microbial contributions to total soil respiration | .. root/rhizosphere respiration can account for as little as 10 percent to greater than 90 percent of total in situ soil respiration depending on vegetation type and season of the year. Studies which have integrated percent root contribution to total soil respiration throughout an entire year or growing season show mean values of 45.8 and 60.4 percent for forest and non-forest vegetation respectively. .. the root contribution to total soil respiration is commonly higher during the growing season and lower during the dormant periods of the year. |
| 821 | Hao, X.Y., Chang, C., Larney, F.J. & Travis, G.R. | Greenhouse gas emissions during cattle feedlot manure composting | 2001 | Compost & Biocontrol; Greenhouse Gases | Journal | J. Environ. Qual.; 30; 376-386 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to determine whether greenhouse gas emissions during composting are affected by the composting method - active (turned over) or passive (no turning) | x; C lost in the forms of CO2 and CH4 was 73.8 and 6.3 kg C Mg-1 manure for the @passive aeration treatment and 168.0 and 8.1 kg C Mg-1 manure for the active treatment. The N loss in the form of N2O was 0.11 and 0.19 kg N Mg-1 manure for the passive and active treatments. Fuel consumption to turn and maintain the windrow added a further 4.4 kg C Mg-1 manure for the active aeration treatment. `Since CH4 and N2O are 21 and 310 times more harmful than CO2 in their global (warming effect, the total GHG emission expressed as CO2-C equivalent was 240.2 and 401.4 kg C Mg-1 manure for passive and active aeration.; Several mechanisms, including nitrification, denitrification and chemo-denitrification, could all potentially contribute to the observed N2O profiles and surface emission H patterns. .. At the beginning, with high NH4+ and low NO3- concentration in the feedlot manure, nitrification rather than denitrification is the major contributor to the increased N2O concentration ..; Conversion of NO2- to NO3- is inhibited by high temperatures, .. high NH4+ content and high pH.; .. denitrification occurs under anaerobic conditions. |
| 836 | Hao, X.Y., Chang, C., Travis, G.R. & Zhang, F.R. | Soil carbon and nitrogen response to 25 annual cattle manure applications | 2003 | Stockless Farming; Soil N Dynamics | Journal | J. Plant Nutr. Soil Sci.; 166 (2); 239-245 | English | Hardcopy:Partial | Field expt. to study the long-term effects of FYM application to soil | For every ton of manure OC added, soil OC increased by 0.181 g kg-1 in the topsoil (0-15 cm)... for every ton of manure TN added, surface soil TN increased @by 0.192 g kg-1. The linear relationship between manure C added & soil C content suggests that the soil had a high capacity for short-term C sequestration. |
| 1386 | Hao, Y., Lal, R., Izaurralde, R.C., Ritchie, J.C., Owens, L.B. & Hothem, D.L. | Historic assessment of agricultural impacts on soil and soil organic carbon erosion in an Ohio watershed | 2001 | Soil Organic Carbon; Soil (General); Tillage | Journal | Soil Sci.; 166 (2); 116-126 | English | Hardcopy:Partial | Soil erosion of plots under conventional and zero tillage and under different rotations was assessed using sediment collection, the caesium-137 exponential equation and the RUSLE methods. It was concluded that the sediment method was the best. The caesium-137 method gave results from 1 to 3 times greater. The RUSLE method gave results 3 to 14 times greater than sediment collection. A ley course gave the lowest erosion rate (zero). The worst was continuous maize. Zero tillage gave much less erosion than any of the ploughed plots. | |
| 325 | Harder, W. & Dijkhuizen, L. | Physiological responses to nutrient limitation | 1983 | Soil Microorganisms | Journal | Annu. Rev. Microbiol.; 37; 1-23 | English | Hardcopy:Full | Review of the ways in which microorganisms respond to limitations in the major nutrients: C, N, P, S, K and Mg. These responses are of 3 types: to increase the rate of transport of the nutrient, to increase the rate of initial metabolism of the nutrient and to rearrange the chemical composition of cellular structures by re-directing fluxes of metabolites containing the nutrient. During C limitation diversion of C into extracellular products is minimised, favouring catabolism to anabolism. | .. the flux of non-limiting C source is generally not tightly balanced to biomass formation and this may lead to a significant accumulation of intracellular reserve materials, extracellular polymers or a variety of low-molecular-weight metabolites.; Phosphate limitation may also have a marked effect on the production of exoenzymes by certain bacteria. |
| 1113 | Harmon, M.E., Ferrell, W.K. & Franklin, J.F. | Effects on carbon storage of conversion of old-growth forests to young forests | 1990 | Greenhouse Gases; Soil Organic Carbon | Journal | Science; 247; 699-702 | English | Hardcopy:Partial | Simulation of C storage by forests. Of harvested wood 15% is left behind as broken or defective, 9% is bark, 30% is lost to sawdust or scrap and only about 42% enters long-term storage such as structural components of buildings. | .. of the 325 Mg of C per ha harvested from a typical old-growth forest 187 Mg of C per ha may be lost to the atmosphere ..; During simulated timber harvest on-site C storage is reduced considerably and does not approach old-growth storage capacity for at least 200 years. .. timber harvest results in a net flux `of CO2 to the atmosphere. |
| 183 | Harris, D., Pathan, A.K., Gothkar, P., Joshi, A., Chivas, W. & Nyamudez, P. | On-farm seed priming: using participatory methods to revive and refine a key technology | 2001 | Miscellaneous | Journal | Agric. Sys.; 69 (1/2); 151-164 | English | Hardcopy:Partial | Farm trials of maize, rice, sorghum and chickpeas comparing soaked seed with dry seed were carried out in India and Zimbabwe. Soaked seed gave significantly better results. | In each trial farmers were asked to soak seed overnight, surface-dry it then sow it in the normal way in a plot next to a plot with dry seed.; Direct benefits in all crops included: faster emergence; better, more uniform stands; less need to re-sow; more vigorous plants; better drought tolerance; earlier flowering; earlier harvest; and higher grain yield. |
| 292 | Harris, G.H. & Hesterman, O.B. | Quantifying the nitrogen contribution from alfalfa to soil and two succeeding crops using nitrogen-15 | 1990 | Soil N Dynamics | Journal | Agron. J.; 82; 129-134 | English | Hardcopy:Full | Field expt. to study the uptake of lucerne-N by maize followed by spring barley. Nearly half the N from the lucerne remained in the soil, nearly all as organic N. Nearly a fifth of this was microbial biomass. About a third of the lucerne-N was lost from the system, probably by denitrification and leaching. Of the 115 kg N/ha applied as lucerne, 24 and 51 kg/ha are taken up by the maize and stored in the soil respectively. | |
| 293 | Harris, G.H., Hesterman, O.B., Paul, E.A., Peters, S.E. & Janke, R.R. | Fate of legume and fertiliser nitrogen-15 in a long-term cropping systems experiment | 1994 | Soil N Dynamics | Journal | Agron. J.; 86; 910-915 | English | Hardcopy:Full | 2-year field expt. using 15N to compare the dynamics in soil of chemical and symbiotically fixed N. The quantities of N recovered in crops and retained in the soil were 40% v. 17% and 17% v. 47% for chemical fertiliser and legume respectively. The average total N loss was around 39% for both sources, but the losses in the first and second years were 38% v. 18% and 4% v. 17% for chemical fertiliser and legume respectively. | Soil microbial biomass was larger in the legume-based than in the fertiliserbased system, but specific respiratory activity was the same. |
| 1241 | Harrison, K., Bol, R. & Bardgett, R. | Do plant species with different growth strategies vary in their ability to compete with soil microbes for chemical forms of nitrogen? | 2008 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 40; 228-237 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to determine whether a plant's capacity to take up N depended on whether it was fast- or slow-growing | @; .. we detected no difference in microbial biomass or microbial uptake of 15N between fast & slow-growing plant species, suggesting that plant traits that regulate nutrient capture, as opposed to plant species-specific interactions with soil microbes, a |
| 61 | Hartl, W., Kromp, B., Erhart, E., Huspeka, C., Meindl, P., Putz, B. & Schwaiger, E. | Neues Bewirtschaftungssystem im oekologischen Feldbau: Evaluierung der agraroekologischen Auswirkungen der 'pfluglosen Mulch-Streifenmischkultur, System Edinger' | 1999 | Mulch; Organic Farming | Book | Hofmann, H. & Mueller, S. (hgbr); Vom Rand zur Mitte: Beitraege zur 5. Wissenschaftstagung zum oekologischen Landbau, Berlin; | German | Hardcopy:Partial | Expt. to compare the Edinger system with conventional cultivation. The mulched beds showed a higher N and moisture content, greater earthworm and arthropod populations. | Aus pflanzenbaulicher Sicht mu es jedoch noch in Hinblick auf die maschinelle Bewirtschaftung, Beerntung und die Bestandesfuehrung von Kultur- und Begruenungspflanzen optimiert werden. |
| 829 | Hartwig, U.A., Wittman, P., Braun, R., Hartwig-Räz, B., Jansa, J., Mozafar, A., Lüscher, A., Leuchtmann, A., Frossard, E. & Nösberger , J. | Arbuscular mycorrhiza infection enhances the growth response of Lolium perenne to elevated atmospheric pCO2 | 2002 | Greenhouse Gases | Journal | J. Exp. Bot.; 53; 1207-1213 | English | Hardcopy:Partial | Expt.s to compare the biomass of perennial ryegrass plants under elevated atmospheric CO2 concentrations with low and high soil N concentrations and with or without innoculation with AM fungi. | Elevated CO2 increased plant biomass by 10% and 17% at low and high levels of soil N respectively. .. at high soil N the presence of symbiotic fungus more `than doubled the plant growth response to atmospheric CO2 enrichment [to 41%]. |
| 1039 | Hassink, J. | The capacity of soils to preserve organic C & N by their association with clay and silt particles | 1997 | Soil Organic Carbon; Soil N Dynamics | Journal | Plant Soil; 191 (1); 77-87 | English | Hardcopy:Partial; PDF:Full | Expt. to compare the quantity of clay- and silt-associated C and N in arable, grassland and uncultivated soils and to quantify the C & N protected by this association | .. the amounts of C & N that can be associated with clay and silt particles [are] limited .. C (g kg-1) = 4.09 + 0.37 x %particles<20 m; N (g kg-1) = 0.40 + 0.037 x %particles<20 m;; .. although the .. arable soils contained less C & N than the corresponding grassland soils, the amounts of C & N associated with clay and silt particles was the same, indicating that the amounts of C & N that can become associated with this fraction had reached a maximum.; [There were] close positive relationships between the proportion of primary particles <20 m in a soil and the amounts of C & N that were associated with this fraction in the top 10 cm of soils .. The observed relationships were assumed to estimate the capacity of a soil to preserve C & N by their association with clay and silt particles.; The amount of C & N in the fraction >20 m was not correlated with soil texture. Cultivation decreased the amount of C & N in the fraction >20 m to a greater extent than in the fraction <20 m, indicating that C & N associated with the fraction <20 m is better protected against decomposition. |
| 1242 | Hassink, J. | Relationship between the amount and the activity of the microbial biomass in Dutch grassland soils: comparison of the fumigation-incubation method and the substrate-induced respiration method | 1993 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 25 (5); 533-538 | English | Hardcopy:Partial | Field expt. to assess whether soil texture and available C affect microbial activity | The ratio biomass-SIR:biomass-FI, indicating the percentage of active microbial biomass, and the ratio C mineralisation:biomass-FI, indicating the activity of the microbial biomass, were both higher in soils with a coarse texture than in soils with a fine texture.. []and] were higher in the upper 10-cm soil layer than in the 10-25-cm layer ..; .. the percentage of active microbial biomass is lower in soils with a fine texture than in sandy soils. This may be caused by the higher grazing pressure of soil fauna on bacteria in soils with a coarse texture... faunal grazing may keep the microbial population in a metabolically more active state. As the volume of a population under grazing pressure always remains under its carrying capacity, rate-limiting factors such as availability of nutrients or energy will be removed and a higher proportion of the population may be active.; Clay particles .. have a stabilising effect on microbial biomass .. This protection capacity .. (e.g. in small pores and on clay surfaces) .. refers to the total microbial biomass. The active biomass is much less protected than the total biomass. |
| 1243 | Hassink, J. | Effects of soil texture and grassland management on soil organic C & N and rates of C & N mineralisation | 1994 | Mineralisation; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 26 (9); 1221-1231 | English | Hardcopy:Partial | Field expt. to measure the effects of soil texture and grassland management on the soil C & N dynamics | The decomposition rate if organic residues ,.. is typically lower in finetextured soils than in coarse-textured soils.; [but]; .. soil texture was not always the dominant factor determining the org. C content .. and C mineralisation rates. Differences in C/N ratio of the SOM and the groundwater table confused the relationship .. The residues of heathland generally have a high C/N ratio. .. Differences in C/N ratio might also result from the presence of inert charcoal .. sandy soils with a high C/N ration contained more inert C than other soils.; Differences in fertiliser N were found not to affect the amount of SOC & N.; .. the amounts of soil C & N and rates of C & N mineralisation were often not significantly different between mowing and grazing. |
| 1244 | Hassink, J. | Effects of soil texture on the size of the microbial biomass and the amount of C & N mineralised per unit of microbial biomass in Dutch grassland soils | 1994 | Mineralisation; Soil Microorganisms | Journal | Soil Biol. Biochem.; 26 (11); 1573-1581 | English | Hardcopy:Partial | Field expt. to investigate the relationship between soil microbial biomass and the rate of C & N mineralisation. | .. in the sandy soils and loams the amounts of microbial biomass were approximately twice as high as the amounts of bacterial biomass, while in the clays they were more than three times as high.; The differences in C/N ratio of the microbes between sandy soils, loams and clays were not caused by differences in the fraction of fungi in the microbial biomass, as this was found to be very small in both sandy soils as well as in loams and clays. |
| 1245 | Hassink, J. | Density fractions of soil macroorganic matter and microbial biomass as predictors of C & N mineralisation | 1995 | Mineralisation; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 27 (8); 1099-1108 | English | Hardcopy:Full | Analysis of soils from arable and grassland to investigate the correlation between mineralisation rates and SOM in different size-density fractions. Bare soil was compared with soils amended with chaff, lucerne and FYM. | For all residue treatments the C/N ratios of OM decreased in the order light, intermediate, heavy macro-OM (fraction >150 m) and non-macro-OM (fraction <150 m).; C & N mineralisation were positively correlated with the amount of C & N in the light fraction and the active microbial biomass. .. C & N mineralisation per unit of total microbial biomass were lower in fine-textured soils than in coarse-textured soils. This is ascribed to a greater physical protection of the OM in fine-textured soils than in coarse-textured soils.; The largest increase in SOC was found in the FYM treatment, which caused a 5.9-fold increase in the sandy soil and a 3.6-fold increase in the clay soil in comparison with bare soil. |
| 1430 | Hassink, J. | Decomposition rate constants of size and density fractions of soil organic matter | 1995 | Mineralisation; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 59 (6); 1631-1635 | English | Hardcopy:Full | Expt.s to study the decomposition rates of OM fractions from different soil types. Five fractions were studied - two microaggregate size fractions (< 20 m and between 20 and 150 m) and three density fractions of OM between 150 and 250 m. The decomposition rates for each fraction did not differ much between different soil types. The rates for the microaggregate size fractions were very low and similar to the rate for total soil C. | Mineralisation of C .. decreased in the order light > intermediate > heavy macro-OM.; .. the rate constants for decomposition decreased in the order light (0.24% d-1) > intermediate (0.098% d-1) > heavy (0.036% d-1) ..; The percentage of soil C present in the light, intermediate and heavy macro-OM fractions in the top 10 cm of grassland soils were 1.5, 5 and 13% respectively. therefore about 80% of the total amount of soil C was present in microaggregates. |
| 1431 | Hassink, J. | Preservation of plant residues in soils differing in unsaturated protective capacity | 1996 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 60 (2); 487-491 | English | Hardcopy:Full | Expts. using 14C as a tracer to test the hypothesis that the amount of newlyadded OM preserved by a soil depends not only on the texture of the soil (soils rich in clay and silt preserving more OM than sandy soils) but also on the degree to which the protective capacity of the clay and silt is already saturated with OM. The amount of newly-added C is said to be related to the soil characteristics by the equation:% of applied C associated with the fraction < 20 m = 6.72 + 0.23 x % of soil particles < 20 m + 0.67 x the saturation deficit.The soils used in the expt. had SOC contents of 0.5-4.3% and microbial biomass of 0.001-0.077%. | During the first 3 days after the application of 14C considerable differences H in 14CO2 production between soils were found that were significantly correlated with the saturation deficit but not with soil texture.; During the first weeks after application most of the 14C applied is either soluble or in the sand-size fraction. With extended incubation most of the preserved 14C has been reported hto associate with clay and silt particles. The microbial 14C may then consist of 0both newly synthesised, not yet stabilised microbial 14C and microbial 14C that is associated with clay and silt particles. |
| 1040 | Hassink, J. & Dalenberg, J.W. | Decomposition and transfer of plant residue 14C between size and density fractions in soil | 1996 | Soil Organic Carbon | Journal | Plant Soil; 179; 159-169 | English | Hardcopy:Partial | Lab. expt. to study the movement of SOM from one soil fraction to another. 65% & 90% of the SOC was found in microaggregates in sandy soil & loam respectively. | .. all plant residues (except lignin-like components) that enter the soil must pass [through] the microbial biomass, [which] partly mineralises them [and] partly converts the residues into new products ..; .. material derived from the grass decomposed much faster than soil-derived C recovered in the same `fractions.; .. there must have been a transfer of 14C from the most labile (fractions (.. the light macro OM fraction, soluble 14C and microbial 14C) to the intermediate macro OM fraction during the first few days after 14C application & to the heavy macro OM fraction during the first weeks after this application.; .. microaggregates contain a large proportion of the most stable OM in soil and protect OM.; .. the binding of organics to mineral particles (leading to the formation of heavy material) can take place very quickly.; .. the decomposition rate of plant-derived C associated with the microaggregate fraction <20 m is affected by the degree of saturation of the protective sites with SOM .. |
| 1432 | Hassink, J. & Whitmore, A.P. | A model of the physical protection of organic matter in soils | 1997 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 61 (1); 131-139 | English | Hardcopy:Partial | Modelling the physical protection of OM as a function of the capacity of clay particles and aggregates to hold OM | .. the physical capacity of a soil to preserve OM is limited. .. the degree of saturation of the protective capacity of a soil with OM would affect the preservation of newly added C in residues. Less of the applied C should be preserved in a soil when all the protective sites were occupied than when sites were available to stabilise organic C.; .. part of the protection being afforded to OM in soils was not related to the clay content of the soil. Between one third and one half of the total protection of OM in clay-rich soils appears to be independent of clay content. This additional protection may occur thorough the stabilisation of OM by organic or ferritic soil colloids or chemical stabilisation ..; .. there is probably a continuum from non-protected to completely protected OM. |
| 1246 | Hassink, J., Bouwman, L.A., Zwart, K.B. & Brussaard, L. | Relationships between habitable pore space, soil biota and mineralisation rates in grassland soils | 1993 | Mineralisation; Soil Microorganisms | Journal | Soil Biol. Biochem.; 25 (1); 46-55 | English | Hardcopy:Partial | Field expt. to investigate the relationships between pore size, microbial and microfaunal populations and mineralisation rates | .. in loams and clays most pores had diameters <1.2 m, whereas in sandy soils most pores had diameters from 6 to 90 m. A close positive correlation was found between the bacterial biomass and the .. pores with 0.2-1.2 m dia. and between the biomass of nematodes & the .. pores with 30-90 m dia. The biomass of fungi and protozoa showed no relationship with .. pore-size .. |
| 1247 | Hassink, J., Neutel, A.M. & Ruiter, P.C. de | C & N mineralisation in sandy and loam grassland soils: the role of microbes and microfauna | 1994 | Mineralisation; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 26 (11); 1565-1571 | English | Hardcopy:Partial | Field expt. to investigate the relationship between mineralisation and microbial biomass | Differences in C mineralisation rates between the 4 grasslands could .. be explained by the differences in bacterial biomass. .. [but] did not correspond with the differences in N mineralisation.; .. the observed C & N mineralisation rates could .. be calculated using different bacterial C/N ratios .. (8 for the sandy soils, 4.5 and 6 for the loams).; .. the contribution of the fauna to C mineralisation was small. .. The direct contribution of the fauna to N mineralisation ranged from 7.3% to 28.0%.; .. the continuous high input of decaying root and leaf material in grassland soils .. seems not to lead to a high biomass but to a high [microbial] activity.; The fraction of fungi in the microbial biomass .. was very small in all soils. |
| 1248 | Hassink, J., Oude Voshaar, J.H., Nuhuis, E.H. & Veen, J.A. van | Dynamics of the microbial populations of a reclaimed-polder soil under a conventional and a reduced-input farming system | 1991 | Organic Farming; Soil Microorganisms | Journal | Soil Biol. Biochem.; 23 (6); 515-524 | English | Hardcopy:Partial | Expt. to compare the microbial populations of two fields, one under conventional farming and the other under reduced inputs | Characteristics of populations changed considerably in time. These changes were larger than differences between the two fields.; .. the size of the microbial biomass was larger on the reduced-input field. |
| 616 | Hassink, J., Whitmore, A.P. & Kubát, J. | Size and density fractionation of soil organic matter and the physical capacity of soils to protect organic matter | 1997 | Soil Organic Carbon | Journal | Eur. J. Agron.; 7 (1-3); 189-199 | English | Hardcopy:Partial; PDF:Full | Study of grassland and arable soils to investigate the idea that the protection of SOM depends both on soil texture and on the degree to which the protective capacity of the soil is already occupied. | Light and intermediate fractions of the macro-OM (> 150 m) respond much faster to changes in C input than smaller size fractions .. [so they] can be used as early indicators of effects of soil management on changes in SOM.; The amount of C in macro-OM is controlled by soil management, while the amount of C protected by clay and silt particles is controlled mainly by soil texture. |
| 137 | Hatley, D.L.J., Garwood, T.W.D. & Johnson, P.A. | The impact of changing farming practices on soil organic matter and soil structural stability of fen silt soils | 2001 | Soil Organic Carbon; Tillage | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the trends in organic matter content in arable soils | At three of the long-term arable sites, SOM levels declined by 0.5-1.7% over the monitoring period. .. At the six ley-arable sites and two of the arable sites there were no changes in SOM levels .. The data presented here suggest that all sites will reach stable or very slowly changing OM levels under continuous arable cropping regimes. It is concluded .. that modern farming systems are not causing a decline in the OM content of fen silt soils. |
| 270 | Hatton, T.J. & Nulsen, R.A. | Towards achieving functional ecosystem mimicry with respect to water cycling in southern Australian agriculture | 1999 | Sustainability | Journal | Agrofor. Syst.; 45 (1-3); 203-214 | English | Hardcopy:Partial | Review of the possibility of improving soil water balance by imitating natural ecosystems | Replacement of these [natural] ecosystems with conventional agriculture has resulted in large-scale disruption of the natural water cycle .. effective water balance control will be achieved only at a leaf area index approaching that of the natural state .. |
| 519 | Haugen-Kozyra, K., Juma, N.G. & Nyborg, M. | Nitrogen partitioning and cycling in barley-soil systems under conventional and zero tillage in central Alberta | 1993 | Mineralisation; Soil N Dynamics; Tillage | Journal | Can. J. Soil Sci.; 73 (2); 183-196 | English | Hardcopy:Partial | Expt. to measure the distribution of N between shoots, roots, microorganisms, soil organic and soil mineral N. At any one time about 98% of the N in the system is in the SOM, about 1% in the crop shoot, only about 0.1% in the roots, nearly 1% in the microbial biomass and a mineralised portion starting at just over 1% and falling to about 0.1% as the crop matures. | In the sort run the mineralisation-immobilisation turnover of N slows under ZT `and OM accumulates.; .. more 15N .. was converted to organic N under ZT than CT, thus ZT systems have the potential of conserving N. |
| 1041 | Hauggaard-Nielsen, H., Neergaard, A. de, Jensen, L.S., Hřgh-Jensen, H. & Magid,J. | A field study of nitrogen dynamics and spring barley growth as affected by the quality of incorporated residues from white clover and ryegrass | 1998 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 203; 91-101 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of incorporated green manures on the following crop | Incorporated residue N was highest in the [fertilised] white clover in pure stand & lowest in the [fertilised] ryegrass in pure stand treatments, ..; The highest crop dry matter production & N uptake was measured in the [fertilised clover pure stand] treatment, followed by the [unfertilised mixed ryegrass/ clover] and the fallow treatments .. |
| 982 | Haumaier, L. & Zech, W. | Black carbon - possible source of highly aromatic components of soil humic acids | 1995 | Soil Organic Carbon | Journal | Org. Geochem.; 23 (3); 191-196 | English | Hardcopy:Partial; PDF:Full | Review of evidence as to the black C origin of humic substances in soil. The non -phenolic substances found in some humic materials may be the final degradation products of non-phenolic parts of lignin or may come from carbonised materials produced in vegetation fires. | .. black C is considered to be a possible source of the chemically most stable aromatic soil C pool.; Soil humic substances .. are considered to be formed during the decay of plant and microbial residues, either by selective preservation and transformation of constituents resistant to biodegradation, e.g. lignin .. and aliphatic polymers, or by condensation of low-molecularweight degradation products such as phenols, .. sugars and amino-acids. |
| 1591 | Hawthorne, J. | Energy usage in food processing and distribution | 1975 | Energy in Agriculture | Journal | Span; 18 (1); 15-16 | English | Hardcopy:Full | The energy used in the transport and processing of crops into food is estimated. The transport and processing of crops into food consumes three times as much energy as the actual production of the crops. Tables of energy inputs into food processing and transport are given. | The financial accountant .. is concerned with a dual demonstration. In the balance sheet he shows the asset position .. the wealth of the company at a fixed point in time. In the profit-&-loss account he takes change with time into account & demonstrates the overall result of a large number of interrelated transactions at the end of a fixed period of time. The cost accountant .. analyses the day-to-day operations of the company in order to discover which of these is effective and which is wasteful. .. Energy accountancy of both sorts is needed. |
| 1387 | Hayes, M.H.B. & Clapp, C.E. | Humic substances: considerations of compositions, aspects of structure and environmental influences | 2001 | Soil Organic Carbon | Journal | Soil Sci.; 166 (11); 723-737 | English | Hardcopy:Partial | A general review of the study of humic substances, including the definition of the term, isolation of the substances and C sequestration | SOC reserves (estimated to be ca. 1500 Pg) are almost three times those in all living matter on earth. .. the C emissions from the soil (arising from microbial transformations of SOM) are considered to be about 60 Pg. [= historical emissions from agriculture ??], which is about ten times more than the emissions from fossil fuels. .. Estimates of the total C sequestration potential through improved management of U.S. cropland have been placed at 75 to 208 Tg .. and this is thought to be possible through land conservation .., intensification of prime agricultural land (which would involve conservation tillage and residue management), irrigation water management and improved cropping systems.; Humic substances are the major components of .. SOM and .. are by far the most abundant organic materials in the environment .. [they are] complicated mixtures of biologically transformed organic debris.; They result from the decomposition of plant and animal residues.; Humic substances are a category of naturally occurring biogenic, heterogeneous organic substances that can generally be characterised as being yellow-to-black in colour, of high molecular weight and refractory. .. However, there is no longer universal acceptance that HS are of high molecular weight.; Humic acids are precipitated at .. pH1 ..; fulvic acids remain in solution at all pH values; and humin materials are not soluble in aqueous acid or base.; .. it would be wrong to attribute to HS all of the C sequestered by SOM. For example, glomalin, a glycoprotein in the hyphae of AM fungi was found at levels of more than 60 mg/cc in tropical soils. .. glomalin content can be correlated with aggregate stability .. it is sorbed to the soil colloidal surfaces, which would explain its resistance to decomposition .. [it] takes several years to decades to turn over in the soil; . |
| 1249 | Haynes, R.J. | Labile organic matter as an indicator of organic matter quality in arable and pastoral soils in New Zealand | 2000 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 32 (2); 211-219 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to test the labile OM content of arable and pastoral soils as an indicator of the OM quality | .. the labile SOM fractions measured (light fraction C, microbial biomass C and water-soluble C) were significantly correlated with organic C content.; Labile OM was more closely correlated with previous cropping history .. than with SOC content.; .. the three measures of labile OM used were closely correlated with one another .. The light fraction represents a transitory pool between fresh residues and humified stable OM. It acts as a reservoir of relatively labile C which supplies the soluble C pool. A large portion of the microbial community is associated with the light fraction and soil respiration rates are often correlated with the light fraction C content. Water-soluble C is the primary energy source for the microbial biomass although, in turn, microbial metabolites (e.g. polysaccharide mucilage) contribute significantly to the soluble C pool. .. it is [also] a primary source of mineralisable N, P and S and it influences the availability of metal ions in soils by forming soluble complexes. |
| 1250 | Haynes, R.J. & Beare, M.H. | Influence of six crop species on aggregate stability and some labile organic matter fractions | 1997 | Green Manure; Roots & Rhizodeposition; Soil (General) | Journal | Soil Biol. Biochem.; 29 (11/12); 1647-1653 | English | Hardcopy:Full; PDF:Full | Lab. expt. to compare the effect on the soil structure of various cereals, grasses and legumes | For the non-legumes in our study, increases in root mass and length density, microbial biomass C, cold and hot water-extractable carbohydrate content and aggregate stability followed the order: barley = wheat < prairie grass < Italian ryegrass.; In comparison with the non-legumes, growth of white clover and lupin resulted in an unexpectedly high aggregate stability and to a lesser extent microbial biomass C content relative to their rather small root mass and length. Lupin, for example, had the highest aggregate stability of all the crops, while white clover had an aggregate stability similar to that of Italian ryegrass..; the higher N content of rhizodeposited organic material .. from the legumes is likely to have been a major difference leading to a larger.. microbial popul'n. |
| 952 | Haynes, R.J. & Naidu, R. | Influence of lime, fertiliser and manure applications on soil organic matter content and soil physical conditions: a review | 1998 | Soil (General) | Journal | Nutr. Cycl. Agroecosyst.; 51; 123-137 | English | Hardcopy:Partial; PDF:Full | Review of the effects on soil properties of lime, chemical fertiliser and animal manure applications | .. liming can result in dispersion of clay colloids & formation of surface crusts. .. both lime & hydroxy-Al polymers formed by pptn of exchangeable Al, can act as cementing agents bonding soil particles together and improving soil structure.; For fertiliser additions short-term effects appear to be relatively rare. Their main effect is a long-term one through an increase in crop production with an attendant increase in SOM content and soil biological activity. For organic manures the major effect is simply the addition of OM to the soil. |
| 1547 | Haynes, R.J., Swift, R.S., Stephen, R.C. | Influence of mixed cropping rotations (pasture-arable) on OM content, waterstable aggregation and clod porosity in a group of soils | 1991 | Soil (General) | Journal | Soil Tillage Res.; 19; 77-87 | English | Hardcopy:Partial | Field study to investigate dependency of the OM content and aggregation of soils on crop rotations | .. the total SOM content remained relatively unchanged, yet microbial biomass C, hot-water-extractable carbohydrate and aggregate stability increased markedly during the pasture phase and declined during the arable period. .. increase in aggregate stability during the short-term pasture is due principally to production of binding carbohydrates .. by the large microbial biomass .. |
| 1114 | Heath, J., Ayres, E., Possell, M., Bardgett, R.D., Black, H.I.J., Grant, H., Ineson, P. & Kerstiens, G. | Rising atmospheric CO2 reduces sequestration of root-derived soil carbon | 2005 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Science; 309; 1711-1713 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to quantify the sequestration of root-derived SOC benerath trees | In temperate and boreal forests the amount of C stored in the soil is about four times as high as that stored in the vegetation and 33% higher than total C storage in tropical forests.; Despite enhanced tree growth, we found a marked decline in sequestration of root-derived C in the soil as CO2 concentration increased ..; The reduced sequestration of root-derived C in the soil under `elevated CO2 was associated with an increase in soil microbial respiration ..; (; .. although soil microbial respiration increased under elevated CO2, the effect of this on the decomposition of native soil C is not known. |
| 984 | Hedges, J.I. & Oades, J.M. | Comparative organic geochemistries of soils and marine sediments | 1997 | Soil Organic Carbon | Journal | Org. Geochem.; 27 (7/8); 319-361 | English | Hardcopy:Full; PDF:Full | Review of research into the composition and dynamics of organic matter in soils and marine sediments | Vascular plants predominate on land, where soils are deeply leached by percolating water & receive OM from falling debris & penetrating roots. The large size of vascular plants & their high conc'ns of carbon-rich bio-macromolecules such as cellulose, lignin & tannin, necessitate recycling by aggressive consortia of microorganisms, including fungi armed with O2-requiring oxidative enzymes. .. plant products are degraded extensively by microorganisms, leaving small organic remnants which are soluble in base and depleted in conventionally measurable biochemicals. Much of the surviving OM is intimately associated with mineral surfaces and enclosed within particle aggregates, and thus may be physically protected from microbial attack. Degradation under oxic conditions is severe .. As a result, even physically protected OM can slowly be mineralised, along with intrinsically resistant substrates such as lignin, pollen, kerogen and coal. |
| 713 | Hedges, J.I., Blanchette, R., Weliky, K. & Devol, A. | Effects of fungal degradation on the CuO oxidation products of lignin: a controlled laboratory study | 1988 | Lignin and CBW | Journal | Geochim. Cosmochim. Ac. ; 52 (11); 2717-2726 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the oxidation products of lignin that has been degraded for varying periods of time by white- and brown-rot fungi | Upon CuO oxid'n most fresh vascular plant tissues yield ratios of vanillic acid to vanillin (Ad/Al)v & syringic acid to syringaldehyde (Ad/Al)s that lie in the range of 0.1-0.2, whereas increasingly elevated ratios are obtained from .. .., lignin structural units in humus and humic & fulvic acids.; .. white-rot fungi are obligate aerobes & do not degrade waterlogged wood efficiently. |
| 983 | Hedges, J.I., Eglinton, G., Hatcher, P.G., Kirchman, D.L., Arnosti, C., Derenne, S., Evershed, R.P., Kögel-Knaber, I., de Leeuw, J.W, Littke, R., Michaelis, W. & Rullkötter, J. | The molecularly uncharacterised component of non-living organic matter in natural environments: a review | 2000 | Soil Organic Carbon | Journal | Org. Geochem.; 31 (10); 945-958 | English | Hardcopy:Partial; PDF:Full | Review of the current state of knowledge of the chemical compos'n of SOM | OM is a thermodynamic anomaly atop a free energy precipice that drops off on all sides to dispersed stable ingredients such as carbon dioxide, water, nitrate & phosphate. Given the high free energy yield when electrons are passed from OM to molecular oxygen,nitrate, transition metal ions & sulphate, it is little surprise that only one or two carbons out of one thousand in org. molecules ultimately escape oxidation to be preserved in marine sediments.; In spite of over half a century of effort & rapidly increasing analytical sophistication, more than half of all the OM in soils ..still remains uncharacterised at the molecular level. |
| 787 | Heeger, R. & Brom, F.W.A. | Intrinsic value and direct duties: from animal ethics towards environmental ethics? | 2001 | Agricultural Ethics | Journal | J. Agric. Environ. Ethics; 14 (2); 241-252 | English | Hardcopy:Partial; PDF:Full | The question of our moral duty towards other living beings is discussed. Does this duty only concern beings that are aware or sentient? And does it differ towards different beings - for example, towards animals and plants and towards collective entities like populations, species and ecosystems? | |
| 900 | Heijden, M.G.A. van, Kilronomos, J.N., Ursic, M., Moutoglis, P., StreitwolfEngel, R., Boller, T., Wiemken, A. & Sanders, I.R. | Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability and productivity | 1998 | Agricultural Ecology; Soil Microorganisms | Journal | Nature (Lond.); 396; 69-72 | English | Hardcopy:Full | Expt. to demonstrate the importance of arbuscular mycorrhizal fungi in ecosystems | .. belowground diversity of arbuscular mycorrhizal fungi is a major factor contributing to the maintenance of plant biodiversity and to ecosystem functioning.; AMF are abundant in soils of most ecosystems [and] form .. symbiotic associations with the roots of ca. 80% of all terrestrial plants species, thereby acting as extensions of plant root systems and increasing the nutrient uptake, especially of phosphorus.; .. the species competition and diversity of AMF communities have the potential to determine plant biodiversity in natural ecosystems.; Both the plant diversity .. and productivity above- and belowground increased with increasing AMF species richness.; Increasing plant diversity has been shown to lead to greater ecosystem productivity. |
| 650 | Heim, A. & Schmidt, M.W.I. | Lignin turnover in arable soil and grassland analysed with two different labelling approaches | 2007 | Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 58; 599-608 | English | Hardcopy:Partial; PDF:Full | Field expt. to measure the rate of turnover of lignin in soil | Results indicate faster apparent turnover for lignin (5-26 years in grassland, 9-38 years in arable soil) compared with bulk SOC (20-26 years in grassland, 51 years in arable soil). Although these calculated lignin turnover times cannot be extrapolated to the whole soil profiles, this paper provides isotopic evidence that lignin in soils is not preferentially preserved .. a considerable prop'n of lignin in temperate soils canbe stabilised for atleast a few decades. |
| 985 | Heim, A. & Schmidt, M.W.I. | Lignin is preserved in the fine silt fraction of an arable Luvisol | 2007 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 38; 2001-2011 | English | Hardcopy:Partial; PDF:Full | Field expt. to trace the fate of lignin in soil | A kinetic model suggests the existence of a fast and a slow decomposing lignin pool in the soil..; [the fraction of lignin reaching the faster pool] is calculated to be 94.9%.; Although .. the slower pool receives only about 5% of the input, it is about 5.6 times larger than the fast pool..; .. stabilisation of lignin biomarkers in soil is not due to their inherent chemical recalcitrance but depends on interaction with mineral matter... a large part of the lignin input to soil never reaches this stable fraction, but turns over more rapidly.; old .. lignin .. had accumulated mainly in the silt (2-20 %m) fraction. |
| 891 | Heinrich, C. | 70 Jahre viehlose Wirtschaft | 1957 | Stockless Farming | Journal | Mitteilungen der Deutschen Landwirtschafts-Gesellschaft; 10.01.1957; | German | Hardcopy:Partial | Two non-organic stockless holdings are described, both near Worms in the Rhine valley: Hof Mundorf, Pfiffligheim (stockless since 1888, apart from two cows and 3 pigs for their own use) and MGckenhuserhof, RheindGrkheim ('stockless' since 1910, apart from 6 cows, 20 pigs, 6 draught horses and 2 draught oxen). On both holdings the lack of animals allows greater care to be taken of the arable land. They use very little chemical fertiliser and little green manure, but their yields are comparable with the neighbouring conventional farmers. The author refers to an earlier article of his (in the August 1949 issue of the same journal), in which he states that 'die Viehhaltung auf 40, ja sogar 30 GV [Grossvieh ??] je 100 ha im sGdlichen Niedersachsengebiet eingeschraenkt werden koenne.' The figures for Hof Mundorf and the MGckenhuserhof are 6 and 7 GV per ha respectively, not including the draught animals. | |
| 736 | Helfrich, M., Ludwig, B., Buurman, P. & Flessa, H. | Effect of land use on the composition of soil organic matter in density and aggregate fractions as revealed by solid-state 13C NMR spectroscopy | 2006 | Soil Organic Carbon | Journal | Geoderma; 136; 331-341 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the differences in the chemistry of OM in soils from different land uses | The forest litter had the largest content of aromatic & alkyl-C... The SOM of the .. forest soil consisted mainly of POM with a high content of spruce litterderived alkyl-C. The SOC stocks in the grassland and maize soil were dominated by mineral-associated SOM, which contained relatively larger proportions of aryl & carbonyl-C. The decrease of the SOC conc'n induced by cultivation resulted in a relative accumulation of aromatic C structures in the mineral-bound SOM. In all soils the free POM had a smaller proportion of alkyl-C & a larger proportion of O-alkyl-C than the POM occluded in aggregates. The mean age of the SOM in the density fractions of the maize soil increased with increasing aromaticity in the order: free POM < occluded POM < mineral-associated OM. |
| 184 | Heller, M.C. & Keoleian, G.A. | Assessing the sustainability of the US food system: a life-cycle perspective | 2003 | Sustainability | Journal | Agric. Sys.; 76, 3; | English | Hardcopy:Partial | The sustainability of the human food cycle is discussed, taking into consideration issues of food consumption as well as food production. Factors threatening the sustainability of the food cycle are reviewed. | .. a widely accepted pragmatic definition of sustainable agriculture does not exist. .. there tends to be agreement that an appraisal of sustainability should integrate economic, social and environmental dimensions.; The long-term future of agricultural production .. cannot be assessed without consideration of the consumption patterns and processes that drive production. |
| 383 | Hellmann, B., Zelles, L., Palojärvi, A. & Bai, Q. | Emission of climate-relevant trace gases and succession of microbial communities during open-windrow composting | 1997 | Compost & Biocontrol; Greenhouse Gases | Journal | Appl. Environ. Microbiol.; 63 (3); 1011-1018 | English | Hardcopy:Partial; PDF:Full | Review of the composting process, the stages through which it passes and the gases evolved during them | @; The emission rates of CO2, CH4 and N2O increased successively during compost maturation: initially in the presence of easily degradable nutrients, during high temp, & after the temp had cooled down respectively.; .. we can characterise the maturation p |
| 1548 | Hendrix, P.F., Han, C.R. & Groffman, P.M. | Soil respiration in conventional and no-tillage agroecosystems under different winter cover crop rotations | 1988 | Cover Crops; Greenhouse Gases; Tillage | Journal | Soil Tillage Res.; 12 (2); 135-148 | English | Hardcopy:Partial | Expt. to study the CO2 emission from soils under conventional and zero tillage | x; Overall CO2 output was significantly higher from NT than from CT soils and from soils cropped to clover than from those cropped to rye.; Ploughing did not stimulate CO2 production in CT as was expected, but annual CO2 production in these systems may have been underestimated. Tillage appeared to affect the timing rather than the total amount of CO2 production. |
| 1726 | Henn, M.R. & Chapela, I.H. | Differential C Isotope Discrimination by Fungi during Decomposition of C3- and C4-Derived Sucrose | 2000 | Uncategorised | Journal | Appl. Environ. Microbiol.; 66 (10); 4180-4186 | English | PDF:Full | ||
| 1252 | Henriksen, T.M. & Breland, T.A. | Evaluation of criteria for describing crop residue degradability in a model of carbon and nitrogen turnover in soil | 1999 | Green Manure; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 31; 1135-1149 | English | Hardcopy:Partial; PDF:Full | Modelling the decompos'n of plant residues, based on the incubation in soil of various plant residues, ranging from OSR haulm to white clover | .. cpds found in the cell cytoplasm (e.g. simple carbohydrates, nucleic acids, amino acids, proteins) are grouped together in a metabolic pool, while cell-wall components (cellulose, hemicellulose, lignin) constitute a structural pool.; On d 100 .. only 7.8% of the initial cellulose content was recovered in the herbage residues, while 26% still remained in the barley straw residues.; .. rapidly growing DPM-decomposers with a low C/N ratio (4.0) initially dominate the microbial biomass, whereas SPM-decomposers (C/N = 6.0) take over when DPM becomes depleted. .. [F/B] biomass and activity successively increases during residue decompos'n .. the C/N ratio of bacteria tends to be lower than that of fungi. |
| 459 | Henriksen, T.M., & Breland, T.A. | Carbon mineralisation, fungal and bacterial growth and enzyme activities as affected by contact between crop residues and soil | 2002 | Mineralisation; Mulch; Soil Microorganisms | Journal | Biol. Fertil. Soils; 35; 41-48 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effect of soil-residue contact on the decomposition of plant structural residues in two soils of differing texture | For clover material poor soil contact increased cumulative C mineralisation by 5% of initial C in the loamy topsoil but had no effect in the silty subsoil. For the more slowly degradable cellulose- and hemicellulose-rich straw, on the other hand, poor soil contact reduced C mineralisation by 6% of initial C.; .. a delayed colonisation or growth of microbes capable of producing extracellular cellulases and hemicellulases is a major reason for reduced straw decomposition under conditions where residue-soil contact is poor.; The positive effect [of poor soil contact on mineralisation of clover residues] may be explained by a reduced volume of detritusphere soil, which by various mechanisms retains a significant fraction of decomposing C from herbaceous crop residues. |
| 1251 | Henriksen, T.M., Breland, T.A. | Nitrogen availability effects on carbon mineralisation, fungal and bacterial growth and enzyme activities during decomposition of wheat straw in soil | 1999 | Mineralisation; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 31; 1121-1134 | English | Hardcopy:Partial; PDF:Full | 70-day expt. to study the decomposition in soil of mature wheat straw, which showed that wheat straw mineralisation may be retarded at N conc'ns well above those frequently found after grain harvest. | N addition often stimulates C mineralis'n from accessible plant constituents, such as non-lignified cellulose, whereas decompos'n of lignin & lignified material is slowed down.; The N requirement for opt. decompos'n has been considered to be about 1.2-1.7% of plant dry matter.; Literature values for the humification coefficient (aH) range from 0.2 to 0.7 and apparently depend on the soil clay content.; The negative N effect on C mineralisation towards the end may .. be due to a negative effect on lignin degrad'n, resulting in reduced availability of the structural carbohydrates in the lignocellulose complex. The latter explanation is supported by the negative effect of N addition on C mineralis'n .. in unamended soil, where humus and, consequently, lignin-like substances were the dominating substrates.; Rapidly proliferating bacteria play an important part during the initial attack on easily decomposable substances, while fungi are the major decomposers of the N-deficient structural straw material. |
| 589 | Hetherington, R. | An input-output analysis of carbon dioxide emissions for the UK | 1996 | Energy Resources; Greenhouse Gases; Sustainability | Journal | Energy Convers. Manage.; 37 (6/8); 979-984 | English | Hardcopy:Full | A table of all industrial products in the U.K. is presented, giving the CO2 intensity of their production, expressed in gm. CO2 per of output. Electricity xproduction is by far the most CO2 intensive, followed by cement, then by ceramics, iron and steel and air transport. | .. an individual's direct consumption of fossil fuels causes CO2 release, which [is] relatively easy to identify and quantify. However, any activity that requires fossil fuel consumption also has an associated release of CO2. This `constitutes the indirect CO2 emissions, which are more difficult to identify and (quantify.; .. current CO2 release will only change if production becomes more efficient. For the U.K. as a whole, energy efficiency increased by less than 5% between 1984 and 1992 .. |
| 760 | Hicke, J.A., Asner, G.P., Randerson, J.T., Tucker, C., Los, S., Birdsey, R., Jenkins, J.C. & Field, C. | Trends in North American net primary productivity derived from satellite observations, 1982-1998 | 2002 | Greenhouse Gases | Journal | Global Biogeochem. Cy.; 16; | English | Hardcopy:Partial | xCO2 enrichment of the atmosphere cannot account for the large increase in NPP during the period studied. Other factors that may have been responsible are better and more intensive agricultural practices, use of GM crops, regrowth of forest on abandoned arable land and increases in summer temperature and precipitation. | NPP increases of 30% or more occurred across the continent from 1982 to 1998. (During this period the atmosphere's CO2 concentration rose by 25.74 ppm. .. for herbaceous crop plants, which display NPP increases of 30% in response to a [standard] 300 ppm increase in atmospheric CO2 enrichment, [the 25.74 ppm increase] would have been expected to increase crop productivity by .. 2.6%. Similarly, for trees, which display NPP increases of 80% in response to a [standard] 300 ppm increase in atmospheric CO2, the expected increase in [NPP] .. would be .. 6.9%. |
| 1115 | Hirst, E. | Food-related energy requirements | 1974 | Energy in Agriculture | Journal | Science; 184; 137 | English | Hardcopy:Partial | Energy use in food production is estimated and compared over time and between different food types. Energy use is much lower in the case of crops than for meat and dairy products. It has increased substantially over time. | The increase in per capita food-related energy [from 1960 to 1970] was due primarily to increased energy use for refrigerators, stoves, freezers and automobiles. Changes in eating habits also contributed ..; American farming achieves such high labour productivity by substituting fuels for labour .. |
| 816 | Hobbs, P.R. | Tillage and crop establishment in South Asian rice-wheat systems: present practices and future options | 2001 | Miscellaneous; Tillage | Journal | Journal of Crop Production; 4 (1); 1-22 | English | Hardcopy:Partial | Review of techniques being introduced in the Indo-Gangetic Plain to improve the yields and reduce production costs in rice-wheat rotations | ... wet ploughing (locally called puddling) is most commonly used to prepare the field for eventual transplanting of rice seedlings. The field is usually ploughed dry, flooded and then puddled (ploughed when flooded) to create a soil with poor soil physical properties and low water infiltration.; For wheat, the following systems are described ...: 1. surface seeding .. no land preparation is used and seed are merely broadcast onto saturated soils. 2. zero-tillage .. wheat is planted directly into the rice stubble without land preparation ... 3. reduced-tillage systems .. a rotovator is used to prepare the soil ahead of a seed drill and compaction mechanism. This allows wheat to be planted at the same time as land is tilled. 4. bed planting systems. |
| 1683 | Hobbs, P.R. | Zero tillage: averting dry wells and depleted soils in South Asia | 2001 | Tillage | Website | www.cimmyt.cgiar.org/whatiscimmyt/ar00_2001/asia/zerotillage | English | Hardcopy:Full | A brief review of South Asia's agricultural problems and how zero tillage can help to overcome them. The main problems are water scarcity and declining soil quality, due to over-intensive cultivation, lack of fallow and failure to replenish SOM. Farmer-driven research into the direct sowing of wheat into rice stubble or even into the preceding rice crop is helping to overcome these problems. Growing crops on permanent raised beds is also being tested. The area of the Indo-Gangetic Plain estimated to be under zero tillage in the 2001-2 season was 300,000 ha, compared with a total area of rice-wheat cultivation of 12 million ha. | Water savings under [raised-]bed planting are even more dramatic than those for zero tillage alone.; Rather than spend long years 'cooking' technologies on expt.[al] stations, the RWC [Rice-Wheat Consortium] and its partners have given farmers promising technologies to test under their conditions. |
| 1003 | Hobbs, P.R. & Gupta, R.K. | Rice-wheat cropping systems in the Indo-Gangetic plains: issues of water productivity in relation to new .. | 2001 | Tillage | Website | Paper presented to the Water Productivity Workshop at IWMI, Colombo, Sri Lanka, 15-16.11.2001 | English | Hardcopy:Partial | [title contd.: resource-conserving technologies] Various resource conserving technologies applicable to rice-wheat cultivation are described, including surface seeding and zero tillage with inverted-T openers. | This [surface seeding] is a traditional farmer practice .. in parts of Eastern India and Bangladesh. Wheat seed is either broadcast before the rice crop is harvested (relay planted) or after harvest. .. The key to success .. is having the correct soil moisture at seeding. Too little moisture results in poor germination and too much moisture can cause the seed to rot. A saturated soil is best. .. In China .. farmers apply cut straw to mulch the soil, reduce evaporative losses and control weeds. The standing stubble also protects the young seedlings from birds. |
| 692 | Hocking, P.J., Kirkegaard, J.A., Angus, J.F., Gibson, A.H. & Koetz, E.A. | Comparison of canola, Indian mustard and Linola in 2 contrasting environments I. Effects of nitrogen fertiliser on dry-matter production, seed yield & seed quality | 1997 | Rape and Biodiesel; Soil N Dynamics | Journal | Field Crops Res.; 49 (2-3); 107-125 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the N-fertiliser response of three oilseed crops | Based on the overall growth and grain yield responses to N fertiliser and on N removal in grain, it is suggested that about 25% more N be applied to canola than to wheat, that Indian mustard receive about the same N fertiliser rate as wheat and that Linola requires about 20% less N than wheat.; The decrease in oil percentage of the oilseeds with increasing N supply reflects the inverse relationships between oil concentration and seed protein content ..; .. there was only a 2% oil decrease accompanying the 1.3 t ha-1 grain yield response to N for canola at Dirnaseer in 1992. Clearly, in this case, oil yield ha-1 increased despite the reduction in oil concentration. |
| 1044 | Hoffland, E. | Quantitative evaluation of the role of organic acid exudation in the mobilisation of rock phosphate by rape | 1992 | Phosphorus Cycling | Journal | Plant Soil; 140; 279-289 | English | Hardcopy:Partial | Modelling the effect of acid exudation rates on phosphate uptake from rock phosphate | Phosphorus-deficient rape plants appear to acidify .. their rhizosphere by exuding malic and citric acid.; The exudation rates measured are far more than adequate to explain the relatively large phosphate uptake from rock P by rape. |
| 384 | Hofrichter, M., Lundell, T. & Hatakka, A. | Conversion of milled pine wood by manganese peroxidase from Phlebia radiata | 2001 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 67 (10); 4588-4593 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the action of purified manganese peroxidase on pine wood | The enzymatic attack resulted in the polymerisation of lower-molecular-mass soluble wood components and in the partial depolymerisation of the insoluble bulk of pine wood ..; ..the disintegration of non-extracted solid lignocellulose (MPW) was accompanied in our present study .. by substantial formation of high-molecular-mass water-soluble fragments resulting from the obvious polymerisation of low-molecular-mass wood components. |
| 385 | Hofrichter, M., Vares, T., Kalsi, M., Galkin, S., Scheibner, K., Fritsche, W. & Hatakka, A. | Production of Mn peroxidase and organic acids and mineralisation of 14C-labelled Xlignin (14C-DHP) during solid-state fermentation of wheat straw with the white-rot fungus Nematoloma frowardii | 1999 | Lignin and CBW; Mineralisation | Journal | Appl. Environ. Microbiol.; 65 (5); 1864-1870 | English | Hardcopy:Partial | Expt. to study the enzymatic degradation of lignin using synthetic 14C-ring-labelled lignin. 58-75% of the label was found in the CO2 and only 3-13% in the fungal biomass and residual straw. | Except for cellulose lignin is the most abundant biological compound found in nature, yet it is degrade by only a small number of microorganisms, primarily basidiomycetes (white rot fungi) .. [which] produce a variety of extracellular enzymes that are though to be involved in lignin degradation, the best characterised of which are laccase, lignin peroxidase and manganese peroxidase (MnP).; In many fungi MnP is though to play the crucial role in the primary H attack on lignin, because it generates the strong oxidant Mn3+.; Dicarboxylic or O-hydroxycarboxylic acids are required for MnP activity .. oxalic acid has been found to be the main organic acid produced ..; Lignocellulose contains high levels of Mn, which, after Ca, K and Mg, is the most abundant metal.; Effective mineralisation and solubilisation of lignin by white rot fungi have 0been demonstrated by using both natural and synthetic 14C-labelled lignins and lignocelluloses. |
| 327 | Hoitink, H.A.J. & Boehm, M.J. | Biocontrol within the context of soil microbial communities: a substrate-dependent phenomenon | 1999 | Compost & Biocontrol; Miscellaneous; Soil Microorganisms | Journal | Annu. Rev. Phytopathol.; 37; 427-446 | English | Hardcopy:Full; PDF:Full | Review of current knowledge of biological control agents | Biocontrol agents require edaphic sources of OM for sustained activity against Pythium and Phytophthora root rots. .. the quality and quantity of the OM are critical to survival and efficacy of bacterial biocontrol agents such as Pseudomonas & Pantoea spp. Rhizosphere deposition products and root exudates clearly do not provide adequate quantities of slow-release sources of bioavailable energy to introduced bacterial biocontrol agents.; Org. amendments such as green manures, stable manures and composts can provide this food base and have long been recognised to facilitate biological control if applied well ahead of planting. |
| 10 | Hoitink, H.A.J., Stone, A.G. & Grebus, M.E. | Suppression of plant diseases by composts | 1996 | Compost & Biocontrol | Book | Bertoldi, M. de, Sequi, P., Lemmes, B., & Papi, T. (eds.); The science of composting; | English | Hardcopy:Partial; Wordperfect:Full | Review of the mechanisms of suppression of plant diseases by compost | Heat exposure during composting kills or inactivates pathogens if the process is monitored properly. Biocontrol agents with the exception of Bacillus spp. also are killed by this heat treatment, however. Thus, biocontrol agents largely must re-colonise composts after peak heating.; The moisture content of compost critically affects the potential for bacterial mesophiles to colonise the substrate after peak heating. Dry composts (<34% moisture w/w) become colonised by fungi and are conducive to Pythium diseases. The moisture content must be high enough (at least 40-50% w/w), so that bacteria can colonise the substrate after peak heating and induce biological control. |
| 405 | Holford, I.C.R. | Comments on intensity-quantity aspects of soil phosphorus | 1991 | Phosphorus Cycling | Journal | Aust. J. Soil Res.; 29 (1); 11-14 | English | Hardcopy:Partial | n/a | .. there are 3 major determinants of available P in soil (i) the concentration or intensity of P in the soil solution; (ii) the quantity of P in the solid phase that will equilibrate with the solution during the life of the plant; and (iii) the buffering capacity, which expresses the dynamic relationship between the solid and solution phases. |
| 406 | Holford, I.C.R. | Soil phosphorus: its measurement and its uptake by plants | 1997 | Phosphorus Cycling | Journal | Aust. J. Soil Res.; 35; 227-239 | English | Hardcopy:Partial | Review of knowledge of availability of soil P and P uptake by crops | The buffering capacity is the ability of the soil solution to resist a change in its P concentration as P is removed by plant uptake or added in fertilisers or organic materials. .. [it is] controlling the relationship between the solid phase P and its concentration in solution. The solid phase P involved in this relationship is only a small proportion of the total P and is known as labile P. It is usually measured by isotopic exchange, but this exchangeable P component does not include the sparingly soluble compounds that also replenish the soil solution as its concentration is depleted .. |
| 407 | Holford, I.C.R. & Doyle, A.D. | Influence of intensity/quantity characteristics of soil phosphorus tests on their relationships to phosphorus responsiveness of wheat under field conditions | 1992 | Phosphorus Cycling | Journal | Aust. J. Soil Res.; 30 (3); 343-356 | English | Hardcopy:Partial | Lab. expt. to study the correlation between soil P tests and wheat yield. Labile or plant-available P is widely regarded as being the same as adsorbed or isotopically exchangeable P, but this is not well correlated with the P uptake of plants. Chemical extraction, e.g. with acidic lactate, may give a better correlation, which implies that non-exchangeable mineral P is also an important part of the labile pool. | because the chemical composition of the labile pool will vary among soils, .. it seems unlikely that a universal measure of the quantity of labile P will ever be possible. |
| 571 | Holland, E.A. & Coleman, D.C. | Litter placement effects on microbial and organic matter dynamics in an agroecosystem | 1987 | Mulch; Soil Organic Carbon; Soil Microorganisms | Journal | Ecology; 68 (2); 425-433 | English | Hardcopy:Full | Lab. and field study to compare the effect of mulching and incorporating straw on SOM dynamics and microbial biomass. The surface-straw treatment showed 44% more fungal biomass, greater retention of added C in the total SOM and in the microbial biomass, higher cumulative respired CO2, slower straw decomposition, higher maximum net N immobilisation and reduced SOM loss, compared with the incorporated-straw treatment. The fungal biomass was, on average, only 0.35% of the bacterial biomass. | .. fungi may be important decomposers of the surface straw .. [but] less important decomposers of the incorporated residues.. surface residue placement increases fungal abundance .. |
| 95 | Holle, R. & Untiedt, H. | Crop rotations on organic farms in northern Germany and development of the wide- row system | 1999 | Miscellaneous | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Review of wheat growing in northern Germany by the Stute wide-row method | The quality effect of the wide-row system may be seen from a content of crude protein of 11.7% & of gluten of 24.0% ... The yield of the wide-row system is less, but the crude protein is higher than of the standard seeding. On average the difference between normal sowing & the wide-row system is about 0.2 t ha-1. |
| 1254 | Holtan-Hartwig, L., Dörsch, P. & Bakken, L. | Comparison of denitrifying communities in organic soils: kinetics of NO3- and N2O reduction | 2000 | Greenhouse Gases; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 32 (6); 833-843 | English | Hardcopy:Partial; PDF:Full | Lab. expt to identify possible differences in community composition among denitrifying bacteria under anaerobic conditions | The results .. suggest that intrinsic differences in community composition of soils exist, with consequences for the emission of N2O. |
| 1433 | Hooker, B.A., Morris, T.F., Peters, R. & Cardon, Z.G. | Long-term effects of tillage and maize stalk return on soil carbon dynamics | 2005 | Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 69; 188-196 | English | Hardcopy:Partial; PDF:Full | 28-year field expt. to study the dynamics of relic and new SOC in maize fields under zero or conventional tillage and with (+) or without (-) residue removal | NT increased SOC significantly .. over CT in treatments with residue returned .. & .. in treatments with residue removed; .. a rapid cycling of returned C4-C suggests that the annual return of aboveground biomass may not increase soil C storage over the long term, once soils have reached a steady-state SOC level.; .. the relative half-life of relic C3-C was strongly influenced by tillage in the upper 15 cm of the soil, with C3-C being retained longer under NT mgmnt. |
| 562 | Hooper, D.U., Chapin, F.S., Ewel, J.J., Hector, A., Inchausti, P., Lavorel, S., Lawton, J.H., Lodge, D.M., Loreau, M., Naeem, S., Schmid, B., Setälä, H., Symstad, A.J., Vandermeer, J. & Wardle, D.A. | Effects of biodiversity on ecosystem functioning: a consensus of current knowledge | 2005 | Miscellaneous | Journal | Ecol. Monogr.; 75 (1); 3-35 | English | Hardcopy:Partial; Word:Partial | Review of current opinion on the relationship between biodiversity and ecosystem stability | The scientific community has come to a broad consensus on many aspects of the relationship between biodiversity and ecosystem functioning ..; Having a range of species that respond differently to different environmental perturbations can stabilise ecosystem process rates in response to disturbances and variation in abiotic conditions. |
| 598 | Hopfenberg, R. & Pimentel, D. | Human population numbers as a function of food supply | 2001 | Sustainability | Journal | Environ. Dev. Sustain.; 3; 1-15 | English | Hardcopy:Partial; PDF:Full | Review of the evidence of a positive causal connection between human population and food supply | .. human population growth varies as a function of food availability.; Food energy is partitioned into four compartments, viz. maintenance, growth, stored energy and reproduction.; If increases continue, the population will ultimately be controlled .. by means of accelerated death rates.; Instead of depending on malnutrition and disease to limit human numbers, a social mechanism in response to a stable food supply, might be for humans to limit their numbers democratically or consensually or to employ incentives.; Marchetti etal (1996) have extrapolated human population data back to 10,000 BCE and show a geometrically increasing population. .. 10,000 BCE .. is the usually agreed-upon beginning of the agricultural revolution.; .. food production increases have slowed since 1983.; Livestock currently consume 130 million tones of grain in the U.S., enough to feed about 400 million people.; Humans are now utilising about 50% of the world's biomass for their own use.; The programme of totalitarian agriculture is to increase food production in order to outpace population growth that is fuelled by the very increases it produces and this is what makes it unsustainable. |
| 11 | Horwath, W.R., Elliott, L.F., Churchill, D.B. & Minshew, H.F. | Processes regulating grass straw composting | 1996 | Compost & Biocontrol; Lignin and CBW; Mulch | Book | Bertoldi, M. de, Sequi, P., Lemmes, B., & Papi, T. (eds.); The science of composting; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the decomposition of dry grass in windrows on soil | Temps. typical of thermophilic composting (>50$C) were commonly observed in the turned windrow treatments... The loss of lignin fraction C indicated that extensive lignin degradation occurred in all treatments including the control. The increased need for C and reduced requirement of N of the thermophilic biomass and the release of soluble N and ammonium during the mesophilic to thermophilic transition explains the extensive decomposition of high C/N ratio (50-60) grass straw during windrow composting. |
| 1116 | Houghton, R.A., Hackler, J.L. & Lawrence, K.T. | The U.S. carbon budget: contributions from land-use change | 1999 | Greenhouse Gases | Journal | Science; 285 (5427); 574-578 | English | Hardcopy:Full; Wordperfect:Full | Estimation of the emission of CO2 in the United States from 1700 to 1990 as a result of land-use change, based on historical data | x; The average rate of growth [of forests in the 1980] (1.4 Mg C ha-1 year-1) was low, indicating that many of the forests and woodlands were aging and their rates of growth were declining. For comparison, net annual uptake in a 55- to 75-year-old New England forest varied between 1.4 and 2.8 Mg C ha-1 year-1.; .. recent analysis of soils in a 55- to 75-year-old New England forest found that soils accounted for only 7 to 15% of the net sink measured for the stand. |
| 1255 | Howard, P.J.A., Howard, D.M. & Lowe, L.E. | Effects of tree species and soil physico-chemical conditions on the nature of soil organic matter | 1998 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 30 (3); 285-297 | English | Hardcopy:Full; PDF:Full | Expt. to study the soil under oak and yew trees on slate and limestone soils in North-west England. Humic soil fractions consist of more or less modified polysaccharides and long-chain alkyl C compounds. Humic acid contains, in addition, aromatic lignin derivatives. | As humic acid is a hetero-polycondensate which is synthesised from a range of possible precursors in a range of possible soil conditions .. there exists a variety of humic acid structures with properties that reflect theirorigin.; .. on slate the SOM contained proportionally more C and therefore had a lower degree of oxidation than that on limestone, which is consistent with different types of transformation of the litter compounds by organisms in soils of low pH and the greater C/N ratios of the samples collected on slate. |
| 1727 | Hu, S., Coleman, D.C., Beare, M.H. & Hendrix, P.F. | Soil carbohydrates in aggrading and degrading agroecosystems: influences of fungi and aggregates | 1995 | Uncategorised | Journal | Agric. Ecosyst. Environ.; 54; 77-88 | English | PDF:Full | ||
| 1434 | Hu, S., Grunwald, N.J., Bruggen, A.H.C. van, Gamble, G.R., Drinkwater, L.E., Shennan, C. & Dennent, M.W. | Short-term effects of cover crop incorporation on soil carbon pools and nitrogen availability | 1997 | Green Manure; Organic Farming; Soil N Dynamics | Journal | Soil Sci. Soc. Am. J.; 61; 901-911 | English | Hardcopy:Full | Field & lab. expts. to study the effect of incorporated green manures on soil carbon and nitrogen under organic and conventional management | .. organic soils were distinct from conv'l soils by their higher total C, N & SMB-C & lower available N.; Residue decompos'n for the first 3-4 weeks was substantially faster .. in organic .. than in conv'l soils.; Substantial amounts of N were mineralised & then lost within a few weeks of residue incorp'n, suggesting the importance of synchronis'n of N release with the need of subsequent crops. |
| 563 | Huang, J.H., Han, X.G. & Chen, L.Z. | Studies on litter decomposition processes in a temperate forest ecosystem: I. Change of organic matter in oak twigs | 1998 | Lignin and CBW; Soil Organic Carbon | Journal | Ecol. Res.; 13 (2); 163 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to study the decomposition of oak twigs | Oak twigs were predicted to reach 95% mass loss within 21 years. During the first 5 years the concentration of protein in the remaining litter increased from 3.5% to 5.5%, while the concentration of hemicellulose decreased from 16.0% to 8.0%. .. there was no obvious change in the concentrations of lignin and cellulose.; First, the C losses due to microbial respiration during litter decompos'n processes can lead to a relative increase in N (protein) conc'n. Second, fungi and bacteria may convert some free N from the decomposing litter into protein and store this protein in their bodies. Third, microbes (mostly fungi) can absorb some inorganic N from soils to adjust their C/N ratio (most appropriate value for those microbes was 20). |
| 651 | Huang, Y.S., Eglinton, G., Hage, E.R.E. van der, Boon, J.J., Bol, R. & Ineson, P. | Dissolved organic matter and its parent organic matter in grass upland soil horizons studied by analytical pyrolysis techniques | 1998 | Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 49 (1); 1-15 | English | Hardcopy:Partial | Expt. to study the formation and alteration of DOM in a peaty gley soil | . despite its solubility in water DOM is not a simple mixture of small monomeric or dimeric compounds. Lignin degradation products in DOM are almost entirely polymeric, although they are smaller and more polar than lignin itself because of oxidative degradation. .. oligomeric structures and water-soluble polymeric materials are formed during the fungal decay of lignin. .. A significant proportion of the carbohydrate content [of DOM] is modified plant or microbial material, which are also present in polymeric or oligomeric forms [e.g. polysaccharides ?].; DOM in soil leachates represents a fraction of SOM that has the highest degree of oxidation has undergone most microbial modification and with lower and more diverse molecular weights.; .. relative to lignin, polysaccharides in the peaty gley are more persistent with increasing depth, because of the contribution of polysaccharides bio-synthesised by fungi and bacteria. |
| 1435 | Huang, Y.S., Li, B.C., Bryant, C., Bol, R. & Eglinton, G. | Radiocarbon dating of aliphatic hydrocarbons: a new approach for dating passive-fraction C in soil horizons | 1999 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 63 (5); 1181-1187 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to determine the ages of lipid (aliphatic hydrocarbon) fractions in three soils found in N. Yorkshire moorland, using mass spectrometry | The low biodegradability of long-chain n-alkanes leads to their persistence in the soil horizons where they were originally deposited. ... their ages are ideal as chronological indicators for soils ...; ... aliphatic hydrocarbons represent a fraction of the passive soil C that persists in soil mineral horizons and infer that their ages correspond with the time of soil deposition. |
| 1256 | Huang, Y.S., Stankiewicz, B.A., Eglinton, G., Snape, C.E., Evans, B., Latter, P.M. & Ineson, P. | Monitoring biomacromolecular degradation of Calluna vulgaris in a 23 year field experiment using solid state 13C-NMR & pyrolysis-GC/MS | 1998 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 30 (12); 1517-1528 | English | Hardcopy:Full; PDF:Full | Study of a 23-year litter-bag study of the decomposition of Calluna vulgaris, using solid state 13C-NMR and pyrolysis-GC/MS (gas chromatography/ mass spectroscopy) | Protein showed rapid decomposition with virtually none remaining after 7 y. The absolute weight losses of the other macromolecules after 23 y in the field show the sequence: polysaccharides > aliphatics/cutin > lignin.; .. part of the remaining polysaccharides in the 23 y decomposed litter can be attributed to microbial production.; Cutin & suberin are polymeric components of the plant outer surface ..; Although the absolute weight loss of polysaccharides is comparatively high throughout the expt., their relative decompos'n rates (i.e. weight loss relative to initial wt.) are low.. during 7-23 y loss of 4.5% polysaccharides .. is lower than loss of 5.2% lignin .. As a result, an increased percentage .. of polysaccharides in the 23-y litter is observed .. Polysaccharides can be more recalcitrant when they are protected by lignin in lignocellulosic complexes. This .. may account for the low loss rate of polysaccharides in our study. |
| 1592 | Hudson, J.C. | Sugarcane: its energy relationships with fossil fuel | 1975 | Energy Resources | Journal | Span; 18 (1); 12-14 | English | Hardcopy:Full | Sugar cane is examined as a source of energy for human use. The net energy that can be obtained from sugar cane is calculated and compared with other sources. Tables of the energy inputs into sugar can production are given. | This relatively high efficiency of sugar cane is due primarily to a C-4 type photosynthetic mechanism, which enables the crop to make use of high levels of radiation, even when soil moisture availability is not ideal.; .. atypical European farmer harvest about 0.35% of the sun's energy available during periods of adequate temperature and rainfall for growth. .. a typical West Indian sugar farm fixes about 0.85% .. 35 t [per hectare] dry matter production, typical of many sugar estates, is equivalent to about 24 t of coal or 14.5 t of oil.; .. [in the tables of energy inputs] a man-day is rated as 12.5 MJ, an ox-day as 75 MJ .. |
| 864 | Hunt, P.G., Karlen, D.L., Matheny, T.A. & Quisenberry, V.L. | Changes in carbon content of a Norfolk loamy sand after 14 years of conservation or conventional tillage | 1996 | Soil Organic Carbon; Tillage | Journal | J. Soil Water Conserv.; 51 (3); 255-258 | English | Hardcopy:Full | 17-year study of tillage effects on a sandy soil | Soil C influences soil characteristics such as water infiltration rate, erodibility, water-holding capacity, nutrient cycling and pesticide adsorptive characteristics.; Annual addition of > 7 Mg ha-1 of crop residues are common for maize, soya beans or wheat ..; .. addition of .. crop residues to conventionally tilled (ploughed or disced) soils does not increase soil C content.; .. the crop residue additions were sufficient for increased C content of a sandy surface soil when surface tillage was absent ..; an increase of OM from 0.5% to 3.0% (C content of 3 to 17 g kg-1) more than doubled available water content. |
| 1007 | Huxham, S.K. | Organic conversion strategies for stockless farming | 2003 | Green Manure; Organic Farming; Stockless Farming | Book | Huxham, S.K.; Organic conversion strategies for stockless farming; | English | Hardcopy:Partial; Wordperfect:Partial | Field expt. to compare the effect of various rotations, during the conversion of stockless conventional farmland to organic, on the soil and on subsequent organic wheat crops | Conversion strategy significantly altered the grain yield of a subsequent organic winter wheat crop.Greatest yields occurred following red clover green manures, which exhibited improved soil structure, attributed to infrequent cultivations and high quantity and quality of crop residue input. Soil structure and texture together account for variations in [organic wheat] establishment, [which was] the main determinant of yield. ... [soil mineral nitrogen] was secondary to the effects of establishment on [organic wheat] yield. |
| 547 | Hyvönen, R., Ĺgren, G.I. & Andrén, O. | Modelling long-term carbon and nitrogen dynamics in an arable soil receiving organic matter | 1996 | Green Manure; Organic Farming; Soil Organic Carbon | Journal | Ecol. Appl.; 6 (4); 1345-1354 | English | Hardcopy:Partial | Modelling changes in soil C and N by comparison with exptal results from a 35year field Swedish expt., in which plots had been given twice-yearly additions of straw, peat, sawdust, FYM, green manure and sewage sludge. The results show that the rate of accumul'n of C in the soil was lowest for the green manure & highest for peat, sewage sludge, sawdust & FYM, in that order. The N accumul'n rate was lowest for sawdust and greatest for sewage sludge & FYM. Peat & green manure were equal at about the mid point in the scale. Green manure gave by far the greatest addition of N to the soil but, because of the very high rate of mineralisation, gave the lowest proportionate N accumulation of any amendment (only 24%). Sawdust, on the other hand, was the only amendment to accumulate more N in the soil than was originally contained in it (400%). | .. the initial lignin content cannot be considered as the most important in determining the long-term accumulation of SOM. |
| 1612 | Hättenschwiler, S. & Vitousek, P.M. | The role of polyphenols in terrestrial ecosystem nutrient cycling | 2000 | Mineralisation; Soil Organic Carbon | Journal | Trends Ecol. Evol.; 15 (6); 238-243 | English | Hardcopy:Full; PDF:Full | Review of current knowledge of the role of polyphenols in nutrient cycling | .. polyphenols could inhibit the activity of digestive enzymes and/or precipitate nutritional proteins ..; Polyphenols have also been recognised as regulators of soil processes, where it has been suggested that they inhibit nitrification3,4, as well as decomposition and nutrient recycling..; .. polyphenols produced by plants could affect the bioavailability of P and base cations.. |
| 1546 | Hĺkansson, I., Stenberg, M. & Rydberg, T. | Long-term experiments with different depths of mouldboard ploughing in Sweden | 1998 | Tillage | Journal | Soil Tillage Res.; 46 (3/4); 209-223 | English | Hardcopy:Partial; PDF:Full | 17-year field trials to establish the optimum depth of tillage | In soils with a high silt content the shallowest ploughing resulted in up to 10% higher yield than deeper ploughing .. In clay soils with relatively stable structure, as well as in sandy soils, the deepest ploughing resulted in the highest yields, probably because of the deeper loosening. At sites where perennial weeds imposed problems, the weed control was better the deeper the ploughing, sometimes increasing the relative yield after deeper ploughing by several percent as compared with shallow ploughing. It may be profitable to plough sandy soils annually as deep as 30 cm, coarse sandy soils perhaps even deeper. In clay and clay loam soils, ploughing deeper than 20-25 cm generally cannot be recommended. In silty soils with an unstable structure mouldboard ploughing, if any, should be shallow (ca.15 cm), and perennial weeds should be controlled by other methods. |
| 798 | Höflich, G., Tauschke, M., Kühn, G. & Rogasik, J. | Influence of agricultural crops and fertilisation on microbial activity and microorganisms in the rhizosphere | 2000 | Organic Farming; Soil Microorganisms | Journal | J. Agron. Crop Sci.; 184 (1); 49-54 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to study the effect of various crops and fertilisers on the microbial activity in the rhizosphere of the crops | Compared to mineral fertilisation long-term (18-20 years) straw and green manuring on sandy loam caused higher microbial activity in the rhizosphere of winter wheat, maize and pea.; The results show that organic manuring stimulates not only microbial activity in the soil but also the colonisation of the rhizosphere with bacteria. |
| 901 | Högberg, P., Nordgren, A., Buchmann, N., Taylor, A., Ekblad, A., Högberg, M., Nyberg, G., Ottosson-Löfvenios, M. & Read, D. | Large-scale forest girdling shows that current photosynthesis drives soil respiration | 2001 | Plant C&N Allocation; Roots & Rhizodeposition | Journal | Nature (Lond.); 411; 789-792 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the allocation of photosynthetic C to the roots of the Scots pine by girdling (cutting a ring round the trunk of the tree, removing the bark and xylem, to stop the flow of sap to the roots, but leaving the phloem, to allow the upward flow of water and nutrients to continue) | .. the ectomycorrhizal mycelial system is strongly dependent on current assimilates. In contrast, there was no reduction in the numbers or biomass of saprotrophic fungi in the girdled relative to the control plots ... In the early-girdled plots soil respiration showed within 5 days a decrease of 27% relative to that measured in control plots. ... By ... the end of June, respiration in the early girdling treatment had reached its maximum. Respiration on control plots continued to increase for a further 7 weeks until mid-Aug, indicating that the increase was due to root rather than heterotrophic activity. This resulted in a 52% lower respiration on early girdled plots compared with on control plots. The late girdling produced even faster effects; soil respiration declined by 37% relative to control plots within 5 days of treatment. This precipitous drop in activity continued such that by 2 weeks the CO2 efflux was 56% lower than in control plots. |
| 94 | Hřgh-Jensen, H. | The proportion of green fallow in stockless farming systems: grain N yield, N leaching and soil organic N | 1999 | Green Manure; Soil N Dynamics | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Modelling the N-dynamics of a stockless organic rotation in order to estimate the minimum amount of ley required in the rotation on a N-conserving clay loam soil and on a N-leaky sandy soil | In the N conserving system the ley proportion should not exceed 11% of the whole rotation, as this gave a high yield potential, low N-leaching and a moderate increase in soil org. N. In the N-leaky system the ley proportion seems optimal around 11% of the whole rotation, as this gave the highest yield potential, moderate N leaching and only a small decrease in soil org. N. Access to animal manure or other N-containing residues may be a prerequisite to obtain an economically viable outcome in a leaky system .. |
| 127 | Hřgh-Jensen, H. | Symbiotic N2 fixation in clover-grass mixtures & nitrogen transfer from clovers to the accompanying grass | 1996 | Green Manure; Soil N Dynamics | Book | Raupp, J. (ed.); Symbiotic nitrogen fixation in crop rotations with manure fertilisation, Proc. 3rd mtg (concerted action AIR3-CT94-1940); | English | Hardcopy:Partial; Wordperfect:Full | Review of methods of measuring the fixation and transfer of atmospheric nitrogen in clover-grass mixtures | .. the quantity of fixed N2 in temperate clover-grass mixtures was found to range from 128-305 kg ha-1 yr-1... Transfer of atmospherically derived N from clover to the associated grass was found to range from 0-44 kg ha-1 yr-1 in cutand-carry systems. In grazed systems under temperate conditions transfer has (been found to be as high as 130 kg ha-1 yr-1.; .. access to inorganic N will decrease N2 fixation through a substitution effect between atmospheric N and soil N/fertiliser N. |
| 128 | Hřgh-Jensen, H. & Schjřrring, J.K. | Residual nitrogen effect of clover-ryegrass sward on a subsequent cereal crop as studied by 15N methodology and mathematical modelling | 1996 | Green Manure; Soil N Dynamics | Book | Raupp, J. (ed.); Symbiotic nitrogen fixation in crop rotations with manure fertilisation, Proc. 3rd mtg (concerted action AIR3-CT94-1940); | English | Hardcopy:Partial; PDF:Full | Field expt. and modelling of the fate of N after incorporation of green manures | The amount of N derived from clover-grass residues was 25 to 43% higher than that derived from residues of ryegrass-only. .. the N uptake in the subsequent winter wheat crop was 23-28 kg N ha-1 higher after clover-ryegrass than after `ryegrass. Up to about 54 kg N ha-1 of the N mineralised from the clover-ryegrass (crop was leached, whereas only 11 kg N ha-1 was leached following grass .. When simulating a delay in ploughing-in of the residues, .. N leaching was reduced to 30 kg N ha-1. When further delaying ploughing to spring, .. N leaching was reduced to 16 kg N ha-1. |
| 617 | Hřgh-Jensen, H. & Schjřrring, J.K. | Residual nitrogen effect of clover-ryegrass swards on yield and N uptake of a subsequent winter wheat crop as studied by use of 15N methodology and mathematical modelling | 1997 | Green Manure; Soil N Dynamics | Journal | Eur. J. Agron.; 6; 235-243 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of incorporated green manures on following wheat crops | Clover-ryegrass swards release a substantially larger amount of N for the succeeding crop than swards of ryegrass in monoculture. A considerable amount of the N released from clover-ryegrass residues may be lost by leaching. |
| 1042 | Hřgh-Jensen, H. & Schjřrring, J.K. | Interactions between white clover & ryegrass under contrasting N availability: N2 fixation, N fertiliser recovery, N transfer and water use efficiency | 1997 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 197 (2); 187-199 | English | Hardcopy:Partial; PDF:Full | Field expt. to study seasonal variations in N cycling in white clover-ryegrass swards | White clover has a thicker, shorter and less branched root system with shorter and fewer root hairs than ryegrass [and is] a weak competitor for nutrients with low mobility in soil, whereas the morphology of the root system may be less important with respect to water and nitrate acquisition. .. In clover-grass swards ryegrass generally absorbs the major part of the available soil N and under ample N conditions white clover is out-competed.; .. the intercropping advantage is not only a question of transfer of atmospherically derived N from clover to ryegrass but also an enhanced ability of the clover-ryegrass mixture to utilise soil N pools.; .. it is generally accepted that the main pathway of transfer is through the microbial biomass .. This transfer can be bi-directional, where the direction at a certain time will depend on the actual competitive balance between clover and ryegrass. |
| 1043 | Hřgh-Jensen, H. & Schjřrring, J.K. | Below-ground nitrogen transfer between different grassland species: direct quantification by 15N leaf feeding compared with indirect dilution of soil 15N | 2000 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 227; 171-183 | English | Hardcopy:Partial; PDF:Full | Field expt. to measure the bi-directional transfer of N between legume and grass | The transfer of N from both clovers to ryegrass occurred within 25 days upon the first labelling event. A very high N transfer occurred from white clover to the assoc'd ryegrass, 4.5 and 7.5 g m-2 in the 1st and 2nd .. years .. The corresponding values for transfer from red clover to the assoc'd ryegrass were `1.7 and 3.6 g m-2. Quantified relatively to the total above-ground N content of white clover- & red clover-ryegrass mixtures, the N transfer exceeded 50% and 10% respectively... The N transfer from 15N-labelled grass to assoc'd clovers constituted .. approx. 8% of the above-ground N content of the mixtures. |
| 1253 | Hřgh-Jensen, H. & Schjřrring, J.K. | Rhizodeposition of nitrogen by red clover, white clover and ryegrass leys | 2001 | Green Manure; Roots & Rhizodeposition; Soil N Dynamics | Journal | Soil Biol. Biochem.; 33 (4/5); 439-448 | English | Hardcopy:Partial | Expt. to quantify the rhizo-deposition of N by red and white clover and ryegrass in leys. It was found that the rhizo-deposition of N by unfertilised red clover, white clover and perennial ryegrass growing in pure stands and by mixtures of red clover-ryegrass and white clover-ryegrass amounted to 64, 71, 9, 89 and 32 g N m-2 respectively over two complete growing seasons. This constituted respectively a 1.26, 2.21, 2.77, 1.05 and 1.52-fold increase over the total N in the shoots harvested during the two production years. | The rhizo-deposited N compounds including fine roots constituted more than 80% of the total plant-derived N in the soil and in all cases exceeded the amount of N present in stubble.; In pure stands and mixtures of clover 84 and 92% respectively of this N [is] derived from biological N2 fixation. It is concluded that rhizo-deposition provides a very substantial input of N to legume-based grassland systems with great consequences for ecosystem N balance and turnover. Furthermore, the amount of atmospheric-derived N in the rhizo-deposits may exceed that in the harvested shoots. |
| 1091 | Hřgh-Jensen, H., Wollenweber, B. & Schjřrring, J.K. | Kinetics of nitrate and ammonium absorption and accompanying H+ fluxes in roots of Lolium perenne and N2-fixing Trifolium repens | 1997 | Green Manure; Soil N Dynamics | Journal | Plant Cell Environ.; 20; 1184-1192 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the differential absorption of nitrate & ammonium by clover & ryegrass | @; For L. perenne rates of net uptake, influx & efflux of NH4+ exceeded those of NO3-, while the opposite was the case in T. repens. Uptake and assimilation of N are associated with a transport of H+ between roots and root medium. These H+ fluxes affect t |
| 693 | Hülsbergen, K.J., Feil, B. & Diepenbrock, W. | Rates of nitrogen application required to achieve maximum energy efficiency for various crops: results of a long-term experiment | 2002 | Energy in Agriculture; Soil N Dynamics | Journal | Field Crops Res.; 77 (1); 61-76 | English | Hardcopy:Partial; Wordperfect:Full | Estimating the maximum energy efficiency of nitrogenous fertiliser application from the results of a 10-year field expt. in which 5 crops were grown with various rates of nitrogenous fertiliser | .sugar beet produced by far the highest net energy output of all the crops.; At optimum N fertilisation the net energy output increased in the order: winter barley<winter wheat<sugar beet.; In calculating the net energy output the yield of straw was considered. Straw contains almost as much energy as the grains (17.7 v. 18.6 MJ/kg).; .. maximum energy fixation per unit ground area (net energy output) and minimum energy use per unit produce (energy intensity) are incompatible objectives. .. the rate of fertiliser N required for maximum net energy output (with by-product) was 142 kg N/ha/yr .. whereas 108 kgN/ha/yr was sufficient for achieving minimum energy intensity.; .. increases in yield are associated with decreases in the concentration of grain protein .. Farmers can offset such a negative protein trend by applying more N fertiliser.. highly productive wheat crops need more fertiliser N to meet the minimum protein concentration standards of the wheat processing industry. |
| 225 | Hülsbergen, K.J., Feil, B., Biermann, S., Rathke, G.W., Kalk, W.D. & Diepenbrock, W. | A method of energy balancing in crop production and its application in a long- term fertiliser trial | 2001 | Energy in Agriculture | Journal | Agric. Ecosyst. Environ.; 86 (3); 303-321 | English | Hardcopy:Partial; PDF:Full | 32-year field expt. to study the time trends of various energy parameters as affected by the rate and form of N fertiliser application | The input of energy .. ranged from 8.9 to 36.9 GJ ha-1 per year in the last crop rotation, depending on the N regime and the crop. .. the average biomass yield of all the crops grown within a rotation was as .. 13.5 t (DM) ha-1 per year; the `output of energy was .. 215 GJ ha-1 per year. .. net energy output .. and energy utilisation improved with time. Winter wheat, fertilised with moderate amounts of mineral and farmyard manure N, showed an increase in net energy output of 86% from 1972 to 1995. During the same period, the energy intensity (input of fossil energy per grain equivalent) declined by 45%, and the output/input ratio increased by 67%. In part, these trends can be attributed to the higher grain yield (+59%).; .. moderate rates of N application are necessary to realise maximum net energy output .. The lowest energy intensity is, however, achieved at lower rates of N application. In organic and extensive conventional farming systems the energy intensity may be reduced to an even lower level by growing crops that are capable of biological N fixation. It seems that energy is poorly used when N fertiliser is not applied. |
| 682 | Ibekwe, A. & Kennedy, A. | Phospholipid fatty acid profiles and carbon utilisation patterns for analysis of microbial community structure under field and greenhouse conditions | 1998 | Soil Microorganisms | Journal | FEMS Microbiol. Ecol.; 26 (2); 151-163 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to compare phospholipid fatty acid profiles and potential carbon source utilisation patterns, which showed that PLFA may be a more sensitive technique for making a quantitative description of soil microbial communities | |
| 315 | Ikerd, J., Devino, G. & Traiyongwanich, S. | Evaluating the sustainability of alternative farming systems: a case study | 1996 | Sustainability | Journal | Am. J. Alternative Agr.; 11 (1); | English | Hardcopy:Partial | The definition of and criteria for sustainability are discussed. An assessment is made of the sustainability of farming systems by their potential environmental, economic and social performance; environmental criteria include soil conservation and energy efficiency; economic criteria include farm profitability, economic competitiveness and return on investment; social criteria include self esteem of farmers and self-perceived quality of life | .. a sustainable agriculture must be environmentally sound, economically viable and socially responsible.; A system that degrades energy less rapidly than it captures solar energy can be sustainable indefinitely. |
| 67 | Illmer, P. | Backyard composting: general considerations and a case study | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to test the effectiveness of small-scale composting | The end-product obtained without mixing [turning] and without SM [structure material] addition is characterised by wet reducing conditions only 1 or 2 cm below the desiccated surface and did not show any further reduction in volume or change in consistency for several months. The end product of the other composting process (mixing, SM addition) showed an acceptable end product .. the best results concerning .. the quality of the end product were achieved by a combination of the two treatments tested, i.e. mixing and SM addition. |
| 489 | Illmer, P. & Schinner, F. | Compost turning - a central factor for a rapid and high-quality degradation in household composting | 1997 | Compost & Biocontrol | Journal | Bioresour. Technol.; 59 (2/3); 157-162 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of turning on the composting rpocess | The speed of degradation, as well as the quality of the end product, was significantly increased through supported mixing with a mechanical stirrer. .. manual mixing also led to better results compared with static composters, but differences were less distinct. |
| 107 | Ilnicki, R.D. & Enache, A.J. | Subterranean clover living mulch: an alternative method of weed control | 1992 | Clover Sward; Stockless Farming; Tillage | Book | Paoletti, M.G. & Pimentel, D. (eds.); Biotic diversity in agroecosystems: a symposium on agroecology and conservation; 249-264 | English | Hardcopy:Partial | A subterranean clover living mulch is assessed as a weed control. It controls weeds better than herbicides | .. subterranean clover used as a living mulch in a no-tillage system provided excellent weed control .. . Treatments without subterranean clover living mulch, including the conventional tillage\herbicide treated checks, had higher weed biomass. Yields of corn, sweet corn, cabbage, snap beans and tomato were not adversely affected by the subterranean clover living mulch.; It may be necessary to mow excessive growth of the sub clover to reduce early competition with some crops .. if grazing is not possible. Or it may be necessary to striptill or chemically kill or suppress vegetative growth in the row prior to or at the time of crop planting .. . |
| 226 | Ingram, J.S.I. & Fernandes, E.C.M. | Managing carbon sequestration in soils: concepts and terminology | 2001 | Greenhouse Gases; Soil Organic Carbon | Journal | Agric. Ecosyst. Environ.; 87; 111-117 | English | Hardcopy:Partial | A review of research on C storage in soils with particular emphasis on the definition of terms. A distinction is drawn between potential and attainable C sequestration, attainable being when climatic restraints are taken into consideration. | .. crop-based agriculture occupies 1.7 billion ha. globally, with a soil C stock of approximately 170 Pg. The oxidation of SOM in cultivated soils is estimated to have contributed approx. 50 Pg C to the atmosphere [= historical emissions from agriculture ??].; .. estimates of the average loss of SOC in the top 1 m. within 2-8 years following conversion of native tropical vegetation to agriculture vary from 15 to 40%. .. in the early 1980s land use changes were estimated to have resulted in the transfer of between 1 and 2 Pg C/year from terrestrial ecosystems to the atmosphere. Between 15 and 17% of this C came from the oxidation of SOC. .. Estimates of the capacity for C sequestration in agricultural soils globally are in the order of 20-30 Pg C over the next 50-100 years.; The fossil fuel requirements for the increased productivity and contribution of C to the soil in managed systems must also be accounted for in the C flux and sequestration calculations. |
| 1257 | Insam, H. | Are the soil microbial biomass and basal respiration governed by the climatic regime? | 1990 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 22 (4); 525-532 | English | Hardcopy:Partial | Study of the microbial biomass and respiration in 21 soils from several diffxerent climatic regions in N. America. Soil microbial biomass and the Cmic/Corg ratio were correlated with precipitation/evaporation and basal respiration and metabolic quotient (qCO2) were correlated with temperature. | .. dormant stages make up the larger part of the biomass, but the small active part contributes over-proportionally to the respiration. .. a high qCO2 is found in soils with a recent input of easily degradable substrates. |
| 964 | Insam, H. & Haselwandter, K. | Metabolic quotient of the soil microflora in relation to plant succession | 1989 | Soil Microorganisms | Journal | Oecologia; 79; 174-178 | English | Hardcopy:Full | Field study of soils on two glacial moraine primary succession sites and a nearby reclamation site, re-vegetated three years before, to test the hypothesis that ecosystem successions accompanied by a decrease in the metabolic quotient @qCO2 of the soil microflora. On the primary succession sites both the SMB and the basal respiration increased with the age of the soil, but the metabolic quotient fell. | .. ecosystems tend to evolve towards less energy-wasting stages, i.e. a lower maintenance-to-structure ratio (Odum, 1969). .. Theoretically .. the amount of standing crop biomass supported by the available energy flow increases to a maximum in the mature or climax stages.; [of ecosystem development]; Carbon input is .. the limiting factor for the .. SMB ..The low level of microbial biomass and activity on the bare soils is due to the very limited C supply.; .. this concept of r- and K-strategists may well be .. explaining the decrease of qCO2 on the successions investigated here. Simple substrate-decomposer relationships dominated by r-strategists would be characteristic of the early stages. With progressing succession the detritus food webs would become more complex. Then slower growing specialists, the K-strategists, would occupy various niches. |
| 822 | Islam, K.R., Mulchi, C.L. & Ali, A.A. | Tropospheric CO2 or ozone enrichments and moisture effects on soil organic carbon quality | 1999 | Greenhouse Gases; Soil Organic Carbon | Journal | J. Environ. Qual.; 28; | English | Hardcopy:Partial | An expt. with the growing of wheat and soya beans in air with different CO2 and ozone concentrations | @; Soil particulate C content was increased under atmospheric CO2 enrichment .. Also increased were the amounts of dissolved C and humic and fulvic acids present in the soil .. So, as the air's CO2 content continues to rise .. we should see .. a slowing o |
| 1436 | Ismail, I., Blevins, R.L. & Frye, W.W. | Long-term no-tillage effect on soil properties and continuous corn yields | 1994 | Soil (General); Tillage | Journal | Soil Sci. Soc. Am. J.; 58 (1); 193-198 | English | Hardcopy:Partial | 20-year study of the effects on the soil and on crop yields of different tillage treatments and different rates of nitrogenous fertiliser. | SOC & N, extractable P, exchangeable Ca, Mg and K and pH were significantly higher with NT than CT in the 0 to 5 cm. depth; [but not below that].; Organic C & N increased with increasing N [fertiliser] rates [but] pH and exchangeable Ca and Mg declined .. |
| 68 | Itavaara, M., Venelampi, O., Vikman, M. & Kapanen, A. | Compost maturity - problems associated with testing | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the phytotoxicity of composts of varying maturity | .. toxicity was .. induced by anaerobicity & no toxicity was formed when aerated .., even though the compost was immature. .. if immature compost is used as a plant growing medium, oxygen consump'n in the medium may be excessive and cause poor plant growth. The formation of toxic anaerobic biodegrad'n metabolites may be induced by high microbial activity under anoxic cond'ns. |
| 1388 | Iyamuremye, F., Dick, R.P. & Baham, J. | Organic amendments and phosphorus dynamics: III. Phosphorus speciation | 1996 | Phosphorus Cycling | Journal | Soil Sci.; 161 (7); 444-451 | English | Hardcopy:Full | Lab. expt. to study the solubility of different phosphorus species in soil with organic (FYM) and inorganic (CaCO3, CaSO4) amendments | P in acid soils may be inadequate for plant nutrition, even though total P levels are high. This is attributable to P precipitation with Al, Fe or Ca or its adsorption by soil mineral colloidal fractions.; Manure treatments .. decreased Al and Fe activity .. [which] was likely the reason for the elevated levels of soluble P in manure-amended soil. .. manure causes P to become more soluble through dissolution of mineral P phases or the precipitation of P is prevented. Although the inorganic treatments had similar effects, they were not always consistent or as dramatic as manure-amended soils. .. Other mechanisms that increased the solubility of P in manure-amended soils are likely related to the increased dissolved organic C and presence of some organic acids that .. reduce the potential for P sorption and precipitation. |
| 1117 | Izaurralde, R.C., McGill, W.B. & Rosenberg, N.J. | Carbon cost of applying nitrogen fertiliser | 2000 | Energy in Agriculture; Greenhouse Gases; Soil Organic Carbon | Journal | Science; 288; 809 | English | Hardcopy:Partial; Wordperfect:Full | Comment on Schlesinger's article Carbon Sequestration in Soils (Science, 1999), in which he asserts that 'the full C cost of N fertiliser .. would effectively negate any net C sink as a result of the application of the fertiliser' and Schlesinger's reply | We analysed the same data and found that they do not support the conclusion that the C costs of N fertiliser negate the associated C sequestered in soil.; Schlesinger bases his conclusion on the use of an unrealistically high N application rate of 336 kg ha-1 year-1. Thus, even with the most conservative cost factor and highest N rate, the C cost of fertiliser N to increase crop production is less than the C sequestered in soil at the Kentucky site.; W.H.S.:; Although the C costs of N fertiliser discount only 66% of the mean C sequestration in the maize fields of Kentucky, other studies, edited for space from my original Policy Forum, have discounts greater than 100%. In all cases the marginal CO2 cost of increasing N fertiliser use exceeds the marginal gain of C sequestration in soils, especially those under no-till management. Thus recommendations for a greater use of N fertiliser ... are unlikely to contribute significantly to Kyoto credits. |
| 1437 | Izaurralde, R.C., McGill, W.B., Robertson, J.A., Juma, N.G. & Thurston, J.J. | Carbon balance of the Breton classical plots over half a century | 2001 | Green Manure; Soil Organic Carbon; Stockless Farming | Journal | Soil Sci. Soc. Am. J.; 65 (2); 431-441 | English | Hardcopy:Full; PDF:Full | The soil C and N contents are compared over a period of 54 years under various rotations and fertiliser treatments (no fertiliser, NPK and FYM). The plot with a lucerne-cereal rotation and added FYM gave the greatest increase in SOC & N. In the continuous wheat rot'n with no fertiliser the SOC & N went down. It is calculated that FYM can sequester C in soil, contradicting Schlesinger (1999). | .. return of manure increases C productivity. Return of 30% of the crop C .. as manure would sustain net soil C sequestration in all WOBHH [cereal-lucerne] rotations with net C productivity >400 kg ha-1 yr-1 .. |
| 165 | Izaurralde, R.C., Rosenberg, N.J. & Lal, R. | Mitigation of climatic change by soil carbon sequestration | 2001 | Greenhouse Gases; Soil Organic Carbon; Tillage | Journal | Adv. Agron.; 70; | English | Hardcopy:Partial | Review of the research on C sequestration in agricultural soils | C has been accumulating at rates exceeding 1 Mg/ha/year in former U.S. crop lands planted to perennial grasses ..; .. when agriculture is converted .. to forest vegetation .. soil C may accumulate at rates ranging from near 0 to 7 Mg/ha/year.; Generally the C concentration and C/N ratio decrease as soil aggregates become smaller but the amount of C held in them increases with decreasing aggregate size.; There are reports that growing-season N2O emissions increase under zero tillage.; .. soils are estimated to provide a sink for between 40 & 80 Pg of C ..; .. restoration of degraded lands & desertification control .. have the potential to sequester from 0.7 to 1.6 Pg C per yr. |
| 788 | Jaber, D. | Human dignity and the dignity of creatures | 2000 | Agricultural Ethics | Journal | J. Agric. Environ. Ethics; 13 (1); 29-42 | English | Hardcopy:Partial; PDF:Full | A critique of the differentiation between human dignity (the moral right not to be humiliated) and the dignity of creatures (their inherent value) | Both notions could be brought together under an all-encompassing concept of the inherent value of living beings .. |
| 1549 | Jacinthe, P.A., Lal, R. & Kimble, J.M. | Carbon dioxide evolution in run-off from simulated rainfall on long-term no-till and ploughed soils in south-western Ohio | 2002 | Greenhouse Gases; Tillage | Journal | Soil Tillage Res.; 66 (1); 23-33 | English | Hardcopy:Partial; PDF:Full | Field expt. to determine erosional SOC export and CO2 evolution in the run-off under zero, chisel and plough tillage. Total SOC was 30.0, 11.2 and 9.4 g C/kg soil and SMB-C was 262.8, 98.8 and 36.1 mg C/kg soil for the three soils resp. | Run-off soil loss was highest in the MP [ploughed] soils with an average sediment delivery rate ... which was 1.4 - 2.8-fold that from the CT and NT soils; Sediment from the NT soil contained twice as much C ... [as] sediment from the CT ... and MP ... soils.; ... the fate of erosion-displaced SOC depends on its biochemical quality ... a larger fraction of C in run-off originating from notillage plots is susceptible to mineralisation than in run-off from intensively tilled soils. ... through its stimulating effect on microbial activity, mineral N availability enhances run-off C mineralisation and CO2 production. |
| 737 | Jackson, L.E., Calderon, F.J., Steenwerth, K.L., Scow, K.M. & Rolston, D.E. | Responses of soil microbial processes and community structure to tillage events and implications for soil quality | 2003 | Soil Organic Carbon; Soil N Dynamics; Tillage | Journal | Geoderma; 114 (3/4); 305-317 | English | Hardcopy:Partial | Presents the results of an expt. to determine the responses of SOM to perturbation in an intensive vegetable cropping system. Three treatments were used - zero tillage, rotovation and disc harrowing. | [The tilled soils] changed most rapidly during the first week after tillage and were nearly identical to the untilled soil after two weeks, [suggesting] that soil microbial community structure responds quickly to disturbance in intensively managed agricultural soils but does not experience prolonged changes.; N mineralis'n is .. greater than C mineralis'n after soil disturbance..; Because microbial processes follow a Q10 response pattern, such that a doubling in activity occurs with a 10$C increase in temp, changes in soil phys. properties may trigger the onset of a longer term increase in C mineralisation rates. |
| 497 | Jackson, L.E., Ramirez, I., Yokota, R., Fennimore, S.A., Koike, S.T., Henderson, D.M., Chaney, W.E. & Klonsky, K. | Soil quality in response to tillage and organic matter management | 2002 | Green Manure; Soil (General); Tillage | Journal | Calif. Agric.; ; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to compare soil quality, efficiency and financial return from growing vegetables under different management systems. | .. the system using minimum tillage with OM [compost+rye green manure] inputs .. was associated with higher total soil C & N and lower BD in the surface soil .. and higher soil microbial biomass .. the potential for nitrate leaching below the root zone was lower than in any other treatment. Yet [it] did not produce high vegetable yields, possibly due in part to slight N, P and moisture limitation, nor was it economically advantageous despite low fuel and input costs. Conventional tillage with OM inputs appears to be a more attractive option for farmers. |
| 1258 | Jackson, L.E., Schimel, J.P. & Firestone, M.K. | Short-term partitioning of ammonium and nitrate between plants and microbes in an annual grassland | 1989 | Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 21 (3); 409-415 | English | Hardcopy:Partial | Field expt. to study the partitioning of soil ammonium and nitrate between plants and microorganisms under grassland | While microbes took up more of both NH4+ and NO3- than plants, microbes competed better for NH4+ than for NO3-.; In pure liquid cultures of both bacteria and fungi, NH4+ can repress NO3- assimilation at concentrations as low as 1 mM. .. the high uptake of NO3- by the microbial population [in the expt.] suggests that at least a portion of the population may have been NH4+ limited.; Daily uptake of NH4+ .. was close to the actual size of the NH4+ pool. The turnover time .. was therefore approx. 1 day. The NO3- pool probably turned over at an even faster rate; NO3- appears to be taken up as fast as it was produced. |
| 1118 | Jackson, R.B., Jobbágy, E., Avissar, R., Roy, S.B., Barrett, D., Cook, C., Farley, K., Maitre, D. le, McCarl, B. & Murray, B. | Trading water for carbon with biological carbon sequestration | 2005 | Greenhouse Gases; Miscellaneous | Journal | Science; 310; 1944-1947 | English | Hardcopy:Partial; PDF:Full | Review of disadvantages of forestation as a means of C sequestration | Carbon sequestration strategies highlight tree plantations without considering their full environmental consequences.; Plantations decreased stream flow by 227 millimeters per year globally (52%), with 13% of streams drying completely for at least 1 year.; For many nations with total annual renewable freshwater <30% of precipitation (Fig. 1B), afforestation is likely to have large impacts on water resources.; ... the higher water use of plantations and decreased stream flow is unlikely to be offset by atmospheric feedbacks operating at larger scales. ... plantations typically increased summer evapotranspiration by >0.3 mm day-1 ... compared with the crop and pasture lands they replaced. |
| 227 | Jackson, W. | Natural systems agriculture: a truly radical alternative | 2002 | Miscellaneous; Sustainability | Journal | Agric. Ecosyst. Environ.; 88 (2); 111-117 | English | Hardcopy:Partial; PDF:Full | Review of the work of the Land Institute, Salina. Cultivation of the soil has casued serious erosion since the very beginningof agraicuture. | The final product is a domestic grain producing prairie with the four functional groups represented (warm-season & cool-season grasses, legumes, sunflower family). These mixtures could comprise domesticated wild species and/or domestic annuals made perennials. Here is the prototypical ecosystem toward solving the 10,000-year-old problem of agriculture. |
| 2 | Jackson, W. & Jackson, L.L. | Developing high seed yielding perennial polycultures as a mimic of mid-grass prairie | 1999 | Miscellaneous; Sustainability | Book | Lefroy, E.C., Hobbs, R.J., O'Connor, M.H. & Pate, J.S. (eds.); Agriculture as a Mimic of Natural Ecosystems; | English | Hardcopy:Partial; Wordperfect:Full | Review of research at the Land Institute to develop suitable perennial grass/ legume mixtures to replace annual cereals.Perennial plants are thought to put much energy into storage organs to survive winter and correspondingly less energy into seeds, compared with annuals, but this is not necessarily so. In some perennial grasses there is a pistillate variant that produces 5 times the seed mass of normal plants, due to feminisation of staminate spikelets. | .. numerous domesticated woody perennials have not only high reproductive efforts but high yields on a per-acre basis as well. For example, .. blueberries .. peach trees .. grapevines ..; the reproductive tiller or seed stalk becomes a net supplier of photosynthate to the rest of the plant.. even when defoliated, the photosynthetic capability of normal [i.e. non-pistillate] seed stalks and inflorescences is entirely sufficient to fill seeds. |
| 936 | Jakobsen, I. & Rosendahl, L. | Carbon flow into soil and external hyphae from roots of mycorrhizal cucumber plants | 1990 | Roots & Rhizodeposition | Journal | New Phytol.; 115; 77-83 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to measure the quantity of photosyntheetic C that passes into the roots, soil and VAM hyphae if ccucumber plants | Belowground respiration in mycorrhizal plants accounted for 27% of the photo assimilated 14C. Organic 14C in the soil represented 3.1% of the fixed 14C and 26% of this was located in external hyphae. .. it was estimated that mycorrhizal events consumed 20% of photo-assimilated 14C. The specific incorp'n of C by the external mycelium inthe hyphal compartment was 41 %g C mg-1 dry wt.d-1. |
| 460 | Jandl, R. & Sollins, P. | Water-extractable soil carbon in relation to the belowground carbon cycle | 1997 | Soil Organic Carbon | Journal | Biol. Fertil. Soils; 25 (2); 196-201 | English | Hardcopy:Partial | Expt. to study the role of water-extractable C as a substrate for microbes | To the extent that the degradable portion of the water-extractable C can be regenerated quickly, it may supply much of the substrate for heterotrophic soil respiration. |
| 263 | Jansen, A.J. | Agro-ecosystems in future society | 1974 | Agricultural Ecology | Journal | Agro-Ecosystems; 1; 69-80 | English | Hardcopy:Full | The future role of agriculture in western Europe is presented through a review of the research project 'Farming in society towards the year 2000' | Traditional good husbandry was replaced by scientific and technical prescriptions. .. Agriculture became a capitalistic market-oriented activity, the peasant farmer an entrepreneur. Profit making, or at least profit-loss accounting, became a basic objective of farm enterprises. .. Agriculture became a more and more specialised industry. Traditional polycultural systems were narrowed down to a few production lines ..; Agriculture .. has made substantial progress in loosening its ties with the natural environment and in its efforts to dominate (and possibly eliminate) the constraints of nature. .. [there is a] loss of awareness .. of the coherence and interdependence between man and his natural environment, which were characteristic of the traditional peasant economies.; ..; Agriculture simply cannot be accepted as becoming .. merely one of the industrial processes in the productive system .. |
| 1100 | Janulis, P. | Reduction of energy consumption in biodiesel fuel life cycle | 2004 | Energy Resources; Rape and Biodiesel | Journal | Renew. Energ.; 29; 861-871 | English | Hardcopy:Full | Calculating the efficiency of the production of biodiesel from rape. The energy consumption in the production of rapeseed is halved when 'bio-fertilisers' and chemical seed preservation are used instead of the conventional chemical fertilisers and thermal seed drying. 10% less energy is used by 'bio-technical' oil extraction methods than by conventional cold pressing. Ethyl, instead of the conventional methyl, esterification produces about 10% more biodiesel from a given quantity of oil. When all these improved technologies are used together, the O/I ratio of biodiesel production (at a rapeseed yield of 3 t/ha) is 2.28, as compared with 1.43 for conventional technology. | |
| 1259 | Janzen, H.H. | Deposition of nitrogen into the rhizosphere by wheat roots | 1990 | Roots & Rhizodeposition; Soil N Dynamics | Journal | Soil Biol. Biochem.; 22 (8); 1155-1160 | English | Hardcopy:Partial | Lab. expt. to quantify the deposition of N by wheat roots growing in soil fertilised with 20 or 100 mg N/kg soil. Studies show that 20-40% of the C transported to the roots may be exuded into the rhizosphere. In wheat up to 20% of photosynthate C can be rhizodeposited. Root exudates have C/N ratios ranging from 2.0 to 2.7 and contain amino-acids and peptides. In this study up to 32% (average 20%) of mineralised N came from the roots. This represented, on average, 36% of the root-derived organic N present at the start of the expt. 18% and 33% of the N released assimilated by the wheat was released into the rhizosphere in the low and high N treatments respectively. This recycling of N by the roots is enhanced under conditions of N deficiency. | .. rhizodeposition may contribute significantly to the N fertility of soils .. [and] may amount to ca. 20 kg N/ha. |
| 1260 | Janzen, H.H. | The soil carbon dilemma: shall we hoard it or use it? | 2006 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 38 (3); 419-424 | English | Hardcopy:Full; PDF:Full | Review of the question as to whether increasing so.l microbial activity and increasing soil carbon storage are conflicting aims | .. OM is most useful, biologically, when it decays. So we face a dilemma: can we both conserve OM & profit from its decay?; With constant C inputs we cannot both increase soil C & increase microbial activity. If we want higher microbial activity, we have to sacrifice SOC; if we want to store more C, we must quash microbial activity. |
| 1261 | Janzen, H.H. & McGinn, S.M. | Volatile loss of nitrogen during decomposition of legume green manure | 1991 | Green Manure; Soil N Dynamics | Journal | Soil Biol. Biochem.; 23 (3); 291-297 | English | Hardcopy:Partial | Lab. expt. to study the effect of legume placement (placed on, suspended above or incorporated into the soil) on loss of ammonia from green manures | NH3 evolution from incorporated green manure was negligible. In contrast, appreciable volatilisation was observed from green manure applied to the surface .. After 28 days an average of .. 3.6% of the N applied had been volatilised.; .. volatilisation rates from green manure are much lower than those from urea and other fertilisers.; .. N recovery by crops is often higher when green manure is incorporated than when retained on the surface. .. Although volatilisation may only remove a small proportion of the green manure N (124% in the case of our study), this fraction represents the most labile N and that which is most important to short-term fertility. |
| 1550 | Janzen, H.H., Campbell, C.A., Izaurralde, R.C., Ellert, B.H., Juma, N.G., McGill, W.B. & Zentner, R.P. | Management effects on soil C storage on the Canadian prairies | 1998 | Greenhouse Gases; Stockless Farming; Tillage | Journal | Soil Tillage Res.; 47 (3-4); 181-195 | English | Hardcopy:Partial; Wordperfect:Full | A review of long-term research on the effect of cropping and fertilising practices (including FYM) on SOC reserves in the Canadian prairies | [It is suggested] that: (1) the loss of SOC upon conversion of soils to arable agriculture has abated; (2) significant gains in SOC (typically about 3 Mg C ha-1 or less within a decade) can be achieved in some soils by adoption of improved practices like intensification of cropping systems, reduction in tillage intensity, improved crop nutrition, organic amendments and reversion to perennial vegetation; (3) changes in SOC occur predominantly in `young' or labile fractions; (4) the change in SOC, either gain or loss, is of finite duration and magnitude; (5) estimates of SOC change from individual studies are subject to limitations and are best viewed as part of a multi-site network; and (6) the energy inputs into agroecosystems need to be included in the calculation of the net C balance.; Although manure [FYM] application can significantly enhance SOC content, part of this increase may reflect C imported from other ecosystems. The addition of manure results in net removal of atmospheric CO2 only to the extent that it enhances primary production via improved soil conditions .. |
| 1262 | Janzen, R.A., Cook, F.D. & McGill, W.B. | Compost extract added to microcosms may stimulate community-level controls on soil microorganisms involved in element cycling | 1995 | Compost & Biocontrol; Soil Microorganisms | Journal | Soil Biol. Biochem.; 27 (2); 181-188 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to test the effect of compost extract [tea] on microbial communities in soil | .. compost extract may control the function of some microbial communities in microenvironments. .. compost extract controls microbial activity by mechanisms in addition to supply of mineral nutrients, such as transfer of growth factors among populations. Not all processes, however, were influenced consistently by compost extract. For example, its addition to the mixed cultures in .. initially N-free .. medium did not influence the final N content.; .. amendment of growth media with compost extract stimulates the function, at the microenvironment level, of some tested populations and communities of soil microorganisms. |
| 1263 | Janzen, R.A., Dormaar, J.F. & McGill, W.B. | A community-level concept of controls on decomposition processes: decomposition of barley straw by Phanerochaete chrysosporium or Phlebia radiata in pure or mixed culture | 1995 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 27 (2); 173-179 | English | Hardcopy:Partial | Lab. expt. to test the interaction between different species of fungi in barley straw decomposition | .. community-level controls on decomposition dynamics integrate physicochemical and population-level controls ..; At 45$C 80% as much CO2 was evolved from straw inoculated with P. chrysosporium in pure culture as from mixed cultures ..; At 20$C P. radiata evolved 3-fold more CO2 in pure culture on barley straw .. than did other tested inocula. |
| 1264 | Jarvis, S.C., Lovell, R.D. & Panayides, R. | Patterns of CH4 emission from excreta of grazing animals | 1995 | Greenhouse Gases | Journal | Soil Biol. Biochem.; 27 (12); 1581-1588 | English | Hardcopy:Partial | Expt. to measure the CH4 emission from cattle and sheep droppings in the field and in the lab. | A strong exponential relationship was determined between total CH4 released and the C-to-N status of the dung, i.e. a greater rate of release with higher N status.; .. the major effect came from dung itself with only a relatively small positive interaction when soil was present.; Although the emissions of CH4 from dung were significant, the amounts were small relative to the estimated total release from a complete livestock production system, i.e. <0.2% of the total CH4 output from a dairy farm. |
| 166 | Jarvis, S.C., Stockdale, E.A., Shepherd, M.A., Powlson, D.S. | Nitrogen mineralisation in temperate agricultural soils: processes and measurement | 1996 | Greenhouse Gases; Mineralisation; Soil N Dynamics | Journal | Adv. Agron.; 57; | English | Hardcopy:Partial | Review of the current knowledge of soil N, its storage and transformation | Soils [contain] on a global basis an estimated 2.4 x 1011 tons of N.; The organic N pool .. is always much larger than the mineral N pool; for example, mineral N .. was only 76 kg N per ha compared with 7 tons per ha of organic N.; Much of any NH4+, NO3- or simple organic N compounds that are released is assimilated rapidly by the SMB population and transformed into the organic N constituents of their cells during the oxidation of suitable C substrates, i.e. it is immobilised. .. biomass N contributes .. substantial amounts of N to the pools of mobile N.; Biomass N .. represents a significant proportion of the total soil N .. for example, 0.5-15.3% ..; .. stimulation of biol. activity in soils due to the readily available C added in manures can lead to .. significant immobilisation of the manure inorganic N pool.; .. extra net mineralisation of approx. 20 kg N/ha occurred with ploughing as compared with direct drilling .. |
| 1265 | Jastrow, J.D. | Soil aggregate formation and the accrual of particulate and mineral-associated organic matter | 1996 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 28 (4/5); 665-676 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the form of OM at different stages in a chronosequence in soil samples taken from virgin and restored natural grassland and conventionally tilled arable land .. In macroaggregate size separates total C, mineral-assoc'd C & macroaggregate-assoc'd C increased in the order: arable < younger restored grassl'd < older restored grassl'd < virgin grassland. With intra-macroaggregate POM-C and free/released POM-C, the C content was again highest in virgin grassland, but arable land was higher than restored prairie. | Intra-macroaggregate POM may be an important agent facilitating the binding of microaggregates into macroaggregates, because it provides nucleating sites for the growth of fungal hyphae and for other microbial activities resulting in the deposition of extracellular polysaccharides. .. a significant proportion of OM inputs were found to become associated relatively rapidly with mineral matter. |
| 1266 | Jastrow, J.D., Miller, R.M. & Lussenhop, J. | Contributions of interacting biological mechanisms to soil aggregate stabilisation in restored prairie | 1998 | Soil Microorganisms; Soil (General) | Journal | Soil Biol. Biochem.; 30 (7); 905-916 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the factors affecting aggregate stability | .. the lengths of two dia size classes of fibrous roots, the length of external mycorrhizal hyphae, microbial biomass C, hot-water soluble carbohydrate C and soil organic C interact to promote the stabilisation of soil aggregates .. [and] accounted for 88% of the variation in macroaggregates >212 m diameter.; .. we were able to confirm the importance of roots and mycorrhizal hyphae as driving factors for macroaggregate stabilisation in a system recovering from disturbance. .. very fine roots appeared to be involved primarily in direct effects such as physical enmeshment; whereas the effects of fine roots were largely indirect through their strong associations with mycorrhizal fungi and their influences on microbial activity. |
| 1009 | Jenkinson, D.S. | The turnover of organic carbon and nitrogen in the soil | 1990 | Soil Organic Carbon; Soil N Dynamics | Journal | Philos. Trans. R. Soc. Lond. B Biol. Sci.; 329; 361-368 | English | Hardcopy:Full | Review of models for the turnover of organic C and N in the soil and a description of a new Rothamsted model | The earlier split of the soil microbial biomass into zymogenous and autochthonous populations is abandoned, as there are no data to test this separation.; By postulating that Broadbalk topsoil contains 3.0 t ha-1 IOM-C [inert OM] and that the annual input of fresh plant C is 1.43 t ha-1, the model predicts that the soil will contain 27.5 t ha-1, .. as observed, .. with an average age of 1400 years.; .. in the Highfield ley-arable expt. at Rothamsted .. 52% of NPP enters the soil each year .. that includes any aboveground plant material that enters the soil. |
| 1045 | Jenkinson, D.S. | The impact of humans on the nitrogen cycle, with focus on temperate arable agriculture | 2001 | Soil N Dynamics | Journal | Plant Soil; 228 (1); 3-15 | English | Hardcopy:Partial; PDF:Full | Review of the contribution of agricultural fertilisers to the nitrogen cycle | Humans now fix some 160 million tonnes of nitrogen per year, of which 98 are fixed industrially by the Haber-Bosch process (83 for use as agricultural fertiliser, 15 for industry), 22 during combustion and the rest is fixed during the cultivation of leguminous crops and fodders. These 160 million tonnes have markedly increased the burden of combined nitrogen entering rivers, lakes and shallow seas, as well as increasing the input of NH3, N2O, NO and NO2 to the atmosphere. .. Losses of N occur from all systems of agriculture, with organic manures being particularly difficult to use efficiently. |
| 1267 | Jenkinson, D.S., Harkness, D.D., Vance, E.D., Adams, D.E. & Harrison, A.F. | Calculating net primary production and annual input of organic matter to soil from the amount and radiocarbon content of soil organic matter | 1992 | Energy Resources; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 24 (4); 295-308 | English | Hardcopy:Partial | Modelling the turnover of C in soils under different managements | The quantities of soil microbial biomass .. in the top 23 cm of soil from the four sites were: Broadbalk Wilderness, 1.571 t C ha-1; Geescroft Wilderness, 0.58 t C ha-1; unmanured plot on Park Grass, 1.621 t C ha-1; unmanured plot on Broadbalk Wheat, 0.47 t C ha-1; NPK plot on Broadbalk Wheat, 0.76 t C ha-1.; NPP thus calculated was 4.0 t C ha-1 yr-1 for the unmanured plot on Park Grass, 2.2 for the unmanured plot on Broadbalk and 5.2 for the NPK plot on Broadbalk. The two Wilderness sites are still accumulating C in both soil and vegetation and here NPP is given by annual input to the soil, plus the annual increment of C in the trees. NPP calculated in this way was 4.8 t C ha-1 yr-1 for Broadbalk Wilderness and 3.3 for Geescroft Wilderness. |
| 572 | Jenkinson, D.S., Meredith, J., Kinyamario, J.I., Warren, G.P., Wong, M.T.F., Harkness, D.D., Bol, R. & Coleman, K. | Estimating net primary production from measurements made on soil organic matter | 1999 | Energy Resources; Soil Organic Carbon | Journal | Ecology; 80 (8); 2762-2773 | English | Hardcopy:Partial | Estimation of the net primary production on two East African sites by analysing the soil for SOC, 14C, 13C, soil microbial biomass, total N, pH and clay content | .. the annual input of C to soil from the ungrazed Kenyan site was calculated to be 388 g C/m2/yr, to the grazed site 380 g C/m2/yr and to the Zambian soil 373 g C/m2/yr. taking the loss of C from the Kenyan sites by burning to be 40 g C/m2/yr, the mean NPP for both Kenyan sites is 424 g C/m2/yr.; .. an old grassland at Rothamsted lost 53% of its C when bare fallowed for 28 years. .. a soil .. at Versailles .. lost 61% of its organic C when kept bare for 62 years. |
| 1483 | Jensen, C., Stougaard, B. & Řstergaard, H.S. | Simulation of nitrogen dynamics in farmland areas of Denmark (1989-1993) | 1994 | Soil N Dynamics | Journal | Soil Use Manag.; 10; 111-118 | English | Hardcopy:Partial | Modelling the leaching of N from farmland soil. The mean measured nitrate content of the soils tested was 37 kg/ha (30 in the spring and 45 in the autumn). | The mean simulated nitrate leaching for the whole of Denmark was 74 kg N/ha/yr. .. The simulated nitrate leaching from soils with a sandy subsoil corresponded to 51% of the applied fertiliser - twice that leached from soils with a loamy subsoil. The application of pig manure resulted in average leaching losses of 105 kg N/ha/yr. .. Where only artificial fertilisers were applied, the simulated mean annual leaching was 59 kg N/ha from spring barley and 40 kg N/ha from winter wheat. |
| 1268 | Jensen, E.S. | Dynamics of mature pea residue nitrogen turnover in unplanted soil under field conditions | 1994 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 26 (4); 455-464 | English | Hardcopy:Partial | 3-year field expt. to study the fate of the N content (2.5%) of mature pea residues when chopped to 10 mm or ground to <3 mm and incorporated into an unplanted soil. With the coarse residue no immobilisation of soil N was observed and only pea residue N was incorporated into the biomass, but with the fine residue a third of the N immobilised in the biomass during the initial decomposition was from the soil N. Total biomass N doubled in the first 10 days after amendment and then declined till after 1 year it was back to the initial level. The content of pea residue N in the microbial biomass reached a maximum after 10 days and represented 19% and 25% of the residual pea N for the coarse and fine treatments respectively. The fine treatment gave a higher retention of residue N in the soil and in the microbial biomass and less leaching of residue N. | Only 1-2% of the residual organic 15N was potentially mineralisable after 2 years of decomposition, indicating that the remaining residue 15N was present in rather recalcitrant SOM.; The total amount of clay-fixed NH4+ was 86 g N/g soil at 90 days and only about 0.2% of the 15N input was found as non-exchangeable NH4+. |
| 1269 | Jensen, E.S. | Availability of nitrogen in 15N-labelled mature pea residues to subsequent crops in the field | 1994 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 26 (4); 465-472 | English | Hardcopy:Partial | Field expt. to measure the amount of N in autumn-incorporated pea residues taken up by subsequent crops. Both winter barley and OSR recovered about 13% of the pea residue N during their initial 3 months of growth. 55-60% of the pea residue N was mineralised. The crop uptake of the mineralised n was 36% and 15% for autumn- and spring-sown crops respectively. This represents 20% and 9% of the total residue N. The pea residue N present in the biomass was 13% of the organic N input and represented 17% of residual input N left in the soil. | At maturity the pea residue N constituted <5% of total crop N ..; .. after 3.3 years 41-45% of the labelled pea residue N was still present in organic form in the topsoil ..; .. the increase in biomass N was found to be almost exclusively derived from the pea residue N and constituted 13% of the total biomass N. |
| 1270 | Jensen, E.S. | Mineralisation-immobilisation of N in soil amended with low C:N ratio plant residues with different particle sizes | 1994 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 26 (4); 519-521 | English | Hardcopy:Full | Field expt. to study the effect on N dynamics of differing fragment sizes (1 mm and 10 mm) of a legume residue. About a quarter of the pea residue N was mineralised 90 days after incorporation into the soil. | The decomposition of plant residues, microbial biomass and metabolites formed during the early decomposition of materials of low C/N ratio is slower with small than with coarse residues, probably due to a better protection of the residues and biomass by clay minerals.; .. the immobilisation of soil N was greater with small than with large particles. This may be .. because a greater proportion of the available C is protected by lignin in the larger particles. |
| 789 | Jensen, K.K. & Sřrensen, J.T. | The idea of 'ethical accounting' for a livestock farm | 1998 | Agricultural Ethics | Journal | J. Agric. Environ. Ethics; 11 (2); 85-100 | English | Hardcopy:Partial | Ethical accounting is proposed, alongside financial accounting, for livestock farms. | Ethical accounting seeks to make available to the farmer information about how his decisions affect the interests of farm animals, consumers and future generations. .. ethical accounting involves value-based planning. |
| 386 | Jensen, L.E. & Nybroe, O. | Nitrogen availability to Pseudomonas fluorescens DF57 is limited during decomposition of barley straw in bulk soil and in the barley rhizosphere | 1999 | Soil N Dynamics | Journal | Appl. Environ. Microbiol.; 65 (10); 4320-4328 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to use a luminescent non-cellulolytic bacterial strain to study the N availability when soil is amended with barley straw. The bacterium experienced no N limitation in sterilised soil, but did in natural soil amended with straw, due to competition for available N with the indigenous cellulolytic microbial population. A similar effect was obtained when the straw-amended sterilised soil was inoculated with a cellulolytic fungus. | .. the activities of cellulolytic microorganisms may affect the availability of energy and specific nutrients to a group of organisms deficient in hydrolytic enzyme activities.; .. shifts in the microbial community composition occur as straw degradation proceeds,with alternating predominance of bacteria and fungi.; .. as straw was mineralised, an increasing fraction of the [luminescent bacterial] population experienced exhaustion of the available N pool .. readily utilisable C compounds were present in the straw and in addition hydrolysed plant residues were made available, due to the activities of the indigenous microbial community. The cellulases and other polymer-degrading enzymes cleave the straw polysaccharides extracellularly and the hydrolysed products are therefore theoretically available to microorganisms other than the actual producers. |
| 1271 | Jensen, L.S., Mueller, T., Magid, J. & Nielsen, N.E. | Temporal variation of C and N mineralisation, microbial biomass and extractable organic pools in soil after oilseed rape straw incorporation in the field | 1997 | Soil Organic Carbon; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 29 (7); 1043-1055 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the seasonal changes taking place within a year of the incorporation of rape straw into an arable soil | Microbial biomass C and N increased very rapidly after the straw amendments and the 31-49% difference from the unamended treatment persisted throughout the winter.; Between 52 and 80% of the initial increase in microbial biomass N was derived from the straw N, with up to 27% of the straw N being incorporated into the microbial biomass. Rapid immobilisation of soil mineral N occurred simultaneously and the sum of this and the straw-derived microbial biomass N on day 7 exceeded the total increase in microbial biomass N, indicating a very rapid turnover of microbial biomass in the first few days. Significant differences in microbial biomass C and N between the straw treatments were still found after nearly 1 y and the decay constant of straw-derived microbial biomass N was estimated to be ca. 0.26 y-1 .. corresponding to a half-life of 2.7 years. |
| 494 | Jeppson, K.H. | Diurnal variation in ammonia, CO2 & water vapour emission from an uninsulated deep litter building for .. pigs | 2002 | Greenhouse Gases | Journal | Biosyst. Eng.; 81 (2); 213-223 | English | Hardcopy:Partial | Expt. to measure the diurnal variation in the emissiion of ammonia, CO2 and moisture from an uninsulated pig-house with a deep-litter system | The CO2 emission during the 6 days at constant airflow rate had a daily mean between 81 and 120 g h-1 per pig with a diurnal variation from 61 to 249% of the mean. The CO2 emission was correlated to the inside air temperature .. and animal activity .. |
| 1012 | Jin, Z., Akiyama, T., Chung, B.Y., Matsumoto, Y., Iiyama, K. & Watanabe, S. | Changes in lignin content of leaf litters during mulching | 2003 | Lignin and CBW; Mulch | Journal | Phytochemistry (Oxf.); 64 (5); 1023-1031 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the change in composition of fallen leaves, collected and put onto soil as a mulch for one year | The estimated lignin contents ranged from 3.9 to 10.0% .. in un-mulched leaf litter. The absolute amounts of the measured lignin somewhat decreased during mulching, while the structure of lignin remaining in leaf litters after mulching was considered not to be very different from its original structure. |
| 701 | Joergensen, V., Kendall, D., Burke, J.I., & Purvis, G. | Exploitation of a sustainable low-input and reduced output system for arable crops | 2006 | Clover Sward | Book | Joergensen, V., Kendall, D., Burke, J.I., & Purvis, G.; Final report of EU contract no. AIR3-CT93-0893; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to test the feasibility of cereal growing in a clover sward | The system is straightforward, easy to apply and is reliable across a range of climates and soil types.; Although bi-crop grain yields are low (at about 4-5 tonnes per hectare) compared with conventionally grown wheat, they do bear favourable comparison with yields of organically grown wheat and have the advantage of continuous (for a few years) cropping of wheat. |
| 271 | Joffre, R., Rambal, S. & Ratte, J.P. | The dehesa system of southern Spain and Portugal as a natural ecosystem mimic | 1999 | Miscellaneous; Sustainability | Journal | Agrofor. Syst.; 45 (1-3); 57-79 | English | Hardcopy:Partial; PDF:Full | Review of the ecological role of dehesas | the dehesa is a man-made ecosystem and .. its two layered structure, tree and grass, is dependent on human practices and management.; .. historical evidence ofthe manipulation of initial ecosystems by man to obtain a savanna- like ecosystem is presented.; Using the concept of ecosystem mimicry the two coexistent components of dehesas can be compared to two distant stages of a secondary succession characterised by very different behaviours.; The structure of dehesas mimics those of tropical savannahs.; The first anthropic action was the clearing of initial oak and pine forests around 4500 BP ..This .. could represent a period of early viticulture and agric. intensification. |
| 1272 | John, B., Ludwig, B. & Flessa, H. | Carbon dynamics determined by natural 13C abundance in microcosm experiments with soils from long-term maize and rye monocultures | 2003 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 35 (9); 1193-1202 | English | Hardcopy:Partial; PDF:Full | Expt. to quantify the C dynamics in soils from long-term rye (C3-plant) and maize (C4-plant) monocultures using natural 13C abundance | Younger C4-derived and older C3-derived percentages of SOC, DOC, MB-C (Cmic) and CO2 from heterotrophic respiration were determined by natural 13C abundance. The percentage of maize-derived C was highest in CO2 (42-79%), followed by Cmic (2346%), DOC (5-30%) and SOC (5-14%) in the surface soils and subsoils of the maize plots.; Strong correlations were found between C4-derived Cmic and C4-derived SOC, DOC & CO2-C, whereas the relationship between C3-derived Cmic and C3-derived SOC, DOC and CO2-C was not as pronounced. The results stress the different importance of former (older than 40 years) and recent (younger than 40 years) litter C inputs for the formation of different C pools in the soil. |
| 738 | John, B., Yamashita, T., Ludwig, B. & Flessa, H. | Storage of organic carbon in aggregate and density fractions of silty soils under different types of land use | 2005 | Soil Organic Carbon | Journal | Geoderma; 128; 63-79 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of differing land-use on the distribution of organic matter between aggregate sizes and density fractions | Total SOC stocks .. including the humus layer were larger at the spruce site (10.3 kg C m-2) as compared with the grassland, wheat & maize (7-8 kg C m-2). However, SOC stocks in the mineral soil were smaller in the forest soil than in the agricultural soils. In the arable soils the aggregate fractions 53-250 %m and 250-1000 %m were the most abundant size fractions, whereas aggregates >1000 %m were most abundant in the grassland and forest soil. The SOC conc'n and the C/N ratio were greater for macroaggregates (>250 %m) than microaggregates (<250 %m) in the field and grassland soils.; Aggregate formation was associated with increased carbon storage as C contents increased with aggregate size in most cases & C contents in all aggregate fractions >53 %m were greater than in the silt & clay fraction (<53 %m).; The amount of C .. stored in the microaggregates was poorly correlated to the amount of SOC in the bulk soil, and hence cultivation, while the amount of SOC stored in macroaggregates was highly correlated to the total SOC concentration. |
| 1119 | Johnson, D., Krsek, M., Wellington, E.M.H., Stott, A.W., Cole, L., Bardgett, R.D., Read, D.J. & Leake, J.R. | Soil invertebrates disrupt carbon flow through fungal networks | 2005 | Roots & Rhizodeposition; Soil Organic Carbon; Soil Microorganisms | Journal | Science; 309; 1047 | English | Hardcopy:Full | Field expt. to study the effect of Collembola on mycorrhizosphere respiration | Annual C flux through soil respiration is ten times greater than fossil fuel combustion ..; A major component of carbon flux from plants to soil occurs through..AM fungi. .. natural densities of the .. fungal-feeding invertebrate P. armata (order Collembola) reduces 13C enrichment of mycorrhizosphere respiration by 32%.; .. AM fungi .. colonise around 80% of land plants .. to produce a nutrient-absorbing network, which, in grassland, can reach up to 100 m in length per gram of soil. |
| 1273 | Johnson, D., Leake, J.R. & Read, D.J. | Transfer of recent photosynthate into mycorrhizal mycelium of an upland grassland: short-term respiratory losses & accumulation of 14C | 2002 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Soil Biol. Biochem.; 34; 1521-1524 | English | Hardcopy:Full; PDF:Full | Lab. study of turf from an upland grassland to investigate the movement of C into the AM fungi. The transfer of recent photosynthate to the AM fungi happens very rapidly. 14CO2 was released by the fungi within 6 hours of labelling. 14C concentrations in shoots, fine roots and bulk soil are in the ratio 2:1.5:1. | Our estimate that 3.4% of the 14C initially fixed is allocated into external AM mycelium is at the lower end of the 1-20% range suggested by several studies.; Approximately 80% of the 14CO2 photosynthetically fixed by the plants in the turfs was lost during the 70 hours pot labelling .. as a result of shoot respiration .. and allocation belowground. |
| 937 | Johnson, D., Leake, J.R., Ostle, N., Ineson, P. & Read, D.J. | In situ 13CO2 pulse-labelling of upland grassland demonstrates a rapid pathway of carbon flux from arbuscular mycorrhizal mycelia to the soil | 2002 | Roots & Rhizodeposition; Soil Microorganisms | Journal | New Phytol.; 153 (2); 327-334 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the translocation of recent photosynthate to the soil via AM fungi in a grassland | .. within 21 h of pulse-labelling .. between 3.9 and 6.2% of the fixed C can be passed through the external mycelium of the AM fungal symbionts to the atmosphere. This equates to 5.4 and 7.7% of the fixed 13C lost by shoot respiration and translocation during this period.; The proportions of fixed 13C released to the atmosphere via AM mycelia were similar to those that were allocated to fine roots ..; .. most recent models of C fluxes between plants and the soil have been based upon the assumption that root exudation, sloughed cells and dead roots provide the only significant pathways for the supply of plant-fixed C to the free-living microbial populations in soils. |
| 809 | Johnson, D.E., Ferrell, C.L. & Jenkins, T.G. | The history of energetic efficiency research: where have we been and where are we going? | 2003 | Greenhouse Gases; Miscellaneous | Journal | J. Anim. Sci.; 81 (13 Supplement 1); E27-E38 | English | Hardcopy:Partial; PDF:Full | Review of the development of animal energetics. Yearly energy requirement of a cow is 16.75 GJ. | The fattening steers retain from 16 to 18% of consumed energy. The largest loss is to the maintenance function (heat of idling), followed by faecal losses and heat of tissue synthesis. On a whole-herd basis the faecal and maintenance components become predominant .. Beyond digestive losses, e.g., as a fraction of the herd's needs for metabolisable energy, the maintenance component predominates, comprising approximately 73% of ME requirements.; Classical mouse to elephant research with mature animals found FHP [fasting heat production] to be proportional to BW0.75. .. FHP = 77 BW0.75. |
| 1274 | Jones, D.L. | Amino acid biodegradation and its potential effects on organic nitrogen capture by plants | 1999 | Roots & Rhizodeposition; Soil N Dynamics | Journal | Soil Biol. Biochem.; 31 (4); 613-622 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the status, degradation and plant absorption of amino acids in soils | .. plants can .. directly absorb and assimilate both organic C (e.g. sugars) and organic N (e.g. amino acids).; .. lost root exudates can be recaptured by the root and external organic nutrients can be absorbed.; .. the mean half-life [of amino acids] in topsoils at 18$C was 1.70.6 h .. On average 34% of the amino acid-C was respired as CO2, whilst 66% was utilised for new cell biomass. |
| 652 | Jones, D.L. & Brassington, D.S. | Sorption of organic acids in acid soils and its implications in the rhizosphere | 1998 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 49 (3); 447-455 | English | Hardcopy:Partial; PDF:Full | Field expt. to investigate the role of organic acids in rhizophere processes | Organic acids have been implicated in many soil processes, including long-term events such as podzolisation and short-term ones such as nutrient mobilisation within the rhizosphere.; ... when organic acids enter solution they rapidly become sorbed onto the soil's exchange complex (>80% within 10 min) ... this sorption will greatly diminish their effectiveness to mobilise nutrients from the rhizosphere. |
| 1275 | Jones, D.L. & Edwards, A.C. | Influence of sorption on the biological utilisation of two simple carbon substrates | 1998 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 30 (14); 1895-1902 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to test the effect of the sorption of glucose and citrate onto minerals on their rate of biodegradation | Citrate and glucose, both 14C-labelled, were added separately to bacterial cultures. In each case they were rapidly degraded with >60% recovered as CO2.; Root exudates, one component of rhizodeposition are variable in composition but usually contain a significant proportion of potentially labile polysaccharides, amino acids and sugars; The bio-availability and biodegradation of two C substrates typically found in root exudates are significantly reduced by the presence of clay and iron hydroxide. Since these interactions were more apparent when the C substrate was added in the form of citrate than glucose, sorption processes are implied.; .. simple C compounds, at concentrations predicted to occur in the rhizosphere are rapidly metabolised by the microbial biomass. This degradation process is reduced by sorption to the solid phase. |
| 1276 | Jones, D.L. & Hodge, A. | Biodegradation kinetics and sorption reactions of three differently charged amino acids in soil and their effects on plant organic nitrogen availability | 1999 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 31; 1331-1342 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the decomposition in soil of 3 amino acids in relation to the strength of their sorption on the soil's mineral component | .. plant roots can .. directly absorb organic N from the soil in the form of amino acids without the need for prior microbial mineralisation to NH4+ & NO3-. .. this form of N may constitute up to 20% of the plant's N requirement under low N input conditions.; ..it appears that root amino acid uptake is independent of inorganic N supply..; ..the strength & amount of sorption follow[ed] the series lysine>glycine>glutamate.. the biological utilisation of the three substrates followed the series glutamate>glycine>lysine.; Lysine & glycine were predominantly used in the production of new cell biomass (80% & 20% of total taken up) while glutamate was used for both growth (65%) & energy production (35%). |
| 938 | Jones, D.L., Hodge, A. & Kuzyakov, Y. | Plant and mycorrhizal regulation of rhizodeposition | 2004 | Roots & Rhizodeposition | Journal | New Phytol.; 163; 459-480 | English | Hardcopy:Full; PDF:Full | Review of current research on rhizodeposition, including its effect on soil pH | .. almost any soluble component present inside the root can be lost to the rhizosphere; however, current evidence suggests that exudation is dominated by low-molecular-weight solutes such as sugars, amino acids & organic acids.. fall into two classes: exudates which are lost simply as a result of passive diffusion & over which the plant exerts little control (basal exudation); and exudates which are released for a specific purpose and over which the plant exerts a close degree of control.; .. there is evidence to suggest that, while C efflux cannot be down-regulated, it can be directly up-regulated to help alleviate stress.; .. a number of exudate components can be actively taken back into the root. .. capture of amino acids from SOM may be a significant source of N..; .. agriculturally important plant species, such as wheat and barley can also take up DON from soils. |
| 768 | Jones, L. | Preliminary trials using a white clover understorey to supply the nitrogen requirements of a cereal crop | 1992 | Clover Sward; Stockless Farming | Journal | Grass Forage Sci.; 47; | English | Hardcopy:Partial | Field expt. on cereals grown in a white-clover sward unde different treatmentsThere was no difference in grain yields between the plots except for the oat plots treated with N fertiliser, which had lower yields due to severe lodging. | The .. cereal was of taller stature and suppressed the legume. This is desirable, because legume-fixed N only becomes available to associated plants following the death of legume tissues and nodules .. Some light must, however, penetrate the crop canopy to ensure survival of the legume.; .. the likelihood of good cereal establishment was increased by suppression of the clover using chemical .. means at sowing. However, for winter-sown cereals clover competition would be declining with falling temperatures. At this time chemical suppression could probably be replaced by intensive grazing by sheep.; To retain the clover sward the cereal must be sown without ploughing by using a direct drill. |
| 322 | Jones, L. & Clements, R.O. | Development of a low-input system for growing wheat in a permanent understorey of white clover | 1993 | Clover Sward | Journal | Ann. Appl. Biol.; 123 (1); 109-119 | English | Hardcopy:Full | Field expt. to test the growing of wheat in a white clover sward | Spring-sown wheat failed to compete with the clover, but wheat sown in the autumn established successfully. .. Yields were low for all treatments [3-4.5 t/ha], probably because of the dry conditions .. and the low soil N status of the site used. .. the clover survived successive cereal crops .. response to fertiliser N diminished with a successive crop, implying a build-up of available soil N ..; .. yields show the intermediate value of about 250 plants/m2 to be suitable for winter wheat ..; .. the second wheat crop showed a 25% increase in yield over the first crop where no fertiliser N was used. |
| 185 | Jones, M.R. | Analysis of the use of energy in agriculture - approaches and problems | 1989 | Energy in Agriculture | Journal | Agric. Sys.; 29; 339-355 | English | Hardcopy:Full | A model of energy use in agriculture is described and used to examine a number of unresolved issues in agricultural energetics, such as the definition of the system boundary, the treatment of labour and the interpretation of the results of the energy analysis. | Agriculture involves the management of biological systems to optimise the flow of solar energy .. toward the output of valuable products. .. External support energy inputs are required to achieve this .. [but they] do not contribute to the solar energy flow .. It is therefore irrelevant to include [solar energy] within the system if the purpose of the analysis is to compare different agric. systems, as the solar energy inputs will be constant for any particular climatic zone.; Four main techniques have been used .. to account for labour in [energy analysis]: measures of human metabolic energy expended, measures of the lifestyle support energy requirement, measures of the marginal energy requirement of employment & use of a zero energy cost. .. [in a] self-sufficient non-industrialised agricultural system .. a measure based on the metabolic energy requ'd to sustain the labour force & dependants .. would .. seem an appropriate measure of labour inputs .. However this value should not be calculated solely from the numbers of hours actually worked .. as this ignores the energy needed to maintain the labour inputs. It would seem reasonable .. to make some deduction for additional energy requirements arising from leisure activities... |
| 96 | Jones, S.A., Harris, P.M. & Gooding, M.J. | Measurement of nitrogen partitioning within different organic systems incorporating strip intercropping, sheep and crop rotation | 1999 | Stockless Farming; Soil N Dynamics | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the transfer of N from green manure to cropped soil by grazing sheep | The .. results demonstrate the potential for this system to maximise the utilisation of the N fixed by the legume crop. The use of grazing animals to distribute the legume N influences the timing of the release of this N & the minimal cultivation methods involved avoid the major nutrient losses following ploughing.; .. grazing increased the N uptake of the later sown vegetable crops and affected the N taken up by the wheat test crop. .. the residual soil mineral N content of the vegetable strips was significantly increased by grazing .. |
| 520 | Jong, E. de, Begg, C.B.M., Kachanowski, R.G. [3 pp. only] | Estimates of soil erosion and deposition for some Saskatchewan soils | 1983 | Soil (General) | Journal | Can. J. Soil Sci.; 63 (3); 608-617 | English | Hardcopy:Partial | An expt.al study of soil loss and deposition using caesium-137 analysis | 137Cs in pCi/cm2 was calculated using the BD [of the soil] .. Calculations indicated soil losses from 20 to 60 k/sq.m. for the upper slopes and soil gains of 25-80 k/sq.m. on the foot slopes over the last 20-25 years. |
| 902 | Jongmans, A.G., Breemen, N. van, Lundstroem, U.S., Hees, P.A.W. van, Finlay, R.D., Srinivasan, M., Unestam, T., Giesler, R., Kelkerud, P.A. & Olsson, M. | Rock-eating fungi | 1997 | Soil Microorganisms | Journal | Nature (Lond.); 389, 16th October; | English | Hardcopy:Full | Pores 3-10 m wide in rock fragments are believed to have been formed by organic acids exuded from the tips of the hyphae of ectomycorrhyzal fungi, which then supply dissolved minerals direct to plants, thus by-passing the toxically high concentrations of aluminium in soils affected by acid rain. | |
| 461 | Jongmans, A.G., Pulleman, M.M. & Marinissen, J.C.Y. | Soil structure and earthworm activity in a marine silt loam under pasture versus arable land | 2001 | Soil (General) | Journal | Biol. Fertil. Soils; 33; 279-285 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the effect of earthworms on the same soil under two different >70-year management systems: pasture and arable land. The pasture had an enhanced earthworm activity and high SOM content compared with the pasture | |
| 348 | Jordan, D., Li, F., Ponder, F., Berry, E.C., Hubbard, V.C. & Kim, K.Y. | The effects of forest practices on earthworm populations and soil microbial biomass in a hardwood forest in Missouri | 1999 | Soil Microorganisms | Journal | Appl. Soil Ecol.; 13 (1); 31-38 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of soil compaction on earthworm populations and soil properties in an oak-hickory forest | Harvesting [of timber] had no effect on either earthworm populations or biomass but had a significant effect on selected soil properties. Harvest levels [e.g. removal of logs, boles and litter] had a significant negative correlation with soil moisture, soil inorganic N and soil microbial biomass C and N.; Soil compaction had a significant impact on reducing the numbers and biomass of these native earthworm species. In addition to compaction reducing pore space in the soil, it may have interfered with the earthworms' life cycle (e.g. cocoon production or juveniles killed). |
| 1004 | Jordan, D., Miles, R.J., Hubbard, V.C. & Lorenz, T. | Effect of management practices and cropping systems on earthworm abundance and microbial activity in Sanborn Field: a 115-year-old agricultural field | 2004 | Miscellaneous; Soil Microorganisms | Journal | Pedobiologia; 48 (2); 99-110 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to asses the effect of management on earthworms and microorganisms | Microbial activity .. was greatest during the spring. Manure, no-tillage and crop rotations that include legumes had the greatest earthworm abundance and microbial activity.; .. conservation tillage, addition of nutrients either in organic or inorganic form for adequate crop production, and favourable soil moisture are all important in maintaining earthworm abundance and microbial activity ..; Undisturbed grass plots generally support high earthworm populations and microbial activity. Manure additions also seem to enhance earthworm populations and microbial activity. |
| 272 | Jose, S., Gillespie, A., Seifert, J. & Biehle, D. | Defining competition vectors in a temperate alley-cropping system in the midwestern U.S.A.: 2. Competition for water | 2000 | Miscellaneous | Journal | Agrofor. Syst.; 48 (1); 41-59 | English | Hardcopy:Partial | Field expt. to study the factors affecting the cropping of maize in avenues of black walnut or red oak, using plastic barriers, trenching or no barrier to restrain the tree roots | The barrier and trench treatments successfully eliminated the belowground root competition between trees and maize ... competition for water rather than ... for light seems to be critical in defining the productivity ... of this alleycropping system. |
| 953 | Jungbluth, T., Hartung, E. & Brose, G. | Greenhouse gas emissions from animal houses and manure stores | 2001 | Greenhouse Gases | Journal | Nutr. Cycl. Agroecosyst.; 60; 133-145 | English | Hardcopy:Partial; PDF:Full | Review of available data on emissions of CO2, CH4 and N20 from livestock houses and manure stores. CO2 emission factors in pig-houses are given as 527-660 and 891 kg place-1 year-1. Respiration chamber measurements gave CO2 emissions from dairy cattle as varying between 4.7 and 7.0 kg LU-1 day-1 for dry cows and fully lactating cows respectively. The average CO2 emission for the whole year was 6.5 kg per LU per day. In a dairy house holding approx. 55 dairy cows and 20 heifers the average CO2 emission was 23.2 kg per hour. 1 LU [livestock unit] = 500 kg liveweight. | |
| 954 | Justes, E., Mary, B. & Nicolardot, B. | Comparing the effectiveness of radish cover crop, oilseed rape volunteers and oilseed rape residue incorporation for reducing nitrate leaching | 1999 | Cover Crops; Soil N Dynamics | Journal | Nutr. Cycl. Agroecosyst.; 55 (3); 207-220 | English | Hardcopy:Partial; PDF:Full | Field expt. to assess the relative effect of a cover crop and crop residues in reducing N leaching. The radish cover crop and the incorporated rape straw reduced N leaching by about a half and a quarter respectively compared with bare soil. | .. the best way [to reduce leaching] .. consists in simultaneously (i) incorporating residues just after harvest and (ii) favouring volunteers by adequate soil tillage (disc harrowing) or (iii) sowing a cruciferous cover crop after cereals harvest. |
| 1046 | Jřrgensen, F.V., Jensen, E.S. & Schjřrring, J.K. | Dinitrogen fixation in white clover grown in pure stand and mixture with ryegrass estimated by the immobilised 15N isotope dilution method | 1999 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 208; 293-305 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the quantity of nitrogen fixed by white clover in pure stands and in mixtures with ryegrass | In pure stand clover 75-94% of the N was derived from N2 fixation and in the mixture 85-97%.; The amount of N fixed in the mixture was 23, 187 and 177 kg N ha-1 in the seeding, 1st & 2nd production years .., whereas pure stand clover fixed 28, 262 and 211 kg N ha-1 in the three years. The apparent transfer of clover N to grass was negligible in the seeding year, but .. contributed 19 and 28 kg N ha-1 to the grass in the first and second production year respectively. |
| 490 | Kaal, E.E.J., Field, J.A. & Joyce, T.W. | Increasing ligninolytic enzyme activities in several white-rot basidiomycetes by nitrogen-sufficient media | 1995 | Lignin and CBW; Soil N Dynamics | Journal | Bioresour. Technol.; 53; 133-139 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of additional nitrogen on white-rot fungi | .. several .. commonly occurring white-rot fungi produce higher ligninolytic enzyme activities in response to a nitrogen-rich medium, in contrast to the physiological model proposed for P. chrysosporium. |
| 97 | Kahiluoto, H. & Vestberg, M. | Impact of cropping system on mycorrhiza | 1999 | Compost & Biocontrol; Green Manure; Organic Farming | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | 15-year field expt. to compare the effect of conventional and low-input farming systems, and fresh v. composted plant residues, on crop mycorrhiza | .. the low-input system with plant residues composted before incorporation was the most favourable of the systems studied for mycorrhiza. .. The low-input system with no composting was more favourable than the conventional systems in terms of growth effect .., but .. after clover incorporation it remarkably inhibited mycorrhiza in comparison to the other systems. |
| 1277 | Kaiser, E.A., Kohrs, K., Kücke, M., Schnug, E., Heinemeyer, O. & Munch, J.C. | Nitrous oxide release from arable soil: importance of N-fertilisation, crops and temporal variation | 1998 | Greenhouse Gases; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (12); 1553-1563 | English | Hardcopy:Full; PDF:Full | Expt. to study the factors affecting the rate of N2O emission from arable soil | 50% of the annual N2O emissions were found during winter, which resulted from both physical release of sub-surface-produced N2O during soil freezing and microbial N2O production during daily thawing and freezing cycles.; The crop species had a significant influence on the N2O emissions. The relative N2O losses from the applied N-fertiliser ranged between 0.7% & 4.1%.; .. the N2O emissions increased with decreasing C/N ratio in organic amendments .. Aulakh etal (1991) confirmed increasing denitrification N-losses with decreasing C/N ratio in plant residues org. amendments ..; The highest N2O losses during winter were observed in the sugar beet fields, due to the small C/N ratio of their crop residues .. |
| 462 | Kaiser, E.A., Kohrs, K., Kücke, M., Schnug, E., Munch, J.C. & Heinemeyer, O. | Nitrous oxide release from arable soil: importance of perennial forage crops | 1998 | Greenhouse Gases; Green Manure; Soil N Dynamics | Journal | Biol. Fertil. Soils; 28; 36-43 | English | Hardcopy:Full; PDF:Full | Field expt. to study N2O emission from soil under different green manures | 47% of the annual N2O losses were observed .. during winter & mainly resulted from N2O production during daily thawing & freezing cycles. .. During the vegetation period, N2O losses & yields were significantly different between the three forage crops. The unfertilised clover plot produced the highest yields and the lowest N2O losses on this soil compared to the highly fertilised ryegrass plot. Total N2O losses from soil under spring barley were higher than those from soil under the forage crops; this was mainly a consequence of N2O emissions after the incorporation of the forage crop residues. |
| 653 | Kaiser, K. & Guggenberger, G. | Mineral surfaces and soil organic matter | 2003 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 54 (2); 219-236 | English | Hardcopy:Partial; PDF:Full | Expt. to study the relationship between the surface area of soil particles and the quantity of adsorbed OM | Because of the small size of micropores (<2 nm) penetration of natural OM molecules, which have minimum dimensions of 1 nm, seems unlikely.; Whereas in a given compartment, i.e. soil horizon, OM sorption and also the relation between OM and SSA [specific surface area] is likely to be under mineralogical control, this is not the case at the scale of the soil profile. There, surface accumulation of OM seems to be under a strong input control. Surface loadings in topsoils receiving large amounts of OM are larger than those with smaller input, regardless of the mineral composition. |
| 986 | Kaiser, K. & Guggenberger, G. | The role of DOM sorption to mineral surfaces in the preservation of organic matter in soils | 2000 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 31 (7-8); 711-725 | English | Hardcopy:Partial; PDF:Full | Expt. to study the role of sorption of DOM in the protection of OM in soils | .. in soil a close assoc'n of OM with the mineral matrix exists.Both the conc'n of soil OM assoc'd with the mineral matrix and the sorption of DOM are related to reactive mineral phases such as Al & Fe oxyhydroxides. Sorption of DOM derived from the oxidative decompos'n of lignocellulose to Al & Fe oxyhydroxides involves strong complex'n bondings between surface metals & acidic .. ligands, particularly with those assoc'd with aromatic structures. .. Because sorption of the more labile polysaccharide-derived DOM on mineral surfaces is weaker, adsorptive & desorptive processes strongly favour the accumulation of the more recalcitrant lignin-derived DOM.. we found the soil OM in an alluvial B horizon and in the clay fraction of a topsoil strongly resembling lignin-derived DOM from the overlying forest floors. Hence, it seems likely that sorption of DOM contributes considerably to the accumulation and preservation of OM in soil. |
| 739 | Kaiser, K., Guggenberger, G. & Zech, W. | Sorption of DOM and DOM fractions to forest soils | 1996 | Soil Organic Carbon | Journal | Geoderma; 74; 281-303 | English | Hardcopy:Partial | Study of the sorption of dissolved OM based on soil samples from 34 sites | The sorption of DOM to soils was related to the contents of OC, Al and Fe oxides/hydroxides and clay.; The sorption of DOM by topsoils was always weaker compared with subsoil horizons. |
| 654 | Kalbitz, K., Kaiser, K., Bargholz, J. & Dardenne, P. | Lignin degradation controls the production of dissolved organic matter in decomposing foliar litter | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 504-516 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of lignin content on the rate of decomposition of dead leaves from various tree species | .. lignin degradation controls the production of DOM from decaying litter ..; Litter decompos'n followed a two-stage model characterised by initially rapid & then decreasing degrad'n with time. In the initial phase of litter decompos'n .. no effects of lignin degrad'n were found.. The production of DOM from litter with larger lignin degrad'n increased in the second phase of decomposition .. |
| 1279 | Kalbitz, K., Schwesig, D., Rethemeyer, J. & Matzner, E. | Stabilization of dissolved organic matter by sorption to the mineral soil | 2005 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 37 (7); 1319-1331 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the stabilisation of DOM by sorption on mineral soil | Sorption of DOM to the mineral soil results in its stabilisation... the main mechanisms for this stabilisation are the selective sorption of intrinsically stable compounds and strong chemical bonds to the mineral soil and/or a physical inaccessibility of OM to microorganisms... The stabilising effect of sorption is relatively large for labile DOM samples and relatively small for stable ones high in aromaticity and complexity of molecules. However, the extent of sorption and the mean residence time after sorption were estimated to be twice as large for stable DOM samples compared to labile ones resulting in a four times larger sorptive stabilisation. We conclude that the stronger the sorption, the greater the amount and stability of sorbed OM. |
| 1278 | Kalbitz, K., Schwesig, D., Schmerwitz, J., Kaiser, K., Haumaier, L., Glaser, B., Ellerbrock, R. & Leinweber, P. | Changes in properties of soil-derived dissolved organic matter induced by biodegradation | 2003 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 35 (8); 1129-1142 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study changes in DOM during a 90-day incubation | .. the incubation of highly degradable DOM solutions [resulted in] an enrichment of lignin-derived aromatic compounds .. increasing contents of phenols & lignin monomers at the expense of lignin dimers and alkylaromatics .. This partial degrad'n of higher-molecular lignin-derived DOM compounds was accompanied by relative increases in the proportions of lower-molecular degradation products and microbial metabolites. Carbohydrates, especially when abundant at high initial contents, seem to be preferred substrate for microorganisms. [There was] also some microbial production of carbohydrates & peptides during DOM degradation.; We can only speculate why these microbial products are not mineralised as fast as carbohydrates initially present in DOM before incubation. |
| 799 | Kamara, A.Y., Akobundu, I.O., Sanginga, N. & Jutzi, S.C. | Effect of mulch from selected multipurpose trees on growth, nitrogen nutrition and yield of maize (Zea mays L.) | 2000 | Mulch; Stockless Farming | Journal | J. Agron. Crop Sci.; 184 (2); 73 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the effect of mulching on maize yield compared with conventional fertiliser | Grain yield was higher in the mulched plots in both years.; Mulch from these species [G. sepium, L. leucocephala] gave higher maize yield than inorganic N fertiliser at 90 kg ha-1.; The increased maize growth and yield produced by the mulch materials in both pots and field can be attributed to improved nutrition of maize.; .. the performance of inorganic N alone without mulch was only comparable to the slow-decomposing S. siamea. Leaching of nutrients in the soil reduces the efficiency of mineral fertilisers in the tropics. |
| 349 | Kandeler, E. & Böhm, K.E. | Temporal dynamics of microbial biomass, xylanase activity, N-mineralisation and potential nitrification in different tillage systems | 1996 | Soil Microorganisms; Tillage | Journal | Appl. Soil Ecol.; 4 (3); 181-191 | English | Hardcopy:Partial; PDF:Full | Expt. to compare the effects of different tillage systems on SIR, xylanase activity, N-mineralis'n & potential nitrification. Annual biomass turnover rates ranged from 1.6 in conventional to 0.8 in minimum tillage. Biomass C as a proportion of total SOC range from 3% to 7%. | .. reduced tillage treatment is not suitable for all soil types, crop species and climates.; .. might have caused the significantly lower biomass C turnover rate (0.99 year-1) of the minimum tillage treatment versus the reduced (1.58 year-1) and conventional (1.50 year-1) treatments.; Minimum and reduced tillage systems tended toward higher N-mineralis'n and xylanase activity in the entire 0-30 cm soil layer. After 4 years of different tillage treatments, only slight changes in OM content were detected and there was no effect on water content. |
| 740 | Kandeler, E. & Murer, E. | Aggregate stability and soil microbial processes in a soil with different cultivation | 1993 | Green Manure; Soil Microorganisms; Tillage | Journal | Geoderma; 56 (1/4); 503-513 | English | Hardcopy:Partial | Expt. to examine the effects of temporary grassland and conventional tillage on aggregate stability and soil microbial processes | Ploughing the grassland reduced aggregate stability and decreased microbial biomass .. Tillage may bury microorganisms and soil enzymes in a deeper soil layer. .. by ploughing .. aggregate stability may be reduced by disruption of aggregates, death of microorganisms and/or decomposition of protected OM. .. the temporary increase of aggregate stability in grassland indicates that permanent vegetation and soil microorganisms are preconditions to maintain high aggregate stability.; Differences in the effect of clover-ryegrass and maize-wheat-barley residues on microbial activities may be related to the narrow C/N ration of the former. A narrow cover-crop C/N ratio is known to favour microbial activities. |
| 1280 | Kandeler, E., Palli, S., Stemmer, M. & Gerzabek, M.H. | Tillage changes microbial biomass and enzyme activities in particle-size fractions of a Haplic Chernozem | 1999 | Soil Microorganisms; Tillage | Journal | Soil Biol. Biochem.; 31 (9); 1253-1264 | English | Hardcopy:Partial; PDF:Full | Expt. to investigate the relationship between microbial/enzyme activity and particle-size fractions and how it is affected by tillage | The aim of our study was to test whether microbial biomass .. of soils under different tillage are mainly associated with the clay fraction, which provides most of the surface available for interaction with microorganisms, or with larger plant debris not associated with the mineral fractions.; Reduced and minimum tillage increased the Corg content of the bulk soil in the 0-10 cm layer from 15.8 to 17.6 mg g-1 Corg mainly due to a higher Corg content of the larger particle-size fractions (>63 m). In contrast, conventional tillage caused a lower Corg contents of the coarse sand fraction in the 20-30 cm layer than minimum tillage treatment. Independent of tillage treatment 80-95% of the biomass N was located in the fractions smaller than 63 m. Soils in the 0-10 cm layer showed similar Nmic-to-Corg ratios in the single particle- size fractions ranging from 0.90 to 4.18 mg Nmic g-1 Corg.; The increasing Corg and Nt contents with diminishing particle-size of arable soils and the decline of the C/N ratio towards the smaller fractions reflects the disappearance of plant debris and its replacement by microbial material of low C/N ratio. The high C/N ratio of the 2000-200 m fraction can be attributed to the POM, which consists mainly of plant residues.; Conventional tillage increased the C/N ratio of the coarse sand fraction in the 20-30 cm layer due to buried particulate organic material. Reduced and minimum tillage enlarged the Corg content of the coarse sand fraction in the 0-10 cm layer mainly due to the crop residues concentrated on the soil surface.; .. reduced tillage systems enriched the soil surface with microbial biomass. Highest concentrations of biomass N were found in the clay particles (2-0.1 m), lowest in the fine sand particles (200-63 m). |
| 1281 | Kandeler, E., Stemmer, M. & Klimanek, E.M. | Response of soil microbial biomass, urease and xylanase within particle size fractions to long-term soil management | 1999 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 31; 261-273 | English | Hardcopy:Partial; PDF:Full | Field expt. to assess long-term effects of FYM and chemical fertilisers on microbial activity in a soil | Miller & Dick (1995) detected a qualitative difference between microbial communities in macroaggregates and microaggregates: the microbial population in macroaggregates had a higher metabolic efficiency.; Cell numbers and microbial biomass are most concentrated in the smaller fractions (fine silt and claysize).; .. analysis on soil microbiological properties clearly showed the overriding effect of FYM; NPK fertilisation and various crops contributed less to explaining of the variation within the data set.; Highest concentrations of ninhydrin-reactive N were found in the clay particles, lowest in the fine sand particles. .. Therefore long-term organic amendments enlarged the capacity of the small-sized fractions to protect soil microorganisms. |
| 463 | Kandeler, E., Tscherko, D. & Spiegel, H. | Long-term monitoring of microbial biomass, N mineralisation and enzyme activities of a chernozem under different tillage management | 1999 | Soil Microorganisms; Soil N Dynamics; Tillage | Journal | Biol. Fertil. Soils; 28; 343-351 | English | Hardcopy:Partial; PDF:Full | 8-year field expt. to test the effect of tillage on soil microorganisms | .. significant treatment effects on microbial biomass, N mineralisation and potential nitrification were observed after a 4-year period.; .. the stratification of the soil microbial biomass within the profile of reduced and minimum tillage systems was probably responsible for the more intensive soil microbial processes near the soil surface compared with conventional tillage. |
| 741 | Karlen, D.L., Ditzler, C.A. & Andrews, S.S. | Soil quality: why and how? | 2003 | Soil (General) | Journal | Geoderma; 114 (3/4); 145-156 | English | Hardcopy:Partial | Review of the development of the concept of soil quality, including a refutation of the critical position taken by Sojka and Upchurch (1999). Various systems of evaluating soil quality are described. | The initial soil quality test kit was developed to provide semi-quantitative indicator data for the 0 to 7.6 cm depth. BD, infiltration rate, water-holding capacity, electrical conductivity, pH, nitrate and respiration were measured.; .. pedotransfer functions .. can be very useful when data for an important indicator may not be available, but other related measurements have been collected. Potential soil quality indicators for which pedotransfer functions have been published include: (1) phosphate adsorption capacity, (2) cation exchange capacity, (3) change in organic matte content, (4) BD, (5) water retention, (6) random roughness, (7) porosity, (8) hydraulic conductivity, (9) seal conductivity, (10) saturated hydraulic conductivity, (11) soil productivity, and (12) rooting depth.; .. the relative index of inherent soil quality .. is an accurate reflection of the soil resource potential in the absence of human intervention and external input of energy resources .. |
| 1438 | Karlen, D.L., Mausbach, M.J., Doran, J.W., Cline, R.G., Harris, R.F. & Schuman, G.E. | Soil quality: a concept, definition and framework for evaluation | 1997 | Soil (General) | Journal | Soil Sci. Soc. Am. J.; 61 (1); 4-10 | English | Hardcopy:Partial | An SSSA AD Hoc Committee on Soil Quality review of the concept of soil quality, viewed from the standpoint of agricultural production. Assessing soil quality from the standpoint of other uses, such as forestry, recreation, mining, etc. would draw attention to other aspects of the nature of soil. A distinction is made between soil quality, which is an inherent characteristic of the soil, and soil health, which relates to its specific condition - whether or not it is functioning at its full potential. | Our recommendation is that soil quality should be evaluated based on soil function, .. focusing on how well a specific soil functions within a defined ecosystem.; Because of the diversity of potential land uses, .. soil quality evaluations should be viewed as relational rather than absolute. .. soils are different and .. for a specific function the quality of soils can be different without necessarily being limiting.; Another perception of soil quality .. was that related to the intrinsic value of soil. This perception focuses primarily on the unique and irreplaceable characteristics of soil resources, apart from their value for crop growth, land use or ecosystem function.; [A study] designed to compare the use of animal manure [FYM], legumes and green manure crops with conventional practices that used inorganic fertilisers and pesticides .. showed little difference in .. SOC, electrical conductivity, pH or BD, [but] soil respiration, faunal populations and infiltration rates indicated higher biological activity with organic .. than with conventional practices. |
| 1551 | Karlen, D.L., Wollenhaupt, N.C., Erbach, D.C., Berry, E.C., Swan, J.B., Eash, N.S. & Jordahl, J.L. | Crop residue effects on soil quality following 10-years of no-till corn | 1994 | Tillage | Journal | Soil Tillage Res.; 31 (2-3); 149-167 | English | Hardcopy:Partial | Results of an expt. to evaluate some proposed soil quality indicators in reaction to three crop residue treatments - removing, maintaining or doubling the residue - under zero tillage | Soil aggregate characteristics, penetration resistance, BD, volumetric water content, earthworm populations, respiration, microbial biomass, ergosterol concentrations and several soil-test parameters (pH, P, K, Ca, Mg, Total-N, Total-C, NH4-N, and NO3-N) were measured ..; Soil aggregates from double residue treatments were more stable in water than those from normal and removal treatments. The double and normal residue treatments had higher total C concentrations and higher levels of microbial activity .. Earthworm populations where crop residues had been removed for 10 years were significantly lower than in either normal or double residue treatments. |
| 1552 | Karlen, D.L., Wollenhaupt, N.C., Erbach, D.C., Berry, E.C., Swan, J.B., Eash, N.S. & Jordahl, J.L. | Long-term tillage effects on soil quality | 1994 | Tillage | Journal | Soil Tillage Res.; 32; 313-327 | English | Hardcopy:Full | Evaluation of the quality of soils from a long-term (12-yr) tillage expt., using systems engineering methodology. Maize yields from the zero-tilled plots were 2.3% down on those from the ploughed plots. The water-filled pore space, BD, wet aggregate stability, biomass C, ergosterol concentration, earthworm population and total N content of the soils were 34%, 4.8%, 28%, 168%, 178%, 47% and 100% higher in the zero-tilled soil than in the ploughed soil respectively. | .. adoption of no-till practices can improve several biological, chemical and physical characteristics of silt loam soils .. [and] would also help to maintain or even increase the amount of crop residue that is returned to the soil. |
| 110 | Karr, J.R. | Health, integrity and biological assessment: the importance of measuring whole things | 2000 | Sustainability | Book | Pimentel, D., Westra, L. & Noss, R.F. (eds.); Ecological Integrity: Integrating Environment, Conservation & Health; | English | Hardcopy:Partial; Wordperfect:Full | Review of the concept of environmental integrity | Several advances have been made in the past decade to spread recognition of the fractured connection between humans and other living systems. All strive to take into account the whole things that have been left out for nearly two centuries. Recognising that conventional neo-classical economics ignores the ecological costs of human activities as well as the value of ecological goods and services, a group of ecologists and economists developed the field of ecological economics.; Another approach examines the extent to which human activities usurp or appropriate the products of Earth's systems. |
| 294 | Katsvairo, T., Cox, W. & Es, H. van | Tillage and rotation effects on soil physical characteristics | 2002 | Soil (General); Tillage | Journal | Agron. J.; 94 (2); 299-304 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the physical and biological properties of the soil under growing maize in various rotations (continuous maize, soya beans!maize, soya bean!wheat/clover-maize) and tillage systems (mouldboard plough, chisel, ridge) | Crop rotation affected earthworm densities shortly after maize emergence but did not affect soil physical measurements, except for infiltration rates ...earthworm densities explained 27% and infiltration rates ... 24% of the variability in maize yields. Tillage, which did not affect earthworm densities, affected all soil physical measurements during vegetative growth but only infiltration rates during reproductive growth of maize. The soya bean!wheat/clover!maize rotation had the greatest earthworm densities and infiltration rates ... mouldboard plough tillage had the greatest infiltration rates ... Maize in the soya bean! wheat/clover!maize rotation yielded about 15 to 25% greater in mouldboard plough tillage than in chisel and ridge tillage. Maize in the soya bean!wheat/clover! maize rotation in mouldboard plough tillage also yielded about 20% greater than maize in the soya beans!maize rotation and about 40% greater than continuous maize, regardless of tillage system. Tillage x crop rotation interactions did not exist for any soil physical measurements ... |
| 1613 | Kaye, J.P. & Hart, S.C. | Competition for nitrogen between plants and microorganisms | 1997 | Soil Microorganisms; Soil N Dynamics | Journal | Trends Ecol. Evol.; 12 (4); 139-143 | English | Hardcopy:Full | Review of current knowledge of the competitive interaction between plants and soil microorganisms for the uptake of organic N, using the resource competition conceptual model, which presupposes that competition only exists if each competitor is N-limited and uses the same N resource. | .. there is a theoretical critical detritus C/N ratio of approximately 30, above which heterotrophic microorganisms are N-limited and below which they are C-limited. .. When heterotrophic microorganisms are N-limited, they may use exogenous sources of N such as soil NH4+ or NO3-, while decomposing detritus.; .. plants assimilate N that is left over after heterotrophic microorganisms are no longer N-limited.; Because plants have long life-spans relative to soil microorganisms, plants may be able to take advantage of the high N fluxes resulting from microbial turnover. .. even if plants/mycorrhizae are relatively unsuccessful competitors for N during individual competition events, they can accumulate N for growth by competing several times for the same N .. and then storing N in plant tissues.; .. recovery of added 15NH4+ was greater in the microbial biomass (46-61%) than in plants (9-11%). Plants recovered 17-26% of added 15NO3-, compared with 37-50% recovered by soil microorganisms.; .. microbial assimilation of NH4+ was unaffected by the presence of plants.; .. organic N uptake was always a substantial fraction of total plant uptake. Some species used organic forms of N preferentially over NH4+. |
| 1282 | Ke, X., Winter, K. & Filser, J. | Effects of soil mesofauna and farming management on decomposition of clover litter: a microcosm experiment | 2005 | Green Manure; Organic Farming | Journal | Soil Biol. Biochem.; 37 (4); 731-738 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of mesofauna on decomposition of clover in soil | Mesofauna significantly accelerated mass loss and C and N release from clover litter.. With mesofauna access, at the end of the expt average clover mass loss was almost twice as high & clover C &N content were 60% lower than without mesofauna.. systems influenced the decompos'n through affecting both element turnover & mesofauna. Although in the first weeks less N was leached from org. farming than from [convl], cumulative N leaching didnot differ between these soils. |
| 606 | Kelleher, B.P. & Simpson, A.J. | Humic substances in soils: are they really chemically distinct? | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Environ. Sci. Technol.; 40 (15); 4605-4611 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the chemical structure of humic acid (HA - the alkaliextractable fraction of humus) using solution-state high-resolution NMR | It has traditionally been thought that extractable HS [humicsubstances] consist of novel categories of structures formed through varying biotransformation processes.; In this study advanced NMR approaches were used to study the major components (proteins, carbohydrates, aliphatic biopolymers & lignin) that are known to be present in HS .. Surprisingly, nearly all of the NMR signals in trad'l HS fractions could be assigned to intact & degrading biopolymers. We therefore suggest that the vast majority of operationally defined humic material [HA] in soils is a very complex mixture of microbial and plant biopolymers and their degradation products but not a distinct chemical category. |
| 714 | Kelleher, B.P., Simpson, M.J. & Simpson, A.J. | Assessing the fate and transformation of plant residues in the terrestrial environment using HR-MAS NMR spectroscopy | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Geochim. Cosmochim. Ac. ; 70; 4080-4094 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the chemical transformation of decaying plant tissues, using (possibly for the first time) high-resolution MAS NMR spectroscopy | Once key components can be identified, the extraordinary resolution of HR-MAS will allow the fate of individual plant components (for example, specific lignin sub-units, specific carbohydrates) to be traced, rather than simply observing the biochemical categories as a whole.; .. HR-MAS NMR spectra demonstrate the relatively fast loss of both hydrolysable and condensed tannin structures from all plant tissues studied. Aromatic (partially lignin) & aliphatic components (waxes, cuticles) tend to persist, along with a small fraction of carbohydrate. |
| 1728 | Kelner, D.J., Vessey, J.K. & Entz, M.H. | The nitrogen dynamics of 1-, 2- and 3-year stands of alfalfa in a cropping system | 1997 | Uncategorised | Journal | Agric. Ecosyst. Environ.; 64; 1-10 | English | PDF:Full | ||
| 1283 | Kemmitt, S.J., Lanyon, C.V., Waite, I.S., Wen, Q., Addiscott, T.M., Bird, N.R.A., O'Donnell, A.G. & Brookes, P.C. | Mineralization of native soil organic matter is not regulated by the size, activity or composition of the soil microbial biomass - a new perspective | 2008 | Mineralisation; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 40; 61-73 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the factors affecting the rate of OM mineralisation in soil | Here we show that SOM mineralisation is independent of microbial biomass size, community structure or specific activity. We suggest that the rate limiting step is governed by abiological processes (which we term the Regulatory Gate hypothesis), which convert non-bioavailable SOM into bioavailable SOM and cannot be affected by the microbial population. This work challenges one of the long-held theories in soil microbiology proposed by Winogradsky, of the existence of autochthonous and zymogenous microbial populations. |
| 310 | Kendall, H.W. & Pimentel, D. | Constraints on the expansion of the global food supply | 1994 | Sustainability | Journal | Ambio; 23 (3); 198-205 | English | Hardcopy:Full | Food productive capacity globally is examined in relation to population, land and water resources and climate change. Various possibilities for the future are reviewed. Global food productive capacity is getting close to its limits, given present technologies. Without a major reordering of world priorities there is little chance of it keeping pace with population growth. The main chances of improvement of the food supply lie in improved agricultural technologies and in diet change. | If humans, especially in developed countries, moved towards more vegetable protein diets rather than their present diets, which are high in animal protein foods, a substantial amount of grain would become available for direct human consumption.; .. we estimate that .. [current] food production is adequate to feed 7 billion people a vegetarian diet .. |
| 903 | Kennedy, T., Naeem, S., Howe, K., Knops, J.M.H., Tilman, D.G. & Reich, P. | Biodiversity as a barrier to ecological invasion | 2002 | Miscellaneous | Journal | Nature (Lond.); 417; 636-638 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the local invasion resistance of plant communities | The diversity resistance hypothesis, which argues that diverse communities are highly competitive and readily resist invasion, is supported by both theory and experimental studies ...; ... we show here that species diversity in small experimental grassland plots enhances invasion resistance by increasing crowding and species richness in localised plant neighbourhoods. |
| 464 | Kerley, S.J. & Jarvis, S.C. | The use of nitrogen-15 natural abundance in white clover (Trifolium repens L.) to determine nitrogen fixation under different management practices | 1999 | Green Manure; Soil N Dynamics | Journal | Biol. Fertil. Soils; 29 (4); 437-440 | English | Hardcopy:Partial; PDF:Full | Inconclusive expt. to study the effect of different management practices on the amount of N fixed by white clover | The %Ndfa in the leaf material of T. repens varied from 34% to 100% between the plots.; Though large differences in 15N and %Ndfa were apparent between the plots, it was not possible to relate these differences to specific management actions. |
| 1439 | Kern, J.S. & Johnson, M.G. | Conservation tillage impacts on national soil and atmospheric C levels | 1993 | Greenhouse Gases; Tillage | Journal | Soil Sci. Soc. Am. J.; 57 (1); 200-210 | English | Hardcopy:Partial | The effect of the widespread adoption of conservation tillage methods in the United States was estimated, using published data and research. It is concluded that zero and minimum tillage reduce emissions by reducing SOC losses and using less fossil fuel. | Conservation tillage systems .. maintain > 30% residue cover on the soil surface.; Maintaining a mulch of crop residues protects the soil surface against raindrop impact and wind, slows evaporation, increases water storage and slows OM decomposition.; Alternative farming practices, such as conservation tillage, are often economically competitive with conventional systems, but the economic success is closely related to the type of government farm assistance.; Conservation tillage may increase the amount of SOC by providing an environment where fungal decomposition is greater than bacterial decomposition. Fungal decomposition results in more recalcitrant decomposition products than bacterial decomposition.; .. conventional tillage requires the energy equivalent of 71 l diesel fuel ha-1 yr-1. .. No-till systems require only 39 [l] ha-1 yr-1.; Of the 39 [l] ha-1 yr-1 required for no-till 27 [l] ha-1 yr-1, or 70%, are needed for manufacturing herbicides. In the conventional system 23% of the energy requirements are allocated to herbicide manufacturing.; [76%] conversion to notill systems .. would result in an increase of 286 to 468 Tg C in the soil ..; .. conversion from conventional .. to no-till practices will prevent 23.8 kg C ha-1 from being released to the atmosphere each year from fossil fuel. |
| 1120 | Kerr, R.A. & Service, R.F. | What can replace cheap oil and when? | 2005 | Energy Resources | Journal | Science; 309; 01 | English | Hardcopy:Partial | Review of future oil supplies and possible alternatives | Optimists - mostly resource economists - argue that oil production depends more on economics and politics than on how much happens to be in the ground. Technological innovation will intervene and production will continue to rise, they say. Even so, mid-century is about as far as anyone is willing to push the peak.; The sun bathes Earth's surface with 86,000 terawatts of energy at all times, about 6600 times the amount used by all humans on the planet each year. Wind, biomass, and nuclear power are also plentiful.; In the US renewables account for just 6% of overall energy production. .. global .. demand [is] expected to grow from approximately 13 terawatts a year now to somewhere between 30 and 60 terawatts by the middle of this century ..; Advances in nanotechnology may help by providing novel semiconductor systems to boost the efficiency of solar energy collectors .. But whether these will come in time to avoid an energy crunch depends in part on how high a priority we give energy research and development. |
| 815 | Keyser, P., Kirk, T.K. & Zeikus, J.G. | Ligninolytic enzyme system of Phanerochaete chrysosporium: synthesised in the absence of lignin in response to nitrogen starvation | 1978 | Lignin and CBW | Journal | J. Bacteriol.; 135 (3); 790-797 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the response of a white-rot fungus to varying N supply | A reproducible sequence of events followed inoculation: 0-24 h, germination, linear growth and depletion of nutrient nitrogen; 24-48 h, cessation of linear growth & de-repression of ammonium permease activity (demonstrating N starvation); 72-96 h, appearance of ligninolytic activity (synthetic 14C-lignin 14CO2). .. appearance of ligninolytic activity occurs irrespective of the presence of lignin .. Addition of NH4+ to cultures immediately prior to the time of appearance of the ligninolytic system delayed its appearance, suggesting that the NH4+ led to interference with synthesis of the enzyme system. |
| 1047 | Khan, D.F., Peoples, M.B., Chalk, P.M. & Herridge, D.F. | Quantifying belowground nitrogen of legumes. 2. A comparison of 15N and nonisotopic methods | 2002 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 239; 277-289 | English | Hardcopy:Partial | Methodological expt. to find the most accurate way of determining the belowground N of four legumes: broad bean, chickpea, mung bean and pigeon pea. The belowground N (root n + soil N) ranged from 30% to 52% of the total plant N. | |
| 573 | Kielland, K. | Amino acid absorption by arctic plants: implications for plant nutrition and nitrogen cycling | 1994 | Mineralisation; Soil N Dynamics | Journal | Ecology; 75 (8); 2373-2383 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the extent of amino-acid absorption by arctic plants | ... inorganic N supplied to plants by mineralisation is not sufficient to meet the annual requirement of N by many tundra species.; ... absorption of three amino acids (glycine, aspartic acid, and glutamic acid) were measured in dominant vascular plant species ...; All species had higher capacity for ammonium uptake ... than for any amino acid. However, at concentrations observed in the field, uptake rates estimated for amino acids were similar to (glycine) or less than (aspartic and glutamic acids) that for ammonium. ... uptake rates of the three amino acids together may account for between 10 and 82% of the total N uptake in the field, depending on species and community. |
| 350 | Kiem, R. & Kandeler, E. | Stabilization of aggregates by the microbial biomass as affected by soil texture and type | 1997 | Soil Microorganisms | Journal | Appl. Soil Ecol.; 5; 221-230 | English | Hardcopy:Partial; PDF:Full | Expt. to study the short-term effect of microorganisms on the stability of soil aggregates. 35 soils of different types were studied. | The results confirmed the importance of a readily available C-source for the rapid stabilisation of aggregates by soil microorganisms.; Among the different mechanisms by which microorganisms interact with the soil structure, the entanglement of particles by fungal hyphae and the polysaccharide-mediated aggregation or stabilisation by bacteria are well understood.; The stability increase produced by the microbial biomass was greatest in the sandy soils (<15% clay) and least in the clays (>35% clay), resulting in an equalising of the stability in the two texture groups at the end of the incubation. |
| 989 | Kiem, R. & Kögel-Knabner, I. | Refractory organic carbon in particle-size fractions of arable soils: II. organic carbon in relation to mineral surface area and iron oxides in fractions <6 μm | 2002 | Soil Organic Carbon | Journal | Org. Geochem.; 33 (12); 1699-1713 | English | Hardcopy:Partial; PDF:Full | Expt. to study the role of mineral surfaces and Fe oxides on the long-term stabilisation of organic C | In two sandy soils OC contents were linearly related to total mineral surface area and the content of the two iron oxide fractions. .. in a loamy soil OC was not correlated with surface area or the iron oxide content. |
| 1284 | Kiem, R. & Kögel-Knabner, I. | Contribution of lignin and polysaccharides to the refractory carbon pool in C-depleted arable soils | 2003 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 35 (1); 101-118 | English | Hardcopy:Full; PDF:Full | Expt. to determine the quantity and origin of the lignin and polysaccharides in the refractory C pool | [A] peculiarity of lignin biodegradation compared with other plant compounds is the co-metabolic character of the degradation process. Lignin does not provide a source of energy or of C for lignolytic organisms and thus a readily metabolisable co-substrate such as carbohydrate is required for an effective lignin degradation.; The soil carbohydrate pool is composed of polysaccharides derived from various sources, i.e. plant and animal tissues, plant mucilage, cellular tissues and extracellular products of soil microbes. .. They represent the major C and energy source for soil organisms, thus governing biological activity. Polysaccharides, mainly those of microbial origin, act as binding agents between soil particles, thus influencing soil structure/aggregation.; .. carbohydrates account for a considerable proportion of SOC. In arable soils, between 15 and 30% of the total SOC is found as polysaccharides ..; The stronger decline of lignin phenols compared with total OC in bulk samples .. indicates a higher contribution of lignin to the labile SOC pool than to the refractory C pool .. Lignin clearly does not accumulate within the refractory C pool of arable soils.; .. it becomes evident that the stable polysaccharide pool, associated with fine separates, consists mostly of microbially-derived sugars. .. Microbial re-synthesis of sugars in soils appears to be an essential pathway for the formation of stable carbohydrates.; Lignin does not appear to be stabilised at the long-term in any fraction. Polysaccharides and lignin are thus different from the viewpoint of long-term stability in soil. Our data indicate that sugars, mainly those of microbial origin, are stabilised over the long-term within fine separates. |
| 987 | Kiem, R., Knicker, H. & Kögel-Knabner, I. | Refractory organic carbon in particle-size fractions of arable soils: I. distribution of refractory C between size fractions | 2002 | Soil Organic Carbon | Journal | Org. Geochem.; 33 (12); 1683-1697 | English | Hardcopy:Full; PDF:Full | Expt. to study the storage of protected organic C in the soil. The fine soil fractions (<6 m) held the highest concentration of soil C - from 65% to 85% of total C - and a higher proportion of the more refractory C compounds. | The turnover time (or mean residence time) of organic compounds in soil ranges from several years to millennia. From this range at least three pools of SOC are derived. Each pool is characterised by an average turnover time, which increases from the active/labile pool (several years) to the intermediate pool (years to decades) to the passive/refractory compartment of org. C (hundreds to thousands of years).; .. a SOM continuum .. ranges from recent plant residues in the sand through partially degraded residues in the silt to strongly processed organic material, presumably dominated by microbially-derived cpds, in the clay .. OC in silt & clay is generally turned over more slowly than the C in sand fractions.; All soil samples were characterised by a gradually decreasing C/N ratio when progressing from sand to silt to clay .. [which] is thought to indicate an increasing decompos'n of the OM, i.e. a progressive degradation of plant litter accompanied by an increasing contrib'n of microbial biomass (of a C/N ratio 812) & its metabolites to the OM..; The unchanged C/N ratio in the depleted plots indicates that N was stabilised to a similar extent as OC in the fine fract'ns. |
| 988 | Kiem, R., Knicker, H., Koerschens, M. & Kögel-Knabner, I. | Refractory organic carbon in C-depleted arable soils, as studied by 13C NMR spectroscopy and carbohydrate analysis | 2000 | Soil Organic Carbon | Journal | Org. Geochem.; 31 (7-8); 655-668 | English | Hardcopy:Partial; PDF:Full | Expt.al study of the refractory organic C fraction in soil | .. SOM .. consist of a compartment of active components with a residence time (or turnover time) of years to decades and a passive (or refractory) fraction remaining in soil for hundreds to thousands of years. ..; active; components are further distinguished into a labile fraction of plant litter and microbial biomass and an intermediate fraction of POM which is stabilised for a few decades. Factors that determine stability of org. C in soil [are] .. chemical recalcitrance of organic molecules against microbial attack, interactions between org. and mineral compounds, and accessibility of organic [matter] to microbes and enzymes. .. the stabilisation of organic C in soils was suggested to be influenced by the clay content ..; .. the labile and intermediate fractions of SOM are .. strongly affected by the type of soil management and the amounts of organic input respectively, whereas the passive/refractory pool should remain unaffected at a time scale of decades ..; [in NMR spectroscopy] .. the ratio of alkyl to O-alkyl C can be taken as an indicator for assessing the degree of decomposition of organic materials. |
| 1048 | Killham, K. & Yeomans, C. | Rhizosphere carbon flow measurement and implications: from isotopes to reporter genes | 2001 | Roots & Rhizodeposition | Journal | Plant Soil; 232; 91-96 | English | Hardcopy:Full; PDF:Full | Review of methods for determining, and distinguishing between, different C fluxes in the root zone | Rhizosphere C-flow represents the pump driving the majority of belowground ecosystem processes.; Pulse-chase techniques have been used .. to study dynamics of C-transfer to the rhizosphere.. The information obt'd .. is strongly dependent on the chase period following the labelling event. Continuous labelling is primarily used to determine plant inputs to soil over an extended time period and includes all kinds of C input: root turnover, root respir'n, root exudation, production of mucilage, etc. One of the main constraints to both approaches is that of distinguishing root from microbial respir'n .. 13C techniques have gone some way towards resolving this difficulty, although 13C signatures in the plant -soil system are not easy to interpret.. in such an inherently noisy system. Recent developments in molecular biology now provide a new opportunity to resolve rhizosphere C-flow & its implications. Reporter gene systems where, e.g., rhizobacteria are marked with .. reporters, overcome the difficulty of distinguishing root & microbial C fluxes & complement the isotopic & more trad. approaches. |
| 939 | King, J., Albaugh, T., Allen, L., Buford, M., Strain, B. & Dougherty, P. | Below-ground carbon input to soil is controlled by nutrient availability and fine root dynamics in loblolly pine | 2002 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | New Phytol.; 154; 389-398 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of the availability of growth-limiting resources on root dynamics in a coniferous forest | ... increased nutrient availability might increase carbon input to soils through enhanced fine root turnover. However, this will depend on the extent to which mycorrhizal root formation is affected, as these mycorrhizal roots have much longer average lifespans than fine and coarse roots.; Fine roots [<1 mm] had average lifespans of 166 d, coarse roots 294 d and mycorrhizal roots 507 d. |
| 817 | Kinsman, R., Sauer, F.D., Jackson, H.A. & Wolynetz, M.S. | Methane and carbon dioxide emissions from dairy cows in full lactation monitored over a six-month period | 1995 | Greenhouse Gases | Journal | J. Dairy Sci.; 78 (12); 2760-2766 | English | Hardcopy:Partial | Field expt. to measure the greenhouse gas emissions over a 112-day period from 118 dairy cows with a mean body weight of 602 kg | .. the CO2 emission was 6137 litres/day/cow and ranged from 5032 to 7427 litres/day/cow.; These values were not corrected for gas emissions from stored manure, which contributed .. 6.1% .. to .. CO2 output ..; .. from stored liquid manure .. CO2 release was equivalent to 381 litres/day/cow.; .. the CO2 emission rate [was] 5756 litres/day/cow (after subtraction of the CO2 emission from manure) .. |
| 171 | Kirchgessner, M., Kreuzer, M., Muller, H.L. & Windisch, W. | Release of methane and of cabron-dioxide by the pig | 1991 | Greenhouse Gases | Journal | Agribiol Res; 44 (2-3); 103-113 | English | Hardcopy:Partial | Expt. using respiration chambers to measure the effect of diet on the exhalation rate of CO2 and CH4 by pigs | .. 2.1 kg CO2/d (41 g/W0.75/d) were released .. on average ..; CO2 was affected by feed intake, by live-weight, by the digestibility of the diet and by the level of body (carbon) retention. Estimates of .. CO2 release from growing, pregnant and lactating pigs were provided. The values obtained in pigs were compared to gaseous exchange of other species (man, cattle, sheep). |
| 790 | Kirchmann, H. | Biological dynamic farming - an occult form of alternative agriculture? | 1994 | Biodynamic Farming | Journal | J. Agric. Environ. Ethics; 7 (2); 173-187 | English | Hardcopy:Full; Wordperfect:Full | Review of the validity of biodynamic farming | As Steiner gave few clear & stringent descriptions, his suggestions & predictions can never .. be tested scientifically. If clearly formulated directives were given, they are scientifically incorrect. Steiner's knowledge was based on subjective insights & visions based on a spiritualistic point of view. A scientific understanding & a development of this .. agriculture is not possible. |
| 326 | Kirk, T.K. & Farrell, R.L. | Enzymatic 'combustion': the microbial degradation of lignin | 1987 | Lignin and CBW | Journal | Annu. Rev. Microbiol.; 41; 465-505 | English | Hardcopy:Partial | Review of research into lignin degradation | The size, non-hydrolysability, heterogeneity and molecular complexity of lignin dictate that its initial biodegradation be oxidative and non-specific. .. In biological systems the oxidative mineralisation of organics, unlike combustion, normally takes a channelled route (i.e. metabolic pathway) .. The initial steps in the depolymerisation of lignin by white-rot fungi are also catalysed by enzymes, but with a non-specificity that leads to a pot-pourri of diverging reactions that is probably unsurpassed by any other enzyme system. .. It is their non-specific subsequent oxidation of lignin that leads us to refer to the process as enzymatic combustion.; Lignin is degraded by a narrower range of microbes than the other major biopolymers. Lignin biodegradation is central to the earth's C cycle .. because lignin physically protects most of the world's cellulose .. from enzymatic hydrolysis.; Lignin is found in higher plants, including ferns, but not in .. mosses or plants of lower taxonomic ranking. Wood and other vascular tissues generally are 20-30% lignin. Most lignin is found within the cell walls ..; Lignin is not biodegraded anaerobically.; .. several nutritional and cultural parameters are important for lignin degradation .. (a) presence of a co-metabolisable substrate, (b) high oxygen tension, .. (f) growth-limiting amounts of nutrient N.; .. lignin is not a growth substrate for white-rot fungi [which] metabolise .. lignin .. only when an alternative C/energy source is present. .. the balance between energy-producing and energyyielding reactions in lignin mineralisation is not known. |
| 387 | Kirk, T.K., Connors, W.J. & Zeikus, J.G. | Requirement for a growth substrate during lignin decomposition by two wood-rotting fungi | 1976 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 32 (1); 192-194 | English | Hardcopy:Full; PDF:Full | Expt. to study the effect of various carbohydrate substrates on the degradation of lignin by wood-rotting fungi. With cellulose, glucose and milled wood lignin as substrates for Phanerochaete chrysosporium the degree of degradation of labelled synthetic lignin after 55 days incubation was 20%, 5% and <0.1% respectively. | .. catabolism of lignin by .. white-rot fungus .. requires a growth substrate; lignin alone is insufficient. |
| 1049 | Kirkegaard, J.A. & Sarwar, M. | Biofumigation potential of Brassicas: I. Variation in glucosinolate profiles of diverse field-grown brassicas | 1998 | Miscellaneous | Journal | Plant Soil; 201; 71-89 | English | Hardcopy:Partial; PDF:Full | Plot expt. to test the biofumigation properties of 76 brassica species and varieties | Brassica species .. contain significant quantities of the thioglucoside compounds known as glucosinolates in their tissues. GSLs are hydrolysed by the myrosinase enzyme (present endogenously in Brassica tissues) to release a range of hydrolysis products including oxazolidinethiones, nitriles, thiocyanates and various forms of volatile isothiocyanates (ITCs).. [which] are known to have broad biocidal activity including insecticidal, nematicidal, fungicidal, antibiotic and phytotoxic effects.; Phenological development in Brassica species is . primarily dependant on photoperiod, with general shortening of phases as daylength increases. .. many species also develop more rapidly when minimum temperatures are lower and some biennial species have an obligate vernalisation requirement as seedlings (e.g. .. B. napus).; Green manure crops are usually required to grow vigorously .., produce a large vegetative biomass and be readily incorporated and decomposed prior to growing a subsequent crop. Thus, Brassica types which remain vegetative .. and produce many leaves rapidly would be desirable. Options include Brassicas insensitive to photoperiod, with a long juvenile phase or biennial types with obligate vernalisation requirements grown during warmer times of the year. |
| 694 | Kirkegaard, J.A., Hocking, P.J., Angus, J.F., Howe, G.N. & Gardner, P.A. | Comparison of canola, Indian mustard and Linola in two contrasting environments. II. Break-crop and nitrogen effects on subsequent wheat crops | 1997 | Rape and Biodiesel; Soil N Dynamics | Journal | Field Crops Res.; 52 (1-2); 179-191 | English | Hardcopy:Partial; PDF:Full | 3-year field expt. to study the effect of oilseed crops on subsequent crops of wheat | . when root disease was present, break crops increased yield of a subsequent wheat crop by 30% and grain protein by 1.3% compared to wheat growing after wheat and among the oilseeds the brassicas gave a greater break-crop benefit than Linola.; The superior break-crop effect of the Brassica species was thought to be due to either (1) enhanced suppression of soil-borne pathogens by biocidal compounds released from Brassica residues or (2) by improvements in subsoil macroporosity by the tap-rooted Brassica species. |
| 1018 | Kirkegaard, J.A., Wong, P.T.W. & Desmarchelier, J.M. | In-vitro suppression of fungal root pathogens of cereals by Brassica tissues | 1996 | Miscellaneous | Journal | Plant Pathol. (Oxf.); 45 (3); 593-603 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the suppression of fungal pathogens by Brassica tissues | The root and shoot tissues of both Brassica species were more suppressive at flowering than maturity and mustard tissues were generally more suppressive than rape. The degree of fungal suppression by the various Brassica tissues was related to the conc'n and type of isothiocyanates released, which varied with Brassica species, tissue age and tissue type. |
| 426 | Kirschbaum, M.U.F. | Will changes in soil organic carbon act as a positive or negative feedback on global warming? | 2000 | Greenhouse Gases; Soil Organic Carbon | Journal | Biogeochemistry (Dordr.); 48; 21-51 | English | Hardcopy:Partial; PDF:Full | Review of the evidence for feedback effects on global warming | The world's soils contain about 1500 Gt of OC to a depth of 1m and a further 900 Gt from 1-2m. A change of total SOC by just 10% would thus be equivalent to all the anthropogenic CO2 emitted over 30 years. Warming is likely to increase the rate of both decompos'n and NPP, with a fraction of NPP forming new OC.; .. with the temp. sensitivity of OC decompos'n being significantly greater than that of NPP, changes in soil C could constitute a significant positive feed back. However, because of negative feed back within the plant-soil system, these changes are likely to be slow, requiring many centuries before approaching new equilibria. Furthermore, because of the additional effect of CO2 concentration on enhancing plant production and SOC storage, the overall feed-back from SOC on the atmosphere is likely to be small. |
| 1285 | Kisselle, K.W., Garrett, C.J., Fu, S., Hendrix, P.F., Crossley, D.A., Coleman, D.C. & Potter, R.L. | Budgets for root-derived C and litter-derived C: comparison between conventional tillage and no-tillage soils | 2001 | Roots & Rhizodeposition; Tillage | Journal | Soil Biol. Biochem.; 33 (7/8); 1067-1075 | English | Hardcopy:Partial | Expt. to study the relative contributions of root- and litter-derived OM to the SOM dynamics | Of the applied label in the root-derived C plots, 35-55%, 6-8%, 3%, 1.6% and 0.4-2.4% was recovered in the shoots, roots, soil, cumulative soil respiration and microbial biomass respectively. The 14C recovered in these pools did not differ between CT and NT treatments, supporting the hypothesis that the rhizosphere microbial biomass in NT and CT may be similar in utilisation of root-derived C. Root exudates were estimated to be 8-13% of the applied label. In litter-derived C plots the percentage of applied label recovered in the POM (3.2-82% [?]), microbial biomass (4-6%) or cumulative soil respiration (12.514.7%) was the same for CT and NT soils. But the percentage of 14C recovered in CT SOC (18-69%) was higher than that in NT (12-43%), suggesting that POM leaching and decomposition occurred at a higher rate in CT than in NT. Results indicate a faster turnover of litter-derived C in the CT plots. |
| 1553 | Kladivko, E.J. | Tillage systems and soil ecology | 2001 | Soil Microorganisms; Tillage | Journal | Soil Tillage Res.; 61 (1-2); 61-76 | English | Hardcopy:Partial; PDF:Full | Review of the effects of tillage practices on soil organism populations, functions and interactions | Although there is a wide range of responses among different species, most organism groups have greater abundance or biomass in no-till than in conventional tillage systems. .. Variations in responses found in different studies reflect different magnitudes of tillage disruption and residue burial, timing of the tillage operations, timing of the measurements and different soil, crop and climate combinations. ... a discussion of challenges for tillage researchers. |
| 228 | Kleinman, P.J.A., Pimentel, D., Bryant, R.B. | The ecological sustainability of slash-and-burn agriculture | 1995 | Miscellaneous; Sustainability | Journal | Agric. Ecosyst. Environ.; 52; 235-249 | English | Hardcopy:Partial; PDF:Full | Review of the factors for & against the sustainability of slash-&-burn farming | Ecologically sound slash-and-burn agriculture is sustainable, because it does not depend upon outside inputs based on fossil energy for fertilisers, pesticides and irrigation. |
| 1687 | Klonowski, W. | Non-linearity and statistics: implications of hormesis on dose-response analysis | 1999 | Miscellaneous; Organic Farming | Website | www.hrabia.ibib.wa.pl/lbaf/PDF_doc/hormesis.pdf | English | Hardcopy:Partial; Wordperfect:Full | Review of the incidence of hormesis in toxicology etc. | We provide several examples of the non-linear dose-response pattern, the phenomenon called hormesis, both chemical and radiation hormesis. .. small amounts of a drug may have a completely opposite effect to a large dose of the same drug .. The same applies to the influence of physical factors like radiation or non-ionising electromagnetic fields. Biological effects of low level exposures are very important but relatively not well-known. .. Small doses of toxic agents may be beneficial. |
| 776 | Klooster, C.E. van't & Heitlager, B.P. | Determination of minimum ventilation rate in pig houses with natural ventilation based on carbon dioxide balance | 1994 | Greenhouse Gases | Journal | J. Agr. Eng. Res.; 57 (4); 279-287 | English | Hardcopy:Partial | Modelling the ventilation rate of naturally ventilated pig houses on the basis of CO2 measurements made using a tracer gas technique. The pigs grew from 7.5 kg to 21 kg in the course of the expt.. | |
| 434 | Knauf, A. | Erfahrungen mit dem Zweischichtenpflug und Gründüngung in einem viehlosen Ackerbaubetrieb | ? | Stockless Farming | Journal | Bioland; 2; | German | Hardcopy:Full | The appropriate machinery for a stockless rotation on loam/sandy loam is discussed. | |
| 882 | Knicker, H. | Stabilisation of N-compounds in soil and organic-matter-rich sediments - what is the difference? | 2004 | Soil N Dynamics | Journal | Mar. Chem.; 92; 167-195 | English | Hardcopy:Full | Review of the mechanisms for the stabilisation of nitrogen in soil | ... amides, most likely deriving from proteinaceous material, represent the major fraction of the organic N in soils ..; .. condensation of N-groups on SOM via amide bonds cannot be excluded.; .. the formation of heteroaromatic N has no major impact on org. N stabilisation ..; .. association of originally labile organic N with minerals may be an additional protection pathway. |
| 1729 | Knicker, H., Hatcher, P.G. & González-Vila, F.J. | Formation of Heteroaromatic Nitrogen after Prolonged Humification of Vascular Plant Remains as Revealed by Nuclear Magnetic Resonance Spectroscopy | 2002 | Uncategorised | Journal | J. Environ. Qual.; 31; 444-449 | English | PDF:Full | ||
| 1286 | Knicker, H., Schmidt, M.W.I. & Kögel-Knabner, I. | Nature of organic nitrogen in fine particle size separates of sandy soils of highly industrialised areas as revealed by NMR spectroscopy | 2000 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 32 (2); 241-252 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the nature of N-containing organic cpds. in soil | From 60 to 90% of the N detectable in the .. soil particle-size fractions were assigned to amides. A smaller signal derives from free amino groups, leading to the conclusion that most of the N was derived from peptide-like structures. The calculated high contribution of peptides to the total org. C & N of the samples confirms earlier studies demonstrating that peptide-like material plays a more important role in refractory SOM formation than commonly thought. Major contributions of N-containing heterocyclic aromatic compounds, formed by recondensation reactions .. were not identified. |
| 574 | Knops, J.M.H. & Tilman, D.G. | Dynamics of soil nitrogen and carbon accumulation for 61 years after agricultural abandonment | 2000 | Soil Organic Carbon; Soil N Dynamics | Journal | Ecology; 81 (1); 88-98 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of agriculture on soil C & N and the rate of recovery in fields abandoned in 1927 | On average agricultural practices resulted in a 75% loss of soil N and an 89% loss of soil C at the time of abandonment. Recovery to 95% of the pre- agricultural levels is predicted to require 180 yr for N and 230 yr for C.; .. literature studies .. show an average loss of 28.6%, which is equivalent to 5.5 kg C/m2 from a steady state of 19.2 kg C/m2 ..; After abandonment, fields .. contain soil with a C/N ratio of 11. This implies that a highly decomposed SOM fraction with a C/N .. close to the microbial turnover signature is the only fraction left.; The rate of C accumulation was negatively dependent on soil C and on the abundance of C3 grasses and forbs and positively dependent on the abundances of C4 grasses and legumes. The rate of N accumulation was not influenced by the abundance of C4 grasses, was negatively related to soil N, field age and the abundance of C3 grasses and forbs and positively related to legumes abundance. This discrepancy between positive effect of C and no effect on N of C4 grass abundance can be explained by the change of C/N ratio over time .. C4 grasses produce higher C/N and are able to produce more biomass under Nlimiting conditions. This litter decomposes more slowly, resulting in a higher C accumulation rate. The positive influence of legumes is likely caused by their fixation of atmospheric N. |
| 352 | Knudsen, I., Debosz, K., Hockenhull, J., Jensen, D.F. & Elmholt, S. | Suppressiveness of organically and conventionally managed soils towards brown foot rot of barley | 1999 | Compost & Biocontrol | Journal | Appl. Soil Ecol.; 12; 61-72 | English | Hardcopy:Partial; PDF:Full | Inconclusive field expt. to assess the effect of management on the suppressive quality of soils | Certain physico-chemical soil properties and mulching with straw seem to have had a positive influence on suppressiveness, while previous cropping with lucerne appears to have influenced suppression negatively. |
| 351 | Knudsen, I., Larsen, K., Jensen, D.F. & Hockenhull, J. | Potential suppressiveness of different field soils to Pythium damping-off of sugar beet | 2002 | Compost & Biocontrol | Journal | Appl. Soil Ecol.; 21 (1); 119-129 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to assess the suppression of pathogens by variouis soils | .. disease expression is correlated with available nutrient supply. There was a clear tendency for low clay content to result in higher disease suppression. .. suppression was of microbial origin. Although texture may play a role in suppressiveness, no clear effect related to any management practice was found. .. sandy soils tend to be more suppressive than clayey soils. |
| 1554 | Koch, H.J. & Stockfisch, N. | Loss of SOM upon ploughing under a loess soil after several years of conservation tillage | 2006 | Tillage | Journal | Soil Tillage Res.; 86 (1); 73-83 | English | Hardcopy:Partial; Wordperfect:Full | 12-year field expt. to study the effect of a single ploughing after sevel years of conservation tillage | One ploughing operation resulted in a substantial loss of organic matter. At 0-30 cm soil depth, losses of SOC and SN occurred within 1-6 months after ploughing, accounting for 4 and 7% of the total initial masses respectively. .. Further losses of SOC and SN from the 0-30 cm layer were small ..; After 7-9 years of conservation tillage, SOC and SN were concentrated in the top 10 cm layer of the soil.; Just one ploughing action after a period of conservation tillage evenly distributes SOM throughout the ploughed layer.; .. in native short-grass prairie steppe soils Bowman etal(1990) reported SOC losses of 62% after 60 years of cultivation. Half of these losses were observed during the first three years of cultivation.; Long-term conservation tillage may, however, decrease yields due to soil compaction in the lower layers of the previously ploughed horizon .. mostly caused by management decisions inappropriate for the local conditions. |
| 712 | Koch, W. | Untersaaten in Herbst-Gemüsekulturen | 1990 | Stockless Farming | Journal | Gemüse; 12; 561-564 | German | Hardcopy:Partial | The use of undersown green crops to reduce nitrate leaching in autumn and winter under late harvested vegetables such as brassicas, fennel and courgettes | Untersaaten kommen dort in Frage, wo die Kultur nach Anfang bis Mitte September geerntet wird und so eine nachtraegliche Gruenduengung zu spaet erfolgen koennte.; Als Untersaaten verwendeten wir dabei Gruenroggen .. und Englischen Raigras. |
| 1121 | Kolber, Z.S. | Getting a better picture of the ocean's nitrogen budget | 2006 | Greenhouse Gases; Miscellaneous | Journal | Science; 312; 1479 | English | Hardcopy:Partial; PDF:Full | Review of recent research showing that nitrogen-fixing bacteria in the ocean are more abundant than previously thought | In the ocean most of [the N fixation] is performed by a ... photosynthetic prokaryote Trichodesmium sp.; Iron is a co-factor in the nitrogenase enzyme complex and nitrogenase activity requires a high energy input that must be satisfied by an .. iron-dependent photosynthetic apparatus.; The unusually high iron requirement makes Trichodesmium dependent on aeolian dust supply. |
| 1440 | Kong, A.Y., Six, J., Bryant, D.C., Denison, R.F. & Kessel, C. van | The relationship between C input, aggregation and SOC stabilisation in sustainable cropping systems | 2005 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 69 (4); 1078-1085 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the stabilisation of C in 10 different rotations | Across the 10 cropping systems annual soil C sequestration rates ranged from !0.35 to 0.56 Mg C ha-1 yr-1. We found a strong linear relationship between SOC sequestration and cumulative C input, with a residue-C conversion to SOC rate of 7.6%. This .. suggests that these soils have not reached an upper limit of C sequestration (i.e. not C saturated). .. C shifted from the <53-%m fraction in low C input systems to the ... macroaggregates in high C input systems. A majority of the accumulation of SOC due to additional C inputs was preferentially sequestered in the microaggregates-within-small-macroaggregates |
| 1122 | Koornhuyse, P. van den, Baldauf, S.L., Leyval, C., Straczek, J. & Young, J.P.W. | Extensive fungal diversity in plant roots | 2002 | Soil Microorganisms | Journal | Science; 295; 2051 | English | Hardcopy:Partial; Wordperfect:Full | Study of fungal species on the roots of the grass Arrhenatherum elatius | Forty-nine different sequences (phylotypes) were found and all were fungal.; The 49 phylotypes are distributed across all fungal phyla (1Chytridiomycota, 8 Zygomycota, 16 Basidiomycota, and 25 Ascomycota). .. [which] include relatives of mutualistic arbuscular mycorrhizal fungi .. we can only speculate on the possible roles of the other 94% of the root fungal diversity .. |
| 1289 | Korsaeth, A., Henriksen, T.M. & Bakken, L.R. | Temporal changes in mineralisation and immobilisation of N during degradation of plant material: implications for plant N supply and nitrogen losses | 2002 | Green Manure; Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 34 (6); 789-799 | English | Hardcopy:Partial; PDF:Full | Expt. to study the N dynamics after the incorporation into the soil of a mixture of a green manure material (undersown white clover) and barley straw | .. the incorporation of a mixture of N-rich white clover material and N-poor barley straw created a transient accumulation of clover-derived inorganic N during the first period. Thereafter microbial N demand during straw C utilisation resulted in net immobilisation of most of the clover-derived inorganic N.; .. net inorganic N accumulation due to degradation of clover-straw mixtures is transient and .. spring incorporation of undersown clover gives a better coincidence of N availability and N uptake by a subsequent crop than does autumn incorporation. .. ploughing as late as possible in autumn appears to be a good alternative to spring ploughing with regard to N leaching, but early autumn ploughing should be avoided.; .. the plants and microorganisms compete for the same N and the success of the plants depend on a proper synchronisation. |
| 229 | Kotto-Same, J., Woomer, P.L., Appolinaire, M. & Louis, Z. | Carbon dynamics in slash-and-burn agriculture and land use alternatives of the humid forest zone in Cameroon | 1997 | Greenhouse Gases; Sustainability | Journal | Agric. Ecosyst. Environ.; 65 (3); 245-256 | English | Hardcopy:Partial; PDF:Full | A study of the C stocks on six slash-and-burn sites in the humid forest zone of Cameroon | Slash-and-burn agriculture, .. as practised by farmers undergoing increased orientation towards markets, results in massive loss of forest system C. The ideal slash-and-burn, where discrete patches of forest are incompletely cleared for short-term cultivation followed by succession to mature secondary forests, is no longer operative.; The original forest contained 308 t C ha-1 and lost 220 t C ha-1 [71.4%] upon conversion to agriculture.; Carbon re-accumulated in the recovering fallows at a rate of 9.4 t C ha-1 yr-1 ..; .. three alternatives to slash-and-burn were identified: commercial cassava cultivation, improved forest conversion and stratified agroforestry. These alternative land uses have the potential to reduce C losses over current practices by 10, 55 and 75 t C ha-1 respectively .. |
| 1290 | Kramer, C. & Gleixner, G. | Variable use of plant- and soil-derived carbon by microorganisms in agricultural soils | 2006 | Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 38; 3267-3278 | English | Hardcopy:Partial; PDF:Full | Field expt. to determine the degree to which recent plant material and older SOM served as C substrates for microorganisms in soils | [In] soils of two sites that had undergone a vegetation change from C3 to C4 plants in the past 20-30 years .. 40-90% of the PLFA C had been fixed since the vegetation change took place. Thus PLFA were more enriched in 13C from the new C4 vegetation than was observed for bulk SOM, indicating recent plant material as preferentially used substrate for soil microorganisms. .. org. C in this soil for the most part cycles rapidly. .. 0-40% of SOC is used as substrate for soil microorganisms. |
| 1291 | Kramer, C. & Gleixner, G. | Soil organic matter in soil depth profiles: distinct carbon preferences of microbial groups during carbon transformation | 2008 | Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 40; 425-433 | English | Hardcopy:Full; PDF:Full | Field expt. to study the change in soil microbial communities with soil depth | .. with increasing soil depth more C derived from decades-old SOM & less recent C.. is used as C source by all microorganisms... different C sources for the two groups of soil bacteria could be determined. Gram-neg. bacteria were foundto use preferably recent plant-derived C & Gram-pos. .. to use more older SOM-derived C.; C sources for fungal biomass also derive from plant debris and SOM .. |
| 892 | Kretschmann, K. | Zehn Jahre erfolgreicher Kartoffelanbau mit Mulch | 2000 | Mulch; Potato Growing | Journal | Natuerlich Gaertnern; 2; 6-8 | German | Hardcopy:Full | A method of growing potatoes under mulch is described. The potatoes are grown year after year on the same plot. | Wenn wir .. Saatkartoffeln .. in den Boden bringen, dann bleibt der Boden drei Wochen lang unbedeckt, da wir die verbliebenen Reste vom Mulchmaterial zur Seite harken. Sind die angebauten Pflanzen zehn Zentimeter hoch, wird mit den Mulchresten und mit neuem Material, sobald es anfaellt, wieder in der gleichen Art fortgefahren. Welche Ergebnisse brachte der Kaartoffelanbau in den letzten zehn Jahren auf immer dem gleichen Standort? .. Im letzten Jahr brachten sie .. den 15-fachen Ertrag .. Die Kartoffeln .. waren immer gesund und vom besten Geschmack. Auch die Lagerfaehigkeit entsprach unseren Erwartungen. |
| 1050 | Krift, T.A.J. van der, Kuikman, P.J., Möller, F. & Berendse, F. | Plant species and nutritional-mediated control over rhizodeposition and root decomposition | 2001 | Roots & Rhizodeposition | Journal | Plant Soil; 228 (2); 191-200 | English | Hardcopy:Partial | Lab. expt. to study the effect of species and N amendment on the rhizodeposition and root turnover of perennial grasses | .. decomposability of both roots and rhizodeposits increased when nitrogen availability increased. .. we suggest .. that species can affect nutrient cycling by differences in rates of rhizodeposition and litter production. |
| 1441 | Kristensen, H.L. & Thorup-Kristensen, K. | Root growth and nitrate uptake of three different catch crops in deep soil layers | 2004 | Cover Crops; Soil N Dynamics | Journal | Soil Sci. Soc. Am. J.; 68; 529-537 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the N uptake of three winter cover crops | There was good agreement between estimates of root depth & distribution .. and results of 15N uptake by the three cover crops: ryegrass, winter rye and fodder radish.; .. other species with deep root depth penetration may be efficient as cover crops for N uptake from deep soil layers, for example, winter rape.; Residual soil NO3 of 18, 59 and 87 kg N ha-1 was left under fodder radish, winter rye and ryegrass respectively. |
| 1292 | Kristensen, H.L., Debosz, K. & McCarty, G.W. | Short-term effects of tillage on mineralisation of nitrogen and carbon in soil | 2003 | Soil Organic Carbon; Soil N Dynamics; Tillage | Journal | Soil Biol. Biochem.; 35 (7); 979-986 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the short-term effects of two types of tillage on mineralisation and microbial N and C pools in a sandy loam under organic plough-tillage management | The field expt. was conducted .. on sandy loam .. with 13% clay, 13% silt, 38% fine sand and 33% coarse sand (Munkholm et al). An in situ analysis of field moist soil after performance of the two tillage types found that large macroaggregates were distributed with 19, 17 and 65% in size classes of <2, 2-4 and >4 mm. respectively.; The simulation of tillage caused .. a small release of N from a pool which was otherwise protected against microbial degradation.; .. the released N originated from the same pool, that is, the soil microbial biomass. The study points to the microbial pool as the main source of labile N which may be released by tillage .. |
| 230 | Kromp, B. | Carabid beetles in sustainable agriculture: a review of pest control efficacy, cultivation impacts and enhancement | 1999 | Miscellaneous; Organic Farming | Journal | Agric. Ecosyst. Environ.; 74; 187-228 | English | Hardcopy:Partial; PDF:Full | Review of current knowledge of carabid beetles and their role in agriculture | Carabids seem to be negatively affected by deep ploughing & enhanced by reduced tillage systems. .. Carabid recruitment is enhanced by ... organic fertilisation and green manuring. Intensive nitrogen amendment might indirectly affect carabids by altering crop density and microclimate.; They are enhanced by crop diversification ... monocrop heterogeneity and weediness as well as by intercropping and the presence of field boundaries ...; Their contribution towards natural pest control in adjacent arable fields, however, is not clearly evidenced. |
| 710 | Krull, E., Baldock, J.A. & Skjemstad, J.O. | Importance of mechanisms and processes of the stabilisation of soil organic matter for modelling carbon turnover | 2003 | Soil Organic Carbon | Journal | Funct. Plant Biol.; 30; 207-222 | English | Hardcopy:Full; PDF:Full | Review of the current knowledge of the protection of OM in soils | While soil texture can affect the soil's capacity for aggregation & adsorption, factors such as soil moisture & temp may further enhance or reduce the extent of physical protec'n. While adsorption & aggreg'n can slow decompos'n processes, it is unlikely that these processes are solely responsible for the high MRTs measured in biologically active surface soils. Accordingly, chem. recalcitrance appears to be the only mechanism by which SOC can be protected for long periods |
| 487 | Kuemmel, B., Langer, Y.I., Magid, J., Neergaard, A. de & Porter, J.R. | Energetic, economic and ecological balances of a combined food and energy system | 1998 | Energy in Agriculture; Energy Resources | Journal | Biomass Bioenergy; 15 (4/5); 407-416 | English | Hardcopy:Partial; PDF:Full | Field expt. to test an alley-cropping system of combined food and energy (CFE) production, in which the fuel is produced from belts of willow, occupying 11% of the arable land, between the crops | Instead of producing biofuel and crops in separate plantations and in monoculture, as is the case with most current agricultural and forestry temperate systems, the CFE exploits other effects of the biofuel strips. These are perceived to be: energy neutrality, increased plant and insect biodiversity, a shelter belt effect, the conservation of N & C, new revenue for farmers, an extensified agriculture, a more varied landscape and a soft biofuel start. ...The system will not only have a low energy demand but it will at least balance its use of fossil derived fuels by its production of solid biofuel. |
| 1123 | Kuhlbusch, T.A.J. | Enhanced: black carbon and the carbon cycle | 1998 | Soil Organic Carbon | Journal | Science; 280; 1903-1904 | English | Hardcopy:Partial; Wordperfect:Full | Review of research on the formation and storage of black carbon in soils and ocean sediments | They calculated annual formation rates for black C of 50 to 200 Tg, with the major fraction (>80%) produced in the residues of fires. This rate of black C formation reduces net CO2 release by permanent deforestation by 2 to 18% and may constitute a substantial fraction of the missing C in the anthropogenically disturbed global C balance. |
| 1555 | Kuipers, H. | Agronomic aspects of ploughing and non-ploughing | 1991 | Tillage | Journal | Soil Tillage Res.; 21 (1-2); 167-176 | English | Hardcopy:Partial | Review of the pros and cons of tillage, concluding in its favour | Zero tillage research revealed: that conventional tillage strongly reduces the weed population, that seedbeds are a great help in getting a good start for arable crops, that ploughing is very effective as a method of residue management, that zero tillage only seldom results in higher yields (except in cases where a second crop can be grown if tillage for that crop can be omitted) and that, therefore, profits are often lower in the zero tillage cropping system. |
| 186 | Kulshreshtha, S.N., Junkins, B. & Desjardins, R.L. | Prioritising greenhouse gas emission mitigation measures for agriculture | 2000 | Greenhouse Gases | Journal | Agric. Sys.; 66 (3); 145-166 | English | Hardcopy:Partial; Wordperfect:Full | Developing a model for estimating the greenhouse gas emissions from the whole Canadian agriculture and agri-food sector [AAFS] (rather than just for the direct emissions from agriculture) | The 100-year global warming potential for CH4 is estimated at 21 times that of CO2, whereas for N2O, the global warming potential is 310 times that of CO2.; .. N2O is the major GHG emitted by agriculture ..; .. for CO2, the sector [AAFS] is a minor contributor at the national level, which is not the case with the other two gases. For N2O emissions, AAFS's share is 59% of the total Canadian GHG emissions and as such is the largest single source of such emissions. For CH4, agriculture is also a major contributor, since 36% of the total Canadian emissions are from the AAFS.; Much of the CO2 emissions at the primary production level are from the release of SOM and the use of energy for farm machinery and transportation.; .. Canadian agricultural soils would become a significant sink of CO2 by 2010 (as opposed to being a net source of CO2 in 1990).. |
| 1293 | Kuperman, R.G. | Litter decomposition and nutrient dynamics in oak-hickory forests along a historic gradient of nitrogen and sulfur deposition | 1999 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 31 (2); 237-244 | English | Hardcopy:Partial; PDF:Full | Field study to examine the effects on litter decomposition of endogenous (i.e. substrate) N | .. litter decomposition rate and nutrient mineralisation increased along the gradient of increasing amounts of atmospheric N inputs. The lack of N immobilisation and overall higher nutrient mineralisation rates in high deposition sites suggest that N availability at these sites exceeded microbial demand for this nutrient. This apparent decreased demand for N in the ecosystems, which are typically N-limited, provides evidence in support of our original hypothesis that forest soils in high deposition sites may be approaching N saturation from long-term and current excessive N inputs. Such N saturation of forest soils has the potential to adversely affect forest ecosystems, may lead to nutritional imbalances in the ecosystems due to the change from N-limited growth to P-limited growth and can lead to forest decline. |
| 601 | Kuylenstierna, J.C.I., Hicks, W.K., Cinderby, S. & Cambridge, H. | Critical loads for nitrogen deposition and their exceedance at European scale | 1998 | Greenhouse Gases; Soil N Dynamics | Journal | Environ. Pollut.; 102, S1; 591-598 | English | Hardcopy:Partial; PDF:Full | Review of different approaches for estimating the critical nitrogen load for different natural and agricultural ecosystems | .. emissions of nitrogen oxides and ammonia are related to eutrophication and acidification. Impacts of eutrophication in terrestrial ecosystems are assoc'd with changes in floristic composition & in ecosystem function & stability.; The critical load for nitrogen is defined as a quantitative estimate of an exposure to deposition of N as NHx and/or NOx below which empirical detectable changes in ecosystem structure and function do not occur according to present knowledge. |
| 838 | Kuzyakov, Y. | Review: factors affecting rhizosphere priming effects | 2002 | Priming Effect | Journal | J. Plant Nutr. Soil Sci.; 165; 382-396 | English | Hardcopy:Partial | Review of the research done on rhizosphere priming effects | About a third to a half of total assimilated C .. is allocated belowground. .. between 10 and 15% of belowground allocated C is respired by roots to generate metabolic energy .. About 15 to 25% of belowground allocated C is exuded from the roots into the soil.; the C/N ration of rhizodeposits [exudates, sloughed cells, root hairs, lysates and mucilage] is higher than that of microorganisms (bacteria), which have a C/N ratio of 5-6.; .. compared to C all other nutrients, including N, are strongly limited in the rhizosphere .. root uptake and intensive microbial growth on easily available C sources lead to temporary immobilisation of all accessible nutrients into growing plant and microbial cells. .. in a root-free soil easily available C is limiting for microbial growth ..; .. reduction of rhizosphere priming effect by application of N fertiliser was observed in many studies. .. low Nmin content alters root morphology. Much more fine roots were produced, the specific root length increased by about three times and the exudation related to root mass increased.; Roots are strongly effective competitors with microorganisms for N and are winning during long-term periods.; The extent of N priming effect decreases .. by rising N supplies. The extra N mineralisation from SOM increases without N fertilisation from 40 up to more than 100 kg N ha-1.; N fertilisation and .. exhausted soil fertility in ploughed soils diminish the importance of RPE .. or lead to negative RPE (preferential substrate utilisation). |
| 1294 | Kuzyakov, Y. | Separating microbial respiration of exudates from root respiration in non-sterile soils: a comparison of four methods | 2002 | Roots & Rhizodeposition | Journal | Soil Biol. Biochem.; 34 (11); 1621-1631 | English | Hardcopy:Partial; PDF:Full | Review of methods for separating the microbial respiration of root exudates from root respiration | .. root respiration contributes about 40-50% to the root-derived CO2 efflux. The remaining 50-60% comprise the microbial decomposition of root exudates & other rhizodeposits. |
| 1295 | Kuzyakov, Y. | Sources of CO2 efflux from soil and review of partitioning methods | 2006 | Roots & Rhizodeposition; Soil Organic Carbon; Soil Microorganisms | Journal | Soil Biol. Biochem.; 38; 425-448 | English | Hardcopy:Full; PDF:Full | Review of the various sources of CO2 efflux from the soil | Five main biogenic sources of CO2 efflux from soils have been distinguished.. They are root respiration, rhizomicrobial respiration, decomposition of plant residues, the priming effect, induced by root exudation or by addition of plant residues, and basal respiration by microbial decompos'n of SOM. These sources can be grouped in several combinations .. including: root-derived CO2, plantderived CO2, SOM-derived CO2, rhizosphere respiration, heterotrophic microbial respiration (respiration by heterotrophs), and respiration by autotrophs. |
| 1296 | Kuzyakov, Y. | Object- versus method-oriented terminology | 2006 | Roots & Rhizodeposition | Journal | Soil Biol. Biochem.; 38; 2999-3000 | English | Hardcopy:Full; PDF:Full | Letter to the Editor in response to the comments by Peter Högberg, Nina Buchmann and David Read on the review 'Sources of CO2 efflux from soil and review of partitioning methods' by Kuzyakov in Soil Biology and Biochemistry, 38 | Despite short turnover times rhizodeposits are energy-rich & easily available C substrates for microorganisms, driving the most intensive C turnover processes in soils. So the lumping together of the CO2 fluxes from the decompos'n of rhizodeposits with the energy-poor CO2 of root respiration would mix substantially and functionally different C fluxes and neglect the contribution of rhizodeposition to the belowground life and turnover of SOM. Besides litter, rhizodeposition and root turnover remain .. the main primary energy & C source for most soil microorganisms.; .. rhizosphere respiration includes microbial decompos'n of hyphae of mycorrhizal fungi, as well as .. of fine and medium roots, root hairs, etc.; .. root respiration .. increases with increasing temp., nutrient supply, salinity, irradiance, CO2 partial pressure & pH decrease... In contrast, rhizomicrobial respiration is mainly resource limited, which means it is driven not by temperature, but by the amount of rhizodeposits .. |
| 1297 | Kuzyakov, Y. & Bol, R. | Sources & mechanisms of priming effect induced in two grassland soils amended with slurry and sugar | 2006 | Priming Effect | Journal | Soil Biol. Biochem.; 38; 747-758 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the mechanism of the priming effect by separating the contribution to soil respiration of three sources: the SOM and two amendments one very labile (sugar) and one less labile (partly humified slurry) | .. priming effects involve a chain of mechanisms: (i) preferential substrate utilisation, (ii) activation of microbial biomass by easily utilisable substrate, (iii) ... increased utilisation of following substrates according to their utilisability and (iv) decline to initial state. |
| 1298 | Kuzyakov, Y. & Cheng, W. | Photosynthesis controls of rhizosphere respiration and organic matter decomposition | 2001 | Priming Effect; Roots & Rhizodeposition; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 33 (14); 1915-1925 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of changing rates of photosysnthesis on the rhizosphere respiration of wheat | The CO2 efflux from unplanted soil amounted to only 12% and 20% of the total CO2 efflux from the soil with non-shaded and shaded plants respectively. On average 75% of total CO2 efflux from the planted soil with prolonged night periods was root-derived. Rhizosphere respiration was tightly coupled with plant photosynthetic activity. ... The total amount of root-derived C respired in the rhizosphere was 17.3 and 20.6% of the total assimilated C for non-shaded and shaded plants respectively.; The tight coupling of priming effect with photosynthesis suggests that root exudates are the main agent responsible for the rhizosphere priming effect .. the cultivation of wheat leads to the increasing decomposition intensity of SOM. However, the results of many long-term field experiments show the opposite picture. The plant cultivation leads to the accumulation of SOM compared to the bare soil. This contradiction can be explained by annual cycles of the accumulation decomposition intensity of SOM. ... in spring and early summer the exudation intensity of growing plants is very high and it leads to the increased microbial growth and activity in the rhizosphere. ... In summer and autumn the active plant growth is finished and the exudation is negligible or is absent. ... Therefore the microbial activity and the decomposition intensity of SOM are reduced. The humification of the plant residues prevails. |
| 839 | Kuzyakov, Y. & Domanski, G. | Carbon input by plants into the soil: review | 2000 | Roots & Rhizodeposition | Journal | J. Plant Nutr. Soil Sci.; 163 (4); 421-431 | English | Hardcopy:Partial | Review of methods for estimating belowground C translocation and of differing translocation patterns between different plant species (cereals, grasses, trees) | Cereals .. transfer 20-30% of total assimilated C into the soil. Half of this amount is subsequently found in the roots and about one-third in CO2 evolved from the soil by root respir'n & microbial utilis'n of root-derived org. substances. The remaining part of below-ground translocated C is incorporated into the soil microorganisms & soil organic matter. The portion of assimilated C allocated belowground by cereals decreases during growth and with increasing N fertilis'n. Pasture plants translocated about 30-50% of assimilates below-ground.. |
| 1051 | Kuzyakov, Y. & Domanski, G. | Model for rhizodeposition and CO2 efflux from planted soil and its validation by 14C pulse labelling of ryegrass | 2002 | Roots & Rhizodeposition | Journal | Plant Soil; 239; 87-102 | English | Hardcopy:Partial | Modelling the below ground metabolic activity of ryegrass. Root respiration and rhizomicrobial respiration contained 7.6% and 6.0% of total photosynthate C respectively, which corresponds to 56% and 44% of total root-derived CO2 efflux from the soil. The contribution of root respiration varied from 17% to 61% of total root-derived CO2, depending on the age of the ryegrass. | .. root respiration of 3-week-old wheat plants accounted for about 41% of the root-derived CO2. |
| 840 | Kuzyakov, Y. & Larionova, A. | Root and rhizomicrobial respiration: a review of approaches to estimate respiration by autotrophic and heterotrophic organisms in soil | 2005 | Roots & Rhizodeposition; Soil Microorganisms | Journal | J. Plant Nutr. Soil Sci.; 168 (4); 503-520 | English | Hardcopy:Partial | Review of methods for separating autotrophic [root] & heterotrophic [rhizomicrobial] respiration in soil | In cereal crops and grasses (wheat, ryegrass, barley, buckwheat, maize, meadow fescue, prairie grasses), RR [root respiration] amounts on average to 48% and RMR [rhizomicrobial respiration] to 52% of root-derived CO2. |
| 465 | Kuzyakov, Y., Biryukova, O.V., Kuznetzova, T.V., Mölter, K., Kandeler, E. & Stahr, K. | Carbon partitioning in plant and soil, carbon dioxide fluxes and enzyme activities as affected by cutting ryegrass | 2002 | Green Manure; Roots & Rhizodeposition | Journal | Biol. Fertil. Soils; 35; 348-358 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the partitioning of carbon in cut ryegrass | .. 4.7% and 2.4% of the 14C in the new shoot parts were translocated from the root and shoot reserves of unfertilised and fertilised plants respectively. Most of the C re-translocated into the new Lolium leaves originated from the stubble and not from the roots. Between 0.5% and 1.7% of the recovered 14C was found in the soil microbial biomass. |
| 1299 | Kuzyakov, Y., Ehrensberger, H. & Stahr, K. | Carbon partitioning and below-ground translocation by Lolium perenne | 2001 | Roots & Rhizodeposition | Journal | Soil Biol. Biochem.; 33 (1); 61-74 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the allocation of photosynthate to roots and rhizodeposition | The losses from shoot respiration were about 36% of the total assimilated C.; Total 14CO2 efflux from the soil (root respiration, microbial respiration of exudates and dead roots) in the first eight days after the 14C pulse labelling increased with plant development from 2.7 to 11 % of the total 14C assimilated by plants.; .. measured root respiration was between 1.4 and 3.5% of assimilated 14C, while microbial respiration of easily available rhizodeposits and dead root residues was between 0.9 and 6.8% of assimilated C.; The average contribution of root respiration to total 14CO2 efflux from the soil was approximately 46%.; Priming effects dueto plant rhizodeposition reach 60 kg of C ha-1 d-1. 14C incorporated in soil micro-organisms .. amounts to 0.8-3.2% of assimilated C. The total below-ground transfer of organic C by Lolium perenne was about 2800 kg of C ha-1. |
| 1300 | Kuzyakov, Y., Friedel, J.K. & Stahr, K. | Review of mechanisms and quantification of priming effects | 2000 | Mineralisation; Priming Effect | Journal | Soil Biol. Biochem.; 32; 1485-1498 | English | Hardcopy:Full; PDF:Full | Review of priming effects in soil. They can be identified by monitoring the increase in CO2 efflux or in the mineralisation of N, which may occur in phase with the increase in microbial biomass (quickly if the added substrate is an easily available source of C, such as glucose or amino-acids, or with a delay if the substrate is slowly decomposing, like wood or roots) or out of phase, when it is caused by the decay of dying microorganisms. | Priming effects are strong short-term changes in the turnover of SOM caused by comparatively moderate treatments of the soil. .. a change (mostly an acceleration) in natural mineralisation processes through a trigger: e.g. input of an easily decomposable energy source, respectively a limiting factor for microbial biomass. .. not only an acceleration of mineralisation (positive priming effect), but also its reduction or an immobilisation of the added C or N. In these cases one speaks of negative priming effects .. |
| 1301 | Kuzyakov, Y., Jones, D.L. | Glucose uptake by maize roots and its transformation in the rhizosphere | 2006 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 38; 851-860 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the uptake of soluble carbohydrates by plant roots | Glucose was rapidly mineralised in soil & the rate of turnover was significantly greater in the rhizosphere in comparison to non-rhizosphere soil. The amount of glucose captured by the maize plants was low (ca.10% of the total 14Cglucose added) in comparison to that captured by the soil microbial biomass. Only small amounts of the 14C-glucose were transported to the shoot (0.6% of the total). The degree of glucose capture by maize roots .. in compet'n with soil microorganisms was similar to similar expts performed for amino acids. |
| 1052 | Kuzyakov, Y., Kretzschmar, A. & Stahr, K. | Contribution of Lolium perenne rhizodeposition to carbon turnover of pasture soil | 1999 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Plant Soil; 213 (1-2); 127-136 | English | Hardcopy:Partial | Lab. expt. to study the contribution of rhizodeposition from a grass to SOC turnover | Total 14CO2 efflux from the soil .. in the first 8 days after 14C pulse labelling decreased .. from 14 to 6.5% of the total 14C input. Root respiration .. was between 1.5 and 6.5% while microbial respiration of .. rhizodeposits and dead root remains were between 2 and 8% of the 14C input. The average contribution of root respiration to total 14CO2 efflux from the soil was approximately 41%.; The contribution of plant roots to total CO2 efflux from the soil .. was about 51%. The total 14C content after 8 days in the soil with roots ranged from 8.2 to 27.7% of assimilated carbon. This corresponds to an underground carbon transfer by Lolium perenne of 6-10 g C m-2 at the beginning of the growth period and 50-65 g C m-2 towards the end of the growth period. |
| 841 | Kuzyakov, Y., Leinweber, P., Sapronov, D. & Eckhardt, K.U. | Qualitative assessment of rhizodeposits in non-sterile soil by analytical pyrolysis | 2003 | Roots & Rhizodeposition | Journal | J. Plant Nutr. Soil Sci.; 166 (6); 719-723 | English | Hardcopy:Partial | Lab. expt. to determine the chemical composition of the rhizodeposits of maize | .. rhizodeposits accounted for 2.8% (loam) .. of recovered 14C .. The 14CO2 evolved, mostly by root respiration, accounted for 3.5-4.0% .. |
| 1053 | Kuzyakov, Y., Raskatov, A. & Kaupenjohann, M. | Turnover and distribution of root exudates of Zea mays | 2003 | Roots & Rhizodeposition | Journal | Plant Soil; 254 (2); 317-327 | English | Hardcopy:Partial | Lab. expt. to study the distribution and turnover of root exudates from maize. Exudates are found mainly in the zone up to 3 mm from the root. No exudates were found further than 10 mm from the root. Organic substances exuded from roots, such as carboxylic and amino acids, are sorbed onto the mineral particles of the soil, changing the composition of the exudate as it diffuses away from the root. | Root exudates .. may (i) modify the solubility, sorption and transport of mineral elements to the roots through change of pH, redox potential and organic complexation; (ii) affect the microbial activity and turnover of microbial biomass; and (iii) improve the soil structure. |
| 200 | Känkänen, H., Eriksson, C., Räkköläinen, M. & Vuorinen, M. | Effect of annually repeated undersowing on cereal grain yields | 2001 | Green Manure | Journal | Agric. Food Sci. Finl.; 10; 197-208 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect on grain yields of repeated undersowing of cereal crops with clover and grasses | Annual undersowing with clovers increased, and undersowing with westerwold ryegrass decreased, cereal grain yields. The grain yield was only slightly lower with a mixture of red clover and meadow fescue than with red clover alone. Westerwold ryegrass did not affect soil mineral N content in spring and the increase attributable to clovers was small. .. Soil fertility was not notably improved during six years of undersowing .. |
| 575 | Köchy, M. & Wilson, S.W. | Litter decomposition and nitrogen dynamics in aspen forest and mixed-grass prairie | 1997 | Soil N Dynamics | Journal | Ecology; 78 (3); 732-739 | English | Hardcopy:Partial | Field expt. to study the effect of litter quality, shading and habitat type on decomposition and N dynamics | Decomposition rates differed greatly between litter types, but varied less between habitat types or shading.; Atmospheric N originating from industrial processes is a potential source of N input even in remoter regions .. Litter N was increased by deposition, but this may not have been sufficient to allow net mineralisation. |
| 1287 | Kögel, I. | Estimation and decomposition pattern of the lignin component in forest humus layers | 1986 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 18 (6); 589-594 | English | Hardcopy:Full | Lab. study of the lignin component of three litter layers (mull, moder and mor) from spruce, beech and ash forest respectively | .. the lignin fraction of forest humus layers is considerably degraded during decomposition .. the mechanisms of lignin decomposition in wood and in litter material are similar. |
| 742 | Kögel-Knabner, I. | 13C and 15N NMR spectroscopy as a tool in soil organic matter studies | 1997 | Soil Organic Carbon; Soil N Dynamics | Journal | Geoderma; 80; 243-270 | English | Hardcopy:Partial | A review of studies of SOM using solid state 13C and 15N NMR spectroscopy, which permits the obtaining of structural information about SOM in bulk soils or fractions without extracting the organic material and can also provide information on soil C and N cycling | |
| 1288 | Kögel-Knabner, I. | The macromolecular organic composition of plant and microbial residues as inputs to soil organic matter | 2002 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 34 (2); 139-162 | English | Hardcopy:Full; PDF:Full | Review of current knowledge of the chemical composition of the plant litter and microbial residues that contribute to the formation of SOM | Although the cell wall polysaccharides of microorganisms are relatively easily decomposed, the basic units such as glucosamine, galactosamine or muramic acid are found in soil after hydrolysis & they accumulate during litter decompos'n.; It is often assumed that melanins represent precursors of humic substances in soil, based on their humic acid-like attributes. .. very little is known about their compos'n or decompos'n in soils.; In plant litter & soils .. the residue contains, besides lignin, .. aliphatic plant components, e.g. cutin & suberin. |
| 743 | Kögel-Knabner, I. & Ziegler, F. | Carbon distribution in different compartments of forest soils | 1993 | Soil Organic Carbon | Journal | Geoderma; 56 (1/4); 515-525 | English | Hardcopy:Full | Expt'l study of mull, moder and mor forest soils. Mull has a litter layer directly on the A mineral horizon and has a high soil faunal activity and rate of litter decomposition. In moder and mor there is a thick forest floor on account of moderate or low faunal activity and slow litter mineralisation. They have a transitional horizon and an amorphous organic horizon above the mineral soil. | |
| 1703 | Kögel-Knabner, I., Chenu, C., Kandeler, E. & Piccolo, A. | Biological and physicochemical processes and control of soil organicmatter stabilization and turnover | 2006 | Uncategorised | Journal | Eur. J. Soil Sci.; 57; 425 | English | PDF:Full | ||
| 837 | Kögel-Knabner, I., Guggenberger, G., Kleber, M., Kandeler, E., Kalbitz, K., Scheu, S., Eusterhues, K. & Leinweber, P. | Organo-mineral associations in temperate soils: integrating biology, mineralogy and organic matter chemistry | 2008 | Soil Organic Carbon | Journal | J. Plant Nutr. Soil Sci.; 171; 61-82 | English | Hardcopy:Full | Review of current knowledge of mineral-associated OM in soils | .. organo-mineral associations spatially isolate C sources from soil biota ..; Compos'n of OM in organo-mineral associations is highly variable, with loamy soils having generally a higher contribution of polysaccharides, whereas mineral -associated OM in sandy soils is often more aliphatic. Though highly reactive towards Fe oxide surfaces, lignin and phenolic components are usually depleted in organo-mineral associations.; Clay-sized organo-mineral associations are preferred habitat for a complex microbial community .. |
| 1600 | Kögel-Knabner, I., Leeuw, J.W. de & Hatcher, P.G. | Nature and distribution of alkyl carbon in forest soil profiles: implications for the origin and humification of aliphatic biomacromolecules | 1992 | Soil Organic Carbon | Journal | Sci. Total Environ.; 117-118; 175-185 | English | Hardcopy:Partial | Expt. to analyse the resistant residues isolated from soils | .. the aliphatic structures in forest SOM can be assigned to mobile and rigid C moieties, .. [which] are possibly associated with different types of macromolecules. One type are the polyesters cutin and suberin from leaves, barks and roots, the other is a resistant non-saponifiable aliphatic biomacromolecule derived from leaves and barks or microorganisms. |
| 1621 | Kögel-Knabner, I., Zech, W. & Hatcher, P.G. | Chemical composition of the organic matter in forest soils: the humus layer | 1988 | Lignin and CBW; Soil Organic Carbon | Journal | Z. Pflanz. Bodenkunde; 151; 331-340 | English | Hardcopy:Partial | Lab. study of the OM in three litter layers (mull, moder and mor) from spruce, beech and ash forest respectively. The aromatic, alkyl, O-alkyl and carbonyl fractions constitute 21%, 23%, 46% and 10% of the C in the forest soil. | .. a decrease of O-alkyl C, an increase of alkyl C and carboxyl groups is observed as depth increases.; .. the percentage of aromatic C remains constant at about 25%. |
| 414 | Köpke, U. & Haas, G. | Vergleich konventioneller und organischer Landbau, Teil II: klimarelevante Kohlendioxid-Senken von Pflanzen und Boden | 1995 | Greenhouse Gases; Organic Farming | Journal | Ber. Landwirtsch.; 73; 416-434 | German | Hardcopy:Full | Calculation of the size of the CO2 sink in organic and conventional farming. The gross and nett sinks for organic and conventional farming are given as 22.8, 22.7, 22.3 and 21.7 tons of CO2 per hectare per year respectively, so organic is only marginally (not significantly ?) better. Annual humus production for different crops varies from 0.6 tons per hectare for potatoes and sugar beet up to 4-5 tons per hectare for grass. | |
| 931 | Köpke, U. & Haas, G. | Farming, fossil fuels and CO2 | 1996 | Greenhouse Gases; Organic Farming; Sustainability | Journal | New Farmer and Grower; spring 1996; 16-17 | English | Hardcopy:Full | Review of papers comparing the energy consumed and CO2 generated in conventional and organic farming. CO2 emissions are significantly lower in organic crop production, due to the greater use of break crops, the greater incidence of weeds and the greater organic content of the soil. The fossil fuel energy consumed in organic farming is only a third of that in conventional, due mainly to the absence of chemical fertilisers and pesticides and less use of animal feed concentrates | .. more CO2 is tied up in the form of SOM in organic farms than is the case with conventional farming. |
| 69 | Körner, I. & Stegmann, R. | N-dynamics during composting: overview & experimental results | 2002 | Compost & Biocontrol; Soil N Dynamics | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Review of current knowledge of the fate of nitrogen during composting | Ammonification was lower during curing than during intensive rotting. .. Ammonification reaches higher rates for non-lignocellulosic substrates compared to lignocelluloses, independent of the N-content of the input material. Nitrification and denitrification occurred only during curing. Nitrification was limited by temperatures above 30$C, pH over 8 and moistened substrate. |
| 1622 | Körschens, M., Weigel, A. & Schulz, E. | Turnover of SOM and long-term balances - tools for evaluating sustainable productivity of soils | 1998 | Soil Organic Carbon | Journal | Z. Pflanz. Bodenkunde; 161; 409-424 | English | Hardcopy:Partial | Review of data from 12 European long-term sites to assess the usefulness of SOM as a criterion for sustainable agricultural production. The following guidelines are suggested for percentage SOM in the plough layer: for sandy soils with 5% and 25% clay/fine silt - 1.0-1.5% and 2.2-2.8% SOM respectively. For loamy soils with 10%, 25% and 35% clay/fine silt - 1.3-2.0%, 2.5-3.3% and 3.2-4.1% SOM respectively. Below these figures fertility will be lacking and above them there will be losses leading to possible pollution, so the optimum C content should not be exceeded. The annual changes in SOM content are almost exclusively in the decomposable part of the OM and amount to only 0.01% (500 kg/ha), even under extreme changes of the fertilising system. The rate of FYM application needed to maintain the SOM constant is about 14 t/ha/yr. | Atmospheric N deposition can amount to about 50 kg/ha/yr. |
| 98 | Lacko-Bartoová, M., Zaujec, A. & tevlíková, T. | Effect of ecological and integrated arable farming systems on crop productivity and soil fertility | 1999 | Organic Farming; Soil Organic Carbon; Tillage | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to compare the effects of ecological and conventional farming systems and of tillage on yields and fertility | the rate of C inputs was the most important factor determining the OM level in the soil... The ecological farming system showed slightly better physical and chemical soil parameters and higher quality of SOM. .. The highest values of Cox, Nbiol, daily soil respiration and nitrification were measured in the ecological system. Differences of crop yields between the systems were greater under minimum cultivation than under conv'l tillage. .. The conventional cultivation in both systems resulted in higher yields. |
| 1302 | Ladd, J.N. & Amato, M. | The fate of nitrogen from legume and fertiliser sources in soils successively cropped with wheat under field conditions | 1986 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 18 (4); 417-425 | English | Hardcopy:Partial | Expt. to study the uptake by two successive wheat crops of legume-fixed and chemical fertiliser N. In the first year about three times as much of the fertiliser N was taken up as the legume N, but about twice as much of the legume N remained in the soil as organic N as of the fertiliser N. | For both legume and fertiliser N uptake for both crops was directly related to input .. |
| 1303 | Ladd, J.N., Amato, M., Grace, P.R. & Veen, J.A. van | Simulation of 14C turnover through the microbial biomass in soils incubated with 14C-labelled plant residues | 1995 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 27 (6); 777-783 | English | Hardcopy:Partial | Expt. to study the 100-day incubation of legume leaves in a clay soil and a sandy loam. Microbial biomass in the sandy soil was consistently about half that in the clay soil. | Plant residue .. decomposed without lag in both soils. During the period of most rapid metabolism (0-2 days) .. decomposition was 1.6 time faster in the sandy loam than in the high-clay soil. Thereafter net rates of decay .. decreased sharply .. and differed only marginally between soils.; .. in contrast to glucose .. plant residue in both soils was far less decomposed during the initial period of rapid attack and accumulated at all stages far less biomass .. per unit of CO2 evolved. |
| 744 | Ladd, J.N., Foster, R.C. & Skjemstad, J.O. | Soil structure: carbon and nitrogen metabolism | 1993 | Soil Organic Carbon; Soil N Dynamics | Journal | Geoderma; 56 (1-4); 401-433 | English | Hardcopy:Partial | Review of C and N metabolism in soils | .. physical protection mechanisms are important determinants of the stability of OM in soils. Such mechanisms confer stability through physical isolation of substrates from decomposer cells and enzymes, partly as a result of their interactions with soil inorganic materials, partly from their association with biologically resistant humic substances.; .. the amounts of input 14C remaining as total organic residues and as microbial biomass were directly correlated with clay contents and (CEC and total pore space). |
| 602 | Lal, R. | Soil carbon dynamics in cropland and rangeland | 2002 | Soil Organic Carbon; Tillage | Journal | Environ. Pollut.; 116 (3); 353-362 | English | Hardcopy:Full; PDF:Full | Assessment of the sustainability of farming systems through C budgeting, based on the energy use of agricultural practices and the soil C sequestration | Most soils in the Midwestern US have lost 30 to 50% of their original pool, or 25 to 40 Mg C/ha, upon conversion from natural to agricultural ecosystems. About 60 to 70% of the C thus depleted can be re-sequestered through adoption of recommended soil and crop management practices.; Fuel purchased for on-farm use: 1 Mg of gasoline = 42.2 GJ; 13.78 kg C/GJ of natural gas; 19.94 kg C/GJ of petroleum liquids; 1 Mg of straw = 3 x 106 kcals.; .. the C/energy input for production of fertiliser is 820 kg C/Mg for N. Energy use for irrigation .. ranges from 85 to 334 kg C/ha/year, with a mean of 150 kg C/ha/year. Irrigation may increase biomass productivity and .. may also increase SOC content by 50-150 kg/ha/year. .. lifting irrigation water requires C-based energy input.; Fuel consumption for various tillage operations .. 12.4 l/ha (557 MJ/ha) for mouldboard plough, 9.2 l/ha (416 MJ/ha) for chisel plough, 6.5 l/ha (293.7 MJ/ha) for discing, 4.0 l/ha (18 MJ/ha) for cultivator, 3.6 l/ha (162 MJ/ha) for inter-row cultivator and 2.9 l/ha (131 MJ/ha) for rotary hoe .. use of conservation tillage or reduced tillage systems saves C/energy input.; .. the energy input for 4 variables (weed control, seedbed preparation, operations, fertiliser manufacture) at 3 levels (high, low, zero) of herbicide use .. was 13.5, 10.3 and 3.9 GJ/ha for maize .. production; 3.8, 3.3 & 1.8 GJ/ha for soya bean .. production; & 8.0, 3.9 & 3.3 GJ/ha for wheat .. production in maize-soya bean-wheat rot'n. |
| 865 | Lal, R., Follett, R.F., Kimble, J.M. & Cole, C.V. | Managing U.S. cropland to sequester carbon in soil | 1999 | Greenhouse Gases; Tillage | Journal | J. Soil Water Conserv.; 54 (1); 374-381 | English | Hardcopy:Full | Estimates of the emission of greenhouse gases from U.S. agriculture and the amount of additional sequestration of C in the soil that could be achieved by better management (including some useful tables) | We estimate total U.S. [greenhouse gas] emissions of 1600 MMTCE [million metric tons C equivalent], including 109 MMTCE from agricultural activities.; The overall contribution .. from production inputs is small .. we estimate 42.9 MMTC annually, which includes 15 MMTC/yr from erosion.; We estimate that U.S. cropland has lost about 5000 MMTC as a result of cultivation. The maximum potential for U.S. cropland to sequester C through adoption of recommended practices is likely in the range of 50 to 75% of the C lost .. , which may be reached over a 25-50 year period.; About 37% of the land farmed in the U.S. is now managed with a CT system.; .. the SOC sequestration potential of conversion to CT ranges from 0.1 to 0.5 MT/ha/yr ..; .. fossil fuel emissions from field manipulations and herbicide production are 53 kg C/ha/yr for plough till .. and 29 kg C/ha/yr for no-till. .. adoption of CT in the U.S. has a total C sequestration potential of 350 MMTC to 1400 MMTC by the year 2020.; The net gain in C through adoption of recommended agricultural practices is 100 MMTC/yr. |
| 1125 | Lal, R., Griffin, M., Apt, J., Lave, L. & Morgan, M.G. | Response to comments on 'Managing soil carbon' | 2004 | Soil Organic Carbon | Journal | Science; 305; 1567-1568 | English | Hardcopy:Full; PDF:Full | Review of the five ways in which soil erosion exacerbates C emission from ecosystems | Most of the C transported with sediment is the labile fraction, which is easily mineralisable; the mineralisable fraction in translocated OM may range from 29% to as high as 70%.; .. the rate of mineralisation may also be increased in depressional sites because of the high proportion of mineralisable fraction.; The losses of carbon can be especially high if the depositional sites, where the labile fraction is concentrated in the top 10 to 20 cm, is tilled frequently.; Because the global C budget cannot be balanced, the so-called missing sink .. lumps in all the uncertainties. The magnitude of unknown sink could be 2 to 4 Gt C/yr or more because of unaccounted-for erosion-induced effects and other sources. |
| 1124 | Lal, R., Griffin, M., Apt, J., Lave, L.& Morgan, M.G. | Managing soil carbon | 2004 | Soil Organic Carbon | Journal | Science; 304; 393 | English | Hardcopy:Full | Review of reasons for zero tillage | Short-sighted farming practices have resulted in loss of an estimated .. 7812 gigatons [of C] from the world's soils.; .. no-till is currently practised on only 5% of the world's cropland.; No-till agriculture, together with leaving crop residue in fields, does have costs. The yield may be lower in poorly drained and compacted soils and in places where springtime warming is slow. Initially more fertiliser may be required .. Crop residue left in the fields would not be available for animal feed, energy production, bio-fuels .. and may increase the incidence of pests and pathogens. |
| 152 | Landers, J.N. | How and why the Brasilian zero tillage explosion occurred | 2001 | Tillage | Book | Stott, D.E., Mohtar, R.H. & Steinhardt, G.C. (eds.); Sustaining the Global Farm: papers from 10th Int. Soil Consv; | English | Hardcopy:Partial | The development of zero tillage in Brasil has been a farmer-led evolution, supported by various local and national, governmental and non-governmental organisations. In 1998 over 20% of the annual summer crops in Brasil (a total area of 8.7 million hectares) were under zero tillage. Zero tillage reduces soil erosion losses by up to 90% and substantially improves rain infiltration rates. | Zero tillage is based on permanent soil cover with crop residues, pre-plant desiccation of weeds, crop rotations including cover crops, specialised planters and drills, maximisation of biological activity and enhanced management capabilities of the farmer, leading to environmental responsibility.; The adoption of this technology represents the gateway to full sustainability ..; .. 'reduced tillage', 'minimum tillage' or 'conservation tillage', which are catch-all terms, embracing and obfuscating zero tillage, while still admitting turing the soil over (an anti-conservation act, because any cultivation oxidises SOM and reduces soil biological activity and diversity) [should be abolished]. |
| 1686 | Landers, J.N. | Zero tillage development in tropical Brasil | 2001 | Tillage | Website | www.fao.org/docrep (F.A.O. Agricultural Services Bulletin no. 147) | English | Hardcopy:Partial | Zero tillage techniques and the history of their adoption in Brasil, especially the role of non-governmental organisations. Also various tables, including one on 'Why don't farmers adopt zero tillage?'. | |
| 928 | Lantinga, E.A. & Dam, A.M. van | Leaf CO2 assimilation and leaf dynamics in cover crops during autumn and winter at two levels of nitrogen supply | 1998 | Cover Crops | Journal | Neth. J. Agric. Sci.; 46; 249-265 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the functioning of rye and radish as cover crops | There was no net growth after mid-November... Tillering in rye ceased in midOctober.; Leaf appearance slows down in October .. Light-saturated net CO2 assimilation rates are halved between September and November. |
| 1556 | Larney, F.J., Bremer, E., Janzen, H.H., Johnston, A.M. & Lindwall, C.W. | Changes in total, mineralisable and light fraction soil organic matter with cropping and tillage intensities in semiarid southern Alberta, Canada | 1997 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 42; 229-240 | English | Hardcopy:Partial; PDF:Full | Quantification of the C & N changes caused by the adoption of continuous cropping and reduced tillage | After 16 years of tillage treatments .. total organic C in the top 15cm ranged from 27.1 to 30.4 Mg ha-1. There were no differences in OM characteristics between plots managed with CT-blade, MT and ZT. However, plots managed with more intensive tillage implements (CT-disc, CT-cultivator) showed significantly lower amounts of organic C, organic N and mineralisable N. Changes in mineralisable N and light fraction C & N indicated that the effects of tillage system were yes, all |
| 791 | Larrčre, C. & Larrčre, R. | Animal rearing as a contract? | 2000 | Agricultural Ethics | Journal | J. Agric. Environ. Ethics; 12 (1); 51-58 | English | Hardcopy:Partial; PDF:Full | An ethic based on utilitarian principles or on the concept of animals having rights is essentially anthropocentric, raises problems about what creatures are covered by it and what are not, and fails to distinguish between wild animals and domestic ones. A distinction should be made between environmental ethics (concerned with populations, species and biotic communities) and animal ethics (concerned with animals individually). Individualist animal ethics are not relevant to the keeping of domestic animals, which should be regulated instead by a 'domestic contract'. This contract underlies the relationship between farmer and animal in old-fashioned extensive animal rearing, but is broken in modern intensive animal rearing. | Our main assumption is Mary Midgley's anthropological assumption, according to which human communities, since the Neolithic Age, have always included various animals, so that relations of sociability have always existed between human beings and animals within the domestic community .. |
| 99 | Larsson, H. | Experiments with leguminous crops in a stockless organic farming system with sugar beet | 1999 | Green Manure; Stockless Farming | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to compare the effects of different green manures on soil structure and on a following sugar beet crop | The best sugar beet root yields were recorded after Trifolium pratense, T. repens & Medicago sativa, while L. perenne had the lowest root yield.; The highest N content in the soil was found after Medicago sativa, Trifolium repens and T. perenne.; In the subsoil the best penetration of roots was found with Medicago sativa, Melilotus officinalis and Trifolium pratense. Very good aggregation of the soil was found with Medicago sativa, Melilotus officinalis, Trifolium pratense and T. repens. |
| 955 | Larsson, L., Ferm, M., Kasimir-Klemedtsson, A. & Klemedtsson, L. | Ammonia and nitrous oxide emissions from grass and alfalfa mulches | 1998 | Greenhouse Gases; Green Manure; Mulch | Journal | Nutr. Cycl. Agroecosyst.; 51 (1); 41-46 | English | Hardcopy:Full; PDF:Full | Field expt. to compare gaseous N emissions from 7-9-cm-thick mulches of high-N and low-N (unfertilised) grass and lucerne with those from bare soil | The .. loss as NH3-N was 8 kg ha-1 from low-N grass, 190 kg ha-1 from high-N grass and 170 kg ha-1 from alfalfa, which is equivalent to 2%, 39% and 17%, respectively of the N applied in the form of .. mulch. On bare soil there was a deposition of 6 kg ha-1.; The estimated loss of N2O-N was 0.4 kg ha-1 from low-N grass, 6 kg ha-1 from high-N grass and 13 kg ha-1 from alfalfa, which is equivalent to 0.1%, 1% and 1% of the N applied in the .. mulch. The loss from bare soil was 0.2 kg ha-1. |
| 1054 | Lavelle, P., Lattaud, C., Trigo, D. & Barois, I. | Mutualism and biodiversity in soils | 1995 | Soil Microorganisms; Soil (General) | Journal | Plant Soil; 170; 23-33 | English | Hardcopy:Partial | Review of the part played by microfauna in soil function | Mutualistic relationships among soil organisms are digestive mutualisms, .. in which microorganisms generally associate with macroorganisms .. to exploit the organic resources in litter and soil.; .. macroorganisms appear to be major regulators of microbial activities.; Microbial communities appear as a huge, largely dormant population .. Macroorganisms, which have the ability to mix and transport the soil and provide energetic substrates, modify the environment at the sale of the microorganisms and may interrupt this dormancy. |
| 1389 | Layese, M.F., Clapp, C.E., Allmaras, R.R., Linden, D.R., Copeland, S.M., Molina, J.A.E. & Dowdy, R.H. | Current and relic carbon using natural abundance carbon-13 | 2002 | Soil Organic Carbon; Tillage | Journal | Soil Sci.; 167 (5); 315-326 | English | Hardcopy:Partial | An expt. to examine he C interactions as a result of different tillage, Nfertilisation and residue treatments and a crop change from a 13-year continuous C4 crop (maize) to a 4-year continuous C3 crop (soya beans) | |
| 1655 | Leach, G. | Energy and Food Production | 1976 | Energy in Agriculture | Book | Leach, G.; Energy and Food Production; | English | Hardcopy:Partial | Various data, including energy ratios for different crops and farming systems, energy requirements of labour, energy inputs for tractor and implement use, energy outputs per unit of labour for different farming systems. | [the labour productivity of primitive food production is so great that it leaves] time for leisure and often a rich cultural life, which has led to many suggestions that hunter-gatherers and pre-industrial farmers, largely by defining wants and needs in terms of resources available, realised `golden age of affluence'.; In the case of simple tools .. used by subsistence agriculturalists a standard figure [for embodied energy] of 90 MJ/kg is assumed [which] is very close to that for manufacturing small to medium sized tractors. |
| 117 | Leake, A.R. | Performance of arable organic farming: a UK experience | 2001 | Stockless Farming | Book | ; Proc. National Tillage Conference 2001, Paper 6, Teagasc, Ireland; | English | Hardcopy:Partial; Wordperfect:Full | Review of stockless organic farming trials in England | .. stockless organic farming can be more productive than its mixed counterpart, supporting the theory that N transfer is more efficient.; .. the benefits of manure to soil structure and biology were noted. Organic C in manure tends to provide a more persistent C source than that from green manures, since the more labile compounds are selectively removed during digestion.; .. mycorrhizal activity was much higher in manured plots. The stockless system appears to depress numbers & activity, similar to levels seen in conventionally fertilised soils. |
| 874 | Leake, A.R. | A report of the results of C.W.S. Agriculture's organic farming expts 1989-1996 | 1999 | Green Manure; Organic Farming; Stockless Farming | Journal | J. R. Agric. Soc. Engl.; 160; 73-81 | English | Hardcopy:Full | Three organic systems were trialled: a mixed organic farm, a stockless allarable farm and a horticultural enterprise. The stockless farm gave only a 2% reduction in profitability compared with conventional agriculture (including subsidies). Its wheat yields increased during the period of the expt. and were consistently higher than those on the mixed organic farm. Its soils suffered phosphate depletion and rock phosphate was applied. Weed control is discussed: perennial weeds, poppies and wild oats have increased locally. Autumn cultivation of leys has been left as late as possible to reduce nitrate leaching. Sowing of winter cereals has also been left late, so as to allow more stale-bed cultivations to take place and to reduce weed germination, due to lower soil temperature. | |
| 1679 | Leake, A.R. | Weed control in organic farming systems | 1999? | Miscellaneous; Organic Farming | Book | ; B.C.P.C. 35th Annual Review of Weed Control; | English | Hardcopy:Full | A comprehensive review of all the techniques for controlling weeds in organic agriculture. | |
| 685 | Leatham, G.F. & Kirk, T.K. | Regulation of ligninolytic activity by nutrient nitrogen in white-rot basidiomycetes | 1983 | Lignin and CBW | Journal | FEMS Microbiol. Lett.; 16; 65-67 | English | Hardcopy:Partial | Lab. expt. to test the effect of varying nitrogen concentration on the ligninolytic activity of 7 different white-rot fungi. The oyster mushroom and another species of cultivated mushroom showed no indication of ligninolysis inhibition by increased N - rather the reverse. | The ligninolytic system of Phanerochaete chrysosporium is .. dependent on the cessation of vegetative growth and the onset of secondary metabolism. Depletion of nutrients, including a utilisable nitrogen source, triggers development of the lignolytic system. .. many amino-acids .. stimulate vegetative growth while suppressing ligninolytic activity.; Full regulation, partial regulation or no apparent regulation by nutrient N was observed for different species tested, indicating that .. the regulation of ligninolytic activity by nutrient N limitation is not a universal phenomenon among white-rot basidiomycetes. |
| 940 | Leavitt, S.W., Pendall, E., Paul, E.A., Brooks, T., Kimball, B.A., Pinter Jr, P.J., Jr., Johnson, H.B., Matthias, A., Wall, G.W. & LaMorte, R.L. | Stable carbon isotopes and soil organic carbon in wheat under CO2 enrichment | 2001 | Greenhouse Gases; Soil Organic Carbon | Journal | New Phytol.; 150; 305-314 | English | Hardcopy:Partial | Expt. in which stable C isotope tracers were used to study the entry of new C into SOC pools under enhanced atmospheric CO2 concentrations. | .. elevated CO2 did not significantly affect the addition of new C to SOC pools .. it is likely that future increases in the air's CO2 content will do so indirectly by stimulating the productivity of N-fixing plants .. elevated CO2 is known to stimulate biological N fixation .. high N availability increased C inputs to SOC pools .. |
| 1055 | Ledgard, S.F. & Steele, K.W. | Biological nitrogen fixation in mixed legume/grass pastures | 1992 | Green Manure | Journal | Plant Soil; 141 (1/2); 137-153 | English | Hardcopy:Partial | Review of research into biological nitrogen fixation and the transfer of N from legumes to grasses. Rate of fixation and belowground transfer from legume to grass is quantified. | BNF by legumes in mixed pastures is influenced by three primary factors: legume persistence and production, soil N status and competition with the associated grasses.; The natural feedback mechanism between BNF and soil N .. may mean greater efficiency of N flow and less potential for loss. |
| 990 | Leeuw, J.W. de | On the origin of sedimentary aliphatic macro-molecules: a comment on recent publications by Gupta et al. | 2007 | Soil Organic Carbon | Journal | Org. Geochem.; 38; 1585-1587 | English | Hardcopy:Partial; PDF:Full | Review of recent work on the origin of the aliphatic component of SOM | .. in addition to the selective preservation of resistant aliphatic biomacromolecules, non-biological aliphatic geo-macromolecules can also be produced from low-molecular-weight lipids upon (oxidative) polymerisation ..; [we] .. recognise morphologically and chemically the abundant presence of a highly aliphatic geopolymer produced from low-molecular-weight unsaturated lipids, a neoformed geopolymer highly comparable to the biomacromolecules cutan & algaenan. .. we excluded the form'n of such geopolymers by thermal processes & speculated that oxidative polymerisation during (very) early diagenesis might have occurred. |
| 929 | Leffelaar, P.A. & Dam, A.M. van | Root, soil-water and nitrogen dynamics in a cover crop-soil system in the Wageningen Rhizolab | 1998 | Cover Crops | Journal | Neth. J. Agric. Sci.; 46; 267-284 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the development of rye & radish cover crops in soil | Cover crops took up 20-30 g N m-2, of which a considerable part (37-48%) was present in dead leaves in March. Rooting depth increased by 2.6 cm day-1 for both species at the start of the growing season. Cover cropping reduced the NO3--N concentration in the soil considerably during the whole duration of the experiments: first in the top layers, then further down the soil profile. The reduction in total leached N was similar to the total crop N uptake. Nitrate-N concentrations in leached water were reduced by 49-85 mg l-1 (by 62-99%) .. |
| 558 | Lefroy, E.C. & Rydberg, T. | Emergy evaluation of three cropping systems in south-western Australia | 2003 | Energy in Agriculture | Journal | Ecol. Model.; 161; 195-211 | English | Hardcopy:Partial; PDF:Full | Calculation of energy consumption in a wheat-lupin rotation, with and without alley-cropping, and in a tagasaste plantation, using the emergy approach (tracing all energy back to the sun) | The results showed that the two largest energy flows in the conventional lupin/ wheat cropping system were wind erosion and purchased inputs of phosphate. The renewable component of production was 15% of total flows in the lupin/wheat system, 30% in the alley-cropping system and 53% in the tagasaste plantation. ... This analysis suggested that once the two agroforestry systems were fully established, the tagasaste plantation was the most efficient at transforming natural resources into goods and services and the most profitable, while the lupin/wheat system was the least energy efficient and the least profitable. |
| 273 | Lefroy, E.C. & Stirzaker, R.J. | Agroforestry for water management in the cropping zone of southern Australia | 1999 | Miscellaneous; Sustainability | Journal | Agrofor. Syst.; 45 (1-3); 277-302 | English | Hardcopy:Partial; Wordperfect:Full | Review of the potential of agroforestry to correct the hydrological imbalance of some agricultural systems | The relative merits of segregating, integrating and rotating trees with crops are .. examined. .. in most cases, trees would need to be widely dispersed over a significant proportion of the landscape to manage deep drainage and salinity. Agroforestry is therefore only likely to be an effective solution to water management where trees can compete directly on commercial terms with conventional agriculture.; .. the transition from exclusively annual-based agriculture to one with a significant component of woody perennials inevitably involves a lag between establishment and first returns to the landholder.; Unlike the young post-glacial soils of the Middle East and Europe from which grain agriculture evolved, it appears we cannot stray far from the original vegetative structure without paying a penalty. |
| 1730 | Lefroy, E.C., Hobbs, R.J., O'Connor, M.H. & Pate, J.S. | What can agriculture learn from natural ecosystems? | 1999 | Uncategorised | Journal | Agrofor. Syst.; 45; 423-436 | English | PDF:Full | ||
| 956 | Lehmann, J., Gebauer, G. & Zech, W. | Nitrogen cycling assessment in a hedgerow intercropping system using 15-N enrichment | 2002 | Miscellaneous; Soil N Dynamics | Journal | Nutr. Cycl. Agroecosyst.; 62 (1); 1-9 | English | Hardcopy:Partial | Field expt. to compare the cycling of nitrogen in monocultural sorghum and sorghum cropped in an avenue of Acacia, using the 15-N enrichment and 15-N balance methods. The 15-N enrichment method did not work. The 15-N balance method showed 3% and 6% N leaching losses under the monocultural and alleycropped sorghum. | 74% to 88% of the applied 15-N was recovered after three cropping cycles, most of in the soil ... Only about 10% of the 15-N was taken up by the aboveground vegetation ... |
| 655 | Leifeld, J. & Kögel-Knabner, I. | Microaggregates in agricultural soils and their size distribution determined by X-ray attenuation | 2003 | Soil (General) | Journal | Eur. J. Soil Sci.; 54 (1); 167-174 | English | Hardcopy:Partial | Expt. to use X-ray attenuation to compare the size distribution of microaggregates < 63 m with that of primary particles in the same size range | .. small particles contribute [preferentially ?] to the formation of microaggregates because the physico-chemical binding is strong. .. the contribution of C to the formation of mechanically stable microaggregates is either negligible compared with non-biotic binding (e.g. inorganic cementing, inter-particle forces) or is sufficient even for arable soils containing little organic C, or both.; The organic C content seems to be a negligible factor in micro-aggregation of agricultural soils. |
| 656 | Leifeld, J., Siebert, S. & Kögel-Knabner, I. | Changes in the chemical composition of soil organic matter after application of compost | 2002 | Compost & Biocontrol; Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 53; 299-309 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effect of compost application on SOM | The lignin contents in the compost-amended soils increased because the composts cont'd more lignin,which altered little even after prolonged decompos'n of the composts in soil.A pronounced decrease in lignin occurred in the soils amended with mature compost only.; Even after 18 mths of incub'n the amount of the lignin & the degree of decompos'n altered only slightly ..; .. During the incubation the relative contents of total polysaccharides decreased by 9-20% (controls) and by 20-49% (compost-amended soils). They contributed preferentially to the decompos'n as compared with the bulk SOM, which decreased between <2% and 20%.; .. non-cellulosic polysaccharides remained fairly constant in the agricultural soils with compost or even increased for some of the controls.; .. the decay of plant-derived hemicelluloses is partly offset by the accumulation of microbial polysaccharides in the agricultural soils. |
| 823 | Leifeld, J., Siebert, S. & Kögel-Knabner, I. | Stabilisation of composted organic matter after application to a humus-free sandy mining soil | 2001 | Compost & Biocontrol; Soil Organic Carbon | Journal | J. Environ. Qual.; 30; 602-607 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the effect of biowaste compost on humus-free sandy mining soil | Characterisation of the OM in particle size fractions indicates increased humification with decreasing particle size and lower mineralisation rates of the OC in fine fractions. Consequently, the enrichment of OM in fine mineral fractions may represent a major stabilisation process controlling SOM storage. Sandy soils incorporate less OC into organo-mineral associates than fine textured soils and therefore have only low OM protection capacities. |
| 466 | Leinweber, P., Haumaier, L. & Zech, W. | Sequential extractions and 31P-NMR spectroscopy of phosphorus forms in animal manures, whole soils and particle-size separates from a densely populated livestock area in northwest Germany | 1997 | Phosphorus Cycling; Stockless Farming | Journal | Biol. Fertil. Soils; 25 (1); 89-94 | English | Hardcopy:Partial; PDF:Full | Of the total P in liquid pig manure (16.2 g kg-1) and dry chicken manure (26.2 g kg-1) 40% was found in residual P and 25-40% in labile (resin and bicarbonate) P. Some manure-derived P reacted with soil oxides and humic substances. | .. excessively manured soils are likely to lose large amounts of P.; .. these soil characteristics unequivocally result from the density of livestock population and excessive manuring. |
| 657 | Leinweber, P., Meissner, R., Eckhardt, K.U. & Seeger, J. | Management effects on forms of phosphorus in soil and leaching losses | 1999 | Phosphorus Cycling | Journal | Eur. J. Soil Sci.; 50; 413-424 | English | Hardcopy:Partial; PDF:Full | Expt. to measure P leaching losses from 20 differently treated sandy soils. The size of soil P fractions was influenced by soil texture, fertilisation and soil management. Labile P was largest in sandy soils and grassland and least in fallow and re-afforested land. The largest total P, labile P and soil P test P was in arable soils under rotated crops with organic and chemical fertilisation. The mean values of total P, labile (resin+bicarb) P and residue P from all 20 soils were 546, 147 and 87 mg kg-1 respectively (which represent 100%, 28% and 16% of total P). The mean values of the PSC (P sorption capacity) and DPS (degree of P saturation) were 19 mmol kg-1 and 59% respectively. The annual P balance varied from +119 kg ha-1 for cut-and-mulched grassland to -144 kg ha-1 for alternative cropping (no chemical fertilisers, one year FYM, one year grass/clover). | .. measures that conserve SOM and maintain high biological activity (permanent grass, application of FYM) increase the proportions of labile P. this is desirable for nutrition of crops but not to diminish leaching losses. |
| 777 | Leiva, F.R. & Morris, J. | Mechanisation and sustainability in arable farming in England | 2001 | Sustainability | Journal | J. Agr. Eng. Res.; 79 (1); | English | Hardcopy:Partial | Environmental, social and economic indicators, reflecting the direct and indirect effects of mechanisation, were used to assess the degree of sustainability of two large farms. | The study confirmed strong links between dominant mechanisation practices and the sustainability of arable farming, especially regarding environmental performance. While it was possible to identify .. mechanisation-related indicators which show the degree of sustainability of mechanised farming, it was not possible to define critical values for these indicators in order to determine whether or not mechanised practices were absolutely sustainable. |
| 594 | Lenssen, N. & Flavin, C. | Sustainable energy for tomorrow's world: the case for an optimistic view of the future | 1996 | Energy Resources | Journal | Energ. Policy; 24 (9); 769-781 | English | Hardcopy:Full | The IPCC (UN Intergovernmental Panel on Climate Change) and the WEC (World Energy Council) scenarios of future energy use are characterised as 'pessimistic', assuming as they do a continued reliance on fossil fuels and nuclear power and a failure to control CO2 emissions. An 'optimistic' scenario is described, in which nuclear power is abandoned, renewable energy sources provide 90% of the world's energy requirements by the year 2100 and the C emissions of the industrialised countries are halved by 2025. An assessment of the land requirements of electricity generation by renewable means is presented (but not of the world's resources of renewable energy). | |
| 866 | Letey, J., Sojka, R.E., Upchurch, D.R., Cassel, D.K., Olson, K.R., Payne, W.A., Petrie, S.E., Price, G.H., Reginato, R.J., Scott, H.D., Smethurst, P.J. & Triplett, G.B. | Deficiencies in the soil quality concept and its application | 2003 | Soil (General) | Journal | J. Soil Water Conserv.; 58 (4); 180-187 | English | Hardcopy:Partial | Review and critique of proposals to establish an index of soil quality | .. no unique functional relationship can be established between crop yield and soil texture, structure, strength, OM and other soil attributes. .. the approach is open to arbitrary value-laden judgements of individuals or groups of individuals.; The present soil quality definition,; The capacity of a specific kind of soil to function; , specifies that soils serve functions. We propose emphasising the 'use' rather than 'function' of soil. .. 'function implies a responsibility assigned to the soil. when one 'uses' soil, responsibility is on the user, which distinctly shapes the concept in a management context.; ..Sanchez .. and co-authors criticised the soil quality paradigm as misleading fad, lacking in scientific rigor, fraught with societal value intrusion and conceptually incompatible [with] air and water quality. |
| 231 | Letourneau, D.K., Drinkwater, L.E. & Shennan, C. | Effects of soil management on crop nitrogen and insect damage in organic vs. conventional tomato fields. | 1996 | Organic Farming | Journal | Agric. Ecosyst. Environ.; 57; 179-187 | English | Hardcopy:Partial | An inconclusive expt. in which tomato plants on 17 farms, some conventional, some organic, were examined for N level & insect damage to test the hypothesis that high N inputs can lead to herbivorous insect damage to crops. The results did not support this hypothesis, which conflicts with the findings of other workers. Various possible reasons are put forward for this conflict. Transplant date has a dramatic effect on insect damage. | However, damage to tomato foliage did not increase with increased N content of the crop. Instead, a weak negative correlation between tissue N and herbivory was detected. |
| 232 | Levi-Minzi, R., Riffaldi, R. & Saviozzi, A. | Carbon mineralisation in soil amended with different organic materials | 1990 | Compost & Biocontrol; Mineralisation; Soil Organic Carbon | Journal | Agric. Ecosyst. Environ.; 31 (4); 325-335 | English | Hardcopy:Partial | Expt. to determine the rate and extent of decomposition of 3 animal wastes (FYM, pig slurry and poultry manure), 2 urban wastes (sewage sludge and municipal refuse compost) and one crop residue (rye straw) in a sandy loam soil | The different rates of application used revealed the pronounced effect of straw on loss of native soil C. Farmyard manure and municipal refuse compost were found to be the materials most resistant to short-term decomposition. |
| 118 | Levy, M., Robinson, J.L. (eds.) | Energy and Agriculture: their Interacting Futures | 1982 | Energy in Agriculture | Book | ; Proc. U.N. university symposium on energy and agriculture futures, Paris; | English | In 1975 agriculture consumed about 3.5% of total global energy consumption (which was 5.7 TWyr/yr), including fertiliser and pesticide production. Of this about 0.1 TWyr/yr was consumed directly on the farm (2% - 5% for irrigation, 0% - 10% for grain drying and the rest for machinery). Only 10% of this direct energy is consumed in the less developed countries and 90% in the industrialised countries. The less developed countries also only consumed about 1/5th of the global total energy used in fertilisers etc. | ||
| 1097 | Lewis, N.G., Razal, R.A. & Yamamoto, E. | Lignin degradation by peroxidase in organic media: a reassessment | 1987 | Lignin and CBW | Journal | Proc. Natl. Acad. Sci. U. S. A.; 84 (22); 7925-7927 | English | Hardcopy:Full | Expt. to investigate the lignin-degrading capabilities of the enzyme ligninase isolated from the white-rot fungus Phanerochaete chrysosporium | .. previous studies using horseradish peroxidase in aqueous media .. concluded that, although internal rearrangement of the lignin substrate can occur, the net effect was not that of lignin depolymerisation.; .. the effect of peroxidase results only in internal rearrangement of the polymeric components and not in severe degradation of lignin. |
| 467 | Liang, B.C., McConkey, B.G., Campbell, C.A., Curtin, D., Lafond, G.P., Brandt, S.A. & Moulin, A.P. | Total and labile soil organic nitrogen as influenced by crop rotations and tillage in Canadian prairie soils | 2004 | Soil N Dynamics; Tillage | Journal | Biol. Fertil. Soils; 39 (4); 249-257 | English | Hardcopy:Partial | long-term field expts. to test the effect of tillage and crop rotations on SON and mineralisable N in the upper layer of a Chernozem. Compared with conventional, zero tillage increased SON by 16-40 kg N/ha/year. In some, but not all, soils tested the material responsible for increased SON due to zero tillage was more labile than the soil humus N and was associated with an increase in mineralisable N. | |
| 715 | Lichtfouse, E., Bardoux, G., Mariotti, A., Balesdent,J.,Ballentine, D. & Macko,S. | Molecular, 13C and 14C evidence for the allochthonous and ancient origin of C16-C18 n-alkanes in modern soils | 1997 | Soil Organic Carbon | Journal | Geochim. Cosmochim. Ac. ; 61 (9); 1891-1898 | English | Hardcopy:Partial; PDF:Full | Field expt. to elucidate the origin of n-alkanes in soil from a maize field | .. C16-C18 soil n-alkanes .. represent a regular input from an external source. Evidence of a large contribution of an ancient source, amounting to more than 65% of the alkane fraction, is given by a 14C-age of 8510 yrs BP. Moreover shortchain n-alkanes from soils, diesel fuel, diesel automobile exhaust and petroleum products exhibit similar distributions and 13C values. These findings suggest that C16-C18 soil n-alkanes represent a non-point-source pollution of ancient hydrocarbons, either carried by aerosols or entering the soil via continuous hydrocarbon seep. from the deep sedimentary rocks of the Paris basin. |
| 1731 | Lichtfouse, E., Dou, S., Giradin, C., Grbly, M., Balesdent, J., Behar, F. & Vandenbroucke, M. | Unexpected 13C-enrichment of organic components from wheat crop soils: evidence for the in situ origin of soil organic matter | 1995 | Uncategorised | Journal | Org. Geochem.; 23 (9); 865-868 | English | PDF:Full | ||
| 824 | Liebig, M.A. & Doran, J.W. | Impact of organic production practices on soil quality indicators | 1999 | Organic Farming; Soil (General) | Journal | J. Environ. Qual.; 28; 1601-1609 | English | Hardcopy:Partial | Study of five organic and five matched conventional farms to evaluate the effect of organic farming on soil quality indicators. The soil on organic farms had lower BD, higher available water capacity, soil respiration, microbial biomass C & N and total C & N than that on conventional farms. | .. there was 22% more organic C .. and 20% more total N on organic farms ..; Inconsistent trends between organic and conventional farms in soil NO3-N and P levels .. indicated that one production practice was not consistently better at minimising potential negative off-site impacts due to nutrient loss to the environment. |
| 323 | Ligneau, L.A.M. & Watt, T.A. | The effects of domestic compost upon the germination and emergence of barley and six arable weeds | 1995 | Compost & Biocontrol; Miscellaneous | Journal | Ann. Appl. Biol.; 126 (1); 153-162 | English | Hardcopy:Partial | Glasshouse expt. to test the effect of leachate from composted household waste on the germination and emergence of crops and weeds. BD of the compost used was 0.32. Reduction in weed emergence could be just due to thickness of compost layer on top of the soil. An earlier expt. had shown that composted FYM mulched on winter wheat and potatoes gave good weed control and improved crop establishment and yield. | .. household compost can successfully suppress the emergence of small-seeded arable weeds in cereals without affecting crop emergence. |
| 1557 | Lindstrom, M.J., Nelson, W.W. & Schumacher, T.E. | Quantifying tillage erosion rates due to mouldboard ploughing | 1992 | Soil (General); Tillage | Journal | Soil Tillage Res.; 24 (3); 243-255 | English | Hardcopy:Partial | Modelling the effect of 100 years of ploughing on soil erosion rates | .. a net loss of soil will occur on convex slope positions .., soil accumulation will occur in concave slope positions and little change occurs in linear slope positions regardless of .. gradient. Calculated average annual net soil movement rates away from convex slop position were up to 30 t ha-1 year-1 .. |
| 867 | Lindstrom, M.J., Schumacher, T.E., Cogo, N.P. & Blecha, M.L. | Tillage effects on water run-off and soil erosion after sod | 1998 | Soil (General); Tillage | Journal | J. Soil Water Conserv.; 53 (1); 59-63 | English | Hardcopy:Partial | A comparison of water run-off and soil erosion in grassland and two tillage systems. The effect on water run-of and soil erosion of simulated rainfall was measured on dry and wet soil under various managements, including ploughing, chiselling, zero tillage and grassland. On dry and wet soil the ploughing and chiselling treatments lost 6.7 and 18.2 t ha-1 and 1.7 and 2.7 t ha-1 soil respectively. The zero tillage and grassland lost 0 - 0.2 t ha-1 and zero soil respectively for both wet and dry treatments. So zero tillage conserves the low water run-off and soil erosion qualities of grassland. | No-till management has preserved the beneficial soil characteristics developed under a sod culture ..; Intensive tillage rapidly changes the physical state of the soil that has been in sod.; No-till avoids the rapid mineralisation of C and N that occurs with tillage.; No-till crop production did not have any water run-off and soil erosion. |
| 1442 | Linn, D.M. & Doran, J.W. | Effect of water-filled pore space on carbon dioxide and nitrous oxide production in tilled and nontilled soils | 1984 | Soil (General); Tillage | Journal | Soil Sci. Soc. Am. J.; 48 (6); 1267-1272 | English | Hardcopy:Full | Expt. to test the soil percentage water-filled pore space as a simultaneous measure of water content and air space in studies of aerobic microbial activity under different tillage treatments at four different locations (soils with BD of 0.9-1.35 (ploughed) and 1-1.45 (zero tillage) Mg/m3). Water-filled pore space was consistently higher in zero-tillage soils (by a factor of 1.1-1.8) and was found to be closely related to microbial activity as measured by CO2 or N2O production. CO2 production and O2 consumption was greatest at WFP = 60%. Oxygen and water were limiting when the WFP was above or below that respectively. Maximum N loss from denitrification occurred when the WFP exceeded 60%. | |
| 1593 | Lipton, M. | Energy and agriculture in poor countries | 1975 | Energy in Agriculture | Journal | Span; 18 (1); 17-18 | English | Hardcopy:Full | A review of agricultural development in poor countries in relation to energy consumption. Agricultural development in poor countries has concentrated on large farms. The food consumption of the poor has decreased. But the capital- and energy-intensive path pursued by the industrialised countries is unsuitable for poor nations. They need to concentrate on small labour-intensive farming. | For each pound sterling of value added, agriculture in poor countries uses less mineral energy than almost any activity and much less than heavy industry. Food farming uses less than non-food and subsistence farming least of all.; .. less of that food would consist of animal products, which are much less efficient than crops at converting energy and land into calories for people ..; .. the most effective way to help those who are deficient in protein is to provide cheap calories to enable them to stop diverting proteins for energy purposes. |
| 187 | Loake, C. | Energy accounting and well-being: examining UK organic and conventional farming systems through a human energy perspective | 2001 | Energy in Agriculture; Labour and Animal Power; Organic Farming | Journal | Agric. Sys.; 70 (1); 275-294 | English | Hardcopy:Full; PDF:Full | A comparison of the energy expenditure patterns of two local farmers - one organic and one conventional - with particular reference to the expenditure of human energy. | The energy budgets illustrate a clear difference in energy efficiency between the farms - the conventional farm has an energy efficiency of 0.43, the organic farm is approximately eight times more energy efficient that the conventional farm with an energy ratio of 3.4.; .. the organic farmer both expended more energy and worked at a higher effort intensity than the conventional.; .. this study has been unable to prove whether organic farming has negative effects [on] farmers, but has certainly placed a question mark over the healthfulness of this method of production. It has revealed an unfavourable ratio of human energy to total energy in the organic system. |
| 658 | Lobe, I., Preez, C.C. du & Amelung, W. | Influence of prolonged arable cropping on lignin compounds in sandy soils of the South African Highveld | 2002 | Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 53; 553-562 | English | Hardcopy:Full; PDF:Full | Expt. to study the fate of lignin from plant residues in arable soil and grassland (with bulk densities of 1.43 and 1.38 respectively). | Long-term arable cropping results in a 20-80% loss of SOM.; Intact lignin is insoluble. .. there is as yet no analytical method to determine accurately the absolute lignin content in mineral soil.; In particle-sized fractions ligninderived phenols showed a progressive degradation of lignin from sand to clay separates.; .. lignin is more resistant than other components of the labile pool of C in the soil.; .. loss rates of lignin followed those of bulk OM in the soil. .. dissipation time of lignin not only controls turnover rates of plant litter but also reflects that of the remaining constituents within a given pool of C, once the more labile parts have been degraded.; .. lignin in mineral fractions is also more rapidly lost upon decomposition than other, potentially more labile, compounds such as polysaccharides. .. the particulate nature of lignin might make it less prone to stabilisation by minerals. In addition lignin is not recycled and re-synthesised by microorganisms in the same way as polysaccharides and amino-acids are.; .. the decomposition of lignin is promoted in soils that are short of N and facilitated by small lignin/N ratios of the litter. |
| 1628 | Lochmann, G. | Moeglichkeiten eines biologischen Landbaus ohne Viehhaltung | 1985 | Stockless Farming | Book | Lochmann, G.; Moeglichkeiten eines biologischen Landbaus ohne Viehhaltung; | German | Hardcopy:Full | Four stockless organic holdings are studied from the point of view of N balance and financial viability. Only the holding with the highest legume content in the rotation had a positive N balance. Although the holdings were currently viable, the viability would gradually diminish with time. The conclusion is that the stockless organic system is, in the long term, unstable. | .. mu gefolgert werden, da die viehlose Wirtschaftsweise die Stabilitaet dieses Betriebssystems langfristig nicht aufrechterhalten kann. |
| 58 | Lockeretz, W. | Major issues confronting sustainable agriculture | 1990 | Sustainability | Book | Francis, C.A., Flora C.B. & King (ed.); Sustainable Agriculture in Temperate Zones; 423-438 | English | Hardcopy:Full | Sustainable agriculture is defined. The evolution of the concept of sustainable agriculture; some fundamental questions relating to the definition of sustainable agriculture. | .. sustainable may mean little more than good. If you like a particular practice, it's sustainable ..; Organic farmers .. do not automatically try to cut down on their use of all types of inputs. In fact, they may compensate by increasing their use of certain other inputs. For example, controlling weeds mechanically instead of with herbicides requires additional implements and fuel .. |
| 82 | Lockeretz, W., Klepper, R., Commoner, B., Gertler, M., Fast, S., O'Leary, D. & Blobaum, R. | Economic and energy comparison of crop production on organic and conventional corn belt farms | 1977 | Energy in Agriculture | Book | Lockeretz, W. (ed.); Agriculture and Energy; 85-101 | English | Hardcopy:Partial | The energy consumption on organic farms compared with conventional ones. Figures are presented for energy consumption, labour requirements, nutrient inputs and turnover for organic and conventional farms. | The organic group consumed appreciably less energy in crop production.; .. the organic farms appeared to be drawing on the reservoirs of P and K [in the soil].; The organic group required 12% more labour to produce $1 worth of crop. |
| 233 | Lockyer, D.R. | Methane emissions from grazing sheep and calves | 1997 | Greenhouse Gases; Stockless Farming | Journal | Agric. Ecosyst. Environ.; 66 (1); 11-18 | English | Hardcopy:Full | Expt. to measure CH4 emissions from grazing sheep and calves under natural conditions. Annual global emission of CH4 is 540 Tg, which constitutes 18% of total global warming potential and of which 15% is derived from the enteric fermentation of domestic animals. In the U.K. the annual emission of CH4 is 11.4 Tg, of which 37% is from agriculture, mainly ruminant animals. | .. with animals [sheep] ranging in age from 7 months to 4.5 years, emission of CH4 averaged 13.3 g day-1 per animal, equivalent to 4.9 kg year-1 per animal.; .. it is estimated that the total UK sheep population could contribute 247 kt of CH4 annually to the atmosphere.; [with] calves, CH4 emissions averaged 74.5 g day-1 per animal .. |
| 234 | Lockyer, D.R. & Champion, R.A. | Methane production by sheep in relation to temporal changes in grazing behaviour | 2001 | Greenhouse Gases; Stockless Farming | Journal | Agric. Ecosyst. Environ.; 86; 237-246 | English | Hardcopy:Partial | Experiment to measure the CH4 exhaled by sheep under differing grazing conditions. CH4 contributes 18% to global warming and is second only to CO2 in its greenhouse effect. It has 25 times more infra-red absorbing capability than CO2. Worldwide, agriculture contributes 15% of the total CH4 emissions (about 540 Tg per annum), mainly from ruminant animals. In the UK the figure is as high as 37% of a total annual CH4 emission of 4.2 Tg, of which sheep contribute 18%. | |
| 603 | Lockyer, D.R. & Jarvis, S.C. | The measurement of methane losses from grazing animals | 1995 | Greenhouse Gases; Stockless Farming | Journal | Environ. Pollut.; 90 (3); 383-390 | English | Hardcopy:Partial; PDF:Full | Expt. to test a new method of measuring CH4 exhalation from grazing sheep | emission of CH4 averaged 14 g day-1 per animal, equivalent to 5.1 kg year-1 per animal. These rates, although lower than some estimates, confirm that CH4 emission from sheep forms a significant proportion of the total CH4 emissions currently attributed to UK agriculture. |
| 100 | Loges, R., Kaske, A. & Taube, F. | Dinitrogen fixation and residue nitrogen of different managed legumes and nitrogen uptake of subsequent winter wheat | 1999 | Green Manure; Soil N Dynamics | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to compare the effects of different management (cropping v. cut-andmulch) and species (red & white clover & lucerne) of green manure on the N supply to the following wheat crop | Cropped grass/legume reached higher N2-fixation than mulched. While green-manure grass-legume left up to 280 kgN ha-1 in mulch, stubble & roots on the field, most cropped grass/legume mixtures left <110 kg N ha-1 in crop residues. Pure legume swards or legume-rich mixtures showed higher N2-fix'n than grass-rich mixtures. |
| 62 | Loges, R., Taube, F. | Ertrag und N-Fixierungsleistung unterschiedlich bewirtschafteter Futterleguminosenbestaende | 1999 | Green Manure; Stockless Farming | Book | Hofmann, H. & Mueller, S. (hgbr); Vom Rand zur Mitte: Beitraege zur 5. Wissenschaftstagung zum oekologischen Landbau, Berlin; 101-104 | German | Hardcopy:Full | Trials were carried out to assess the N-fixing performance of various leguminous green crops in relation to various factors, particularly whether or not grass was included in the seed mixture and whether the crop was harvested or just cutand-mulched. The results showed the great advantage of harvesting (done 4 times a year) over cut-and-mulching (done twice a year) in regard to N fixing, giving about twice the level of fixation. Including grass in the mixture gave a substantially higher DM yield (15-25% higher than the pure stand), although the N fixation was about the same. Red clover was only slightly better than lucerne in respect of DM and N fixing, while both were much better than white clover. The figures for green manure yield (tons/ha) were 9.85, 9.07, 6.31, 12.76 and 4.58 and, for N fixing (kg/ha), 254.5, 246.3, 220.6, 248.0 and zero for red clover, lucerne, white clover, red clover/grass and grass alone respectively. | |
| 696 | Lopez-Bellido, L., Lopez-Bellido, R.J. & Redondo, R. | Nitrogen efficiency in wheat under rainfed Mediterranean conditions as affected by split nitrogen application | 2005 | Miscellaneous; Soil N Dynamics | Journal | Field Crops Res.; 94 (1); 86-97 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the nitogren use efficiency of wheat when fertiliser application is one-off and when it is split three ways | Mean wheat use of N fertiliser ranged from 14.1% when applied at sowing to 54.8% when applied as a top dressing at the beginning of stem elongation. The mean annual contribution of soil residual N and mineralisation was 152 kg N ha-1, representing a considerable proportion of total wheat N uptake, ranging from 83.2% when N fertiliser was applied in the autumn to 49.4% when it was applied at stem elongation. .. Application of N fertiliser to wheat, preferably as a top dressing, between tillering & stem elongation, is a strategy to be recommended. |
| 695 | Lopez-Bellido, R.J. & Lopez-Bellido, L. | Efficiency of nitrogen in wheat under Mediterranean conditions: effect of tillage, crop rotation and N fertilisation | 2001 | Miscellaneous; Soil N Dynamics | Journal | Field Crops Res.; 71 (1); 31-46 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the nitrogen use efficiency (NUE) of wheat crops with various fertiliser rates, tillage systems and rotations | Soil [nitrate] & mineralised N content were not influenced by the tillage system employed... NUE .. were also greater using CT than NT... yield was higher for all rotations than for wheat monoculture. Continuous wheat gave the lowest value for NUE, whilst the WS [wheat-sunflower] rotation was the most efficient, since the two crops complement each other perfectly in terms of water and N use. Wheat yield showed no additional response to fertiliser rates over 100 kg N ha-1. |
| 745 | Lorenz, K., Lal, R., Preston, C.M. & Nierop, K.G.J. | Strengthening the soil organic carbon pool by increasing contributions from recalcitrant aliphatic bio(macro)molecules | 2007 | Soil Organic Carbon | Journal | Geoderma; 142; 1-10 | English | Hardcopy:Full; PDF:Full | Review of current knowledge of the contribution of aliphatic macromolecules to the SOC pool | Biomacromolecules in soils are stabilised against biodegradation by selective preservation due to biochem. recalcitrance & physical protection. The chemical recalcitrance may be an inherent property of the molecular structure (e.g. alkyl C chains in lipids, aromatic structures in aromatics & phenolics), but can also be attained through formation of cross-linkages between biomacromolecules, which inhibits enzymatic degradation, and by non-enzymatic polymerisation of lowmolecular-weight compounds into macromolecules.; .. increasing the SOC pool by land-use and management practices should also include strategies to increase the proportion of aliphatic compounds in the belowground biomass. |
| 904 | Losey, J.E., Rayor, L.S. & Carter, M.E. | Transgenic pollen harms monarch larvae | 1999 | Miscellaneous; Organic Farming | Journal | Nature (Lond.); 399; 214 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the effect of pollen from genetically modified maize on the larvae of monarch butterflies | Bt maize plants might represent a risk because most hybrids express the Bt toxin in pollen and maize pollen is dispersed over at least 60 metres by wind.; Larval survival (56%) after four days of feeding on leaves dusted with Bt pollen was significantly lower than survival either on leaves dusted with untransformed pollen or on control leaves with no pollen (both 100%). ... there was no mortality on leaves dusted with untransformed pollen ... |
| 111 | Loucks, O. | Pattern of forest integrity in the eastern U.S. and Canada: measuring loss and recovery | 2000 | Miscellaneous; Sustainability | Book | Pimentel, D., Westra, L. & Noss, R.F. (eds.); Ecological Integrity: Integrating Environment, Conservation & Health; | English | Hardcopy:Partial; Wordperfect:Full | Review of the decline in primary production in N. American forests | The large-scale state-wide decline in forest growth over nearly 20 years in West Virginia is . from 2.64%/yr to 0.33%/yr, the latter 14% of the original |
| 1559 | Loveland, P. & Webb, J. | Is there a critical level of organic matter in the agricultural soils of temperate regions: a review | 2003 | Soil Organic Carbon | Journal | Soil Tillage Res.; 70 (1); 1-18 | English | Hardcopy:Partial; PDF:Full | A review of the quantitative exptal evidence for the existence of an OM threshold level, below which a potentially serious decline in soil quality will occur | Although soil scientists would expect to find different behaviour in different soils at different critical concentrations of SOM, it seems widely believed that a major threshold is 2% SOC (ca. 3.4% SOM) ..; the quantitative evidence for such thresholds is slight, although there is some evidence that there might be a desirable range of SOC covering a wide spectrum of soils ..; There is also little quantitative evidence that reduction in SOC concentrations in the soils of England and Wales will have marked effects on other soil properties or crop yields. |
| 138 | Loveland, P., Webb, J. & Bellamy, P. | Critical levels of soil organic matter: the evidence for England and Wales | 2001 | Soil Organic Carbon | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Review of the evidence for and against the existence of a critical threshold for SOM content | .. there is little consistent evidence that there are critical thresholds of SOC above or below which soil physical properties change significantly; there isa growing body of evidence that the active fraction of SOM is a more important factor in controlling change in soil props than total SOM, but there are insufficient data for the amounts and kind of active SOM for soils in the UK to [allow] firm conclusions about the magnitude of its affect on soil behaviour; there are insufficient data to explore thoroughly the relationships and interactions between other factors which affect soil physical behaviour.. |
| 468 | Luca, T.H. de, Drinkwater, L.E., Wiefling, B. & Nicola, D.M. de | Free-living nitrogen-fixing bacteria in temperate cropping systems: influence of nitrogen source | 1996 | Organic Farming; Soil Microorganisms; Soil N Dynamics | Journal | Biol. Fertil. Soils; 23(2); 140-144 | English | Hardcopy:Partial | Comparison of free-living N-fixing bacteria popul'ns in 3 plots fertilised with chemicals, FYM & leguminous green manure gave inconclusive results. | |
| 590 | Ludwig, B. | On the sustainability of future energy systems | 1997 | Energy Resources | Journal | Energy Convers. Manage.; 38 (15/17); 1765-1776 | English | Hardcopy:Full | A method of technology assessment based on fuzzy logic is presented and applied to energy conversion technologies, taking into account environmental aspects. The method is applied to assessing the sustainability of four primary energy carriers - coal, solar power, uranium and fast-breeder reactors. The method comes out with a similar categorisation of solar power and fast breeder reactors. | |
| 659 | Ludwig, B., John, B., Ellerbrock, R., Kaiser, M. & Flessa, H. | Stabilization of carbon from maize in a sandy soil in a long-term experiment | 2003 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 54; 117-126 | English | Hardcopy:Full; PDF:Full | Field expt. to study the study the carbon dynamics in soil under long-term maize cropping | The amounts of C derived from maize .. after 39 years of continuous maize cropping were 9.5% of the total OC (where unfertilised) and 14.0% (where NPK had been applied). Fertilisation did not affect the residence time of carbon in the soil. The amounts of C derived from maize in water extracts were 21% of the total OC (where unfertilised) and 22% (where NPK had been applied).; .. 64% (unfertilised) or 53% (NPK) of the OC in the Ap horizon were inert. |
| 548 | Ludwig, D. | The end of the beginning | 1996 | Sustainability | Journal | Ecol. Appl.; 6 (1); 16-17 | English | Hardcopy:Full | Review of the paper by Arrow et al. (1995) 'Economic growth, carrying capacity and the environment' | .. human population size and the rate of consumption of resources will ultimately be limited. Either we will limit growth in ways of our choosing or it will be limited in ways that are not of our choosing.; .. our dependence upon the environmental resource base cannot be changed. There is no technological fix that will enable the present pattern of consumption to continue indefinitely .. What can and will be changed is ourselves. How will that change be made? Will it be the result of conscious choice .. or .. a result of our inability to adapt? |
| 1623 | Luetzow, M. von & Ottow, J.C.G. | Einfluss von konventioneller und biologisch-dynamischer Bewirtschaftungsweise auf die mikrobielle Biomasse und deren Stickstoff-Dynamik in Parabraunerden der Friedberger Wetterau | 1994 | Organic Farming; Soil Microorganisms; Soil N Dynamics | Journal | Z. Pflanz. Bodenkunde; 157; 359-367 | German | Hardcopy:Partial | Study of organic (biodynamic) and conventional farms with particular reference to the microbial biomass and the N dynamics in the soil. The rate of turnover of biomass C is much higher and of biomass N slightly higher on the conventional farm than on the organic one. The variation in the biomass C/N ratio shows that the N-content of the microorganisms changes according to the N supply. The sharp increase in biomass on all fields during plant growth may be ascribed to increased rhizodeposition. | |
| 353 | Lupwayi, N.Z., Arshad, M.A., Rice, W.A. & Clayton, G.W. | Bacterial diversity in water-stable aggregates of soils under conventional and zero tillage management | 2001 | Soil Microorganisms; Tillage | Journal | Appl. Soil Ecol.; 16 (3); 251-261 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the influence of tillage on bacterial diversity in soil | The diversity of soil bacteria was greater under ZT than under CT & greater in larger soil aggregates than in smaller aggregates during the crop cycle... microbial biomass and mineralisable C are greater in larger soil aggregates than in smaller aggregates, due to protection of organic C by soil aggregates ... CT results in smaller soil aggregates compared with ZT. .. soil tillage may adversely affect soil microbial dynamics through, amongst other factors, deterioration of soil structure. |
| 1304 | Lynch, D.H., Voroney, R.P. & Warman, P.R. | Use of 13C and 15N natural abundance techniques to characterise carbon and nitrogen dynamics in composting and in compost-amended soils | 2006 | Compost & Biocontrol; Soil Microorganisms | Journal | Soil Biol. Biochem.; 38 (1); 103-114 | English | Hardcopy:Partial; PDF:Full | Field expt. to test the use of 13C and 15N natural abundance techniques as a means of studying C and N dynamics during composting and in compost-amended soil | [title contd.: in composting and in compost-amended soils]; C, N, 13C and 15N content were monitored during nine months covered (thermophilic; >40$C) composting of maize silage. The C concentration was reduced from 10.34 to 1.73 g C (g ash)-1 or 83.3% during composting. N losses comprised 28.4% of initial N content.; One and two years after application [of compost to soil, 95 and 89% (maize silage compost), 75 and 63% (sewage sludge compost) and 88 and 42% (dairy manure compost) of applied compost C remained in the soil, with the majority (80-90%) found in particulate (>53 m) and light fractions. However, C4 compost (CSC) was readily detectable (12% of compost C remaining) in mineral (<53 m) fractions. .. We can conclude that composts are highly recalcitrant with prolonged C storage in non-mineral soil fractions. |
| 1305 | Lynch, J.M. & Panting, L.M. | Cultivation and the soil biomass | 1980 | Soil Microorganisms; Tillage | Journal | Soil Biol. Biochem.; 12 (1); 29-33 | English | Hardcopy:Full | Field expt. to study the effects of tillage on soil biomass | The biomass was significantly greater [by, on average, 25%] where the soil had been direct-drilled than where it had been ploughed, probably because plant roots were more abundant after direct drilling.; The biomass evidently remains at a fairly constant amount until the spring, when .. it increases to a maximum around June .. |
| 1306 | Lynch, J.M. & Panting, L.M. | Variations in the size of the soil biomass | 1980 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 12 (6); 547-550 | English | Hardcopy:Full | Field expt. to study the biomass in soils under differing management. Biomass was ca.15% lower in zero-tilled than in ploughed arable soils. Increase in root density promotes microbial growth. | Where the soil has been kept in grass for 9 years, the biomass was greater by a factor of three than that in soil of the same kind that had been in arable cultivation for the previous 4 years.; Over 2 years the organic C content of the surface 5 cm .. was consistently greater in the direct-drilled .. than in the ploughed .. soils. |
| 1056 | Lynch, J.M. & Whipps, J.M. | Substrate flow in the rhizosphere | 1990 | Roots & Rhizodeposition | Journal | Plant Soil; 129; 1-10 | English | Hardcopy:Full | Review of current knowledge of the C dynamics of the rhizosphere. Rhizodeposition consists of: 1. lysates from the autolysis of root cells, including sloughed-off root-cap cells, root cortical tissue and senescent whole roots; 2. secretions, such as enzymes and polymeric carbohydrates, which depend on metabolic processes for their release; 3. water-soluble exudates, such as sugars, amino-acids, organic acids and hormones, which leak from the roots without the use of metabolic energy; 4. gases such as ethylene and CO2. The bacterial population of the rhizosphere is up to ten times larger than would be expected from the mass of rhizo-deposited substrate. This may be due to the occurrence among the microbial population of dormancy, cryptic growth (organisms living off dead cells) and oligotrophy (organisms living off very low C inputs derived directly from the air). | |
| 306 | Lääniste, P., Jőudu, J. & Eremeev, V. | Oil content of spring oilseed rape seeds according to fertilisation | 2004 | Rape and Biodiesel | Journal | Agron. Res.; 2 (1); 83-86 | English | Hardcopy:Full | Field expt. to study the effect on the oil content of rape seeds of fertilising with different micronutrients. The soil used had 2.4% OM and 78 mg/kg available P. Mg and Mn were the only micronutrients that significantly increased oil content. | Growing of one ton of .. rape requires 55 kg of N, 25 kg of P, 50 kg of K and 20 kg of S. Besides principal mineral fertilisers, rape is very exacting to microelements as well: it needs 3-5 times more Ca, B, Mg and Mn than corn.; .. oil content in the seeds dry matter was 40.7-44.5% in different variants. |
| 1558 | López-Bellido, L., López-Garrido, F.J., Fuentes, M., Castillo, J.E. & Fernández, E.J. | Influence of tillage, crop rotation and nitrogen fertilisation on SOM and nitrogen under rain-fed Mediterranean conditions | 1997 | Soil Organic Carbon; Soil N Dynamics; Tillage | Journal | Soil Tillage Res.; 43; 277-293 | English | Hardcopy:Partial | A six-year inconclusive expt. to study the SOM and mineral N content under various two-course wheat rotations and various tillage regimes. | Continuous no-tillage in Mediterranean Vertisols under rain-fed conditions did not increase the OM and the extractable mineral N content of the soil after six years. .. [there is a] need for a longer period so that any significant changes in the OM and N content in the soil may be observed. |
| 660 | Lützow, M. von, Kögel-Knabner, I., Ekschmitt, K., Matzner, E., Guggenberger, G., Marschner, B. & Flessa, H. | Stabilisation of organic matter in temperate soils: mechanisms and their relevance under different soil conditions - a review | 2006 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 426-445 | English | Hardcopy:Full; PDF:Full | Review of the mechanisms for the stabilisation of organic matter in soils | ... our analysis of mechanisms shows that: (i) the soil biotic community is able to disintegrate any OM of natural origin; (ii) molecular recalcitrance of OM is relative, rather than absolute; (iii) recalcitrance is only important during early decomposition and in active surface soils; (iv) during late decomposition and in the subsoil, the relevance of spatial inaccessibility and organo-mineral interactions for SOM stabilisation increases. We conclude that major difficulties in the understanding and prediction of SOM dynamics originate from the simultaneous operation of several mechanisms. |
| 296 | Ma, L., Peterson, G.A., Ahuja, L.R., Sherrod, L.A., Shaffer, M.J. & Rojas, K.W. | Decomposition of surface crop residues in long-term studies of dry-land agroecosystems | 1999 | Soil (General) | Journal | Agron. J.; 91; 401-409 | English | Hardcopy:Partial | 13-year field expt. to study and model the decomposition of crop residues on the surface of the soil | Douglas & Rickman (1992) assumed a first-order decay of crop residues .. based on cumulative degree-days and the rate constant was related to residue initial N content and average moisture condition. .. They found that a two-stage decomposition model was better for buried residues and a one-stage .. for aboveground and surface residues.; Stott et al (1990) monitored surface residues .. and found that 35-42% of residue weight was lost in 30 weeks. |
| 1390 | MacCarthy, P. | The principles of humic substances | 2001 | Soil Organic Carbon | Journal | Soil Sci.; 166 (11); 738-751 | English | Hardcopy:Partial | Review of current state of knowledge of humic substances | Humic substances are .. a category of .. biogenic heterogeneous organic substances that can generally be characterised as being yellow-to-black in colour, of high molecular weight and refractory.; The word humus is often used synonymously with humic substances ..; .. it is a challenge to identify the point in the decay process at which the transition from non-humic to humic substance has occurred.; Humic substances comprise an.. amorphous mixture of .. chemically reactive yet refractory molecules produced during .. the decay of bio-matter ..; .. humic substances can serve as a reservoir for holding micronutrients in the soil .. contribute to the acid-base buffering ability of soils .. are able to bind mineral particles together .. contributing to .. dissolution of minerals, binding of small organic molecules, reduction of metal ions and mediating as an electron shunt in microbial and abiotic redox reactions.; In contrast to the highly specialised and individualised roles of molecules in biological processes, the functions of humic substances .. do not necessitate the participation of specific molecules of uniquely defined molecular structures. |
| 274 | Mafongoya, P.L., Giller, K.E. & Palm, C.A. | Decomposition and nitrogen release patterns of tree prunings and litter | 1998 | Lignin and CBW; Soil Organic Carbon; Soil N Dynamics | Journal | Agrofor. Syst.; 38; 77-97 | English | Hardcopy:Full; PDF:Full | Review of research into the factors affecting the rate of decay and N release from prunings of agroforestry trees. Of the 27 tree species reviewed all but four were legumes. The C/N ratio of their litter varied between 10 and 25 (14 and 32 for the non-leguminous species). | Only about 20% of the N released from tree prunings or litter is taken up by the current crop. Much of the remaining 40% to 80% of the applied organic N is incorporated into SOM.; Soluble C .. is the most important plant constituent in determining immediate patterns of nutrient release, microbial growth and activity and perhaps rates of nutrient cycling. [It] varies depending on the species, plant part & plant's stage of maturity. Green foliage usually contains 20% to 30% soluble C, much of which can be polyphenols.; .. where green foliage is applied to the soil, the soluble forms of C (including polyphenols) .. will .. have a dominating influence on microbial growth and activity and net nutrient mineralisation or immobilisation.; .. materials with N conc'ns greater than 20 mg g-1 [C/N = 20] are considered of high quality, although this can be modified by high lignin and polyphenol contents.; .. the (polyphenol+lignin)/N ratio seems to be the most robust indicator to predict mass loss and nutrient release ..; The long-term effects of building up SOM pools may be more important .. than short-term nutrient release patterns.; Incorporation of prunings into the soil also results in faster decomposition .. [and] results in a bacterial dominated community, while fungi dominate with surface placement. |
| 1308 | Magid, J., Cadisch, G. & Giller. K.E. | Short and medium term plant litter decomposition in a tropical Ultisol elucidated by physical fractionation in a dual 13C and 14C isotope study | 2002 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 34 (9); 1273-1281 | English | Hardcopy:Partial; Wordperfect:Full | Expt'l study of plant litter decomposition using 13C natural abundance and labelling with 14C | C/N ratios tended to decrease with decreasing size of the fractions and increasing density from 37 in the lightest coarsest fraction to 8 in the finest heaviest fraction .. indicating increased decomposition and chemical stabilisation of the C initially present The C/N ratio of the heavy fractions >1.6 g cm-3 smaller than 100 m was between 8 and 13, close to the C/N ratio of SOM indicating an advanced stage of decomposition.; Microorganisms and microbial metabolites tend to be associated with fine organo-mineral fractions .., as indicated by the relationship of C/N ratio with particle size and density. |
| 1309 | Magid, J., Gorissen, A. & Giller, K.E. | In search of the elusive 'active' fraction of soil organic matter: three size-density fractionation methods for tracing the fate of homogeneously 14C-labelled plant materials | 1996 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 28 (1); 89-99 | English | Hardcopy:Partial; PDF:Full | Expt. to study size and density methods of fractionating SOM after amendment with ryegrass shoots, which normally had a C/N ratio of 18, but 37 when grown in an atmosphere enriched with CO2. | Fractionation by size and density thus seems a more powerful approach for separating SOM fractions than fractionation based on density alone.; .. the most important substrates were soluble and non-complexed macro-OM, but not C associated with fine particles. .. We set out to examine the active SOM fractions. However, the added 14C-labelled plant material was utilised preferentially by the soil microorganisms and thus the breakdown of native SOM cannot be elucidated directly from these data.; .. the clay and silt fractions contain both very old and young OM, as was indicated in our results .. Thus the; active; fractions of native SOM are probably distributed among particles of various size and density and an isolatable active fraction is likely to remain elusive. |
| 1057 | Magid, J., Henriksen, O., Thorup-Kristensen, K. & Mueller, T. | Disproportionately high N-mineralisation rates from green manures at low temperatures: implications for modelling and management in cool temperate agroecosystems | 2001 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 228; 73-82 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the decomposition of legumes in soil at low temps | [title contd.: modelling and management in cool temperate agroecosystems]; There was a strong temp effect on the rate of CO2 evolution .. there was no concomitant retardation of N mineralis'n at low temps.; .. an important factor is a decrease in the bioavailability of C-rich polymers at low temps and thus a preferential utilisation of N-rich low molecular substances. Nitrification was not effectively deterred at 3$C.; The rapid release of N means that it is very important not to incorporate the plant material too early, as leaching loss of mineralised N may then occur. This is exacerbated by the apparent substantial nitrification occurring even at 3$C. .. a late incorporation should allow sufficient time for N mineralis'n to become available for the subsequent crop. |
| 1310 | Magid, J., Jensen, L.S., Mueller, T. & Nielsen, N.E. | Size-density fractionation for in situ measurements of rape straw decomposition: an alternative to the litter-bag approach? | 1997 | Lignin and CBW; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 29 (1); 1125-1133 | English | Hardcopy:Partial; PDF:Full | Field expt. to see whether measurements of soil POM could replace the conventional litter-bag method for study litter decomposition | During the first 4 months the POM in the amended treatments decreased quite rapidly and more slowly during the remaining 16 months. By separating the total POM into light (# <1.4 g cm-3) and heavy (# >1.4 g cm-3) fractions, further resolution of the residue decomposition was possible. The heavy fraction C was completely unaffected by the application of residues and apparently consisted mainly of native OM with a low rate of decay. The differences in POM between treatments could be attributed completely to differences in the light POM fraction. .. in light fractions .. cellulose was preferentially utilised in the early stages of decompos'n... the initial lignin conc'n was high in the light fraction (20%) compared with that of the rape straw (15%). Thus the native light fraction must have been rich in lignin... The estimates of decompos'n from POM were in qualitative agreement with estimates of decompos'n based on field scale CO2 fluxes, but indicated a considerably higher turnover in the initial phase |
| 1732 | Magid, J., Neergaard, A. de & Brandt, M. | Heterogeneous distribution may substantially decrease initial decomposition, long-term microbial growth and N-immobilization from high C-to-N ratio resources | 2006 | Uncategorised | Journal | Eur. J. Soil Sci.; 57; 517-529 | English | PDF:Full | ||
| 1733 | Magill, A.H. & Aber, J.D. | Long-term effects of experimental nitrogen additions on foliar litter decay and humus formation in forest ecosystems | 1998 | Uncategorised | Journal | Plant Soil; 203; 301-311 | English | PDF:Full | ||
| 275 | Main, A.R. | How much biodiversity is enough? | 1999 | Sustainability | Journal | Agrofor. Syst.; 45 (1-3); 23-41 | English | Hardcopy:Partial; PDF:Full | Review of the role of biodiversity in the concept of agriculture as a mimic of nature | Subsistence farmers seek to avoid starvation and so adopt a risk-averse strategy, which tends to ensure that regardless of the fluctuation between seasons some crops will yield a harvest. The mimicry of nature is very close. .. industrial .. farming seeks to maximise yield through an emphasis on monocultures. This is a high-risk strategy if environments are unpredictable.; .. weeds or pests .. are modern examples of the response of nature to reduced biodiversity or the availability of unexploited or poorly exploited resources. .. when production is left unused, the system is open to invasion.; .. such socalled [eco-system] functions are the incidental consequences of the organisms present making a living. The temptation to see the perceived function as in some sense meeting design criteria must be resisted. Agriculture on the other hand is different. It is all about meeting design criteria. |
| 1657 | Makhijani, A. & Poole, A. | Energy and Agriculture in the Third World | 1975 | Energy in Agriculture | Book | Makhijani, A., Poole, A.; Energy and Agriculture in the Third World; | English | Hardcopy:Partial | A study of energy inputs into agriculture in various third-world communities. Some useful tables of energy inputs and crop yields and a comparison of six different communities. | The use of animals to supplement human labour .. increases energy use per unit of land, but tractors, when used as a substitute for animal labour, decrease the energy requirements. |
| 1020 | Malagoli, P., Laine, P., Le Deunff, E., Rossato, L., Ney, B. & Ourry, A. | Modelling nitrogen uptake in oilseed rape cv. Capitol during a growth cycle using influx kinetics of root nitrate transport systems and field exptal data | 2004 | Rape and Biodiesel; Soil N Dynamics | Journal | Plant Physiol. (Rockv.); 134; 388-400 | English | Hardcopy:Partial | Modelling the nitrate uptake of rape plants | .. the high-affinity transport system accounted for about 89% of total NO3- uptake (18% and 71% for constitutive .. and inducible high-affinity transport systems respectively) when no fertiliser was applied. The low-affinity transport system accounted for a minor proportion of total N uptake and its activity was restricted to the early phase of the growth cycle. .. N fertilisation in spring increased the duration of its contribution to total N uptake. |
| 1098 | Malloch, D.W., Pirozynski, K.A. & Raven, P.H. | Ecological and evolutionary significance of mycorrhizal symbioses in vascular plants | 1980 | Soil Microorganisms | Journal | Proc. Natl. Acad. Sci. U. S. A.; 77 (4); 2113-2118 | English | Hardcopy:Full | A review of the literature on mycorrhizae | About four fifths of all land plants form endo-mycorrhizae, whereas several groups of trees and shrubs .. form ecto-mycorrhizae. Among legumes Papilionoideae and Mimosoideae have endo-mycorrhizae and usually form bacterial nodules.; .. ecto-mycorrhizae are unknown in monocots.; Orchids are obligately mycotrophic; in nature their seeds will germinate only in the presence of suitable fungi. The orchidaceous mycorrhiza is unique because the endophytic fungus also supplies the plant with C at least during the orchids's heterotrophic seedling stage.; Most woody plants require mycorrhizae to survive and most herbaceous plants need them to thrive.; ectotrophic mycorrhizae confer a selective advantage on their phytobionts .. in extreme environments, perhaps from their direct role in breaking down leaf letter and more specialised and controlled recycling of nutrients to the plants concerned. The mycobionts may have the ability, lacking in the phytobionts, to utilise organic N taken directly from decaying leaves or ammonia-rich soils. |
| 1606 | Mankin, K.R., Ward, A.D. & Boone, K.M. | Quantifying changes in soil physical properties from soil and crop management: a survey of experts | 1996 | Soil (General); Tillage | Journal | Trans. ASAE (Am. Soc. Agric. Eng.); 39 (6); 2065-2074 | English | Hardcopy:Partial | Survey of the effects of soil and crop management on soil physical properties carried out among U.S. soil experts | If SOM is high, tillage causes a rapid decline and NT causes a modest increase. If SOM is low, tillage results in a small continuous decline, whereas NT results in a relatively large rapid increase.; Tillage creates macropores; traffic and weather reduce them; . |
| 705 | Mansson, K.F. & Falkengren-Grerup, U. | The effect of nitrogen deposition on nitrification, C and N mineralisation and litter C/N ratios in oak (Quercus robur L.) forests | 2003 | Mineralisation; Soil N Dynamics | Journal | For. Ecol. Manag.; 179 (1-3); 455-467 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study N dynamics in soil from an oak forest | In the present study deciduous forest soils dominated by Q. robur were used. These soils have a high OM turnover with no humus layer and a thin litter layer that often is almost completely decomposed before the next autumn leaf-fall. .. there are no distinct organic layers in these soils.; Micro-organisms must be N limited to respond to N addition by increased decomposition rate and an increase in respiration. .. in most forest ecosystems heterotrophic microorganisms are generally considered to be limited by C and would consequently not be favoured by additions of N.; Our observation that N addition is associated with somewhat enhanced soil respiration is in agreement with the general experience of litter decomposition as long as easily degradable C sources such as cellulose and hemicellulose are available, while negative effects have most often been found in recalcitrant materials in the later stages |
| 160 | Mansvelt, J.D. van, Mulder, J.A., Lenstra, G., Nierop, H.C. van & Buys, J. | The place of ruminants in a sustainable agriculture: food production and land use: necessity or added value? | 1994 | Stockless Farming | Book | ; Congress lectures 31st World Vegetarian Congress, The Hague, Holland ; | English | Hardcopy:Full | The advisability and feasibility of stockless farming is discussed, taking into consideration human dietary requirements and animal welfare as well as agronomic factors. Food autonomy models for the Netherlands and Mali are developed under conventional, lacto-vegetarian, vegan and mixed farming regimes. | |
| 605 | Marland, G., Fruit, K. & Sedjo, R. | Accounting for sequestered carbon: the question of permanence | 2001 | Greenhouse Gases; Soil Organic Carbon | Journal | Environ. Sci. Policy; 4; 259-268 | English | Hardcopy:Partial; PDF:Full | Review of methods of accounting for carbon sequestered in soil under the Kyoto agreement | ... using C sinks in the terrestrial biosphere to offset emissions from other sources has been criticised on several grounds ... it has been suggested that sequestering C in the biosphere might be different from reducing greenhouse gas emissions from fossil fuels in three fundamental ways:; If activities succeed in increasing the C in the biosphere, will it stay there (the permanence issue)? If activities succeed in increasing the rate of C accumulation in the biosphere, how long will it be possible to continue at the increased rate (the saturation issue)? If activities succeed in increasing C stocks in the biosphere, is it possible to accurately ... measure and affirm that it has been done (the verifiability issue)?; ... saturation and verification ... do not seem to raise compelling questions unique to land-use change and forestry activities. The fundamental issue that is unique to sequestration projects is the one of permanence. |
| 588 | Marland, G., Garten, C.T., Post, W.M. & West, T.O. | Studies on enhancing carbon sequestration in soils | 2004 | Greenhouse Gases; Soil Organic Carbon; Tillage | Journal | Energy; 29; 1643-1650 | English | Hardcopy:Full; PDF:Full | Review of current research on C sequestration in soils | On average a change from conv'l tillage to no-till agriculture .. resulted in a C sequestration rate of 570140 kg C ha-1 yr-1. Rates of C sequestration .. are predicted to reach a maximum in 5-10 years and decline toward 0 kg C ha-1 yr-1 in 15-20 years as a new steady state for soil C is approached.; .. the duration of sequestration following an enhancement in rotation complexity is longer (4060 yrs) than that for a decrease in tillage..; .. the C sequestered in soil is supplemented by 46 kg C ha-1 yr-1 of avoided emissions because of decreased fuel use .. & is offset by 13 kg C ha-1 yr-1 of additional emissions off-farm because of increased use of agricultural inputs like fertiliser and pesticides. |
| 1598 | Marland, G., West, T.O., Schlamadinger, B. & Canella, L. | Managing soil organic carbon in agriculture: the net effect on greenhouse gas emissions | 2003 | Greenhouse Gases; Soil Organic Carbon; Tillage | Journal | Tellus; 55B; 613-621 | English | Hardcopy:Partial; PDF:Full | Modelling the net emission of greenhouse gases from agriculture | A change from conventional tillage to no-till agriculture .. will result in net C sequestration in the soil that averages 337 kg C ha-1 yr-1 for the initial 20 yr, with a decline to near zero in the following 20 yr & continuing savings in CO2 emissions because of reduced use of fossil fuels. The long-term results .. can generally be expected to show decreased net greenhouse gas emissions. |
| 1058 | Marriott, C.A., Hudson, G., Hamilton, D., Neilson, R., Boag, B., Handley, L.L., Wishart, J., Scrimgeour, C.M. & Robinson, D. | Spatial variability of soil total C & N and their stable isotopes in an upland Scottish grassland | 1997 | Soil Organic Carbon; Soil N Dynamics | Journal | Plant Soil; 196 (1); | English | Hardcopy:Partial | Expt. to study the spatial variation in the total C & N content of the soil | .. to obtain statistically independent samples in this system, a sampling distance of .. 13.5 m is required. |
| 1311 | Marriott, E. & Wander, M.M. | Qualitative and quantitative differences in particulate organic matter fractions in organic and conventional farming systems | 2006 | Organic Farming; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 38; 1527-1536 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of differing farming systems on the nature and amount of POM in arable soil | Org. farming systems had greater quantities of C & N in the [occluded] oPOM and [coarse fraction] and greater [available] N contents in all POM fractions considered. The oPOM's C/N ratio (16-19) was least in the manure+legume-based organic, intermediate in the legume-based organic and greatest in the conv. systems. Trends in oPOM C/N and [available] N abundance suggested occluded POM was most decomposed, and possibly a greater N reservoir, in the manured soils. .. org. mgmnt simultaneously increased the size of the labile N reservoir and the amount of POM protected within aggregates; .. occluded POM is more decomposed in manure+legume- than in legume-based organic systems. |
| 1443 | Marriott, E. & Wander, M.M. | Total and labile soil organic matter in organic and conventional farming systems | 2006 | Organic Farming; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 70; 950-959 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the quality and quantity of SOM in org. & convl. soils | The org. systems had higher SOC & TN conc'ns than conv. systems, whether or not manure was applied. The POM-C, POM-N & IL-N conc'ns didn't differ between manure +legume & legume-based org. systems. The amount of N recovered in POM & IL-N was similar. Org. mgmnt enriched soil POM-C & -N by 30 to 40% relative to the conv'l control & this level of enrichment was 2-4 times greater than that in any other fraction.; .. org. farming practices increased the SOC conc'ns of surface soils by 14% compared with conv. counterparts. Legume-based & manure+legume-based org. mgmnt resulted in similar increases in SOM conc'ns compared to conv'l systems. |
| 842 | Marschner, B., Brodowski, S., Dreves, A., Gleixner, G., Gude, A., Grootes, P.M., Hamer, U., Heim, A., Jandl, G., Ji, R., Kaiser, K., Kalbitz, K., Kramer, C., Leinweber, P., Rethemeyer, J., Schäffer, A., Schmidt, M.W.I., Schwark, L. & Wiesenberg, G.L.B. | How relevant is recalcitrance for the stabilisation of organic matter in soils? | 2008 | Soil Organic Carbon | Journal | J. Plant Nutr. Soil Sci.; 171; 91-110 | English | Hardcopy:Full | Review of the question of whether the chemical recalcitrance of substances of plant origin plays any role in SOM stabilisation | .. the presented results do not provide much evidence that the selective preservation of recalcitrant primary biogenic compounds is a major SOM-stabilisation mechanism. Old SOM fractions with slow turnover rates were generally found only in association with soil minerals. The only non-mineral-associated SOM components that may be persistent in soils appear to be black & fossil C. |
| 469 | Marstorp, H. | Influence of soluble carbohydrates, free amino acids and protein content on the decomposition of Lol. multiflorum shoots | 1996 | Soil Organic Carbon | Journal | Biol. Fertil. Soils; 21 (4); 257-263 | English | Hardcopy:Partial | 1-week lab. expt. to ascertain the influence of the plant residue composition on the initial paths of decomposition. Shoot residues with a range of N contents (from 2.0-5.2%) were compared. | The shoots with the two highest N contents showed net N mineralisation during the first respiration peak, whereas at a lower N content there was net immobilisation. ..soluble carbohydrates and free amino-acids were important C and energy sources for the decomposers during the ... first respiration peak. |
| 470 | Marstorp, H. | Interactions in microbial use of soluble plant components in soil | 1996 | Soil Organic Carbon | Journal | Biol. Fertil. Soils; 22 (1); 45-52 | English | Hardcopy:Partial | Lab. expt. to study the mineralisation of amino-acids and proteins alone and in combination with glucose. Amino-acids and glucose appeared to be mineralised by the same microorganisms, but protein and glucose - by different ones. | |
| 167 | Martens, D.A. | Nitrogen cycling under different soil management systems | 2001 | Soil N Dynamics | Journal | Adv. Agron.; 70; | English | Hardcopy:Partial | Review of the effect of tillage on soil N dynamics. Less N is leached out of zero-tilled soils, due to greater N immobilisation and uptake by plants. Zero tillage also reduces run-off and sediment losses. | It is evident that conventional tillage systems are not sustainable, due to their destructive nature.; From 1990 to 1994 in Iowa the percentage of NT maize increased from 3.7% to 19.1% .. but decreased to 11.8% .. in 1998. .. On a nationwide basis the trends found in Iowa .. are .. occurring. No-tillage maize production .. decreased from 18% in 1994 to 16.4% in 1998 .. an Iowa farmer .. reported a consistent 13% yield reduction due to poor spring performance .. with NT ..; Studies have determined that NT continuous maize yielded less than CT, but equal for maize-soya bean rotation.; .. an early spring N mineralisation problem may exist with continuous NT maize.; .. the disadvantages associated with conservation tillage include: higher herbicide costs .., lower [soil] temperatures at planting time, decreased soil pH due to stratification of acidproducing fertilisers on the soil surface, .. with poorly drained soils increase [in] the wetness limitation [and] .. slower timing in the spring of N availability. |
| 1312 | Martens, D.A. | Plant residue biochemistry regulates soil carbon cycling and carbon sequestration | 2000 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 32 (3); 361-369 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the decompos'n of plant residues in soil | During the decomposition stages, biotic and abiotic reactions lead from the decomposition of plant residues to a complex mixture of aromatic compounds of plant and microbial origin that compose the bulk of stable OM. Readily available constituents, such as cellulose, peptides and most simple organics, will rapidly be mineralised for energy and the synthesis of microbial biomass. More resistant compounds, especially lignins and other plant phenolic compounds, are decomposed more slowly & combine with the products of microbial synthesis to constitute the main component of humus.; .. the longevity of the changes in soil props measured with org. residue addition is related to the rate of residue decompos'n. .. materials that are quickly decomposed exert a rapid stabilisation effect, which is transient. Materials that are slower to decompose require a longer time for max. aggreg'n to occur, but aggreg'n effects are effective for a longer period. |
| 1734 | Martens, D.A. | Relationship Between Plant Phenolic Acids Released during Soil Mineralization and Aggregate Stabilization | 2002 | Uncategorised | Journal | Soil Sci. Soc. Am. J.; 66; 1857-1867 | English | PDF:Full | ||
| 1313 | Martin, J.K. & Kemp, J.R. | Carbon loss from roots of wheat cultivars | 1980 | Roots & Rhizodeposition | Journal | Soil Biol. Biochem.; 12; 551-554 | English | Hardcopy:Partial | Lab. expt. to study the loss of carbon from the roots of different wheat cultivars during the first 4 weeks of growth | There were no significant differences between cultivars .. |
| 1444 | Martin, J.P., Haider, K. & Kassim, G. | Biodegradation and stabilisation after 2 years of specific crop, lignin and polysaccharide carbons in soils | 1980 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 44; 1250-1255 | English | Hardcopy:Full | Expt. to trace the fate of lignins and other components of plant residues in the soil | .. the organisms utilising the lignin carbons do not obtain appreciable energy from lignin that they can use for growth purposes and the lignin is largely broken down by organisms primarily utilising other substrates as C sources.; .. C was utilised by the soil organisms for synthesis of microbial cells and polymers, which were subsequently stabilised by linkage into humus polymers, by adsorption into humic acids or by other processes.; .. a major portion of the residual lignin carbons are stabilised in the humic acid fraction and do not enter the biomass, whereas the polysaccharide C of wheat straw is largely incorporated into microbial cells and products.; .. lignins .. decompose most rapidly in soil during the early stages of decomposition, but months and years instead of days and weeks are involved in the most rapid decomposition phase. |
| 697 | Martini, E., Buyer, J.S., Bryant, D.C., Hart, T. & Denison, R.F. | Yield increases during the organic transition: improving soil quality or increasing experience? | 2004 | Organic Farming | Journal | Field Crops Res.; 86; 255-266 | English | Hardcopy:Partial; PDF:Full | Field expt. to investigate the reasons for crop yield increases after organic conversion | .. there was no overall improvement in soil quality with duration of organic management.; An alternative hypothesis, not tested directly, is that previously reported yield increases result from improved management with increasing experience, not improving soil quality. |
| 661 | Mary, B., Beaudoin, N., Justes, E. & Machet, J.M. | Calculation of nitrogen mineralisation and leaching in fallow soil using a simple dynamic model | 1999 | Mineralisation; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 50 (4); 549-566 | English | Hardcopy:Partial | Modelling nitrogen dynamics in two field expts. over 9 and 20 mths. with and without crop residues (wheat or rape straw) | |
| 1314 | Mary, B., Fresneau, C., Morel, J.L. & Mariotti, A. | C & N cycling during decomposition of root mucilage, roots and glucose in soil | 1993 | Priming Effect; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 25 (8); 1005-1014 | English | Hardcopy:Partial | Lab. expt. using 13C natural abundance and 15N labelling to study C & N dynamics and priming effect in loam soil with 3 different amendments: glucose, root mucilage and roots. | The priming effect was greater for glucose than for mucilage or roots ..; .. glucose induced no priming effect for N, as opposed to C.; The most frequently accepted hypothesis is an enhanced mineralisation of endogenous OM, whose decomposition may be facilitated by the reactivation of the soil microflora. .. The second hypothesis .. seems more plausible .. the priming results from the turnover of microbial C. The unlabelled C contained in the microbial cells that become involved in substrate biodegradation would be mineralised during the growth period and after, during the turnover of dead cells by the secondary populations.; .. the C/N ratio of the newly formed biomass was .. lower for mucilage than for roots or glucose. This suggests that the mucilage biomass was essentially bacteria, whereas the root and glucose biomass included fungal populations. |
| 1315 | Mary, B., Recous, S. & Robin, D. | A model for calculating nitrogen fluxes in soil using 15N tracing | 1998 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (14); 1963-1979 | English | Hardcopy:Partial; PDF:Full | Modelling N flux in the soil using the FLUAZ programme | N re-mineralisation was significant and occurred almost simultaneously with N immobilisation. .. estimates of gross N transformations could be seriously erroneous if re-mineralisation is not accounted for.; .. re-mineralisation [and] reduction of nitrate into ammonium. The two processes are .. difficult to distinguish from each other .. However, dissimilatory reduction of nitrate into ammonium occurs only at very low oxido-reduction potentials, lower than denitrification. This process is therefore unlikely in aerobic incubations, remineralisation being more plausible.; .. immobilisation of NH4+ and NO3- take place simultaneously in soil, even though there is a preferential uptake of NH4+. This .. could .. result from the lower mobility of NH4+ ions in soil solution due to adsorption, rather than the physiological response of microbes .. NO3- assimilation was strongly but not completely inhibited by the presence of NH4+. |
| 1059 | Mary, B., Recous, S., Darwis, D. & Robin, D. | Interactions between decomposition of plant residues and nitrogen cycling in soil | 1996 | Mineralisation; Soil N Dynamics | Journal | Plant Soil; 181; 71-82 | English | Hardcopy:Partial | 2-year field expt. to study the mineralisation and immobilisation of N during decomposition of plant residues in agricultural soils. | .. mineralisation and immobilisation .. can take place simultaneously .. immobilisation of mineral N frequently occurs where .. net mineralisation is found .. conversely, ammonification continues even when N immobilisation is the dominant process.; .. the soil microflora can directly assimilate .. organic N compounds .. from plant residues or from dead biomass. .. [So] Net microbial assimilation .. [is] the sum of gross immobilisation of inorganic N and direct assimilation of organic N compounds.; .. under field conditions .. the immobilisation potential is very high and .. often higher than available mineral N. Therefore plant residue decomposition could be .. controlled by N. Under limiting N conditions immobilisation lasts longer but with lower rate. |
| 883 | Masiello, C.A. | New directions in black carbon organic geochemistry | 2004 | Soil Organic Carbon | Journal | Mar. Chem.; 92; 201-213 | English | Hardcopy:Full | Review of current knowledge of black carbon in soils. BC may constitute up to 35% of SOC. | ... the interaction of microbes and BC is not well understood. ... very small losses of charcoal after 120 days [confirm] the refractivity of BC but [suggest] that some microbial degradation is possible.; ... suggesting the existence of a relatively labile BC fraction that decomposes on the timescale of 1000s of years. |
| 1561 | Masri, Z. & Ryan, J. | Soil organic matter and related physical properties in a Mediterranean wheat-based rotation trial | 2006 | Green Manure; Soil Organic Carbon | Journal | Soil Tillage Res.; 87 (2); 146-154 | English | Hardcopy:Partial; Wordperfect:Full | 12-year field expt. to study the effect of including legumes in rotations on SOM, yields and soil quality in an arid climate | Some rotations, e.g. medic and vetch, significantly increased SOM ..; .. cereal/legume rotations, in addition to being biologically and economically attractive, also enhance soil quality and thus promote soil use sustainability.; Medic has an extensive root system, which contributes OM in the root zone rather than merely leaf fall on the soil surface. The positive influence of medic on soil profile OM extended to 50-60 cm. |
| 1658 | Mather, A.S. | Land and its use | 1986 | Agricultural Ecology | Book | Mather, A.S.; Land Use; | English | Hardcopy:Partial | Land is viewed as a resource, as an ecosystem and as a base for economic activity, including agriculture. Energy flows through the land ecosystem are compared for different land uses and different types of agriculture. | Net primary production (NPP) is the increment of plant material over time. .. tropical rain forests have the highest NPPs .. A characteristic of manipulated ecosystems or land-use systems is that their NPPs are usually lower than those of the natural ecosystems that they displace.; .. increases in yield or output are bought by inputs of energy. .. most western forms of agriculture are extremely inefficient .. In contrast, many more primitive forms of cultivation are more efficient.; .. the energy ratios of farming systems in the south of England fell from around 40 to around two between 1826 and 1971. |
| 440 | Mathur, S.P., Owen, G., Dinel, H. & Schnitzer, M. | Determination of compost biomaturity. I. Literature review | 1993 | Compost & Biocontrol | Journal | Biol. Agric. Hortic.; 10; 65-85 | English | Hardcopy:Partial; Wordperfect:Full | Review of methods of assessing the maturity of composts | Immature composts pose problems of malodours and fire during storage, flies and bag-bursting during marketing and phytotoxicity and pollution during use.; .. the main cause of phytotoxicity of immature composts [is] .. the organic intermediate products of decomposition. This toxicity is similar to allelopathy in its damage to crops, but of a quite different nature, because the injury is not caused by a single compound. Both short chain aliphatic acids (low fatty acids or volatile fatty acids) such as acetic acid and various phenolic compounds produced during active decomposition of organic compounds suppress seed germination, root proliferation and crop yields. |
| 427 | Matson, P.A., McDowell, W.H., Townsend, A.R. & Vitousek, P.M. | The globalisation of N deposition: ecosystem consequences in tropical environments | 1999 | Greenhouse Gases; Soil N Dynamics | Journal | Biogeochemistry (Dordr.); 46 (1-3); 67-83 | English | Hardcopy:Partial | Review of the effects on plant growth of anthropogenic N deposition in the tropics | Human activities have more than doubled the inputs of nitrogen into terrestrial systems globally.; The consequences of anthropogenic N deposition for ecosystem processes and N losses have been studied primarily in N-limited ecosystems in the temperate zone; .. tropical ecosystems, where plant growth is most often limited by some other resource, will respond differently ..; .. anthropogenic inputs of N into tropical forests are unlikely to increase productivity and may even decrease it, due to indirect effects on acidity and the availability of phosphorus and cations. |
| 1128 | Matson, P.A., Parton, W.J., Power, A.G., Power, A.G. & Swift, M.J. | Agricultural intensification and ecosystem properties | 1997 | Agricultural Ecology; Sustainability | Journal | Science; 277; 504-509 | English | Hardcopy:Full; PDF:Full | Review of the effects of agricultural intensification on natural ecosystems | .. sustainability may be defined as meeting current production goals without compromising the future in terms of resource degradation or depletion. The challenge .. is to realise increased production while avoiding the more extreme of the [negative] effects .. The development of more ecologically designed agricultural systems that re-integrate features if traditional agricultural knowledge and add new ecological knowledge into the intensification process can contribute to meeting this challenge. The renewed interest in agroforestry, intercropping and mixed arable-livestock systems is an indication of the interest in ecologically designed systems.; Requirement for increased food production that the world faces, particularly in the tropical regions, cannot conceivably be met without increased nutrient inputs. |
| 591 | Matsuhashi, R., Hikita, K. & Ishitani, H. | Model analyses for sustainable energy supply, taking resource and environmental restraints into consideration | 1996 | Energy Resources | Journal | Energy Convers. Manage.; 37 (6/8); 1253-1258 | English | Hardcopy:Full | A mathematical model is designed to test the sustainability of different energy use scenarios over a period of 200 years. If the criterion for the development of energy resources continues to be financial, as it is at present, the model gives an unsustainable outcome. If, on the other hand, financial incentives are used to force the development of renewable energy resources, etc., then the model shows a sustainable outcome. But the latter is based on the possibly unjustifiable assumption that CO2 sequestration technology grows to a maximum capacity of about 350 Mt of C per year over the first 100-year period. | .. [the] present world is judged to be unsustainable both from resource and environmental viewpoints.; .. [the] construction of renewable energy system[s] inevitably requires non-renewable energy such as fossil fuels.; .. utilisation of FBR (fast-breeder reactor[s]) and nuclear fusion is not considered, since there exists a large uncertainty associated with these technologies.; .. the energy balance for photovoltaics ([the] ratio of output energy to the energy required to construct [them]) is very low - around 2.4, including BOS (balance of the system). |
| 1594 | Matthews, J. | Energy consumption in agricultural field work | 1975 | Energy in Agriculture | Journal | Span; 18 (1); 25-26 | English | Hardcopy:Full | Ways of reducing fossil fuel consumption in agricultural field operations are reviewed. Tables are given of the fuel consumed in various farm applications | .. in the .. U.K., for example, tractors and other field machines account for 37% of the petroleum fuel energy. This is approximately 25% of the total energy [of fossil fuel origin] taken by farms .. These figures exclude the very considerable energy input in agricultural chemicals, which probably equals approximately that of the fuels. Another significant contribution to agriculture's real input is that used in the production of agricultural machinery. An Australian study .. has emphasised the relatively large proportion - 85% of the total - which can be involved after the food leaves the farm in transport, retailing and cooking. |
| 966 | Mayer, J. & Hess, J. | Welchen Beitrag zur Stickstoffversorgung leisten Koernerleguminosen? | 1997 | Green Manure; Stockless Farming | Journal | Ökologie und Landbau; 3; 18-22 | German | Hardcopy:Partial | A review of the questions how much N pulse crops fix in the soil and whether green crops can be replaced by pulse crops in order to increase farm incomes. It appears that pulse crops fix only a small fraction of the quantity of N that green crops do. The proportion of the N in leguminous crops that comes from fixation is around 70%. Red clover used as a green manure gives a net N fixation of 312 kg/ha, whereas, used as a fodder crop, it only gives 160 kg/ha after deduction of losses in the livestock and the manure. | Bei viehloser Wirtschaftsweise betraegt der [Stickstoff-]Saldo der Leguminosengruenbrache das 10 bis 20-fache des Saldos der Koernerleguminosen.; Bei Erbsen scheint es eine klare Tendenz zu negativen Salden zu geben.; Bisher ist es in der Praxis nicht moeglich, die Hoehe der biologischen Stickstoff-Fixierung mit einfachen Methoden hinreichend genau zu schaetzen und genaue StickstoffFlaechenbilanzen zu berechnen. |
| 884 | Mayer, L.M. | The inertness of being organic | 2004 | Soil Organic Carbon | Journal | Mar. Chem.; 92; 135-140 | English | Hardcopy:Full | Review of the stabilisation of organic matter in soils | Recalcitrant organic-organic linkages often account for protection on shorter time scales. Biota intentionally create many of these linkages, leading to selectively preserved organic matter, and various humification reactions may produce others. On longer time scales exclusion of biota or their digestive agents accounts for most protection, induced by factors such as clay mineral protection and anoxia. Longer-term protection proceeds through a succession of different mechanisms, acting co-operatively. |
| 716 | Mayer, L.M., Schick, L., Hardy, K., Wagai, R. & McCarthy, J. | Organic matter in small mesopores in sediments and soils | 2004 | Soil Organic Carbon | Journal | Geochim. Cosmochim. Ac. ; 68 (19); 3863-3872 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the relationship between protected OM & pore volume in soils | Although smaller mesopores are shown to have sufficient volumes to contain significant fractions of the total OM, only small fractions of total OM were found to reside in them. These results are consistent with preferential assoc'n between OM and aluminous clay particle edges, rather than the largely siliceous clay faces that contribute most surface area and form pore walls. While simple enclosure within smaller mesopores cannot, therefore, explain protection, network effects working at larger size scales may account for exclusion of digestive agents and hence OM protection. |
| 533 | Maynard, A.A. | Compost: the process and research | 2000 | Compost & Biocontrol | Journal | Bull. Conn. Agr. Exp. Stat.; 966; | English | Hardcopy:Partial; PDF:Full | Review of curent knowledge on making and using compost | The ideal C/N ratio for most compost organisms is 30:1 .. Efficient composting with C/N ratios between 25 and 35:1 has been reported.; There are several inoculants or; starters; on the market, but independent tests indicate that no benefit is gained from these products.; High nitrogen fertilisers, such as blood meal or urea, are also sometimes added to a compost pile to speed decomposition of materials with a high C/N ratio .. while these fertilisers gave the piles of leaves an initial boost and helped them heat faster, the unfertilised piles attained the same temperatures in a few days and there was no difference in the overall composting time.; Depending on the materials used, the nitrogen concentration of finished compost can vary from 0.5% (leaf compost) to 2% (manure or biosolid compost). .. 1 inch of compost is equivalent to 50 t/acre. |
| 328 | Mazzola, M. | Assessment and management of soil microbial community structure for disease suppression | 2004 | Compost & Biocontrol | Journal | Annu. Rev. Phytopathol.; 42; 35-59 | English | Hardcopy:Partial; PDF:Full | Review of methods of managing soil microorganisms for disease suppression | Although the suppressive nature of certain soils appears to be constitutive, a number of disease-suppressive soils attain that state through specific mgmnt practices, such as continuous crop monoculture. The presence of native as well as arable soil systems that are suppressive to specific soil-borne plant disease /pathogens suggests that the manipulation of microbial antagonists resident to specific ecosystems may be a viable disease management strategy. |
| 139 | Mazzoncini, M., Croce, L., Barberi, P., Menini, S. & Bonari, E. | Crop management systems to conserve soil fertility after long-term set-aside in southern Italy | 2001 | Organic Farming; Tillage | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to test the effect of different management systems on SOM & N | The preliminary results of our study suggest that in Southern Italy, where high summer temperatures enhance SOM mineralisation rates and low rainfall limits biomass production, the adoption of a low-input system based upon no- tillage seems more appropriate .. In this respect crop rotation and inclusion of legume crops seem less important than the crop management system type.. |
| 1704 | McCalla, A.F. | Agriculture and food needs to 2025: why we should be concerned | 1994 | Uncategorised | Website | Sir John Crawford MemoriaLl ecture, 1994 | English | PDF:Full | ||
| 1126 | McCarl, B.A. & Schneider, U.A. | Greenhouse gas mitigation in U.S. agriculture and forestry | 2001 | Greenhouse Gases | Journal | Science; 294; 2481-2482 | English | Hardcopy:Full | An existing agricultural sector model is expanded to include greenhouse gases | .. U.S. croplands could sequester 75 to 208 MMT annually for 20 to 50 years.; .. mitigation programmes may generate substantial side benefits. |
| 1307 | McCarty, G.W., Meisinger, J.J., Jenniskens, F.M.M.[abstract only] | Relationships between total-N, biomass-N and active-N in soil under different tillage and N fertiliser treatments | 1995 | Soil N Dynamics; Tillage | Journal | Soil Biol. Biochem.; 27 (10); | Expt.s to study the effect of tillage and nitrogenous fertiliser treatments on the distribution of N in arable soils | .. whereas geographic location, N fertilisation and depth generally had little influence on .. describing the linear relationships between total-N, biomass-N and active-N, tillage had a marked influence on [them]. Such results indicated that tillage may substantially influence the distribution of N among different pools within agricultural soils. | ||
| 1560 | McFarland, M.L., Hons, F.M. & Lemon, R.G. | Effects of tillage and cropping sequence on soil physical properties | 1990 | Soil (General); Tillage | Journal | Soil Tillage Res.; 17; 77-86 | English | Hardcopy:Partial | 6-year field expt. to study the effect of tillage and rotation on soil physical properties and aggregation. In zero-tillage soil microaggregation was 5-30% (average 15%) higher than in conventionally tilled soils. Tillage did not affect soil BD or strength. Rotation affected all three properties. | |
| 295 | McGuire, A.M., Bryant, D.C. & Denison, R.F. | Wheat yields, nitrogen uptake and soil moisture following winter legume cover crop vs. fallow | 1998 | Green Manure; Soil N Dynamics | Journal | Agron. J.; 90; 404-410 | English | Hardcopy:Full; PDF:Full | Inconclusive expt. to compare N dynamics and wheat yields after fallow, fallow fertilised with chemical fertiliser or with green manure from another plot and green manure grown on the same plot and either incorporated or cut and removed. The N content in the wheat averaged 49, 31, 24, 19 and 9 g kg-1 at tillering, stem elongation, booting, just before flowering and maturity | .. wheat or barley crops take up only small amounts (9-33%) of the legume N incorporated the previous year, compared with fertiliser N recoveries by crops of 40 to 70%. .. 22 to 79% of the legume N could be recovered as organic N in the soil. With long-term use of legume cover crops mineralisation of this added organic N might be sufficient to sustain adequate wheat yields. |
| 1656 | McMullan, J.T., Morgan R. & Murray, R.B. | Energy Resources and Supply | 1976 | Energy Resources | Book | McMullan, J.T., Morgan R. & Murray, R.B.; Energy Resources and Supply; | English | Hardcopy:Partial | The photosynthetic yield, i.e. the fixation of C and solar energy by photosynthesis, is assessed. | Applying a correction of 15 per cent to allow for respiration, the total gross yield of photosynthesis is .. approximately 4.5 x 1010 tonnes of organic C per annum. .. .. the average efficiency for photosynthesis .. turns out to be 0.25 per cent, the figure for land plants being slightly higher at 0.4 per cents. Even a well-cultivated crop such as maize is only about 1 per cent efficient .. |
| 354 | Mele, P.M. & Carter, M.R. | Species abundance of earthworms in arable and pasture soils in south-eastern Australia | 1999 | Soil (General) | Journal | Appl. Soil Ecol.; 12 (2); 129-137 | English | Hardcopy:Partial | Earthworm populations were studied on 84 arable and pasture sites. | An overall average density of 89 earthworms per sq.m., with 61% of the sites containing less than 100 [worms] per sq.m. and an average species richness of 1-2 per site, contrasts sharply with the average density of 400 per sq.m. and 5-10 species per site recorded for European soils.; Soils under pasture supported on average 3.2 times more earthworms than those under cropping. |
| 576 | Melillo, J.M., Aber, J.D. & Muratore, J.F. | Nitrogen and lignin control of hardwood leaf litter decomposition dynamics | 1982 | Lignin and CBW; Soil N Dynamics | Journal | Ecology; 63 (3); 621-626 | English | Hardcopy:Partial | Field expt. using litter bags to study the decomposition of leaves in a hardwood forest over one year. The rate of decomposition was negatively correlated with the lignin/N ratio. Initial concentrations of lignin and N in the leaves averaged 15% and 0.9% respectively. Beech leaves, however, had 24.1% lignin and decayed much slower than the rest. | If relatively large amounts of exogenous N are available to the microorganisms involved in litter decomposition, .. initial N content of the litter may not exert as great an influence on decomposition rate and lignin content .. may become more important ..; .. the higher the initial lignin content, the greater the amount of N immobilised per unit of C respired. .. the amount of humus formed from plant litter would be positively correlated with the litter's original lignin content. .. The amounts of N bound in humus can be large. The N content of .. humus is between 5.0 and 5.5%. Since humus compounds are relatively resistant to decomposition, the n bound in humus .. will be released slowly. |
| 1445 | Mendes, I.C., Bandick, A.K., Dick, R.P. & Bottomley, P.J. | Microbial biomass and activities in soil aggregates affected by winter cover crops | 1999 | Cover Crops; Green Manure; Soil Microorganisms | Journal | Soil Sci. Soc. Am. J.; 63; 873-881 | English | Hardcopy:Full; PDF:Full | Field expt. to compare the effect of legume (red clover) and non-legume (triticale) cover crops on the soil properties | .. cover cropping did not significantly influence aggregate-size distribution, TOC or TKN on any sampling date, [but] it did significantly influence SMBC .., mineralisable C & N .. and b-glucosidase activities ..; .. both TOC and TKN levels [were] consistently lower in soil removed from the cereal treatment, which indicates that the use of triticale as a cover crop may promote mineralisation of soil organic matter. .. TKN levels were consistently greater in all aggregate-size classes of the legume treatment than in either fallow or cereal treatments .. |
| 843 | Merbach, W., Garz, J., Schliephake, W., Stumpe, H. & Schmidt, L. | The long-term fertilisation experiments in Halle (Saale), Germany: introduction and survey | 2000 | Soil (General) | Journal | J. Plant Nutr. Soil Sci.; 163 (6); 629-638 | English | Hardcopy:Partial | Review of results to date of long-term fertilisation expts. at Halle | Changes in soil ecological props due to fertilisation and rotation were only evident after 30 yrs & new steady states sometimes took 70 yrs to occur.; In the long term the C & N contents of the soil largely depend on the amount of hardly decomposable OM applied with org. fertilisation. High mineral N doses, with consequent high crop & root residues, increased the humus content of the soil. |
| 1659 | Merrill, R. | Radical Agriculture | 1976 | Agricultural Ecology | Book | Merrill, R.; Radical Agriculture; | English | Hardcopy:Partial | A review of problems of modern agriculture, criticising modern agriculture and suggesting a need for radical change. | .. the era of cheap abundant food is over and .. the cornucopia has been a short-term marvel with long-term costs to society.; .. we have become affluent at the expense of agriculture, not because of it.; ..one of the basic dilemmas of our time [is] What happens to agriculture when its traditional energy base is exhausted?; .. most researchers ares still operating from a basic set of assumptions that prevent new questions being asked: for example, that the sole purpose of agriculture is to produce high yields; that fossil fuels and other cheap energy will continue to supply agriculture with all of its energy needs; and that agriculture can only operate 'efficiently' in an industrial milieu. |
| 355 | Meyer, K., Jörgensen, R.G. & Meyer, B. | The effects of reduced tillage on microbial biomass C and P in sandy loess soils | 1996 | Soil Microorganisms; Tillage | Journal | Appl. Soil Ecol.; 5 (1); 71-79 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of tillage on microbial biomass C and P | The use of a rotary cultivator especially led to a compaction of the 10-20 cm layer, but also of the 20-30 cm layer. In this compacted part of the previous plough layer the amount of microbial biomass and its specific activity were markedly reduced, indicating deteriorated conditions for microbial performance. In the layers between 0-30 cm depth, the ratio biomass C/soil organic C was positively correlated with the qCO2 and negatively with the bulk density. This clearly indicates that the reduction in microbial biomass must be caused by a reduced input of plant material, i.e. by energy deficiency, and not by stress due to reduced oxygen concentrations in the compacted 10-30 cm layer ... For this reason, forms of reduced tillage other than ... a rotary cultivator should be chosen as a substitute for ploughing. |
| 317 | Midwood, A.J., Haggarty, P., McGaw, B.A., Mollison, G.S., Milne, E. & Duncan, G.J. | Validation in sheep of the doubly labelled water method for estimating CO2 production | 1994 | Greenhouse Gases | Journal | Am. J. Physiol. Regul. Integr. Comp. Physiol.; 266 (1); 169-179 | English | Hardcopy:Partial | Expt. to compare the measurement of CO2 production by sheep using an isotope tracer method and the conventional respiration chamber method. The mean rate of CO2 production was 378.8 l/day from four sheep averaging 57.7 kg liveweight. The average manure production was 261.5 g/day | |
| 1562 | Mielke, L.N. & Wilhelm, W.W. | Comparisons of soil physical characteristics in long-term tillage winter wheat-fallow tillage experiments | 1998 | Tillage | Journal | Soil Tillage Res.; 49; 29-35 | English | Hardcopy:Full; PDF:Full | Field expt. to compare the physical properties (particularly water infitration rates) of previously uncultivated soil (native sod) with cultivated soil under ploughing and reduced and zero tillage | In the previously cultivated site ... most physical characteristics were the same for the tillage treatments. In the native sod site most the physical characteristics were different between tillage treatments and native sod was usually at the extreme range of values. Infiltration of water is affected by several soil characteristics. Infiltration rate curves for the tillage treatments on the previously cultivated site show no separation. For the native sod site infiltration rates were generally largest for sod and decreased as the tillage method with greater amount of soil disturbance increased. |
| 1735 | Mikha, M.M. & Rice, C.W. | Tillage and Manure Effects on Soil and Aggregate-Associated Carbon and Nitrogen | 2004 | Uncategorised | Journal | Soil Sci. Soc. Am. J.; 68; 809-816 | English | PDF:Full | ||
| 428 | Mikutta, R., Kleber, M., Torn, M. & Jahn, R. | Stabilization of soil organic matter: association with minerals or chemical recalcitrance? | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Biogeochemistry (Dordr.); 77; 25-56 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the mechanism of stabilisation of OM in subsoils | Stable OM was defined as that material that survived treatment of soils with .. NaOCl. Mineral-protected OM was extracted by subsequent dissolution of minerals by .. HF. OM resistant against NaOCl and insoluble in HF was considered as recalcitrant OM. .. Of the stable OC, amounting to 2.4-20.6 g kg-1 soil, mineral dissolution released on average 73%. Poorly crystalline Fe & Al phases explained 86% of the variability of mineral-protected OC. .. Recalcitrant OC (0.4- 6.5 g kg-1 soil) contributed on average 27% to stable OC and the amount was not correlated with any mineralogical property. Recalcitrant OC .. was mainly composed of aliphatic (56%) and O-alkyl (13%) C moieties. Lignin phenols were only present in small amounts in either mineral-protected or recalcitrant OM (mean 4.3 and 0.2 g kg-1 OC). The results confirm that stabilisation of OM by interaction with poorly crystalline minerals and polymeric metal species is the most important mechanism for preservation of OM in these acid subsoil horizons. |
| 495 | Milgen, J. van, Noblet, J., Dubois, S. & Bernier, J.F. | Dynamic aspects of oxygen consumption and carbon dioxide production in swine | 1997 | Greenhouse Gases | Journal | Br. J. Nutr.; 78 (3); 397-410 | English | Hardcopy:Partial | Modelling the changes in oxygen and in CO2 concentration inside a respiration chamber on the basis of animal metabolism and physical characteristics | |
| 297 | Miller, D.A. | Allelopathy in forage crop systems | 1996 | Allelopathy; Green Manure | Journal | Agron. J.; 88; 854-859 | English | Hardcopy:Full | Review of allelopathic effects in the cultivation of grass and legumes | Allelopathy is defined as the .. effects of one plant on another through the production of chemical compounds that escape into the environment. .. Perennial forage species may contain water-soluble inhibitory substances that are autotoxic, as well as inhibitory to other species (heterotoxicity).; Reestablishment of alfalfa immediately after alfalfa has usually resulted in poor stands due to autotoxicity ..; .. no .. evidence of autoxicity if alfalfa was seeded conventionally 2 weeks after ploughing an old alfalfa stand or seeded no-till 3 weeks after spraying the old stand with glyphosate.; .. the degree of toxicity of different alfalfa plant parts..in order of decreasing inhibition: leaf, seed, complete plant mixture, soil surrounding plant, root, flower, stem.; .. plant symptoms [of autotoxicity are] being dwarfed, spindly, yellowish green plants with irregular .. brown lesions on the .. roots and only a few nodules, which were ineffective.; .. inhibition in decreasing order: alfalfa, birdsfoot trefoil, ladino [white ?] clover, red clover, reed canarygrass, smooth bromegrass, timothy and orchardgrass.; .. alfalfa hay extracts caused the greatest delay in seed germination and seedling growth of all test species. |
| 356 | Miller, R.M. & Dick, R.P. | Dynamics of soil C and microbial biomass in whole soil and aggregates in two cropping systems | 1995 | Green Manure; Soil Organic Carbon; Soil Microorganisms | Journal | Appl. Soil Ecol.; 2; 253-261 | English | Hardcopy:Full; PDF:Full | Field expt. to compare vegetable rotations with and without leguminous green manure courses in respect of their carbon dynamics and microbial biomass. The legume rotation soil had a higher microbial biomass, higher microbial biomass/ SOC ratio, higher labile OM pool (POM and DOC), 35% more macroaggregates and 35% less microaggregates than the rotation without legumes. Aggregate size was negatively correlated with qCO2 and positively with microbial biomass and the microbial biomass/SOC ratio. | .. alternative systems that maintain plant root activity most of the year and have biennial legume-green manure incorporations can improve soil aggregation within a relatively short time of 2 years. .. a qualitative difference can exist between microbial communities in macroaggregates and microaggregates. |
| 161 | Millington, S. | Stockless organic farming - research and development | 90? | Green Manure; Stockless Farming | Book | ; Internal Elm Farm document ?; | English | Hardcopy:Full | Preliminary results of the first four years of the Elm Farm and Luddesdown trials are given. These include crop yields and the ANPP and soil N accumulation of the leguminous green manures. | [the Luddesdown rotations were] on a thin calcareous soil. .. [the] field trial at Elm Farm [was] on a clay loam soil following a four-year ley ..; On the [Elm Farm] site rock phosphates and lime were the only soil amendments used ..; Crop quality has been good, although some winter wheats have shown low protein levels (ranging from 1.3 to 1.9% N).; .. wild oats and .. couch grass populations are increasing on some of the plots ..; .. the soil nutrient status has remained stable or increased slightly in each rotation .. |
| 154 | Millington, S., Stopes, C.E., Woodward, L. & Vogtmann, H. | Rotational design and the limits of organic systems - the stockless organic farm? | 1990 | Stockless Farming | Book | Unwin, R. (ed.); British Crop Protection Monograph no. 45; | English | Hardcopy:Partial | Methods for controlling pests and diseases in all-arable organic systems are reviewed. Preliminary results of the Elm Farm and Luddesdown stockless trials are briefly alluded to. | Nutrient budgets for most of these [trial] rotations appear unfavourable, but such an exercise does not necessarily reflect the potential availability of soil nutrients from mineralisation of OM or solubilisation from soil reserves by crop roots, residues or green manures. Results so far have revealed no deficiency problems .. Crop yields and quality have been acceptable.; Such rotations may .. experience a build-up of weed populations over time .. Results so far show no such increase. .. Disease problems .. have not so far been experienced. |
| 1060 | Miltner, A., Kopinke, F.D., Kindler, R., Selesi, D., Hartmann, A. & Kastner, M. | Non-phototrophic CO2 fixation by soil microorganisms | 2005 | Soil Microorganisms | Journal | Plant Soil; 269; 193-203 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to investigate the fixation of CO2 by bacteria in the dark | CO2 fixation .. was linearly related to respiration during the first phase of incubation (about 20-40 days). The fixation amounted to 3-5% of the net respiration. After this phase, the CO2 fixation decreased to 1-2% of the respir'n. The amount of C fixed by an agricult. soil corresponded to 0.05% of the OC present in the soil at the beginning of the expt. .. virtually all of the fixed CO2 was converted to organic cpds. the process is mainly driven by aerobic heterotrophic microorganisms [&] represents a signif. factor of microbial activity in soils. |
| 957 | Minami, K. | Atmospheric methane and nitrous oxide: sources, sinks and strategies for reducing agricultural emissions | 1997 | Greenhouse Gases; Soil N Dynamics | Journal | Nutr. Cycl. Agroecosyst.; 49; 203-211 | English | Hardcopy:Full; PDF:Full | Review of the sources and mitigation methods of CH4 and N2O emissions from soils | Biological generation of CH4 in anaerobic environments (natural and man-made wetlands, enteric fermentation & anaerobic waste processing) is the major source of CH4 .. Aerobic soils oxidise 10-20% of CH4 production ..; Agricultural anthropogenic sources of N2O emissions are thought to arise from fertilisation of soils with mineral N, fertilisation with animal manures (this N is partly recycled mineral N and relocated soil mineral N), N derived from biological Nfixation (legume crops and free living N-fixing microbes), N from atmospheric deposition and N from enhanced soil N mineralisation.; A variety of factors control rates of the two microbial processes that produce N2O, nitrification and denitrification, and N2O yield. .. Important factors are soil water content, temp, nitrate or ammonium conc'ns, available org. C for denitrification and pH. |
| 850 | Molope, M.B., Grieve, I.C. & Page, E.R. | Contributions by fungi and bacteria to aggregate stability of cultivated soils | 1987 | Soil Microorganisms | Journal | J. Soil Sci.; 38; 71-77 | English | Hardcopy:Full | Lab. expt. to study the effect of fungi and bacteria on soil aggregate stability | Shortly after cultivation there is a regain .. of aggregate stability .. Most of this increase .. is the result of a flush of biological activity .. In the long run aggregate stability declines as SOM is depleted by being used as an energy substrate by soil organisms.; Growth of fungal hyphae .. corresponded to temporary stability increases in .. aggregates .. Bacterial growth accompanied the fall in stability associated with fungal decline but had little direct effect in stabilising soil aggregates. |
| 1316 | Monaghan, R. & Barraclough, D. | Contributions to nitrogen mineralisation from soil macroorganic matter fractions incorporated into two field soils | 1997 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 29 (8); 1215-1223 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to measure the amount of mineralisation of N in macroorganic matter incorporated into two different grassland soils | Approx. 2.4% & 13.7% of the N in the incorporated macro-OM isolated from the different soils was mineralised over the 66 d following incorporation. This represented approx. 3.4% & 2.3% of the cumulative gross N mineralisation .. This low contrib'n suggests that most of the N mineralised .. is derived from other forms of SOM assoc'd with mineral particles.; .. why the two macro-OM fractions released different amounts of N was a reflection of the higher lignin content in [one] fraction relative to the [other] (14.7% vs 11.1%). |
| 471 | Mosier, A.R. | Soil processes and global change | 1998 | Greenhouse Gases | Journal | Biol. Fertil. Soils; 27 (3); | English | Review of the contribution of soil processes to global warming. 30% of CH4 and 70% of N2O emissions are produced in the soil. | During the past 250 years the atmospheric concentrations of CO2, CH4 and N2O have increased by 30, 145 and 15% respectively. | |
| 905 | Mosier, A.R., Schimel, D.S., Valentine, D., Bronson, K.F. & Parton, W.J. | Methane and nitrous oxide fluxes in native, fertilised and cultivated grasslands | 1991 | Greenhouse Gases | Journal | Nature (Lond.); 350; 330-332 | English | Hardcopy:Full | An expt. to measure CH4 and N2O emissions from soils, using the closed chamber method | .. N fertilisation and cultivation can both decrease CH4 uptake and increase N2O production ..; The N2O flux .. was highest immediately following precipitation, when CH4 uptake was lowest.; .. semi-arid grasslands represent a significant global sink for CH4. |
| 1317 | Moyano, F., Kutsch, W. & Schulze, E.D. | Response of mycorrhizal, rhizosphere and soil basal respiration to temperature and photosynthesis in a barley field | 2007 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Soil Biol. Biochem.; 39; 843-853 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of changing temp. and photosynthesis rate on the soil respiration of an arable field | Temperature can be a strong controlling factor for respiration rates under certain conditions, but the limiting factors in many, if not most, cases are those determining substrate availability, e.g. water status and assimilate supply.; Results showed differences in temp. response for the different respiring components [root, mycorrhizal and basal respiration]. .. Factors other than temp. effects on enzymatic activity can be limiting the increase of respiration with temperature in field conditions, namely, those determining substrate availability... Whereas a certain amount of respiration will be for maintenance and thus have a direct response to temperature, growth respiration will be controlled by the amount of photosynthates available and only be affected by temp. when these are not limiting. |
| 559 | Mueller, T., Jensen, L.S., Magid, J. & Nielsen, N.E. | Temporal variation of C & N turnover in soil after OSR straw incorporation in the field: simulations with the soil-plant-atmosphere model DAISY | 1997 | Rape and Biodiesel; Soil Organic Carbon | Journal | Ecol. Model.; 99; 247-262 | English | Hardcopy:Partial; PDF:Full | Modelling soil C & N dynamics, using data from a 1-year field trial on a sandy loam with and without the incorporation of 8 t/ha of rape straw | .. the C/N ratio of LPOM after .. straw incorporation decreased from 60 to 20 during decompos'n. .. the lignin content of the LPOM increased and the cellulose content decreased. .. 60 is low compared to the C/N ratio of 92 found for the non-soluble part of the original rape straw and may indicate a fast colonisation by microorganisms in the initial phase.; .. qCO2 in 139 arable soils .. varied widely between 0.005/day .. and 0.07/day ..; The microbial turnover rate is the sum of the death rate [and] maintenance and growth respiration.; The calculated normalised turnover rates of SMB were between 0.0017/day and 0.0043/day ..; .. glucose ..appears to have a utilisation efficiency of 0.69 .. Added substrates are mostly expected to have much smaller utilisation efficiencies than glucose. Values reported in the literature are in a range between 0.1 and 0.53 g SMB-C/g substrate-C. |
| 235 | Mummey, D.L., Smith, J.L. & Bluhm, G. | Assessment of alternative soil management practices on N2O emissions from US agriculture | 1998 | Greenhouse Gases; Tillage | Journal | Agric. Ecosyst. Environ.; 70 (1); 79-87 | English | Hardcopy:Full; PDF:Full | Modelling is used to simulate the N2O emissions from grassland and arable land under zero and conventional tillage. Heavily fertilised or wet crops, like rice, cotton and vegetables, had the greatest N2O flux (6.5-8.4 kg N2O-N ha-1 year-1). | N2O is produced in soil primarily by two dissimilar energy producing microbial processes, nitrification and denitrification. N2O production by both processes is regulated by complex interactions between N availability, soil moisture and oxygen status and soil type, texture, pH and organic C content.; .. no-till management in areas that are relatively warm and wet may result in N2O emissions similar to or less than conventional tillage .. N2O emissions were greater for no-till systems in drier regions, because of increased soil moisture.; 0.75% of N applications will eventually reach the atmosphere as off-site N2O emissions resulting from N leaching, run-off and NOx and NH3 volatilisation. |
| 441 | Munro, T.L., Cook, H.F. & Lee, H.C. | Sustainability indicators used to compare properties of organic and conventionally managed topsoils | 2002 | Organic Farming; Soil (General) | Journal | Biol. Agric. Hortic.; 20; 201-214 | English | Hardcopy:Partial | A review is made of research into soil under org. & conventional management & on this basis a number of variables are selected as potential soil sustainability indices: SOM, total N, available phosphorus, potassium and magnesium, soil pH, topsoil depth and topsoil shear strength. These variables were then measured on 14 paired (organic and conventional) farm sites in eastern England and the values of the variables were subjected to statistical analysis to find the ones that showed a significant difference: SOM, total N, available phosphorus and potassium, topsoil depth and soil shear strength. [The argument is circular!] | .. in the last 15 years of the twentieth century SOM levels in U.K. agricultural soils have fallen by an average of 0.49% ..; Soil shear strength is inversely related to soil water content. .. [it] was found to be significantly lower in organic fields .. this indicates greater friability .. and an increased workability. |
| 472 | Murata, T. & Goh, K.M. | Effects of cropping systems on soil organic matter in a pair of conventional and biodynamic mixed-cropping farms in Canterbury, New Zealand | 1997 | Organic Farming; Soil Organic Carbon | Journal | Biol. Fertil. Soils; 25 (4); 372-381 | English | Hardcopy:Partial | Field expt. to study the C & N dynamics in the soil under grass and arable on conventional and biodynamic farms. There was an increase of total C & N under grass and a decrease under arable on the biodynamic farm, but not on the conventional one (perhaps due to N fertiliser application). | The humin fraction was strongly related to both labile and stable SOM fractions, suggesting that humin contained non-extractable strongly complexed SOM components with mineral matter and.. plant and microbial residue components. |
| 1692 | Murdock, L., Daz-Zorita, M., Herbek, J., & Grove, J.H. | Effect of continuous no-tillage in a corn-wheat-double-crop soya bean rotation on yields and soil properties | 01? | Tillage | Website | www.wheatimprovement.org/forum/4 (NAWG (N.Am. Wheat Growers ?) | English | Continuous zero tillage is compared with conventional tillage in a 2-year maize/wheat and soya bean rotation over an 8-year period. In only three of those years (all low-yielding years) does the wheat yield from conventional tillage exceed that from zero tillage. The overall yield of maize was around 10% higher from zero tillage, but there was no significant difference in soya bean yields. There were no significant differences between the two systems in respect of SOM, soil pH, soil NPK content or soil BD. Soil in the zero tillage system had higher penetration resistance, but it was still below 2 MPa - the critical level for normal root growth. | ||
| 140 | Murphy, D.V., Dise, N., Goulding, K.W.T., Macdonald, J., Peake, C., Redfern, P. & Stockdale, E.A. | Can concepts of N saturation developed for forest systems be applied in arable soils? | 2001 | Soil N Dynamics | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the balance between N mineralisation and immobilisation in an arable soil | In forest ecosystems and undisturbed grasslands, the N cycle was thought to be highly conservative, where high rates of mineralisation were balanced by high rates of immobilisation with minimal net N mineralisation or nitrification. However, additions of N in atmospheric deposition can disrupt the soil N cycle.; The ratio of gross nitrification to NH4+ immobilisation has been used to assess the absolute potential of the soil to exchange N with the wider environment. The greater the ratio, the more likely a soil is to lose N via leaching or denitrification. .. This ratio can be used to assess the N saturation of forested soils.; .. ratios of gross nitrification to NH4+ immobilisation were .. dominantly <1 (average 0.7), except where a cereal followed peas (2.1) or where oilseed rape was grown (average of 1.0 for three sites). Where the same soil was sampled before and after cultivation in autumn 1997, the ratio of gross nitrification to NH4+ immobilisation increased rapidly (within 1 day). |
| 621 | Murray, P.J. & Clements, R.O. | Transfer of nitrogen between clover and wheat: effect of root herbivory | 1998 | Clover Sward; Green Manure; Soil N Dynamics | Journal | Eur. J. Soil Biol.; 34 (1); 25-30 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of root herbivory on the transfer of nitrogen from white clover to wheat plants | ... 7% of the N in the wheat plants originated from clover.; Transfer of N from a N-fixing plant to a non-fixing companion plant in the soil can occur via a number of pathways in addition to the generally accepted process of death, decay and subsequent mineralisation of root and nodular tissue. Other pathways which have been proposed are exudation from legume roots and via mycorrhizal associations between the plants .. Some workers found significant transfer of N, while others found little or no evidence of transfer. |
| 958 | Murray, P.J., Gill, E., Balsdon, S.L. & Jarvis, S.C. | A comparison of CH4 emissions from sheep grazing pastures with differing management intensities | 2001 | Greenhouse Gases; Stockless Farming | Journal | Nutr. Cycl. Agroecosyst.; 60 (1-3); 93-97 | English | Hardcopy:Partial | Expt. to measure the CH4 emissions from sheep grazing on pastures fertilised with white clover or differing rates of N fertiliser. No significant differences in overall CH4 emission were found. | |
| 1736 | Murty, D., Kirschbaum, M.U.F., McMurtrie, R,E. & McGilvray, H. | Does conversion of forest to agricultural land change soil carbon and nitrogen? a review of the literature | 2002 | Uncategorised | Journal | Glob. Change Biol.; 8; 105-123 | English | PDF:Full | ||
| 19 | Myers, R.J.K., Noordwijk, M. van & Vityakon, P. | Synchrony of nutrient release and plant demand: plant litter quality, soil environment and farmer management options | 1997 | Mineralisation; Miscellaneous; Soil N Dynamics | Book | Cadisch, G. & Giller, K.E. (eds.); Driven by Nature: Plant Litter Quality and Decomposition. C.A.B. International; | English | Hardcopy:Partial; Wordperfect:Full | Review of measures that increase synchrony of nutrient release and uptake | Twelve synchrony hypotheses [include]: The maximum crop yield achievable by the use of inorganic .. fertiliser inputs can be approached or exceeded by optimising the time of applic'n, placement & quality of org. nutrient sources .. plant uptake of mineral N applied at planting can be increased by simultaneous application of a low-N organic material,which temporarily immobilises N early in the crop growth cycle and remineralises N later on. Stabilisation of OM in the soil is enhanced by the add'n of mineral N simultaneously with the addition of org. materials of high C/N ratio. Residues high in lignin will result in a low net mineralisation and plant uptake in the first cropping season, but will produce a greater residual effect in subsequent seasons. The nutrient uptake efficiency of the system will be increased by plants that have more rapidly growing, deeper and more extensive root systems. The need for exact synchrony and crop demand can be reduced by storage of nutrients within the crop in excess of the crop's immediate requirement for growth. |
| 1129 | Myneni, S. | Formation of stable chlorinated hydrocarbons in weathering plant material | 2002 | Miscellaneous; Soil Organic Carbon | Journal | Science; 295; 1039-1041 | English | Hardcopy:Partial; PDF:Full | Field expt. to investigate the natural occurrence of chlorinated hydrocarbons | ... aromatic organo-Cl compounds are the most abundant forms of Cl in the weathered plant material and ... their concentration increased with humification. The concentration of aliphatic Cl remained constant or started to decline relative to the aromatic Cl as the humification of plant material continued. When compared with the Cl forms in humified plant material, the live plant tissue of plants has hydrated and H-bonded Cl- without any detectable chlorinated organics. However, their occurrence at increasing concentrations in the recently fallen plant leaves and in humified leaves in the leaf litter suggests that Cl- of living plant tissue is rapidly converted to organo-Cl.; ... halogenation of natural organic molecules may play a critical role in the stability and the storage of different types of C and other biologically important elements in soils ... |
| 101 | Mäder, P., Fließbach, A., Alföldi, T. & Niggli, U. | Yield of a grass-clover crop rotation and soil fertility in organic and conventional farming systems | 1999 | Biodynamic Farming; Organic Farming | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | 20-year field expt. to compare the crop yields and fertility of a soil under conventional, organic and biodynamic agriculture | The crop yield of the two biological systems was markedly lower than of the two conventional systems .. Average reduction over all crops figured about 20%. Potato yield in the biological systems was around 40% lower than in the conventional plots.; Most parameters that can be assessed to measure microbial pool sizes and microbial activity (basal respiration, enzyme activities) showed the same ranking among the treatments of the trial: NOFERT = CONMIN < CONFYM < BIOORG < BIODYN.; A steady increase of [the] metabolic quotient (qCO2) was stated in the order: BIODYN < BIOORG < CONMAN < CONMIN. The lower metabolic quotient in the organically fertilised systems, especially in the bio-dynamic system, indicates that these populations can utilise organic substances more efficiently than populations from minerally fertilised soils. |
| 1127 | Mäder, P., Fließbach, A., Dubois, D., Gunst, L., Fried, P. & Niggli, U. | Soil fertility and biodiversity in organic farming | 2002 | Biodynamic Farming; Organic Farming; Soil (General) | Journal | Science; 296; 1694-1697 | English | Hardcopy:Full; PDF:Full | 21-year study to compare the agronomic and ecological performance of organic and biodynamic farming systems with two conventional systems - one using exclusively chemical fertiliser and the other using chemical plus FYM. Nutrient input was 34 to 51% lower in the organic systems but the yields were only 20% lower. The energy use was only 13 GJ/ha/yr compared with 24 GJ/ha/yr in the purely chemical system. The biodynamic system had the highest soil microbial biomass and the greatest diversity of microorganisms and carabids. | |
| [also comm | Soil aggregate stability .. was 10 to 60% higher in the organic plots than in the conventional plots.; We found a positive correlation between aggregate stability and microbial biomass. | |||||||||
| 408 | Möller, A., Kaiser, K., Amelung, W., Niamskul, C., Udomsri, S., Puthawong, M., Haumaier, L. & Zech, W. | Forms of organic C and P extracted from tropical soils as assessed by liquid-state 13C- and 31P-NMR spectroscopy | 2000 | Phosphorus Cycling; Soil Organic Carbon | Journal | Aust. J. Soil Res.; 38; 1017-1035 | English | Hardcopy:Partial | NMR-spectroscopic study of the vertical distribution of C and P in four tropical soils - one arable and four forest soils | Highly weathered soils of the tropics are usually depleted in P-containing primary minerals. Release of plant-available P by rock weathering is therefore limited. .. tropical soils are generally rich in Al and Fe hydrous oxides and consequently they tend to fix polyvalent oxyanions such as phosphate irreversibly due to chemisorption and occlusion. Without fertilisation the pool of plant-available P .. is maintained primarily by the microbial-mediated mineralisation of plant and animal debris.; .. the increase of O-alkyl C proportions with depth resulted from microbial re-synthesis of carbohydrates and the decrease of aromatic and phenolic C .. reflected the breakdown of structural components of plant litter ..; Charred organic material releases aromatic C into the soil. The charred residues seem to be not stable .. |
| 967 | Möller, K. | Wie können die Erträge im ökologischen Kartoffelbau gesichert werden? | 2002 | Potato Growing | Journal | Ökologie und Landbau; 123 (3); 35-37 | German | Hardcopy:Partial; PDF:Full | Review of recent research on the factors affecting the yields of potatoes | .. da N-Versorgung und Krautfulebefall gemeinsam 73 Prozent der ermittelten Ertragsschwankungen erklren.; .. da der N-Versorgung eine sehr viel strkere Bedeutung fGr die Erklrung der Ertragsschwankungen zukommt als der Gesamtwachstumsdauer der Bestnde (und damit indirekt dem Krautfulebefall).; .. da ein Kartoffelbestand bis zu einer Zerst?rung von 50-60 Prozent der Blattflche kaum im Wachstum beeintrchtigt wird. Erst .. bei einer Krautzerst?rung von 70 bis 80 Prozent kommt das Knollenwachstum zum Erliegen. |
| 63 | Möller, K., Reents, H.J. | Einfluss verschiedener Zwischenfruechte nach Koernererbsen auf die Nitratgehalte im Boden und das Wachstum der Folgefrucht (Kartoffeln, Weizen) | 1999 | Cover Crops; Green Manure; Soil N Dynamics | Book | Hofmann, H. & Mueller, S. (hgbr); Vom Rand zur Mitte: Beitraege zur 5. Wissenschaftstagung zum oekologischen Landbau, Berlin; 109-112 | English | Hardcopy:Full | Expt. in which, after the harvest of a crop of peas, various cover crops were sown: rape, white clover (Perserklee), peas, tares and rye. They were ploughed in in Oct. or Feb. and followed by winter wheat and potatoes respectively. The best wheat yields, in terms of both quantity and quality, were after tares, followed by peas and white clover. Rape, either by itself or mixed with white clover or peas, gave much worse wheat yields. The potato yield was also best after tares and, in one of the years, worst after rape. Up to the time when they were ploughed in all the cover crops caused very marked reduction in soil nitrate content - to a level at which there was no danger of leaching. The greatest reduction in soil nitrate was caused by rape, either alone or in combination with other crops. Rape also reduced soil nitrate content after being ploughed in [through immobilisation ??]. While winter ploughing and spring sowing/planting gave rise to no significant nitrate leaching, the autumn ploughing and sowing gave dangerously high levels of soil nitrate, especially after a leguminous green manure. This might be reduced by ploughing the green manure in later. | |
| 560 | Müller, T., Thorup-Kristensen, K., Magid, J., Jensen, L.S. & Hansen, S. | Catch crops affect nitrogen dynamics in organic farming systems without livestock husbandry: simulations with the DAISY model | 2006 | Cover Crops; Stockless Farming; Soil N Dynamics | Journal | Ecol. Model.; 191; 538-544 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of winter-hardy & non-w-h. cover crops on leaching of N in org. farming. W-h. cover crops were rotavated into the soil at the beginning of April, which gave rise to a sudden increase in soil Nmin & Nmic, which gradualy declined again over 5-6 weeks & then remained fairly constant. The decomposition of winter-killed plant material started in winter and was over by early April. | |
| 521 | N'dayegamiye, A., Angers, D.A. | Organic matter characteristics and water-stable aggregation of a sandy loam soil after 9 yrs of wood-residue applications | 1993 | Lignin and CBW; Soil (General) | Journal | Can. J. Soil Sci.; 73 (1); | Study of the effect on soil of a 9-year biennial application of tree clippings at rates of 25, 50 and 100 Mg ha-1, with and without supplementary nitrogenous fertiliser. The soil C/N ratio remained roughly constant at about 21 except for the soil treated with nitrogenous fertiliser only, where the C/N ratio sank to 19.5. The SOC and total N contents rose significantly with increasing rate of wood residue application. In the case of C the increase was in both the light and heavy (humified) fractions. | .. wood-residue applications had no effect on water-stable macroaggregation.; [>250 m] | ||
| 522 | N'dayegamiye, A., Dube, A. | L'effet de l'incorporation de matieres ligneuses sur l'evolution des proprietes chimiques du sol et sur la croissance des plantes | 1986 | Lignin and CBW; Soil (General) | Journal | Can. J. Soil Sci.; 66; 623-631 | French | Hardcopy:Full | 4-year expt. to study the effect of amending the soil in the first and third years with chipped wood (mainly maple, birch and ash at rates of 25, 50 and 100 t/ha, with and without pig slurry) on the N and OM content, the cation exchange capacity, the C/N ratio of the soil and the crop yields. After four years the total N content of the soil increased when amended with chipped wood (more so when slurry was also used), but decreased slightly in the control and when slurry was used by itself. The C/N ratio had gone up to 20-21 compared with the value of 17 for the control and the plot treated with slurry alone, although biologically active soils generally have a C/N ratio under 12. The SOM content, which started as 4.6%, increased by about a quarter on chipped wood treated plots but went down on the control and on plots treated with slurry alone. In the second and fourth years, when no amendments were added to the soil, the crop yields were much higher than on the control plot, indicating that one year after amendment the N that was initially immobilised had become available to the crops again. | [translated]; The total N content of the soil remained at the same level as the control in all treatments with chipped wood. .. Also there was a strong immobilisation of the N of the slurry by the micro-organisms that decompose the lignin. |
| 906 | Naeem, S. | Biodiversity equals instability? | 2002 | Miscellaneous; Sustainability | Journal | Nature (Lond.); 416; 23-24 | English | Hardcopy:Partial; Wordperfect:Full | Review of arguments for and against the hypothesis that more biodiverse ecosystems are more stable, based on the paper by Pfisterer & Schmid (2002), who suggest that a more productive ecosystem is not necessarily more stable. | The central idea of niche complementarity is that a community of species whose niches complement one another is more efficient in its use of resources than an equivalent set of monocultures. .. niche complementarity can explain why higher diversity tends to lead to higher productivity .. one would expect that more efficient communities would fare better in the face of stress. .. complementarity among species in a diverse plot could be its downfall when faced with perturbation. Niche complementarity is disrupted and so the whole community suffers. But this is not a problem for less diverse plots. |
| 907 | Naeem, S., Thompson, L.J., Lawler, S.P., Lawton, J.H. & Woodfin, R.M. | Declining biodiversity can alter the performance of ecosystems | 1994 | Sustainability | Journal | Nature (Lond.); 368; 734-737 | English | Hardcopy:Full | Study of the performance of three ecosystems with differing biodiversities. The performance was judged on the basis of respiration, plant productivity, water retention, nutrient retention and decomposition. | Our study demonstrates .. that loss of biodiversity, in addition to loss of genetic resources, loss of productivity, loss of ecosystem buffering against ecological perturbation and loss of .. valuable resources, may also alter or impair the services that ecosystems provide. |
| 1318 | Nannipieri, P., Muccini, L. & Ciardi, C. | Microbial biomass and enzyme activities: production and persistence | 1983 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 15 (6); 679-685 | English | Hardcopy:Partial | Lab. expt. to study the increase and persistence of microbial biomass in soil amended with labelled nitrate and either glucose or ryegrass | Although microbial biomass and the biochemical activities tested increased in the soils treated with energy supplies, they eventually decreased to the level of the control soil.; newly synthesised biomass in a glucose- and nitrateamended soil was short-lived, .. decreasing rapidly and approaching the level in the unamended soil after 22 days. |
| 1737 | Narasimhan, K., Basheer, C., Bajic, V.B. & Swarup, S. | Enhancement of Plant-Microbe Interactions Using a Rhizosphere Metabolomics-Driven Approach and Its Application in the Removal of Polychlorinated Biphenyls | 2003 | Uncategorised | Journal | Plant Physiol. (Rockv.); 132; 146-153 | English | PDF:Full | ||
| 1130 | Naylor, R., Steinfeld, H., Falcon, W., Galloway, J., Smil, V., Bradford, E., Alder, J. & Mooney, H. | Losing the links between livestock and land | 2005 | Stockless Farming | Journal | Science; 310; 1621-1622 | English | Hardcopy:Full; PDF:Full | Review of the effects of the globalisation of the livestock industry on the environment | The most dramatic shift has been toward the production of monogastric animals, such as chickens and pigs, which use concentrated feeds more efficiently than cattle (or sheep) ..; .. a balanced Chinese diet of the early 1990s containing 20 kg meat per capita per year was produced from an average land area of just over 1000 m2/capita, whereas a typical Western diet required up to four times that area... If the world's population today were to eat a Western diet of roughly 80 kg meat per capita per year, the global agricultural land required for production would be about 2.5 billion hectares - two-thirds more than is presently used. |
| 1446 | Needelman, B.A., Wander, M.M., Bollero, G.A., Sims, G.K. & Bullock, D.G. | Interaction of tillage and soil texture: biologically active soil organic matter in Illinois | 1999 | Soil Organic Carbon; Tillage | Journal | Soil Sci. Soc. Am. J.; 63 (5); 1326-1334 | English | Hardcopy:Partial | Expt., based on samples taken over a two year period from conventional and zero tillage farms in Illinois, U.S.A., to study the effect of tillage practices on the quantity and vertical distribution of biologically active SOM (principally POM, which is composed of sand-sized incompletely decomposed organic materials) | Several long-term studies have suggested that no-till practices do not increase SOM sequestration in all situations.; .. the adoption of conservation tillage has not increased SOM storage in the upper 30 cm of Illinois farm fields. .. the use of NT increased accumulation of SOM in the surface 5 cm of the soil at the expense of SOM retained at depth.; Tillage may have had little effect .. in soils with high sand content because of limited unsaturated protective capacity. |
| 1319 | Neely, C.L., Beare, M.H., Hargrove, W.L. & Coleman, D.C. | Relationships between fungal and bacterial substrate-induced respiration, biomass and plant residue decomposition | 1991 | Green Manure; Soil Microorganisms | Journal | Soil Biol. Biochem.; 23 (10); 947-954 | English | Hardcopy:Partial | Expt. to study the decomposition of plant residues in relation to microbial respiration | Plant residues included crimson clover (Trifolium incarnatum), hairy vetch (Vicia villosa), crabgrass (Digitaria sanguinalis), winter rye (Secale cereale), grain sorghum (Sorghum bicolor) and chestnut oak (Quercus prinus) leaves.; Decomposition rate constants (k) were greatest for V. villosa, followed by T. incarnatum, D. sanguinalis, S. cereale, S. bicolor and Q. prinus.; .. on an individual species basis lignin content was best correlated to dry matter weight loss.. Total SIR [substrate-induced respiration] was greatest on T. incarnatum and V. villosa, followed by D. sanguinalis, S. bicolor, S. cereale and Q.prinus. Across all sample dates residue C/N ratio was the best predictor of total SIR. Measurements of potential fungal and bacterial activity by SIR as well as biomass-C estimates by direct counts indicated that fungi were the dominant decomposers of these surface residues.; For most residues lignin content through time exerted the greatest influence on fungal SIR and fungal biomass-C. |
| 473 | Neergaard, A. de & Gorissen, A. | Carbon allocation to roots, rhizodeposits and soil after pulse labelling: a comparison of white clover and perennial ryegrass | 2004 | Green Manure; Roots & Rhizodeposition | Journal | Biol. Fertil. Soils; 39; 228-234 | English | Hardcopy:Partial; Wordperfect:Full | Lab. study of C dynamics in grass/clover ley using C-14 | Root growth and rhizodeposition constitute a significant sink for assimilated C in plants and this is the major C energy input in most soil ecosystems, serving as a substrate for soil micro-organisms and playing an important role in the soil C balance.; .. ryegrass contributes substantially more to belowground C pools than the clover, suggesting that it is the ryegrass that is primarily responsible for the soil-carbon-building capacity observed in clover-grass leys.; 14C losses by shoot respiration stopped within 4 days and after this .. the input of assimilated 14C to belowground compartments was greater in grass (52%) than in clover (36%). During the next 4 weeks, 14C allocation belowground increased in grass (up to 75% at day 30), but remained constant in clover (37% at day 30). .. In clover, 14C was incorporated sooner into stable plant and soil pools and less was released in rhizodeposition than in grass. This was confirmed by the 14C in the soil microbial biomass that decreased fastest in the clover treatment.; After initiation of labelling, export of 14C from the assimilating leaf initiates within 30 min. Assimilated 14C has been recovered in roots and as root respiration after 0.5-2 h, as exudates after 2 h and in the soil microbial biomass after 3 h. Peak losses by respiration occur within the first days after the pulse label and the maximum translocation rate to belowground structures has been shown to occur between 0.5 and 3 h after labelling. |
| 130 | Neergaard, A. de & Magid, J. | Rhizosphere effects on soil microbial biomass size and turnover in a soil of high and low fertility | 2001 | Roots & Rhizodeposition; Soil Microorganisms | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study nitrogen dynamics in the rhizosphere | Within 2 weeks the total amount of SMB-N was roughly doubled in the rhizosphere of the two different soils [one fertilised and the other nutrient-depleted]. The effect of root deposition extended 1-3 mm into the soil, with the largest effect observed in the fertile soil. Increased decompos'n of labile .. SOM in the rhizosphere or revitalisation of dormant organisms was indicated by an increase in the SMB .. in the soil fractions nearest the root mat. This effect was not significant in the nutrient-depleted soil. |
| 618 | Neergaard, A. de, Hauggaard-Nielsen, H., Jensen, L.S. & Magid, J. | Decomposition of white clover and ryegrass components: C & N dynamics simulated with the DAISY soil organic matter sub-model | 2002 | Green Manure; Soil Organic Carbon; Soil N Dynamics | Journal | Eur. J. Agron.; 16; 43-55 | English | Hardcopy:Partial; PDF:Full | Modelling plant residue decomposition in a grass/clover ley | .. the root material was mineralised slower than the shoot material of either plant species ..; Root material, containing casparian strips, suberin, lignified tissues & other structural components, provides a more recalcitrant material than shoots.; The lignin content was initially poorly correlated with C mineralisation rates, but had the highest correlation of the evaluated parameters at the end of the expt.; Between day 22 & 29 correlation between the CO2 evolution rate & the water-soluble fractions dropped sharply, indicating that the water- soluble substances were no longer affecting C mineralis'n.; ..a pool consisting of microbial residuals could act as a buffer between the SMB and the mineral pool. The microbial residuals could consist of empty hyphae, cell walls and other recalcitrant substrates. |
| 662 | Neergaard, A. de, Magid, J. | Influence of the rhizosphere on microbial biomass and recently formed organic matter | 2001 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Eur. J. Soil Sci.; 52; 377-384 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study rhizosphere effects on the roots of ryegrass | The rhizosphere is the soil adjacent to roots that is directly influenced by rhizodeposits exuded from the roots.; Decomposable C is abundant as a result of rhizodeposition, whereas other nutrients are scarce because of competition between the plant and other organisms in the rhizosphere.; If roots are evenly distributed with a root length density of 15 cm cm-3 and an effective rhizosphere of 1 mm, half of the soil volume will be within this zone. Hence, the processes in the rhizosphere, rather than those in the bulk soil, may dominate in the topsoil of a ley.; The length of root hair .. rarely exceeded 1 mm.; .. microbial biomass at the root surface doubled during the first 8 days. At day 15 the microbial biomass had further increased .. and the rhizosphere effect had extended 2.5 mm .. The microbial 14C increased threefold near the roots .. as a result of assimilation of previously formed microbial residues..; .. the increase in microbial biomass in the rhizosphere is relatively small (2-10 times increase). |
| 276 | Neher, D.A. | Soil community composition and ecosystem processes: comparing agricultural ecosystems with natural ecosystems | 1999 | Organic Farming; Soil Microorganisms | Journal | Agrofor. Syst.; 45 (1-3); 159-185 | English | Hardcopy:Partial; PDF:Full | Review of the state of knowledge of links between agricultural and natural ecosystems | .. modern agriculture operates in a 'paradigm of ignorance.'; .. soil microbes and fauna play important roles in ecosystem function. Unfortunately, many modern agricultural practices correspond with a decline in abundance and alter the composition of soil communities, which subsequently affects ecological processes. Interruption to the cycling of C, N, phosphorus and/or water prevents crops from obtaining all requirements ..; Soil organisms play principal roles in several ecosystem functions, i.e. promoting plant productivity, enhancing water relations, regulating nutrient mineralisation, permitting decomposition and acting as an environmental buffer. Agricultural soils would more closely resemble soils of natural ecosystems if management practices would reduce or eliminate cultivation, heavy machinery and general biocides; incorporate perennial crops and organic material; and synchronise nutrient release and water availability with plant demand. |
| 357 | Neher, D.A., Barbercheck, M.E., El-Allaf, S.M. & Anas, O. | Effects of disturbance and ecosystem on decomposition | 2003 | Lignin and CBW | Journal | Appl. Soil Ecol.; 23; 165-179 | English | Hardcopy:Partial; PDF:Full | Rather inconclusive expt. to study the decomposition of different kinds of wood in the soil as a means of assessing the degree of disturbance of a natural ecosystem | Because decomposition of organic materials is measured easily and serves as an integrator of the collective activities of organisms within a soil food web, decomposition has the potential to serve as an indicator of soil condition. The rate of decomposition is a function of many characteristics and processes including chemical composition or quality of the organic material, temperature, moisture and composition of the decomposer community. Therefore, a significant difference in the rate of decomposition between similar sites may signal either a change in decomposer community or condition of biotic and abiotic resources at a site. |
| 114 | Neuhoff, D., Schulz, D.G. & Köpke, U. | Yield and quality of potato tubers: effects of different intensity and kind of manuring (biodynamic or organic) | 1999 | Biodynamic Farming; Organic Farming; Potato Growing | Book | ; Proc. 12th IFOAM Scientific Conference, Mar del Plata; | English | Hardcopy:Full; PDF:Full | Field expt. to compare the organic and biodynamic cultivation of potatoes. There was no significant difference in the dry weight yield in any of the trials. The only significant yield difference was in the fresh weight yield in one year on one site only. | Although present data show a small positive impact on yield and tuber quality, a clear advantage of using the biodynamic preparations cannot be established from these results. |
| 879 | Neumann, H., Loges, R. & Taube, F. | Bicropping im Ökologischen Landbau | 2002 | Clover Sward; Stockless Farming | Journal | Landwirtschaft ohne Pflug; 6; 18-21 | German | Hardcopy:Full | Gives the preliminary results of an expt. in the sowing of wheat into a white clover sward, compared with conventional cultivation. The Stute method is said to have the following weaknesses: low yields, weed problems, high cultivation costs and soil erosion (because the soil between the rows is bare through the winter). Bi-cropping, on the other hand, is said to have the following advantages: promoting soil organisms, contributing to soil fertility, reducing nutrient leaching in winter, saving energy and machine costs and fixing N in parallel to the growth of the cereal crop, thus avoiding the need for a legume course in the rotation. The results of the expt. so far show that bi-cropping reduces N leaching, increases earthworm populations and gives a lower yield of higher protein grain. | |
| 1641 | Neumann, H., Loges, R. & Taube, F. | Entwicklung eines pfluglosen Getreideanbausystems für den Ökologischen Landbau: Bi-cropping von Winterweizen und Weißklee | 2004? | Clover Sward; Stockless Farming | Website | English | Hardcopy:Partial | 4-year field expt. to compare clover-sward and conventional methods of growing winter wheat. The yields from the clover-sward method 34-60% lower than from the conventional, but the grain protein content was 12% higher. The oats and rye sown after ploughing the stubble yielded 30% more after the clover sward than after conventional production. Increasing the wheat row-spacing to 36 cm gave a further yield reduction of 12%, but mulching the clover between the wheat rows more than compensated for this, raising the grain yield by about 30%. | ||
| 1689 | Neumann, H., Loges, R., Taube, F. | Bicropping im ökologischen Winterweizenanbau: eine Alternative zum Anbausystem der Weiten Reihe? | 2003? | Clover Sward; Stockless Farming | Website | www.orgprints.org/00001207 | English | Hardcopy:Partial | 4-year field expt. to compare the growing winter wheat in the conventional way (with ploughing) with the clover sward method and the Stute methods at different row widths (12, 36 and 48 cm). Compared with conventional growing, in the clover sward method the yields were 50-75% lower, chiefly as a result of a much lower mineral nitrogen content in the soil and of competition from the clover, but the grain protein content was 11% higher. The wide-row system also gave a reduced yield (9-12% lower) and a slightly (1%) higher protein content. | Beim Anbau im Weite-Reihe-Hacksystem besteht je nach Fruchtfolge und Standort die Gefahr von Bodenfruchtbarkeitsproblemen. In stark reliefiertem Gelnde kann es aufgrund der Gber Winter mangelnden Bodenbedeckung durch die weiten Reihen zustzlich zu erheblichen Erosionsschden kommen.; Durch den Verzicht auf den Einsatz des Pfluges und die ganzjhrige Bodenbedeckung bietet das [Bi-cropping]Verfahren neben dem Schutz des Bodens folgende Vorteile: Minderung der Nhrstoff- bzw. Nitrat-Auswaschung, Einsparung von Energie- und Maschinenkosten, biologische N2-Bindung parallel zum Wachstum des Getreides und dadurch Einsparung von Hauptfrucht-Leguminosen in der Fruchtfolge. |
| 1320 | Neve, S. de & Hofman, G. | N mineralization and nitrate leaching from vegetable crop residues under field conditions: a model evaluation | 1998 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (14); 2067-2075 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the fate of N from vegetable (lettuce and Brassicas) residues in a sandy loam soil | .. N losses by leaching in winter can be high when vegetable crop residues are incorporated, even when there is little mineral N in the soil at the time of incorporation.; N losses by leaching resulting from crop residue incorporation can be severe, but even mineralisation from soil organic matter alone can cause important N losses when the soil is left bare. |
| 1321 | Neve, S. de, Sáez, S.G., Daguilar, B.C., Sleutel, S. & Hofman, G. | Manipulating N mineralization from high N crop residues using on- and off-farm organic materials | 2004 | Compost & Biocontrol; Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 36; 127-134 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the N dynamics in soil amended with a high N crop residue (leek leaves) alone & in conjunction with 12-wk-old compost, 20-wk-old compost, straw & tannic acid. Tannic acid was used as an example of polyphenols, which reduce N availability by inhibiting N mineralisation. The soil samples were amended with molasses to prime the re-mineralisation of the N. The 12-week compost gave the highest degree of immobilisation & re-mineralisation. | All materials added .. except the low C/N compost, resulted in significant immobilisation of the residue N.; With straw, max. immobilisation was observed about 50 days after the start of the incubation and then immobilised N started to re-mineralise gradually.; In the [12-wk] compost treatments the immobilised leek residue N was probably in a labile form (newly formed & largely unprotected microbial biomass and metabolites) and was readily re-mineralised through the strong stimulation of microbial activity in soil by the molasses addition. |
| 236 | Nguyen, M.L. & Haynes, R.J. | Energy and labour efficiency for three pairs of conventional and alternative mixed cropping (pasture-arable) farms in Canterbury, New Zealand | 1995 | Energy in Agriculture; Organic Farming | Journal | Agric. Ecosyst. Environ.; 52; 163-172 | English | Hardcopy:Full; PDF:Full | Comparing the energy and labour efficiency of conventional and organic mixed farms | .. livestock production in NZ has a lower energy input. For example, for sheep meat production on the conventional study farms, the energy requirement ranged from 11.3 to 16.3 MJ kg-1 protein. This is considerably lower than the 465 and 348 MJ kg-1 protein reported for mutton and beef production respectively in the UK (White, 1975) and the 423 MJ kg-1 protein calculated by Pimentel et al. (1980) for intensive feedlot beef production in USA.; In this study the mean fertiliser N input to wheat and barley was 55 kg N ha-1 or about 10 kg N t-1 grain. This is considerably lower than the 20-30 kg N t-1 for wheat found in the UK (Leach, 1975) or the 35 kg N t-1 reported for wheat in North Dakota (Pimentel et al., 1983).; Stanhill (1990) showed that crop yields under organic farming are commonly within 10-20% of those obtained under conventional agriculture. However, in this study .. the ratio of alternative to conventional yields for cereals ranged from 0.58 to 0.75 .. The reasonably high cereal grain yields (5-7 t ha-1) in association with the relatively low fertiliser N inputs resulted in an energy efficiency ratio for conventional production (range 9.9-17.4, mean 13) that was considerably higher than that normally observed in USA and Europe. For example, in the USA Pimentel et al. (1983) calculated values of 4.5 for maize and 2.4 for spring wheat production.; Over the whole rotation, the annual energy input per hectare for conventional agriculture .. was approximately twice that for alternative farms .. |
| 237 | Nguyen, M.L., Haynes, R.J. & Goh, K.H. | Nutrient budgets and status in three pairs of conventional and alternative mixed cropping farms in Canterbury, New Zealand | 1995 | Organic Farming | Journal | Agric. Ecosyst. Environ.; 52; 149-162 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the nutrient budgets of organic and conventional farms | N budgets were positive at all three alternative farms, with biological N2 fixation accounting for most or all of the N input. One alternative farm had positive P and S budgets because of additions of compost, phosphate rock and elemental S... at the other two alternative farms, net removal of P .. occurred. Levels of total .. P and available P in soils were also lower on alternative than conventional farms. Production on these alternative farms is relying on soil reserves of P .. & additions of P ,, will be required .. to sustain current production levels. Organic C content .. tended to be higher under alternative than conventional pastoral management. |
| 396 | Ni, J.Q., Hendriks, J., Coenegrachts, J. & Vinckier, C. | Production of CO2 in a fattening pig house under field conditions. I. Exhalation by pigs | 1999 | Greenhouse Gases | Journal | Atmos. Environ.; 33 (22); 3691-3696 | English | Hardcopy:Full | The CO2 exhalation rate of pigs was measured under differing conditions and a model was developed on the basis of the expt.al results. This model was compared with previously reported theoretical models. | The measured TCERs [tranquil CO2 exhalation rates] ranged from 41.5 to 73.9 g CO2 per hour per pig for pigs from 32 to 105 kg. When pigs were very active, the CO2 exhalation rate could be about 200% of the TCER ..; Daily mean CO2 exhalation rate .. was about 110% of the TCER. |
| 397 | Ni, J.Q., Vinckier, C., Hendriks, J. & Coenegrachts, J. | Production of CO2 in a fattening pig house under field conditions. II. Release from the manure | 1999 | Greenhouse Gases | Journal | Atmos. Environ.; 33 (22); 3697-3703 | English | Hardcopy:Full | The CO2 released from pig manure was measured by two different methods and a model was developed on the basis of the expt.al results. This model was compared with previously reported theoretical models. | The mean CO2 release rates .. of 135 days' field measurement was .. 1123 g/h .. the average ratio of the CO2 release rate and the TCER [tranquil CO2 exhalation rate] .. was 37.5%, ranged from 23.8% for total pig weight of 1501-2000 kg to 58.2% for total pig weight of 5001-5500 kg. .. for a fattening pig of 70 kg the CO2 release was 539 g/d. |
| 1484 | Nicholson, F.A., Chambers, B.J., Mills, A.R. & Strachan, P.J. | Effects of repeated straw incorporation on crop fertiliser N requirements, soil mineral nitrogen and nitrate leaching losses | 1997 | Soil N Dynamics | Journal | Soil Use Manag.; 13; 136-142 | English | Hardcopy:Full | 11-year field expt. to test the effects on soil and crop N supply of straw disposal by burning and incorporation, either by just ploughing or by a prior tine cultivation followed by ploughing. Straw disposal technique had no consistent effect on crop yield, crop N uptake, SOC, TN (total N), RMN (readily mineralisable N) or SMN (soil mineral N). | .. changes in soil OC due to straw incorporation are likely to take many years to reach significance .. |
| 1322 | Nicolardot, B. & Molina, J.A.E. | C & N fluxes between pools of soil organic matter: model calibration with longterm field experimental data | 1994 | Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 26 (2); 245-251 | English | Hardcopy:Partial | Modelling the flux of C and N between SOM pools | Four organic pools were included .. viz. plant residues (decay rate constant = 0.3 d-1); microbial biomass with a labile (0.33d-1) and a resistant (0.04 d-1) component; humads (0.006 d-1); and stable OM (5.5 x 10-5 d-1).; .. the active soil organic fraction represented 13-35% of the total SOM. |
| 991 | Nierop, K.G.J. | Origin of aliphatic compounds in a forest soil | 1998 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 29 (4); 1009-1016 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the insoluble non-hydrolysable fraction in the soil of a beech/Scots pine forest by pyrolysis and thermochemolysis | The .. non-aliphatic pyrolysis products .. indicate the presence of polysaccharides, proteins/peptides, tannins & (very little) lignin. .. The alkenes & alkanes are commonly [said] to be derived from insoluble non-hydrolysable aliphatic polymers, such as cutan & suberan.. until now these polymers have only been observed in aboveground plant tissues, such as cuticles & barks.; .. alkenes & alkanes aren't restricted to pyrolysates of cuticles & periderms of above-ground plant parts, but can also be derived from roots. Pyrolysis & thermochemolysis data of the soil samples reveal unambiguous evidence for the presence of suberin & a suberan-like polymer & .. show the importance of root material to SOM. |
| 992 | Nierop, K.G.J. & Filley, T.R. | Assessment of lignin and (poly-)phenol transformations in oak (Quercus robur) dominated soils by 13C-TMAH thermochemolysis | 2007 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 38; 551-565 | English | Hardcopy:Partial; PDF:Full | Field expt. to test the suitability of 13C-labelled tetramethylammonium hydroxide thermochemolysis to study the phenolic organic matter in an oak forest soil | Lignin, demethylated lignin, hydrolysable tannin and other phenolic acids could be distinguished .. indications of the relative distribution of these sources among the soil horizons was determined.; .. a progressive lignin alteration was found .., but the differences in litter input among plant materials (leaves, bark, branches, roots) also potentially affected the lignin patterns within and between both profiles. .. important insights into the rapid changes in lignin chemistry between organic and mineral horizons were provided, as this method permitted enhanced distinction between fresh source input and decomposition. |
| 1323 | Nobili, M. de, Contin, M., Mondini, C. & Brookes, P.C. | Soil microbial biomass is triggered into activity by trace amounts of substrate | 2001 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 33 (9); 1163-1170 | English | Hardcopy:Full; PDF:Full | Lab. expt. to test the effect on the soil mocrobial biomass of treatment with trigger solutions (trace amounts of glucose, amino acids or root exudates). They caused the biomass to evolve about 2-5 times more C as CO2 than was contained in the original trigger solution. | Addition of trigger solutions to soils recently amended with cellulose produced an accelerated rate of mineralisation of the cellulose ..; .. while SOM can provide sufficient energy for considerable basal metabolism of the soil microorganisms .. for many months without further organic inputs .., it provides insufficient energy to increase or even maintain this biomass. .. the biomass must largely rely on accumulated endogenous energy reserves for long-term survival.; A relatively small investm't in energy to maintain the cell in a state of metabolic alertness, to take immediate advantage of a food event, .. could therefore be a better strategy, in evolutionary terms than one dependent upon emergence from a dormant state.; shift .. to an active state is initiated by the cells sensing molecular signals or trigger molecules derived from the substrate. |
| 358 | Noordwijk, M. van | Decomposition: driven by nature or nurture? | 1996 | Mineralisation; Soil Organic Carbon | Journal | Appl. Soil Ecol.; 4; 1-3 | English | Hardcopy:Partial; Wordperfect:Full | Review of mechanisms controlling the decompostion of plant residues in soil | Research on the decomposition of mixed residues has .. yielded examples both of increased and decreased N mineralisation: synergy may be common where residues of different C/N ratios are mixed and N mineralised from low C/N.. residues can be used by organisms attacking the low quality litters; inhibiting effects may occur where substances such as soluble polyphenolics from one residue affect decomposition of nearby other organic sources; The substantial amounts of charcoal found in many (sub)tropical soils, especially of savanna ecosystems with frequent fire, show that long-term carbon sequestration may be based on other processes than so far envisioned .. Fires might contribute more to C sequestration in the long term than natural vegetation and its nearly complete processes of decomposition. |
| 1061 | Noordwijk, M. van & Cadisch, G. | Access and excess problems in plant nutrition | 2002 | Mineralisation; Mulch; Soil N Dynamics | Journal | Plant Soil; 247; 25-40 | English | Hardcopy:Partial | Review of global crop nutrient problems | .. use efficiencies of 30-40% for fertiliser N characterise the main grain production systems of the world.; .. a plant residue with a low C/N ratio, low lignin and polyphenol content, may be considered high quality in terms of a fast N release, but will be considered of low quality for the purpose of mulch for soil erosion protection.; A basic concept in nutrient access and excess issues is that of mean residence time in the rooted soil layers .. high C/N and/or high lignin/polyphenol content will increase residence time, but such effects are more difficult to control to ensure at the same time sufficient nutrient availability for current demand. |
| 277 | Noordwijk, M. van & Ong, C.K. | Can the ecosystem-mimic hypothesis be applied to farms in African savannahs? | 1999 | Agricultural Ecology; Sustainability | Journal | Agrofor. Syst.; 45 (1-3); 131-158 | English | Hardcopy:Partial; PDF:Full | Review of the agricultural possibilities for ecosystem mimicry | The first ecosystem mimic hypothesis suggest clear advantages if man-made land use systems do not deviate greatly in their resource use patterns from natural ecosystems typical of a given climatic zone. The second hypothesis claims that additional advantages will accrue if agroecosystems also maintain a substantial part of the diversity of natural systems.; Strong competition between plants adapted to years with different rainfall patterns may stabilise total system productivity ..; The currently prevailing negative perception of competition in mixed systems remains valid if one component dominates the total value the farmer expects to derive from a system. |
| 264 | Norman, M.J.T. | Energy inputs and outputs of subsistence cropping systems in the tropics | 1978 | Energy in Agriculture | Journal | Agro-Ecosystems; 4; 355-366 | English | Hardcopy:Full | Some examples from the literature of studies of tropical subsistence agriculture are re-examined from the viewpoint of energy inputs and outputs. Subsistence energy balances are calculated. Basal metabolic and gross work energy expenditures for humans and draft animals are given as: 0.25, 1.00, 1.5 and 6.0 MJ/hour respectively. Average net human energy input for rain-fed cropping systems are give as 631 MJ/ha for hoe cultivation and 202 MJ/hectare when draft animals are used. Output\input ratios for rain-fed hoe cultivation vary from 10:1 to 20:1, where input means only crop production energy. However, gross farm family energy expenditure exceeds crop production energy by a factor of 2.5 to 5. So, if input means gross energy expenditure, the output/input ratio may be as low as 1.5. In a bad season, when yields are only half the average, the ratio will be only 0.75. | .. the farmer or farm worker is expending energy throughout the day and not merely when he is directly engaged in crop production and ancillary activities. Hence in calculating subsistence energy balance the appropriate input is his gross energy expenditure throughout the day or year. |
| 1131 | Normile, D. | Consortium aims to supercharge rice photosynthesis | 2006 | Miscellaneous | Journal | Science; 313; 423 | English | Hardcopy:Partial; PDF:Full | Review of a proposed research project to genetically engineer a C4 rice plant | ... IRRI has not been able to increase the optimal rice yield appreciably in 30 yrs. The Green Revolution was about producing a new body for the rice plant. Dramatic increases in yields resulted from the introduction of semi-dwarf varieties that could absorb more fertiliser & take the increased weight of the grains without keeling over ...; ... C4 plants are 50% more efficient at turning solar radiation into biomass. Theoretical predictions and some expts at IRRI indicate that a C4 rice plant could boost potential rice yields by 50% while using less water and fertiliser. |
| 703 | Norse, D. | Multiple threats to regional food production: environment, economy, population? | 1994 | Miscellaneous; Sustainability | Journal | Food Policy; 19 (2); 133-148 | English | Hardcopy:Partial | Review of possible future threats to food security | .. environmental degradation, economic growth, the population explosion and climate change pose present or potential threats to food security.; Over- simplification has generated the claim that these factors present an unprecedented challenge to world food security. [The] alternate perspective holds that technological advances and policy corrections could overcome food production constraints and achieve sustainable growth. Both views need to be challenged, though the paper concludes that the latter carries more strength. |
| 238 | Nortcliff, S. | Standardisation of soil quality attributes | 2002 | Soil (General) | Journal | Agric. Ecosyst. Environ.; 88; 161-168 | English | Hardcopy:Full | A review of the literature on the question of soil quality indicators | .. soils frequently perform several functions simultaneously, not independently. Any evaluations of the quality of the soils must consider this multi-functional role.; .. although there [is] considerable activity devoted to the development and evaluation of sustainable soil management systems, together with the development of associated soil quality indices, these efforts are often hampered by a lack of agreement on what constitutes acceptable measurements of sustainability.; SOM has been widely promoted as a key indicator of soil quality, particularly in agricultural soils .. but there has been no consensus on what the critical level of SOM should be in an agricultural soil .. |
| 909 | Northup, R., Yu, Z., Dahlgren, R. & Vogt, K.A. | Polyphenol control of nitrogen release from pine litter | 1995 | Mineralisation; Soil N Dynamics | Journal | Nature (Lond.); 377; 227-229 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the uptake of N by trees growing on nutrient-poor soil | .. the polyphenol conc'n of decomposing Pinus .. litter controls the proportion of N released in dissolved organic forms relative to mineral forms (NH4+ + NO3-). .. this feedback to soil conditions controls the dominant form in which litter N is mobilised, facilitating N recovery .., minimising N availability to competing organisms and attenuating N losses from leaching and denitrification. .. Plant communities adapted to strongly acidic and infertile soils can sustain productivity despite low N availabilities and high potential for N loss from the ecosystem.; DON is found to be the dominant vehicle of N transport .. most of this DON is not composed of free amino acids or proteins but rather is assoc'd with humic substances such as protein-tannin complexes.; Tannins form strong complexes with proteins that are sparingly soluble & recalcitrant to decompos'n. .. but some ectomycorrhizal fungi associated with coniferous forests have been shown to utilise this N source. .. Ericoid mycorrhizae .. also .. produce extracellular enzymes that mineralise N from protein-tannin complexes. |
| 1563 | Nyborg, M., Solberg, E.D., Izaurralde, R.C., Malhi, S.S &, Molina-Ayala, M. | Influence of long-term tillage, straw and N fertilizer on barley yield, plant N-uptake and soil-N balance | 1995 | Soil N Dynamics; Tillage | Journal | Soil Tillage Res.; 36; 165-174 | English | Hardcopy:Partial | 11-year field expt. to study the effect of tillage, straw and N fertiliser on yield and N uptake of barley. Both yield and N uptake were down (by about 14%) under zero tillage. | Retention rather than removal of straw tended to reduce barley yield for the initial 6 years and 2 year at site 1 and site 2 respectively.; Immobilisation of N by straw occurred during the first few years of the expt., but disappeared thereafter.; Retention of straw, annual addition of urea N at 56 kg/ha and zero tillage practices contributed to an increase in organic C .. |
| 1062 | Nziguheba, G., Palm, C.A., Buresh, R.J. & Smithson, P.C. | Soil phosphorus fractions and adsorption as affected by organic and inorganic sources | 1998 | Phosphorus Cycling | Journal | Plant Soil; 198 (2); 159-168 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the fate of P from plant residues (tithonia and maize), with and without superphosphate, over 16 weeks | Phosphorus deficiency is one of the largest constraints to food production in tropical African soils due to low native P and high P fixation by iron and aluminium oxides. .. Organic inputs generally cannot provide sufficient P for crop growth due to low tissue P concentrations, but organic inputs can increase P availability in P-fixing soils. Organic anions formed by decomposition of organic inputs can compete with P for the same adsorption sites and thereby increase P availability in soil. Organic inputs may thus allow a more complete utilisation of soil P by plants. .. organic materials can increase or decrease the P adsorption of a soil depending on the type of organic material, its P concentration and the amount added. Organic materials containing 0.31% or more P decreased the soil P adsorption capacity while those containing 0.22% or less P increased the amount of P adsorbed.; A high-quality organic material .. increased labile .. soil P over a 16-week period .. due to a net release of P from the plant, but also to a decrease in P adsorption capacity.; .. the combination of tithonia with TSP [super-phosphate] .. consistently increased microbial C and P. This .. may be associated with increased biological activity and mineralisation of more recalcitrant fractions of P. |
| 908 | Näsholm, T., Ekblad, A., Nordin, A., Giesler, R., Högberg, M., Högberg, P. | Boreal forest plants take up organic nitrogen | 1998 | Mineralisation; Soil N Dynamics | Journal | Nature (Lond.); 392; 914-915 | English | Hardcopy:Partial; PDF:Full | Field expt. to demonstrate the uptake of organic N by various boreal plants by injecting 13C,15N-labelled glycine into the mor layer of a pine forest | ... these plants, irrespective of their different types of root-fungal associations (mycorrhiza), by-pass nitrogen mineralisation. ... at least 91, 64 and 42% of the nitrogen from the absorbed glycine was taken up in intact glycine by the dwarf shrub, the grass and the trees respectively. Rates of glycine uptake were similar to those of 15N-ammonium. |
| 577 | Näsholm, T., Huss-Danell, K. & Högberg, P. | Uptake of organic nitrogen in the field by four agriculturally important plant species | 2000 | Soil N Dynamics | Journal | Ecology; 81 (4); 1155-1161 | English | Hardcopy:Full; PDF:Full | Field expt. to show the uptake of organic N (in the form of 13C,15N-labelled glycine) by some plants used in agriculture (Phleum pratense, Trifolium hybridum, T. pratense, Ranunculus acris) | .. a minimum of 19-23% of the glycine-derived N was taken up as intact amino acid.; Although .. organic N might be less important for agricultural plants than for forest plants, ... a substantial fraction of the total N uptake could theoretically be met by organic N sources in agricultural settings. |
| 1324 | O'Hara, G.W. & Daniel, R.M. | Rhizobial denitrification: a review | 1985 | Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 17 (1); 1-9 | English | Hardcopy:Full | Review of current knowledge of denitrification by nitrogen-fixing bacteria | .. N losses are occurring from some field soils as a result of rhizobial denitrification. This denitrification can occur in normally aerated soil .. the N losses are similar in magnititude to the N gained by symbiotic rhizobial N fixation, ..; .. anaerobic & symbiotic cells were capable of immediate denitrification .. aerobically grown cells required a 60-min anaerobic incubation before denitrification would occur .. |
| 549 | O'Neill, R.V., Kahn, J.R., Duncan, J.R., Elliott, S., Efroymson, R., Cardwell, H. & Jones, D.W. | Economic growth and sustainability: a new challenge | 1996 | Sustainability | Journal | Ecol. Appl.; 6 (1); 23-24 | English | Hardcopy:Full | Review of the paper by Arrow et al. (1995) 'Economic growth, carrying capacity and the environment' | The Science article focused on the inverted U relationship between environmental quality and GDP. [With growth in GDP the environment gets worse and then it gets better.] But this empirical relationship adopts a trivial definition of environmental quality : emissions of specific pollutants, compared across cast differences in culture, resources and scales. A subset of pollutants in a limited number of places cannot be accepted as surrogates for the complex interactions between economic growth and the environment on which growth depends.; Economic development may achieve air that does not smell like rotten eggs, but may still cause irrevocable damage to our life-support system. |
| 1564 | O'Sullivan, M.F. & Simota, C. | Modelling the environmental impacts of soil compaction: a review | 1995 | Soil (General) | Journal | Soil Tillage Res.; 35; 69-84 | English | Hardcopy:Full | A theoretical study of soil compaction, combining theoretical and empirical models of soil compaction with models of environmental impact (on soil N and energy use) and models of crop production (crop growth and root growth). | Denitrification tends to increase with compaction.; The efficiency of N use by crops tends to be decreased by compaction.; .. the activity of soil organisms depends strongly on the amount of biomass produced by crop plants ..; Root growth is directly affected by physical factors other than mechanical impedance, namely water, aeration and temperature ..; one of the main factors affecting structure and compactability is the SOM content. Compactability can be decreased markedly by small increases in OM. |
| 141 | O'Sullivan, M.F., Vinten, A.J.A. & Ball, B.C. | Carbon and nitrogen losses after ploughing out grass and grass-clover swards | 2001 | Soil Organic Carbon; Soil N Dynamics; Tillage | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | 3-yr field expt. to study the environmental effect of ploughing out grass- clover swards | The residual N value from long-term low-input grass-clover swards to subsequent arable crops was lower than the residual N value from moderately fertilised grass swards .. due to the lower N content of the macro-OM (roots etc) in the grass-clover swards before cultivation. In the first year after ploughing out of long-term grass swards, less nitrate leached from winter cereals than from spring cereal stubble... Reduced tillage reduced mineral N losses to drains, but on this soil type it also resulted in a larger requirement for fertiliser N .. No-tillage and deep ploughing retained more carbon than conventional ploughing. However there were large losses of N as N2O from no-tillage and initially significant losses of nitrate from deep ploughing. |
| 1660 | O.E.C.D. | The Energy Problem and the Agro-food Sector | 1982 | Energy in Agriculture | Book | ; The Energy Problem and the Agro-food Sector; | English | Hardcopy:Partial | global energy consumption in agriculture | |
| 409 | Oades, J.M. & Waters, A.G. | Aggregate hierarchy in soils | 1991 | Soil Organic Carbon | Journal | Aust. J. Soil Res.; 29 (6); 815-828 | English | Hardcopy:Partial | Lab. study of aggregates in 3 differently textured soils | .. aggregate hierarchy occurs in Alfisols and Mollisols because organic materials are the dominant stabilising agents in larger aggregates, but in the Oxisol oxides are dominant stabilising agents and prevent the expression of aggregate hierarchy caused by organic materials.; .. microscopic studies indicated the potential role of roots and hyphae in the stabilisation of larger aggregates and for fragments of roots as nuclei for smaller aggregates. |
| 474 | Oberson, A., Besson, J.M., Maire, N. & Sticher, H. | Microbiological processes in soil organic P transformations in conventional and biological cropping systems | 1996 | Organic Farming; Phosphorus Cycling | Journal | Biol. Fertil. Soils; 21 (3); 138-148 | English | Hardcopy:Partial | Field study of organic P in soils after 13 years of conventional and organic cropping | Labile organic P, extracted by 0.5M NaHCO3, was not affected by the farming systems.; The level of phosphatase activity and mineralisation of organic C [in the organic systems] indicated a higher turnover of organic substrates and thus of organic P ..; .. residual P consists of more than 7)% organic P ..; .. chemically resistant organic P participates in short-term accumulation and mineralisation processes. |
| 1063 | Oglesby, K.A. & Fownes, J.H. | Effects of chemical composition on nitrogen mineralisation from green manures of seven tropical leguminous trees | 1992 | Green Manure; Mineralisation; Soil N Dynamics | Journal | Plant Soil; 143; 127-132 | English | Hardcopy:Partial | Lab. expt. in which leaves and succulent twigs from leguminous trees were incubated with soil to determine the rates and controls of net N release | Cumulative net N mineralisation was negatively correlated with initial soluble polyphenol content in the early phases of decomposition (1-8 weeks) and with initial lignin content in the later phases (4-12 weeks). Neither initial percent N for lignin/N ration were strongly correlated with N mineralisation.; .. cumulative net N mineralisation for all species was positive from 2.5 weeks onward .. |
| 564 | Ohashi, M., Gyokusen, K. & Saito, A. | Contribution of root respiration to total soil respiration in a Japanese cedar (Cryptomeria japonica D. Don) artificial forest | 2000 | Roots & Rhizodeposition | Journal | Ecol. Res.; 15; 323-333 | English | Hardcopy:Partial; PDF:Full | Field expt. to separate root respiration from total soil respiration | The average contribution of root respiration to total soil respiration.. was 49%. After taking root decomposition into consideration, the contribution of root respiration to soil respiration increased from 49 to 57%. |
| 1738 | Olchin, G.P., Ogle, S., Frey, S.D., Filley, T.R., Paustian, K. & Six, J. | Residue Carbon Stabilization in Soil Aggregates of No-Till and Tillage Management of Dryland Cropping Systems | 2008 | Uncategorised | Journal | Soil Sci. Soc. Am. J.; 72; 507-513 | English | PDF:Full | ||
| 1325 | Olk, D.C., Cassman, K.G., Schmidt-Rohr, K., Anders, M.M., Mao, J.D. & Deenik, J.L. | Chemical stabilisation of soil organic nitrogen by phenolic lignin residues in anaerobic agroecosystems | 2006 | Lignin and CBW; Soil N Dynamics | Journal | Soil Biol. Biochem.; 38; 3303-3312 | English | Hardcopy:Full; PDF:Full | Review of current understanding of the reasons for decline in rice yields | During the Green Revol'n of the 1960s, plant breeders developed early maturing semi-dwarf varieties of lowland rice that allow two or even three rice crops per year...; During the subsequent decades, yields gradually declined in some of these long-term expts.; Soil analyses from some of these systems have found an accumulation of phenolic lignin compounds in SOM. Phenolic compounds covalently bind nitrogenous compounds into recalcitrant forms ..; Anaerobic decompos'n of crop residues may be the key feature of anaerobic cropping systems that promotes the accumulation of phenolic lignin residues and hence the covalent binding of soil N.; Schmidt-Rohr etal (2004) used SPIDER to identify agronomically significant quantities of anilide N in the mobile humic acid fraction, a young ligninrich humic fraction .. the slower mineralisation of anilide N could contribute substantially to the decreased availability of soil N. |
| 663 | Olk, D.C., Samson, M.I. & Gapas, P. | Inhibition of nitrogen mineralization of young humic fractions by anaerobic decomposition of rice crop residues | 2007 | Lignin and CBW; Soil Organic Carbon; Soil N Dynamics | Journal | Eur. J. Soil Sci.; 58; 270-281 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the reasons for declining rice yields in continuous irrigated lowland rice production | Phenolic cpds. accumulated in MHA [mobil humic acid] fraction of the rice-rice rotation, especially with anaerobic decomposition of crop residues.; .. anaerobic decomposition of crop residues is [probably] the primary cause of the longterm decrease in crop uptake of soil N in continuous rice rotations.; .. phenolic lignin cpds. chemically bind organic N in continuous rice cropping where anaerobic decomposition is practised. |
| 1017 | Olofsdotter, M., Jensen, L.B. & Courtois, B. | Improving crop competitive ability using allelopathy - an example from rice | 2002 | Allelopathy; Organic Farming | Journal | Plant Breed.; 121; 1-9 | English | Hardcopy:Full; PDF:Full | Review of allelopathy and its occurrence in rice cultivars | Weeds are one of the major constraints to plant production worldwide. Successful breeding for disease and insect resistant cultivars .. have lead to a reduction in the demand for fungicides and insecticides, while herbicide use is still increasing worldwide.; .. chemical defence mechanisms through either mycorrhiza symbioses or allelopathy are part of the competition between plants.; .. allelopathy accounted for 34% of overall competitive ability in rice. For strongly allelopathic cultivars allelopathy was the dominant factor determining competitive ability.; Elroy Rice .. defined allelopathy as the effect(s) of one plant on other plants through the release of chemical compounds in the environment. This definition is largely accepted and includes both positive (growth promoting) and negative (growth inhibiting) effects. |
| 810 | Oltjen, J.W. & Beckett, J.L. | Role of ruminant livestock in sustainable agricultural systems | 1996 | Stockless Farming | Journal | J. Anim. Sci.; 74; 1406-1409 | English | PDF:Full | Arguments for keeping animals in farming are presented: they convert resources from pasture, crop residues and wastes into food edible for humans; land that is too poor or too erodible to cultivate becomes productive; forages are grown on 25% of arable land to minimise water and soil erosion; crops and livestock together make sustainable practices such as crop rotations and production of legume or grass forages possible; livestock improve living standards on family farms, providing more employment opportunities in rural areas. Figures are presented to demonstrate that dairy farming increases the amount of humanly digestible protein available. | It is not always true that cropland used for animal feed production could produce as many or more calories and protein when that cropland is used to produce human food crops.; Too often the opponents of animal agriculture evaluate the desirability of animal production on gross caloric efficiency or protein intake/output values. However, in many cases the feeds used in animal production are not humanly consumable and in order to determine the true efficiency of animal production, humanly consumable energy and protein intake should be used for efficiency comparisons. |
| 278 | Ong, C.K. & Leakey, R.R.B. | Why tree-crop interactions in agroforestry appear at odds with tree-grass interactions in tropical savannahs | 1999 | Sustainability | Journal | Agrofor. Syst.; 45 (1-3); 109-129 | English | Hardcopy:Partial; Wordperfect:Full | Review of function of trees in agroforestry systems in comparison with tropical savanna | Mature savannah trees have a high proportion of woody above-ground structure compared to foliage, so that the amount of water saved (largely by reduction in soil evaporation) is greater than water lost through transpiration by trees. By contrast, in agroforestry practices such as alley cropping, where tree density is high, any beneficial effects of the trees on microclimate are negated by reductions in soil moisture due to increasing interception losses and tree transpiration.; .. alley cropping with fast-growing regularly pruned trees is analogous to early succession characterised by a high degree of competition, while parkland agroforestry with widely spaced trees is analogous to later stage succession with opportunities for temporal and spatial complementarity. |
| 1739 | Oorts, K., Bossuyt, H., Labreuche, J., Merckz, R. & Nicolardot, B. | Carbon and nitrogen stocks in relation to organic matter fractions, aggregation and pore size distribution in no-tillage and conventional tillage in northern France | 2007 | Uncategorised | Journal | Eur. J. Soil Sci.; 58; 248-259 | English | PDF:Full | ||
| 1132 | Oost, K. van, Govers, G., Quine, T.A. & Heckrath, G. | Comment on 'Managing Soil Carbon'(I) | 2004 | Greenhouse Gases; Soil Organic Carbon | Journal | Science; 305; 1567B | English | Hardcopy:Full; PDF:Full | Comment on Lal et al (2004) to the effect that tillage-induced erosion (followed by redistribution of soil within the field or by deposition elsewhere) leads to C sequestration rates that are of the same order of magnitude as the projected annual potential C sequestration rate of 10-40 g C/m2 from conversion of agricultural land to zero tillage. | |
| 1133 | Oost, K. van, Quine, T.A., Govers, G., Gryze, S. de, Six, J., Harden, J.W., Ritchie, J.C., McCarty, G.W., Heckrath, G., Kosmas, C., Giraldez, J.V., da Silva, J.R. & Merckx, R. | The impact of agricultural soil erosion on the global carbon cycle | 2007 | Miscellaneous | Journal | Science; 318; 626 | English | Hardcopy:Partial | Review of the data on erosion of arable soils & its effect on the soil C sink | We estimated a global carbon sink of 0.12 (range 0.0-6-0.27) Pg of carbon per year resulting from erosion in the world's agricultural landscapes. Our analysis directly challenges the view that agricultural erosion represents an important source or sink for atmospheric CO2. |
| 1607 | Osada, T., Rom, H.B. & Dahl, P. | Continuous measurement of nitrous oxide and methane emission in pig units by infrared photoacoustic detection | 1998 | Greenhouse Gases | Journal | Trans. ASAE (Am. Soc. Agric. Eng.); 41; | English | Hardcopy:Full | Field expt. to measure the emission of CO2, NH3, N2O and CH4 from pig houses over a full fattening period of 8 weeks. The live weight increased from 32 kg to 86 kg (average = 59 kg). CO2 emission (excluding manure) was 0.97 kg/pig/day, which gives an average of 16.5 g/kg liveweight/day. Manure was produced at a rate of 0.3 m3/pig and had a dry matter content of 5.4%. CO2 emission from manure was 17.85 g/pig/day. | |
| 1326 | Owen, A.G. & Jones, D.L. | Competition for amino acids between wheat roots and rhizosphere microorganisms and the role of amino acids in plant N acquisition | 2001 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 33 (4/5); 651-657 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the uptake of organic acids by wheat roots | .. the plant roots could only capture on average 6% of the added amino acid with the remainder captured by the microbial biomass. .. organic N may be of only limited consequence in high-input agricultural systems. We suggest that this is a result of the higher conc'ns of NO3- in agricultural soil solutions, the slow movement of amino acids in soil relative to NO3-, the rapid turnover of amino acids by soil microorganisms and the poor competitive ability of plant roots to capture amino acids from the soil solution. |
| 1134 | Pacala, S.W., Hurtt, G.C., Baker, D., Peylin, P., Houghton, R.A., Birdsey, R.A., Heath, L., Sundquist, E.T., Stallard, R.F., Ciais, P., Moorcroft, P., Caspersen, J.P., Shevliakova, E., Moore, B., Kohlmaier, G., Holland, E., Gloor, M., Harmon, M.E., Fan, S.M., Sarmiento, J.L., Goodale, C.L., Schimel, D. & Field, C.B. | Consistent land- and atmosphere-based U.S. carbon sink estimates | 2001 | Greenhouse Gases | Journal | Science; 292; 2316-2319 | English | Hardcopy:Full | The rate of accumulation of C in the soil of the United States is estimated by two methods. Arable soils in the U.S. sequestered C at an annual rate of 0.22 Mg/ha, compared with Houghton et al. (1999)'s figure of 0.76 Mg/ha. 0.035 Pg C per year was exported from the U.S. by rivers, which, if it all came from arable land, would amount to 0.19 Mg/ha. | For the period 1980-89 .. the United Sates was a sink for C .. of 0.30 to 0.58 Pg C per year .. the net flux of C from the atmosphere to the land was .. 0.37 to 0.71 Pg C per year.; These estimates are considerably larger than earlier land-based estimates of 0.08 to 0.35 Pg C per year .. [They are not] significantly different from the values of 0.81 to 0.84 Pg C per year the authors calculate for the United Sates based on the .. atmospheric analysis of Fan et al. (1998) .. [It is also] equivalent to 20 to 40 per cent of [US] fossil fuel emissions [???].; .. emission rates of CO2 from combustion of fossil fuel have increased almost 40% in the past 20 years but the amount of CO2 accumulating in the atmosphere has stayed the same or even declined slightly.; Before th middle of the 19th century about 80 million ha of land burned annually [in the U.S.] .. The area burned has now been reduced by nmore than 95% .. |
| 239 | Pacini, C., Wossink, A., Giesen, G., Vazzana, C. & Huirne, R. | Evaluation of sustainability of organic, integrated and conventional farming systems: a farm and field-scale analysis | 2003 | Organic Farming; Sustainability | Journal | Agric. Ecosyst. Environ.; 95; 273-288 | English | Hardcopy:Partial; PDF:Full | Expt. to compare the financial and environmental sustainability of organic and conventional farms | The OFSs [organic farming systems] perform better than .. CFSs [conventional farming systems] with respect to N losses, pesticide risk, herbaceous plant biodiversity and most of the other environmental indicators. However, on hilly soils erosion was found to be higher in OFSs than in CFSs.; .. herbaceous plant biodiversity and crop production are not always conflicting variables.; .. the fact that OFSs in most cases environmentally perform better than .. CFSs does not mean ipso facto that they are sustainable when compared to the intrinsic carrying capacity and resilience of a given ecosystem. |
| 1327 | Palm, C.A., & Sanchez, P.A. | Nitrogen release from the leaves of some tropical legumes as affected by their lignin and polyphenolic contents | 1991 | Green Manure; Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 23 (1); 83-88 | English | Hardcopy:Partial | Lab. expt. in which rice straw and leaf material from several leguminous plants was incubated for 8 weeks in order to study the N dynamics. The cumulative concentrations of extractable NH4+ and NO3- ranged from 0.8 to 30.1 and from 36.2 to 44.5 g N/g soil respectively. The ratio of NH4+ to NO3- lay in the range 2-20% except for 3 species. | The amount of N mineralised during the 8 weeks as compared to the control soil ranged from +46% to -20% of the N added in plant material. Net mineralisation was not correlated to %N or %lignin in the leaf material but was found to be negatively correlated to the polyphenolic concentration.; Polyphenolics could bind to organic N (e.g. amino-acids and proteins) in the leaves, making N unavailable, or could bind to the soluble forms of organic N released from the leaves, forming resistant complexes in the soil. |
| 240 | Palm, C.A., Gachengo, C.N., Delve, R.J., Cadisch, G. & Giller, K.E. | Organic inputs for soil fertility management in tropical ecosystems: application of an organic resource database | 2001 | Soil Organic Carbon | Journal | Agric. Ecosyst. Environ.; 83; 27-42 | English | Hardcopy:Partial; PDF:Full | A database of organic materials that can be used to provide fertility and SOM in tropical farming systems. For each material is given, at least, the plant species (of which almost 300 are mentioned), part of the plant used (e.g. fresh leaves, fallen leaves, stems or roots) and the N, P and K concentrations. Other data given, when available, includes resource quality parameters such as macronutrient, lignin and polyphenol content, decomposition rates, N release rates, digestibility indices, location, climate, soil and the source of the information. | As the quantity of traditional organic inputs, such as crop residues and animal manures, declines in many farming systems as a result of reduced yields and other uses for animal feed, fuel and fibre, farmers are now faced with finding alternative or supplementary sources of nutrients. |
| 241 | Palm, C.A., Swift, M.J. & Woomer, P.L. | Soil biological dynamics in slash-and-burn agriculture | 1996 | Miscellaneous; Sustainability | Journal | Agric. Ecosyst. Environ.; 58; 61-74 | English | Hardcopy:Partial; PDF:Full | Review of the effect of slash-and-burn agriculture on the soil | The productivity & sustainability of traditional slash-and-burn agriculture relies on the short-term disruption through clearing & burning, and subsequent restoration through fallowing, of biological processes & components. The failure of many current slash-and-burn systems is a result of the long-term uncoupling of the processes, through increased cropping & decreased fallow periods. |
| 188 | Panesar, B.S. & Fluck, R.C. | Energy productivity of a production system: analysis and measurement | 1993 | Energy in Agriculture | Journal | Agric. Sys.; 43; 415-437 | English | Hardcopy:Partial | Energy productivity theory is applied to U.S. agriculture. Multifactor and total factor productivities (MFP and TFP) are calculated for agricultural systems. The weighted aggregation of different energy inputs and a new method for the segregation of energy outputs have been developed and used to calculate MFP. In contrast to the energy productivity calculated using TFP and the traditional method of MFP, that using the new method of MFP was found to be responsive to changes in technology and energy situations. | The energy productivity of the United States' agricultural system decreased with time until it reached its minimum level in 1979. After 1979 it increased until at least 1983 ..; .. during 1948-83 .. the rate of decrease of energy productivity decreased with time .. [whereas] capital MFP remained essentially constant ..; Inputs to a production system can be broadly classified as energy, capital and management. Managerial capabilities affect consumption of capital and energy and thereby affect output. Thus we presume that managerial effects are included in capital and energy and that all production systems inputs could be classed as capital and energy. |
| 189 | Pankhurst, C.E., Doube, B. & Gupta, V.V.S.R (eds.) | Biological Indicators of Soil Health | 1999 | Soil (General) | Journal | Agric. Sys.; 60 (1); | English | Hardcopy:Partial | A review of a book dealing with biological indicators of soil health. The book produces no evidence of a correlation between biological activity in the soil and its long-term health. | .. they define soil health as the continued capacity of soil to function as a living system to sustain biological productivity, promote human, animal and plant health and maintain water and air quality. This definition properly focuses on the external impacts of soil health on human and environmental welfare. A major weakness of this book, however, is a lack of evidence that the proposed biological indicators bear any relationship to specific soil properties that affect human, animal or plant health or water and air quality.; Future efforts to find biological indicators of soil health and long-term sustainability should .. focus on and compile data that relate biological indicators to plant productivity and potential negative impacts of land management on the environment. |
| 475 | Pankhurst, C.E., Kirkby, C.A., Hawke, B.G. & Harch, B.D. | Impact of a change in tillage and crop residue management practice on soil chemical and microbiological properties in a cereal-producing red duplex soil in NSW, Australia | 2002 | Soil Microorganisms; Tillage | Journal | Biol. Fertil. Soils; 35; 189-196 | English | Hardcopy:Full; PDF:Full | 3-year field expt. to study the effect of tillage and crop residue mgmt. on the soil and soil microorganisms | A change from DD [direct drilling] to CC [ploughing with straw burning] or SI [ploughing with straw incorporation] practice resulted in a significant decline, in the top 0-5 cm of soil, in organic C, total N, electrical conductivity, NH4-N, NO3-N, soil moisture-holding capacity, microbial biomass and CO2 respiration [and] .. in the microbial quotient (the ratio of microbial biomass C to organic C).; The ratio of fungal to bacterial fatty acids in the 0- to 5-cm soil also declined .., reflecting a shift towards a more bacteria-dominant microflora as a result of increased tillage of the soil. |
| 279 | Pannell, D.J. | Social and economic challenges in the development of complex farming systems | 1999 | Sustainability | Journal | Agrofor. Syst.; 45 (1-3); 393-409 | English | Hardcopy:Partial; Wordperfect:Full | Review of factors affecting the feasiblity of new farming systems | the most important challenges in developed countries are: (a) developing a farming system that is in fact more profitable than current practice; (b) assessing whether a system is in fact more profitable than current practice; and (c) overcoming the problem of deep uncertainty about the technology. In developing countries one must add the additional challenges of (d) high interest rates/high discount rates; and (e) insecure or inequitable land tenure. |
| 1661 | Paoletti, M.G., Pimentel, D. (eds.) | Biotic Diversity in Agroecosystems - a symposium on agroecology and conservation issues | 1992 | Agricultural Ecology | Book | Paoletti, M.G. & Pimentel, D. (eds.); Biotic diversity in agroecosystems: a symposium on agroecology and conservation; | English | See under Ilnicki, R.D., Enache, A.J. (1992) | ||
| 54 | Parente, G. & Frame, J. | Alternative uses of white clover | 1993 | Clover Sward; Green Manure; Stockless Farming | Book | ; F.A.O. REUR Technical Service 29, White clover in Europe: State of the Art; | English | Hardcopy:Partial | A review of the uses of white clover | An important alternative use for white clover is as a support to arable cropping systems .. While ploughing [the clover] in is a traditional way, more novel methods have been investigated, e.g. the direct drilling of maize into a perennial ryegrass/white clover mixture previously harvested for silage, with the regrowth between cultivated strips being cut and left as a mulch.; Preliminary work on the concept of growing cereals in a white clover understorey has shown promise. |
| 746 | Parfitt, R.L., Theng, B.K.G., Whitton, J.S. & Shepherd, T.G. | Effects of clay minerals and land use on organic matter pools | 1997 | Mineralisation; Soil Organic Carbon | Journal | Geoderma; 75; 1-12 | English | Hardcopy:Partial | Expt. to study the distribution of OM in various native and arable soils, including permanent pasture | There is a relatively labile OM fraction that is much younger & is more similar to plant materials. It is usually present in the largest particle fractions of soils & is composed of carbohydrates, proteins, polyphenols (e.g. lignin) & alkyl groups. The carbohydrates & proteins are readily degraded in soils, whereas the polyphenols decompose more slowly. The alkyl groups associated with the fine clay fractions are the most recalcitrant.; .. the OM [in some soils] is stabilised by iron oxides & allophane .. both of which have a small particle size & a large specific surface.; .. a measure of specific surface area may be useful .. a modifying parameter to give a closer simulation of C & N turnover. |
| 242 | Parkinson, D. | Linkages between resource availability, microorganisms and soil invertebrates | 1988 | Soil Organic Carbon; Soil Microorganisms | Journal | Agric. Ecosyst. Environ.; 24 (1-3); 21-32 | English | Hardcopy:Partial | A study of the factors affecting OM decomposition in cool temperate forest | The patterns and rates of organic-matter decomposition are determined by the qualities and quantities of the materials being decomposed, the 'inoculum potential' of the decomposer organisms, the competitive and synergistic interactions between these organisms and by climatic variables (temperature and moisture).; .. considerable biological activity occurs in decomposing litter during the rigorous winter period. Freeze-thaw cycles appeared to be less important than simple freezing and biological activity beneath snow. |
| 1328 | Parshotam, A., Saggar, S., Searle, P.L., Daly, B.K., Sparling, G.P. & Parfitt, R.L. | Carbon residence times obtained from labelled ryegrass decomposition in soils under contrasting environmental conditions | 2000 | Soil Organic Carbon | Journal | Soil Biol. Biochem.; 32 (1); 75-83 | English | Hardcopy:Full; PDF:Full | Lab expt. to study the turnover of OM in pasture soils amended with ryegrass | .. between 28 and 36% of the 14C remained at the end of 12 months and between 18 & 32% at the end of 2 yr; in our previous study between 20 & 45% remained at the end of 12 months and between 14 and 40% at the end of 2 yr. Previously soils with very high specific surface areas were used and system MRTs [mean residence times] ranged between 2 & 4 yr; in this present expt surface areas were lower and MRTs were between 1 & 2.5 yr. In this study MRTs for microbial biomass 14C were also lower.. soil surface area may have a greater effect than do environmental factors on turnover of both microbial biomass C and OM. |
| 476 | Paré, T., Dinel, H., Schnitzer, M. & Dumontet, S. | Transformations of carbon and nitrogen during composting of animal manure and shredded paper | 1998 | Compost & Biocontrol | Journal | Biol. Fertil. Soils; 26; 173-178 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the mineralisation of C & N during composting | .. composting resulted in a decrease of total, water-soluble and acid-hydrolysable C, whereas non-hydrolysable C remained relatively constant during the composting period. .. NH4+-N and acid-hydrolysable N were converted into NO3--N and non-hydrolysable N forms towards the end of the composting period.; under relatively abundant C conditions, .. the addition of N stimulates microbial growth & respiration & thus C mineralisation.; .. humus-like associated N contributes to lower the C/N ratios, but it requires much more microbial energy to access this N form for C mineralis'n.; N cpds present in the non-hydrolysable fraction of composts are not easily available to microorganisms ..; .. as composting progressed, the prop'n of lignin in composted materials increased. |
| 664 | Paterson, E. | Importance of rhizo-deposition in the coupling of plant and microbial productivity | 2003 | Roots & Rhizodeposition; Soil Microorganisms | Journal | Eur. J. Soil Sci.; 54 (4); 741-750 | English | Hardcopy:Full | Review of research done on the interaction between plant roots & soil microorganisms. Root exudates can affect the rhizosphere directly, especially hydrogen ions exuded by root-pumps, which can alter the pH of the rhizosphere. But most of the effects of root exudates are indirect, for example, through the coupling of plant and microbial productivity and through priming effects. | Where C is available in excess of N, fungal popul'ns can become more prevalent, because they have larger C/N ratios and proportionately smaller requirements for N.; The turnover of the microbial biomass in the rhizosphere is rapid (order of hours to days) and is driven by the input of deposits from roots. .. This sequence of events: microbial immobilis'n of N induced by rhizodeposition, the release of N as the microfauna consume the microbes and the acquisition of that N by the plants, is termed the microbial loop.; .. the balance between mineralisation & immobilis'n of N in soil depends strongly on the availability of mineral N & the recalcitrance of the native OM. Input of energy-rich rhizodeposits with large C/N ratios to soils with large amounts of mineral N is likely to result in strong immobilis'n of N, because microbes will use rhizodeposits more readily than the older OM.; .. small additions of organic material to a soil often invoke the release of relatively large amounts of C & N from OM in that soil. The effect is termed priming .. |
| 761 | Paterson, E., Hall, J.M., Rattray, E.A.S., Griffiths, B.S., Ritz, K. & Killham,K. | Effect of elevated CO2 on rhizosphere carbon flow and soil microbial processes | 1997 | Roots & Rhizodeposition; Soil Organic Carbon; Soil Microorganisms | Journal | Glob. Change Biol.; 3; 363-377 | English | Hardcopy:Partial; PDF:Full | Review of methods for measuring changes in soil microbial activity and rhizodeposition as a consequence of increasing atmospheric CO2 pressure | Direct effects of increased aboveground CO2 conc'n on soil microbial communities and processes are unlikely, due to the high .. pCO2 of the soil atmosphere in most terrestrial ecosystems.; The predominant finding with respect to litter quality for plants grown in elevated CO2 environments is for increased C/N ratios & such changes would be expected to directly influence decomposition processes and microbial decomposer communities in soil. Organic inputs from living roots to surrounding soil (rhizosphere), which include exudates, secretions & sloughed off cells, are collectively termed rhizodeposition. It is likely that this form of input will also be changed at elevated CO2. |
| 38 | Patriquin, D.G., Baines, D. & Abboud, A. | Soil fertility effects on pests and diseases | 1995 | Organic Farming | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 161-174 | English | Hardcopy:Full | Field expt. to study the effect of soil N content on the susceptibility of broad beans to black-fly attack | As a test of the hypothesis that plants more dependent on N2-fixation are less attractive to aphids than plants that are less dependent on N2-fixation, we examined the nodulation of adjacent aphid-infested and non-infested plants of equivalent stature. As predicted, the average per plant nodule weight of aphidinfested plants was significantly lower than that of uninfested plants. |
| 26 | Paul, E.A. & Juma, N.G. | Mineralisation and immobilisation of soil nitrogen by microorganisms | 1981 | Mineralisation; Soil N Dynamics | Book | Clark, F.E. & Rosswall, T. (eds.); Terrestrial Nitrogen Cycles: Processes, Ecosystem Strategies and Management Impacts; | English | Hardcopy:Partial | Various N cycles in different systems are described and simulated with a model | .. total organic soil N was divided into four fractions, one living fraction the microbial biomass - and three dead ones - the active, the stabilised and the old fraction.; The old fraction [accounted] for about 50% of total soil N. |
| 747 | Paul, E.A., Collins, H.P. & Leavitt, S.W. | Dynamics of resistant soil carbon of Mid-western agricultural soils measured by naturally occurring 14C abundance | 2001 | Soil Organic Carbon | Journal | Geoderma; 104; 239-256 | English | Hardcopy:Partial; PDF:Full | Field expt. to measure the size and mean residence time of the SOC fraction not hydrolysed by 6M HCl (NHC) | Mid-western US soils .. were found to contain from 33% to 65% of their SOC in the non-hydrolysable fraction. .. The MRTs of the SOC of surface horizons of soil ranged from modern to 1100 years with an average of 560 years. !!FThe MRT increased to an average of 1700 years in the 25-50-cm depth increment and 2757 years at 50-100 cm. The NHC was 1340 years greater at the surface and 5584 years at depth. The MRTs of the total SOC were inversely correlated to sand and directly related to clay content. Silt did not have a significant effect on the MRT of total SOC, but was significantly correlated with the MRT of the NHC. |
| 1447 | Paul, E.A., Follett, R.F., Leavitt, S.W., Halvorson, A., Peterson, G.A. & Lyon, D.J. | Radiocarbon dating for determination of soil organic matter pool sizes and dynamics | 1997 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 61 (4); 1058-1067 | English | Hardcopy:Partial | Expt. to determine the size and age of the resistant SOM fractions in various soils by 14C dating. Soil samples were subjected to hydrolysis with 6M HCl. The non-hydrolysable residues, consisting of a relatively biologically inactive pool of OM (mostly humus & other lignin-related substances) & constituting about half of the total SOM, was radiocarbon dated. The oldest sample was about 7000 years old, found on one site at a depth of 90 to 120 cm. Most of the samples taken from the plough layer (0 to 30 cm) measured between 1500 and 3000 years. | Three SOM pools, decaying according to first-order reaction kinetics, have been shown to best describe C dynamics.; Acid hydrolysis removes proteins, nucleic acids & polysaccharides.. [It] does not solubilise the lignin, phenols & some cellulose of plant residues. [It} left 42% of the C of wheat straw & 34% of the C of maize residues undissolved.; Humic acids were the oldest materials .. fulvics were much younger and humins were intermediate in age.; The resistant fractions are so old that, although of great importance from a structure, water, nutrient and pesticide adsorption standpoint, they play a small role in nutrient cycling.; C-14 dating gives us pool sizes and fluxes of the resistant fractions as well as an indication of the overall pedogenic characteristics. 13C and longterm incubation will measure the dynamics of the more active fractions. |
| 359 | Paul, E.A., Harris, D., Collins, H.P., Schulthess, U., Robertson, G.P. | Evolution of CO2 and soil carbon dynamics in biologically managed, row-crop agroecosystems | 1999 | Greenhouse Gases; Soil Organic Carbon | Journal | Appl. Soil Ecol.; 11 (1); 53-65 | English | Hardcopy:Partial; PDF:Full | Measurement of the CO2 fluxes from lab. incubated soils, in conjunction with acid hrydrolysis (to determine the size of the resistant pool) and C dataing (to determine the mean residence times), was used to study the size and dynamics of the three soil C pools: active, slow and resistant. The sizes and the MRTs were 2.5%, 42.5%, 55% and 44 days, 10 years and 170-1435 years respectively. | The CO2 flux was not significantly correlated with soil moisture. Better correlations were obtained with air temp. than with .. soil temperatures.; The efflux of CO2-C .. was seasonally dependent in the cultivated crop [but] .. the less-disturbed sites had fairly constant CO2 flux over the growing season ..; .. the old resistant pool .. contains 56% of the SOC in the disturbed sites with a MRT of 1435 years. .. [it] does not participate in short term changes but stabilises structure, supplies exchange complexes and other adsorption sites. The active pool is of the same general size as the microbial biomass in these plots. It is not comprised exclusively of this source as it is the entry point of residues into the soil ..; The sharp change in the lab. evolution rates that occurs between 50 and 70 days demarcates the active and slow pools. The slow pool with more than 40% of the C and a turnover rate under these conditions of 9-13 years in the field is central to soil fertility and ecosystem sustainability. .. While 40% of fertiliser 15N was left in the SOM after growth of a fertilised crop, growth of a subsequent crop removed only 5-10% of the 15N. Later crops removed 1-2% of the stored soil N each year.; Nine percent of the CO2 was predicted to evolve from the surface residue, 70% from the 0 to 25 cm depth and 21% from lower depths. |
| 20 | Paustian, K., Agren, G.I. & Bosatta, E. | Modelling litter quality effects on decomposition and soil organic matter dynamics | 1997 | Soil Organic Carbon | Book | Cadisch, G. & Giller, K.E. (eds.); Driven by Nature: Plant Litter Quality and Decomposition. C.A.B. International; | English | Hardcopy:Partial; Wordperfect:Full | Review of existing mathematical models of SOM decay and of how they represent the various components of litter quality | We propose a conceptual framework in which litter quality can be broken down into chemical, physical & inhibitory factors. .. these factors can be articulated as modifiers of growth or uptake rates and substrate availability. .. litter quality has been incorporated into most decomposition models in a fairly rudimentary way by defining discrete litter fractions or pools. More recently, the concept of a continuous quality spectrum has been formalised. Despite substantial differences in structure and assumptions many different decomposition models can successfully fit the time-course of different types of decomposing litter. |
| 1485 | Paustian, K., Andren, O., Janzen, H.H., Lal, R., Smith, P., Tian, G., Tiessen, H., Noordwijk, M. van & Woomer, P.L. | Agricultural soils as a sink to mitigate CO2 emissions | 1997 | Greenhouse Gases; Lignin and CBW; Stockless Farming | Journal | Soil Use Manag.; 13; 230-244 | English | Hardcopy:Full | Review of the capacity of agricultural soils to act as a sink for CO2. The C levels of natural soils can be regarded as the practical upper limit to C storage potential, but there are exceptions. Some cultivated soils, as a result of intensive management, high OM inputs or increased P fertilisation, have C levels much higher than the original native soil. | By itself C sequestration in agricultural soils can only make modest contributions (e.g. 3-6% of total fossil C emissions) to mitigating greenhouse gas emissions.; estimated pre-cultivation C stocks of 222 Pg on the present area of cultivated land. .. estimated current agricultural soil C stocks at 168 Pg ..; The effects of litter quality also seem to have a more lasting effect on total soil C levels.. Most forage & annual crop residues have lignin contents in a relatively narrow range, usually between 5% & 15%. .. in less convent'l systems, such as agroforestry, additions of recalcitrant woody tissues and tree leaves, having high C/N ratios and high lignin content, have been proposed as a means of building soil C stocks and regulating soil nutrient availability. Animal manure [FYM] is also effective in building soil C stocks.Animal manures have a high proportion of recalcitrant materials, because labile cpds have been selectively removed in digestion. Not all the gain in soil C from manure applications represents a net removal of atmospheric CO2; much is simply a redistribution .. |
| 1565 | Paustian, K., Elliott, E.T. & Carter, M.R. | Tillage and crop management impacts on soil C storage: use of long-term experimental data | 1998 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 47 (3-4); vii-xii | English | Hardcopy:Partial; Wordperfect:Full | Brief review of research on tillage and manaagement effects on soil C | Global estimates .. put the potential for C sequestration through improved agricultural practices at 0.40.6 Pg (billion metric tonnes) per year, or about 610% of current C emissions from fossil fuels.; No-till not only reduces soil disturbance and thus decomposition but also enables more water conservation, making possible more intensive crop rotations hence greater C inputs.; Reilly and Fuglie give a perspective on whether yields can be expected to continue to increase into the future and what factors are likely to constrain future yield growth.; The classic Old Rotation cotton expt. in Alabama is described by Mitchell and Entry. Their results highlight the importance of N supply, in this case either through fertiliser addition or legume cover crops, in increasing C inputs and maintaining soil C levels. |
| 1448 | Paustian, K., Parton, W.J. & Persson, J. | Modelling soil organic matter in organic-amended and nitrogen-fertilised long-term plots | 1992 | Green Manure; Lignin and CBW; Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 56; 476-488 | English | Hardcopy:Partial | The rate of SOM accumulation was studied over a thirty-year period under bare fallow and under cereal crops with chemical fertiliser and various organic soil amendments. After 30 years of treatments with these amendments the C content of the soil (initially 1.5% or 3.7 kg/m-2) increased by 10-30% (in line with the lignin contents) when the straw and sawdust were supplied with supplementary N. Without that N they only increased the SOC content by 0.8% and 14% respectively. The C/N ratio (originally 9.4) fell in the control plots to around 8.5 and rose to around 10 after the sawdust treatments. The SOC content fell by 8%, 22% and 30% in the chemical-only, no-amendment and bare-fallow plots respectively. | Most of the treatment differences in SOM could be explained by the rate of OM input, its lignin content and C/N ratio plus the effect of N fertiliser on belowground C inputs.; .. OM levels with FYM addition exceed treatments with comparable additions of GRM [green manure] or crop residues..; .. the proportion of OM input that goes into the metabolism and production of microbial biomass is controlled by OM quality (i.e. structural vs. metabolic plant residue).; The availability of N, either in organic forms or as fertiliser, has a major influence on SOM levels. |
| 1329 | Paustian, K., Schnürer, J. | Fungal growth response to carbon and nitrogen limitation: application of a model to laboratory and field data | 1987 | Soil Microorganisms | Journal | Soil Biol. Biochem.; 19 (5); 621-629 | English | Hardcopy:Partial | Modelling the growth of fungal hyphae in conditions of varying C & N supply | Fungi are prominent decomposers of N-poor plant polymers, which comprise a large proportion of OM inputs to soil. Mechanisms that may enable fungi to grow in N-deficient environments include lysis and reassimilation from degenerate hyphae [in the case of lignolytic fungi], directed growth to areas of locally higher N concentration and translocation of cytoplasm to hyphal apices from mycelium in substrate-depleted regions.; .. fungi are able to remain active at lower water potentials than other soil microorganisms.; .. more rapid hyphal extension at low N occurred at the expense of total biomass increase.; Model results suggested that hyphal length increases were highly subsidised by translocation of cytoplasm.; It is likely that the degree to which fungi can tightly recycle their own N is highly species specific and is .. most strongly developed in woo-decaying fungi. |
| 429 | Paustian, K., Six, J., Elliott, E.T. & Hunt, H.W. | Management options for reducing CO2 emissions from agricultural soils | 2000 | Greenhouse Gases; Tillage | Journal | Biogeochemistry (Dordr.); 48 (1); 147-163 | English | Hardcopy:Partial; PDF:Full | A review of agronomic methods of reducing CO2 emission from soil. Includes a detailed description of how SOM cycles between free POM and aggregates. | Crop-based agriculture occupies 1.7 billion hectares globally, with a soil C stock of about 170 Pg. .. terrestrial systems have contributed as much as half of the increases in CO2 emissions from human activity in the past two centuries .. Of the past anthropogenic CO2 additions to the atmosphere, about 50 Pg C came from the loss of SOM in cultivated soils.; Physical disturbance associated with intensive soil tillage increases the turnover of soil aggregates and accelerates the decomposition of aggregate- associated SOM. No-till increases aggregate stability and promotes the formation of recalcitrant SOM fractions within stabilised micro- and macroaggregate structures. Expts. using 13C natural abundance show up to a two-fold increase in mean residence time of SOM under notill v. intensive tillage. .. fossil fuel inputs for different management practices need to be factored into a total agricultural CO2 balance. |
| 748 | Payan, F., Jones, D.L. & Beer, J. | Dynamics of size-density fractions of soil organic matter following the addition of tree litter to organic coffee farms | 2007 | Lignin and CBW; Soil Organic Carbon | Journal | Geoderma; 141; 15-22 | English | Hardcopy:Partial; PDF:Full | Field expt. to test the effect on the SOM of leguminous tree pruning amendment | Soil macro-OM represented only a small proportion of total SOM (3-6% of total). .. the total amount of SOM did not change over time; significant temporal changes in the size of the macroorganic fraction were observed, which appeared to be largely independent of the mgmt regime. The light density fraction seemed to be the most responsive fraction & .. it may provide a qualitative indicator of the active fraction of SOM; the size of the macroorganic fraction did not provide a reliable indicator of the rate of litter decomposition or nutrient release. |
| 1740 | Pearson, J. & Stewart, G.R. | The deposition of atmospheric ammonia and its effects on plants | 1993 | Uncategorised | Journal | New Phytol.; 125; 283-305 | English | PDF:Full | ||
| 1741 | Peigné, J., Ball, B.C., Roger-Estrade, J. & David, C. | Is conservation tillage suitable for organic farming? A review | 2007 | Uncategorised | Journal | Soil Use Manag.; 23; | English | PDF:Full | ||
| 388 | Pel, R., Oldenhuis, R., Brand, W., Vos, A., Gottschal, J. & Zwart, K.B. | Stable-isotope analysis of a combined nitrification-denitrification sustained by thermophilic methanotrophs under low-oxygen conditions | 1997 | Compost & Biocontrol; Soil Microorganisms | Journal | Appl. Environ. Microbiol.; 63 (2); 474-481 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the nitrogen dynamics during composting at low oxygen partial pressure (pO2 = <2%) | .. substantial N loss .. was not due to the volatilisation of ammonia but was the result of combined nitrification & denitrification. Thermophilic methanotrophs were probably responsible for the observed non-autotrophic ammonia oxidation. .. this is the first time that nitrification has been demonstrated to exist (as a quantitatively important process) at a temp. exceeding 40$C.; .. methanotrophs indeed are capable of a quantitatively important oxidation of ammonia. This extensive oxidation of ammonia even occurs in the absence of methane, suggesting that elements of a lithotrophic metabolism are involved. |
| 1095 | Penfold, C.M., & Miyan, M.S. | Organic farming: now and the future | 1998 | Biodynamic Farming; Organic Farming | Book | Penfold, C.M., & Miyan, M.S.; Proc. 9th Australian Agronomy Conference, Adelaide; | English | Hardcopy:Partial; Wordperfect:Full | 8-yr field expt. to compare conventional, orgaanic & biodynamic farming | Soil C increased on the conv. treatment .., while extractable P was lowest on the biodynamic treatment. .. there was lower: microbial biomass C on the integrated [conv.] treatment, microbial activity on the biodynamic treatment and mycorrhiza infection of medic roots on the conv. treatment. The soil aggregate stability was less in the integrated [conv.] system. |
| 400 | Penfold, C.M., Miyan, M.S., Reeves, T.G. & Grierson, I.T. | Biological farming for sustainable agricultural production | 1995 | Biodynamic Farming; Organic Farming | Journal | Aust. J. Exp. Agric.; 35; 849-856 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to compare conventional, organic and biodynamic farming | After 6 years significant differences between systems are apparent in .. & soil available P levels [which], on the biodynamic & org. treatments, have declined 12 & 9% respectively since the start of the trial, while both the integrated and conv'l treatments have increased soil P levels... it is too early in the trial to state categorically that anyone system is more sustainable than another..; Prep'n BD 500, which is sprayed onto the soil to enhance microbial activity, had no detectable impact on the microbial biomass in the biodynamic treatment during the 2 yrs ..; .. the [biodynamic] wheat yield, at 2.4 t/ha, was low. |
| 1064 | Peoples, M.B., Herridge, D.F. & Ladha, J.K. | Biological nitrogen fixation: an efficient source of nitrogen for sustainable agricultural production | 1995 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 174; 3-28 | English | Hardcopy:Partial | Review of the role of N fixation by leguminous plants in world agriculture. 48% of the world's arable land is under cereals, 14% under temp. pasture and fodder crops, 12% under oil seeds, 2% under fruit and veg. and 1% under fibres, rubber and oil palm. In a ley up to 70 kg N/ha (average 25 kg/ha) is transferred directly from the legume to the grass. This represents up to 70% (average 37%) of the N in the grass and up to 25% (average 12%) of the total N fixed by the legume. The transfer mechanism may be rhizodeposition, direct mycorrhizal connection between legume and grass or grazing of legume roots by soil fauna. Litter fall from tropical woody legumes can contribute 10-25 t/ha of OM to the soil, including 250-290 kg N/ha. | It is necessary for the three most important cereals, wheat, rice and maize, to take up 20-40 kg soil N/ha over a period of 3-5 months .. Productive pastures .. may assimilate >100 kg N/ha/year.; Yield increase by crops following .. legumes are .. equivalent to 30-80 kg fertiliser N/ha. .. values of 100 kg fertiliser N/ha or greater have also been reported. |
| 1065 | Peoples, M.B., Ladha, J.K. & Herridge, D.F. | Enhancing legume N2 fixation through plant and soil management | 1995 | Green Manure; Soil N Dynamics | Journal | Plant Soil; 174; 83-101 | English | Hardcopy:Partial | Review of factors affecting the amount of N fixed by legume crops. The amount can be increased by: 1. inoculating the soil with rhizobia; 2. keeping soil pH close to neutral; 3. keeping the soil NO3 concentration low; and 4. improving the growth of the legume plants with appropriate fertilisers (not N). | There has to be an upper limit on BNF [biologically fixed N] .. a theoretical upper limit of 635 kg N/ha for soya bean and more than 300 kg N/ha for pigeon pea and groundnut. .. in practice the levels of N2 fixation .. may often be only a fraction of the potential.; .. it is difficult to predict situations where inoculation might not be necessary.; High levels of soil nitrate can be a potent inhibitor of N2 fixation ..; .. even relatively low levels of soil nitrate are capable of depressing BNF.; In intercropping systems competition for soil mineral N between legumes and cereals can result in stimulation of BNF and increased harvest of total N of interplanted crops.. |
| 534 | Pereira, P.M. & Pires da Fonseca, M. | Conservation ecology: nature vs. nurture: the making of the montado ecosystem | 2003 | Miscellaneous; Sustainability | Journal | Conserv. Ecol.; 7 (3); | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study the factors determining the development of montado (dehesa) | In trying to distinguish anthropogenic from biophysical processes, we found that both were equally important as drivers of montado biodiversity. |
| 86 | Perelman, Michael | Efficiency in agriculture: the economics of energy | 1976 | Energy in Agriculture | Book | Merrill, Richard (ed.); Radical Agriculture; 65-86 | English | Hardcopy:Partial | Small farms are more efficient, more area-productive and socially more desirable than large ones | .. the degree to which labour is displaced [i.e. labour productivity] is not necessarily an accurate estimate of agricultural efficiency.; As noted by Rene Dubos: Agricultural efficiency cannot be measured only in terms of agricultural yields [i.e. area productivity]. Another criterion is the amount of energy required for the production of a given amount of food. And when modern agriculture is judged on this basis, its efficiency is often found to be very low.; Much of the energy used in the distribution and processing of food should be charged to the organisation of agricultural production which has minimised production costs through regional specialisation. This specialisation requires that food be transported longer distances and also that much food be processed to avoid spoilage in the often circuitous road from farmer to consumer.; The problem is that agriculture is supposed to be an energy-producing sector of the economy. Harvested crops capture solar energy and store it as food or some other useful product. Yet the energy captured is small compared with the energy used in the process. |
| 875 | Perez-Maldonado, R.A., Norton, B.A. & Kerven, G.L. | Factors affecting in vitro formation of tannin-protein complexes | 1995 | Green Manure; Soil N Dynamics | Journal | J. Sci. Food Agric.; 69; 291-298 | English | Hardcopy:Partial | Lab. expt. to establish the effect of pH and type of protein and tannin on the extent of tannin-protein complexation in material from two leguminous plants. Generally, 20-45% of available plant protein may interact with condensed tannins from leguminous plants. | Condensed tannins and hydrolysable tannins are water-soluble phenolic compounds found in many dicotyledonous plants and have the characteristic phenolic reactions and the ability to precipitate proteins and other polymers.; .. when the ratio of pure tannin to protein exceeds 1:1, there is sufficient tannin to precipitate all available protein. |
| 417 | Perry, D.A., Amaranthus, M.P., Borchers, J.G., Borchers, S.L. & Brainerd, R.E. | Bootstrapping in ecosystems | 1989 | Soil Microorganisms; Sustainability | Journal | Bioscience; 39 (4); 230-237 | English | Hardcopy:Partial; Wordperfect:Full | Review of recent research on reciprocal interactions between plants, microorganisms and the soil | Systems characterised by strong positive interactions among their components can be complex,productive and quite stable under conditions to which they are adapted, but when key linkages are disrupted they are fragile and subject to threshold changes .. some ecosystems are continually pulling themselves up by their own bootstraps. Through close mutual interactions between plants and soil organisms, these ecosystems create the conditions that allow the systems to persist.; Though a bootstrapping system may be quite stable, it is also poised;its stability is not of a ball lying in the bottom of a potential well but of a dancer in arabesque.; Diversity in the plant community, the microbial community and the ecosystem as a whole plays a seminal role in buffering against disturbance and maintaining healthy links between plants and soils. |
| 585 | Persson, J. & Nasholm, T. | Amino acid uptake: a widespread ability among boreal forest plants | 2001 | Soil N Dynamics | Journal | Ecol. Lett.; 4 (5); 434 | English | Hardcopy:Partial | Expt. to demonstrate the uptake of amino acids by 31 species of boreal plants | ... all plant species tested, representing a wide variety of plant types, have the ability to take up amino acids ... uptake rates were unrelated to mycorrhizal associations as well as habitat soil amino acid concentrations and plant nitrogen availability dependence ... |
| 477 | Perucci, P., Dumontet, S., Bufo, S.A., Mazzatura, A. & Casucci, C. | Effects of organic amendment and herbicide treatment on soil microbial biomass | 2000 | Soil Microorganisms | Journal | Biol. Fertil. Soils; 32 (1); 17-23 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effects of herbicides on soil microorganisms | Both herbicides exerted a detrimental effect on soil microbial biomass and its biochemical properties.; The detrimental effects seemed to be reduced by organic amendments. |
| 190 | Pervanchon, F., Bockstaller, C. & Girardin, P. | Assessment of energy use in arable farming systems by means of an agroecological indicator: the energy indicator | 2002 | Energy in Agriculture; Organic Farming; Sustainability | Journal | Agric. Sys.; 72 (2); 149-172 | English | Hardcopy:Full; Wordperfect:Full | The authors propose an energy indicator (IEn) to evaluate environmental impacts due to energy consumption of arable farming systems to help farmers to manage their energy inputs at the field level according to the guidelines of integrated agriculture. IEn is based on the energetic analysis of four types of energy: two for indirect energy (pesticides and fertilisers) and two for direct energy (machinery and irrigation systems). The assessed values of energy consumption are then converted into a mark between 0 (for intensive conventional farming) and 10 (for organic farming). The reference value is 7 (for 'integrated' conventional farming). IEn needs only data that are available on farms or are easily assessed and will be implemented with a set of seven other agro-ecological indicators to assess environmental sustainability of farms. The energy consumption of intensive and integrated conventional agriculture and organic farming are given as 40,000, 9000 and 3500 MJ/ha respectively. | Energy cost due to machinery production is not considered because farmers always have a non-reducible pool of machinery (e.g. a plough, a spreader, a sower and a sprayer) ..; We .. calculate the energy consumption per unit of hectare instead of per unit of product .. The advantage of the second solution is not to grant a good value for IEn to very extensive systems with a low energy use due to very low productivity .. If an energy indicator is used alone as an assessment tool of sustainability it is certainly relevant to base it on the productivity and not on the surface .. in our case, IEn will be used with a set of other indicators and its use is restricted to 'normal' arable farming systems of Western Europe which are quite intensive. A 'normal' situation means that farmers are trying to obtain the highest or economically optimal yield. |
| 1742 | Petersen, S.O., Debosz, K., Schjřnning, P., Christensen, B.T. & Elmholt, S. | Phospholipid fatty acid profiles and C availability in wet-stable macro-aggregates from conventionally and organically farmed soils | 1997 | Uncategorised | Journal | Geoderma; 78; 181-196 | English | PDF:Full | ||
| 910 | Pfisterer, A.B. & Schmid, B. | Diversity-dependent production can decrease the stability of ecosystem functioning | 2002 | Sustainability | Journal | Nature (Lond.); 416; 84-86 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the effect of perturbation on species-rich ecosystems | According to the insurance hypothesis of biodiversity, resistance and resilience should increase with species richness, because a greater number of species can express a greater range of responses to environmental perturbation. This increases the likelihood that some species with previously low performance will increase their performance and compensate for others. However, responses of an ecosystem to perturbation may depend on the form of the relationship between the response variable and biodiversity.; If diversity already has a positive effect on ecosystem functioning under unperturbed conditions, outcomes leading to positive diversity-resistance relationships may be less likely than outcomes leading to negative [ones]. |
| 811 | Phetteplace, H.W., Johnson, D.E. & Seidl, A.F. | Simulated greenhouse gas emissions from beef and dairy systems | ? | Greenhouse Gases | Journal | J. Anim. Sci.; 77, suppl.1; 145 | English | Hardcopy:Partial | Modelling the CH4, N2O and CO2 emissions from beef and dairy cattle at different ages | CO2 emissions were estimated to be 403 g/kg weaned weight for cow-calf, 68 and 57 g/kg gain for stockers and feeders respectively and 32 g/kg milk for the dairy systems. |
| 142 | Philipps, L. | The effects of all-arable organic rotations on soil organic matter levels and the phosphorus and potassium status over the period 1987-1998 | 2001 | Organic Farming; Soil Organic Carbon; Stockless Farming | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to test the effect of stockless organic rotations on the soil OM and nutrients | There was a significant decline in SOM levels over time across all three rotations. The most notable change occurred in the first 4 yrs of the trial, cycle 1, as the mgmnt changed from a grassland to an arable system. Between cycle 1 and 2 the SOM percentage fell from 3.02 to 2.58%. .. There were no significant changes in the available phosphorus over time, although slow- release rock phosphate had been applied to the green manure crops when soil analysis revealed a deficiency. .. Levels of potassium were not affected over the 11 years of the trial, despite no application of supplementary fertilisers or livestock residues. |
| 102 | Philipps, L., Welsh, J.P. & Wolfe, M.S. | Ten years experience of all-arable rotations | 1999 | Green Manure; Stockless Farming | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; 71-77 | English | Hardcopy:Full; Wordperfect:Full | Stockless organic farming is a viable option in the U.K. | .. N accumulation from green manure crops is capable of supporting three years of cash cropping, provided that the green manure crop establishes well.; There were no overall declines in cash crop yields over the eleven-year period ..; The dry matter of weed harvest in all the winter wheat crops showed no significant relationship with time.; The levels of disease and pests did not increase during the expt. and never reached levels that would be expected to restrict the performance of the crops. |
| 119 | Philipps, L., Welsh, J.P., Bulson, H.A.J. & Woodward, L. | Agronomic viability and potential economic performance of three organic fouryear rotations without livestock, 1988-1998 | 1999 | Stockless Farming | Book | ; Proceedings of the 12th IFOAM Conference, Argentina, 1999; 109-115 | English | Hardcopy:Full | Stockless farming has the potential to be an agronomically and economically viable option on organic farms. | There was no significant relationship between yield and the number of years for which the expt. has been running for the first winter wheat crops.. or the wheat after potatoes .. . The second winter wheat .. and the winter wheat after field beans .. both showed significant decline in grain yield with time.; The dry matter of weeds at harvest in all winter wheat crops showed no significant relationship with time.; The level of disease and pests has not increased during the duration of the expt. and never reached levels that would be expected to restrict the performance of crops.; .. there was a significant trend in the level of P over time, with the level increasing in all cases .. . The level of K also showed a significant and positive trend over time ..; Throughout the expt. rock phosphate was applied at a maximum rate of 180 kg/ha of P2O5 .. . |
| 1697 | Phillips, L. | Agronomic viability of three organic four-year rotations without livestock, 1988-1998 | Uncategorised | Journal | EFRC newsletter ; ; | English | Hardcopy:Full | |||
| 1135 | Pielke, R.A. | Land use and climate change | 2005 | Miscellaneous | Journal | Science; 310; 1625-1626 | English | Hardcopy:Partial | Review of ways in which changes in land use can change climate | ... between one-third and one-half of our planet's land surfaces have been transformed by human development.; Change and variability in land use by humans and the resulting alterations in surface features are major but poorly recognised drivers of long-term global climate patterns.; ... the regional changes in surface temperature, precipitation and other climate metrics can be as large as, or larger than, those that result from the anthropogenic increase of well-mixed greenhouse gases. |
| 1566 | Pierce, F.J. & Burpee, C.G. | Zone tillage effects on soil properties and yield and quality of potatoes (Solanum tuberosum L.) | 1995 | Potato Growing; Tillage | Journal | Soil Tillage Res.; 35; 135-146 | English | Hardcopy:Partial | Field expt. to compare the effects of conventional and zone tillage (sub-soiling in the row) on potato production. Zone tillage sometimes gave better & sometimes worse results than ploughing. | |
| 1567 | Pierce, F.J., Fortin, M.C. & Staton, M.J. | Immediate and residual effects of zone-tillage in rotation with no-tillage on soil physical properties and corn performance | 1992 | Tillage | Journal | Soil Tillage Res.; 24; 149-165 | English | Hardcopy:Partial | 3-year field expt. to compare the effect of zone tillage with chisel ploughing and zero tillage on soil properties and maize yields on a sandy loam | .. zone tillage .. improved the physical condition of the soil .. relative to the zero-tillage treatment [but] had little effect on the maize yield ..; Soil strength as measured by the cone index approached 3.0 MPa in the zero-tillage treatment and was reduced to <0.5 MPa by zone tillage .. BD, total and airfilled porosity and saturated hydraulic conductivity were all improved by chisel ploughing and zone tillage.; .. soil structural quality improvement is not necessarily related to increases in maize yield. |
| 85 | Pimentel, D. | Energy flow in agrosystems | 1984 | Energy in Agriculture | Book | Lowrance, R., Stinner, B.R. & House G.J. (eds.); Agricultural Ecosystems - Unifying Concepts; 121-131 | English | Hardcopy:Full | Some of the major changes that have taken place in human and fossil fuel inputs as agriculture has evolved and intensified are reviewed. | Horse power is slightly more efficient than tractor power in producing [maize]; however, 20% more land is required plus 10 times more [labour] than the tractormechanised system. |
| 1662 | Pimentel, D. | Handbook of Energy Utilisation in Agriculture | 1980 | Energy in Agriculture; Green Manure | Book | Pimentel, D.; Handbook of Energy Utilisation in Agriculture; | English | Hardcopy:Partial | Tables of energy consumption in various agricultural processes, including some figures on energy cost of seeds and of baled lucerne hay. | An energy audit of baled alfalfa hay production .. Total fossil energy input 2,990,921 [kcal/ha] .. Dry matter yield (15% H2O) 10,000 kg [per ha] |
| 24 | Pimentel, D. & Dazhong, W. | Technological changes in energy use in U.S. agricultural production | 1990 | Energy in Agriculture | Book | Carroll, C.R., Vandermeer, J.H. & Rosset, P. (eds.); Agroecology; | English | Hardcopy:Partial | Traces the increase in use of energy in U.S. agriculture and reviews ways of improving efficiency. | Labour with simple tools can perform most agricultural tasks more efficiently than most large machines. |
| 1664 | Pimentel, D. & Pimentel, M. | Food, Energy and Society | 1979 | Energy in Agriculture; Labour and Animal Power; Stockless Farming | Book | Pimentel, D., Pimentel, M.; Food, Energy and Society; | English | Hardcopy:Partial | Data on animal power as an energy source, energy use in crop production and energy use in food processing, packaging and preparation. Animals and machines require a much greater total expenditure of energy than manpower, but take less time to complete the task. Tables of energy inputs and outputs are provided for various crops in various countries. The energy requirements of carnivorous, vegetarian and vegan diets are compared. The efficiency of different fuels for cooking is compared. | .. plant foods provide over 70% of the protein consumed by man.; The production of animal protein costs not only in terms of energy, labour and land needed to grow the plants but also the direct cost of animal husbandry itself. Then too the relatively inefficient conversion of plant protein into animal protein makes it clear that animal protein is expensive to produce ..; the pure vegetarian [i.e. vegan] diet is more economical in terms of fossil energy than either of the other two types of diets [carnivorous and lactovegetarian].); Cooking food in developing nations requires nearly 2/3 of the total energy expended in the food system, while production requires about 1/3 of the total. |
| 418 | Pimentel, D., Allen, J., Beers, A., Guinand, L., Linder, R., McClaughlin, P., Meer, B., Musonda, D., Perdue, D., Poisson, S., Siebert, S., Stoner, K., Salazar, R. & Hawkins, A. | World agriculture and soil erosion | 1987 | Soil (General) | Journal | Bioscience; 37 (4); 277-281 | English | Hardcopy:Full | Soil erosion threatens world food production. The effect of erosion on crop production; causes of erosion and how it can be controlled. | [The] renewal rate [of soil] is .. 0.3 to 2 t/ha/yr.; Soil loss rates, generally ranging from 10 to 100 t/ha/yr on cultivated lands, are exceeding soil formation rates by at least tenfold. |
| 599 | Pimentel, D., Bailey, O., Kim, P., Mullaney, E., Calabrese, J., Walman, L., Nelson, F. & Yao, X. | Will limits of the earth's resources control human numbers? | 1999 | Sustainability | Journal | Environ. Dev. Sustain.; 1; 19-39 | English | Hardcopy:Full; PDF:Full | Analysis of the main global environmental resources and how large a population they will sustain | Even if we adopted a worldwide policy resulting in only 2.1 children born per couple, more than 60 years would pass before the world population stabilised at approximately 12 billion.; .. humans should voluntarily limit their population growth, rather than letting natural forces control their numbers for them.; Achieving an average European standard of living ($12.31 per capita/year) or an average U.S. standard of living ($26,000 per capita/ year) appears unrealistic for most countries ..; .. we suggest 0.5 ha of cropland per capita with an intense agricultural production system (about 8 million kcal/ha) and diverse plant and animal diet for the people.; .. World-wide soil erosion averages approximately 30 t/ha/yr .. it takes approximately 500 years for 2.5 cm of topsoil to form under agricultural conditions.; [= about 0.7 t/ha/yr] |
| 243 | Pimentel, D., Berardi, G. & Fast, S. | Energy efficiency of farming systems: organic and conventional agriculture | 1983 | Energy in Agriculture; Organic Farming | Journal | Agric. Ecosyst. Environ.; 9 (4); 359-372 | English | Hardcopy:Partial | The energy efficiency of organic and conventional farming are compared. The energy efficiency, labour requirements and yield were assessed for the production of maize, wheat, potatoes and apples for organic and conventional farming - in maize and wheat production organic was 29 - 70% more energy efficient that conventional but in potato and apple production 7 - 93% less energy efficient. | The amount of energy expended for food production, distribution and preparation in the United States represents about 17% of total U.S. energy; approximately one third (6%) of this is used for food production ..; .. the adoption of organic technologies has several constraints. First, labour productivity averaged 22 - 95% less than for conventional production. .. Another constraint is the availability of adequate quantities of organic fertiliser like manure .. |
| 1094 | Pimentel, D., Giampietro, M. & Bukkens, S.G.F. | An optimum population for North and Latin America | 1998 | Sustainability | Journal | Popul. Environ.; 20 (2); | English | Hardcopy:Partial | Estimating the optimum population of the continents on the basis of land resources | North and South America .. should have no more than 200 million people, or a total of 400 million. |
| 1136 | Pimentel, D., Harvey, C., Resosudarmo, P., Sinclair, K., Kurz, D., McNair, M., Crist, S., Shpritz, L., Fitton, L., Saffouri, R. & Blair, R. | Environmental and economic costs of soil erosion and conservation benefits | 1995 | Sustainability | Journal | Science; 267; 1117-1121 | English | Hardcopy:Partial | The financial costs of soil erosion and of soil conservation are estimated. The soil loss from conventionally tilled land varies between 20 and 90 tons per ha, whereas for zero tillage it varies between 0.02 and 1.3 tons per ha. The erosion from undisturbed natural soil (grass and forest) is 0.07 and 0.02 tons per ha respectively. | To adequately feed people a diverse diet, about 0.5 ha of arable land per capita is needed, yet only 0.27 ha per capita is available. In 40 years only 0.14 ha per capita will be available ..; the average rate of soil formation [is] about 1 ton ha-1 year-1. |
| 419 | Pimentel, D., Hepperly, P., Hanson, J., Douds, D.D. & Seidel, R. | Environmental, energetic and economic comparisons of organic and conventional farming systems | 2005 | Energy in Agriculture; Organic Farming; Stockless Farming | Journal | Bioscience; 55 (7); 573-582 | English | Hardcopy:Partial; Word:Partial; Wordperfect:Full | Field expt. to compare conventional, organic animal and organic legume systems. In normal rainfall conditions there was little difference in yields between the three systems, but in drought conditions the organic systems yielded significantly higher than the conventional. The organic systems consumed about 30% less energy per hectare than the conventional. The two organic systems retained more C in the soil, resulting in a significantly higher SOM content than the conventional. | Soil carbon increased 27.9%, 15.1% and 8.6% in the organic animal, organic legume and conventional systems respectively. |
| 1137 | Pimentel, D., Hurd, L.E., Bellotti, A.C., Forster, M.J., Oka, I.N., Sholes, O.D. & Whitman, R.J. | Food production and the energy crisis | 1973 | Energy in Agriculture; Stockless Farming | Journal | Science; 182; 443-449 | English | Hardcopy:Full | Energy analysis of U.S. maize production. The I/O ratio is shown to have fallen from 3.7 in 1945 to 2.8 in 1970. Use of FYM requires a smaller energy input than chemical fertilisers and leguminous green manures even less. | In 1970 about 2.9 million kcal [of fossil fuel energy] was used by farmers to raise an acre of [maize] .. [This] represents a small portion of the energy input when compared with the solar energy input. During the growing season about 2043 million kcal reaches a 1-acre [maize]field; about 1.26% of this is converted into [maize] and about 0.4% into maize grain .. itself.; If manure were substituted for chemical fertiliser, the savings in energy would be .. 1.1 million kcal per acre. .. the energy saved by planting a legume for green manure would be .. 1.5 million kcal/acre.; .. the estimated acreage [of crops in the U.S.] is 1.4 acres per capita.; .. only 16.6% of a [person's disposable mean income .. in the U.S. was spent for food in 1970.; To reduce energy inputs green revolution and U.S. agriculture might employ such alternatives as rotations and green manures to reduce the high energy demand of chemical fertilisers and pesticides. |
| 911 | Pimm, S.L. | The complexity and stability of ecosystems | 1984 | Sustainability | Journal | Nature (Lond.); 307; 321-325 | English | Hardcopy:Partial | Review of research into ecosystem stability with particular reference to the controversy over whether simple ecosystems are more or less stable than complex ones | A system is deemed stable if and only if the variables all return to the initial equilibrium following their being perturbed from it.... Resilience [means] how fast the variable return towards their equilibrium following a perturbation. |
| 912 | Pimm, S.L. | In search of perennial solutions | 1997 | Sustainability | Journal | Nature (Lond.); 389; 126-127 | English | Hardcopy:Partial; PDF:Full | Review of research on the substitution of annual crops by perennial ones | Perhaps by historical accident, human beings domesticated their annual wild relatives, not the perennial ones.Harvesting annuals leaves the soil bare and vulnerable to erosion by wind and rain.Annual grains alone deplete the soil's fertility; added fertilisers are needed to make up the losses. .. the norm is single-species plantings. These lack resistance to weeds, insects and disease ..; The Land Institute's favoured mix .. consists of four wild perennials with naturally high seed yields. They represent one each of the functional classes present in all native prairies: a cold- and a warm-season grass (for grain production), a legume (with a protein-rich seed) and a sunflower (for oil)... these four species, plus a minimum of four from the dozen other candidates .. assemble to a near weed-free mix within three years of planting. |
| 1568 | Pinheiro, E.F.M., Pereira, M.G. & Anjos, L.H.C. | Aggregate distribution and soil organic matter under different tillage systems for vegetable crops in a Red Latosol from Brazil | 2004 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 77; 79-84 | English | Hardcopy:Full; PDF:Full | Field expt. to study the effect of different tillage systems on SOM and soil aggregate distribution. In the surface soil (0-5 cm) SOC content and soil aggregation increased in the order bare soil < conventional tillage < contour tillage with animal traction < zero tillage < grassland. Below 5 cm the differences between tillage systems were not significant. | The highest organic carbon concentration in GR [grassland] may have been related to the higher input and renovation of aerial and root biomass. Roots greatly influence the formation and stabilisation of soil aggregates. .. conversion from grass pasture to a vegetable rotation system under CT may result in high loss of SOM and poor aggregation. Biomass inputs under vegetable cropping were not sufficient to maintain C with CT, but were with NT. |
| 360 | Pitkänen, J. & Nuutinen, V. | Earthworm contribution to infiltration and surface run-off after 15 years of different soil management | 1998 | Soil (General) | Journal | Appl. Soil Ecol.; 9 (1/3); 411-415 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of earthworms on the hydraulic porperties of a soil | The only discernible difference between the tillage treatments was that Lumbricus terrestris was present only in unploughed soils, although in very low numbers. During the rains there were no significant differences between the treatments in volumes of percolated water, but there was significantly less runoff from spring stubble-cultivated soil than from autumn-tilled soils. |
| 1449 | Plante, A., Conant, R.T., Stewart, C., Paustian, K. & Six, J. | Impact of soil texture on the distribution of soil organic matter in physical and chemical fractions | 2006 | Soil Organic Carbon | Journal | Soil Sci. Soc. Am. J.; 70 (1); 287-296 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to investigate how the distribution of SOC between different pools vaies with soil texutre | We found no relationship between soil texture and unprotected C (coarse and fine POM).; Biochemically protected C (non-hydrolysable C) increased with increasing clay content in whole-soil samples, but the proportion of non-hydrolysable C within silt- and clay-sized fractions was unchanged.; Mineral- associated or chemically protected organic C was strongly affected by the soil silt and clay contents, as would be expected through the role of surface properties.; As the amount of silt or clay increased, the amount of C stabilised within easily dispersed and microaggregate-associated silt or clay fractions decreased. |
| 70 | Poggi-Varaldo, H.M., Gomez-Cisneros, E., Rodriguez-Vazquez, R., Trejo-Espino, J. & Rinderknecht-Seijas, N. | Unsuitability of anaerobic compost from solid substrate anaerobic digestion as soil amendment | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the suitability of anaerobic compost as a soil amendment | The anaerobic compost coming from feedstocks with increasing proportion of lignocellulosic fraction were of higher quality and gave the lowest chemical oxygen demand, biochemical oxygen demand, volatile organic acids and total ammonia N concentrations in the extract and the highest germination indices. However, high total oxygen uptake, moderate-to-high conc'ns of volatile org. acids & ammonia and germination indices under 60% indicated that the anaerobic compost was not suitable for direct use as a soil improver. |
| 666 | Poirier, N., Derenne, S., Balesdent, J., Chenu, C., Bardoux, G., Mariotti, A. & Largeau, C. | Dynamics and origin of the non-hydrolysable organic fraction in a forest and a cultivated temperate soil as determined by isotopic and microscopic studies | 2006 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 719-730 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the origin of the non-hydrolysable OM fraction in a native forest soil and the same soil after cleaaring and 35 years of maize cultivation | Extensive degradation (c. two thirds) of the non-hydrolysable material inherited from the forest soil took place upon clearing & continuous maize cropping for 35 years. It thus appeared that the great resistance of this material to drastic acid and base lab. hydrolyses is not paralleled by a great resistance to biodegradation ..; .. such a conspicuous uncoupling between non-hydrolysable and stable carbon is probably a general feature of OM in soil .. |
| 665 | Poirier, N., Derenne, S., Balesdent, J., Mariotti, A., Massiot, D. & Largeau, C. | Isolation and analysis of the non-hydrolysable fraction of a forest soil and an arable soil (Lacadée, SW France) | 2003 | Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 54; 243-255 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the stable non-hydrolysable fraction of a soil under two different treatments: forest and arable cultivation | The optimised protocol .. produced a non-hydrolysable fraction that accounted for about 6% of the OC in the soil.Its constituents included aliphatic moieties, melanoidins, black carbon and .. small amounts of condensed tannins. .. There were some quantitative differences between the non-hydrolysable fractions of the forest and arable soil. The latter had the larger C/N ratio and substantially more aliphatic character. Lignin made a negligible contribution to the resistant fraction of both soils. .. a close parallel does not exist between a high resistance to laboratory hydrolysis and the ability to survive degradation in soil. .. the non-hydrolysable lignin polymers identified in maize leaves did not appear in the residue from the arable soil; this suggests that these chemically resistant macromolecules are readily degraded biologically in the soil. |
| 993 | Poirier, N., Derenne, S., Balesdent, J., Rouzaud, J.N., Mariotti, A. & Largeau,C. | Abundance and composition of the refractory organic fraction of an ancient tropical soil (Pointe Noire, Congo) | 2002 | Soil Organic Carbon | Journal | Org. Geochem.; 33; 383-391 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the structure of the refractory organic fraction in a tropical soil | ... OM at depth in this soil is entirely composed of stable carbon with a very low turnover rate (14C age of ca. 8300 years) and originated from the forest to which the present vegetation (savannah) succeeded. The refractory fraction only accounted for ca. 5% of the total carbon of the soil. A conspicuous uncoupling is therefore observed in this soil between stable and refractory carbon.; the refractory fraction ... showed (i) the lack of both ligneous materials and aliphatic resistant materials such as cutans and suberans, (ii) abundant contribution of melanoidins with a high degree of condensation and cross-linking and (iii) the presence of two types of particles of black carbon. |
| 994 | Poirier, N., Derenne, S., Rouzaud, J.N., Largeau, C., Mariotti, A., Balesdent, J. & Maquet, J. | Chemical structure and sources of the macromolecular resistant organic fraction isolated from a forest soil (Lacadée, south-west France) | 2000 | Soil Organic Carbon | Journal | Org. Geochem.; 31; 813-827 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the structure of the resistant organic fraction in a forest soil | The insoluble non-hydrolysable macromolecular material .. from a forest soil .. Such a resistant material, which accounts for ca. 25% of total humin, was .. chiefly composed of melanoidins & black C ... highly aliphatic moieties only afford a minor contrib'n to the refractory material of the Lacad)e soil.; The complex polyaromatic structures collectively termed black C, a term synonymous in the literature with charcoal, correspond to the residues of incomplete combustion produced from vegetation fires and burning of fossil fuels.; Melanoidintype macromolecules might also be a source for some aliphatic & aromatic moieties in the refractory fraction of SOM. Melanoidins are complex insoluble macromolecules, highly resistant to chem. degradation, formed by random condensation of monomers and other alteration products of amino acids and carbohydrates. |
| 995 | Poirier, N., Sohi, S., Gaunt, J.L., Mahieu, N., Randall, E., Powlson, D.S. & Evershed, R.P. | The chemical composition of measurable soil organic matter pools | 2005 | Lignin and CBW; Soil Organic Carbon | Journal | Org. Geochem.; 36; 1174-1189 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study some SOM fractions that could be used as variables in a mathematical model of SOM decompos'n. Three fractions are used: FR-SOM (free POM); IA-SOM (intra-aggregate POM); and M-SOM (mineral-associated SOM) | FR-SOM comprises a mixture of relatively fresh unaltered plant debris, together with a rather more decomposed component.; .. the carbohydrates present in FRSOM were predominantly plant-derived.; The distrib'n of lignin oxid'n products was similar for wheat straw and FR-SOM, but the conc'n in FR-SOM was much lower.; The IA-SOM frac'n .. comprise primarily microbial metabolites, displaying .. a carbohydrate conc'n .. almost half that of FR-SOM.; The lignin content of IA-SOM did not greatly differ from that observed for FR-SOM, which conflicts with the view that preferential utilis'n of other components might lead to its accumul'n in more degraded fractions. The findings agree with our earlier reports concerning the instability of lignin in soil.; The M-SOM fraction accounted for more than 90% of organic C in the soil, but its compos'n could only be partially established using NMR & FTIR, due to their sensitivity to matrix effects.; The total carbohydrate conc'n of M-SOM was very similar to that of FR-SOM but with .. a high prop'n of microbial metabolites. Microbial activity (especially bacteria) is thought to be assoc'd with fine mineral particles.; The conc'n of lignin biomarkers in M-SOM was lower than in the FRSOM & IA-SOM fractions ..; The NMR technique .. tends to overestimate alkyl groups .. |
| 868 | Popp, J., Hoag, D. & Ascough, J. | Targeting soil conservation policies for sustainability: new empirical evidence | 2002 | Soil (General); Sustainability | Journal | J. Soil Water Conserv.; 57 (2); 66-74 | English | Hardcopy:Partial | In order to test the sustainability of conservation programmes a model is put together, based on three definitions of sustainability (based on economic, ecological or temporal welfare objectives), namely, profit maximisation, production preservation and soil quality preservation, and three sustainability criteria, namely, substitutability, uncertainty and reversibility. The model was tested on nine different soils - three stable ones, three neutral and three erosion-susceptible ones. For each soil a soil quality index was calculated. | Results showed that, while conservation efforts may be helpful in achieving all of [the] versions of sustainability on stable soils, conservation impacts are ambiguous or in direct conflict [with] sustainability targets on other soils. .. conservation may be best applied to the stable soils. |
| 298 | Porter, G., Opena, G., Bradbury, B., McBurnie, J. & Sisson, J. | Soil management and supplemental irrigation effects on potato: I. soil properties, tuber yield and quality | 1999 | Green Manure; Potato Growing | Journal | Agron. J.; 91; 416-425 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effects of irrigation, green manures (pea, oat, hairy vetch) and org. amendments (compost, FYM) on potato production | Total yields were significantly increased by the amendment treatment .. The amendments increased tuber decay .. during all 3 yr. Irrigation treatments significantly increased total yields .., while significantly reducing specific gravity & increasing tuber size. Irrigation also increased tuber decay incidence in 2 of 3 yr. .. the green manure rotation crop had no significant effect on yields or tuber quality compared with the oat rotation. |
| 762 | Post, W.M. & Kwon, K.C. | Soil carbon sequestration and land-use change: processes and potential | 2000 | Greenhouse Gases; Soil Organic Carbon | Journal | Glob. Change Biol.; 6; | English | Hardcopy:Partial | A review of work done on the SOC sequestration rates of arable land that had reverted to forest or grassland, which averaged 33.5 g C per sq.m. per year. For the entire U.S. this would give a total SOC accumulation of 0.05 Pg per year. This is a very small proportion of the total northern hemisphere SOC accumulation rate of 1-2 Pg C per year. So most of the C accumulation must be in vegetative biomass, not in the soil. | |
| 913 | Post, W.M., Emanuel, W.R., Zinke, P.J. & Stangenberger, A.G. | Soil carbon pools and world life zones | 1982 | Soil Organic Carbon | Journal | Nature (Lond.); 298; 156-159 | English | Hardcopy:Full | The global soil C pool is estimated as 1395 Pg, compared with an average of 1607 Pg in six quoted sources. | |
| 711 | Postma, A. et al. | High income impediment to low energy consumption | 1995 | Sustainability | Journal | Gas (Netherlands); 115 (11); | English | Hardcopy:Partial | A study of the energy consumption and budgetary choices made in three households with different incomes shows that the higher the income the higher the overall energy consumption tends to be. But lifestyle is an important factor as well, especially for people with higher incomes. Energy saving options include making less flights to far-away countries, dining out more often, driving less kilometres and smaller cars, giving up second cars, buying low energy appliances and high efficiency light bulbs, consuming less meat and buying durable clothes. | no quotes |
| 244 | Poudel, D.D., Horwath, W.R., Lanini, W.T., Temple, S.R. & Bruggen, A.H.C. van | Comparison of soil N availability and leaching potential, crop yields and weeds in organic, low-input & conventional farming systems in northern California | 2002 | Mineralisation; Organic Farming; Soil N Dynamics | Journal | Agric. Ecosyst. Environ.; 90; 125-137 | English | Hardcopy:Partial; PDF:Full | Plot-scale expt. to compare the N dynamics and crop yields of different farming systems | The organic and low-input systems showed 112% and 36% greater PMN [potentially mineralisable N pools than the conventional systems, respectively. However, N mineralisation rates of the conventional systems were 100% greater than in the organic and 28% greater than in the low-input system. Average tomato fruit yield for the 5-year period (1994-1998) was 71.0 Mg ha-1 and average maize yield was 11.6 Mg ha-1 and both were not significantly different among farming systems.; The lower potential risk of N leaching from lower N mineralisation rates in the organic and low-input farming systems appear to improve agricultural sustainability and environmental quality while maintaining similar crop yields.; Cover crop-based farming systems appear to have a larger PMN pool, but a slower, more continuous release of mineral N throughout the growing season, while conventional systems supplied mineral N in pulses as a result of fertiliser management.; .. post-harvest N management strategies appeared necessary to conserve N for future crop use while minimising the risk of N leaching .. |
| 191 | Poudel, D.D., Horwath, W.R., Mitchell, J.P. & Temple, S.R. | Impacts of cropping systems on soil nitrogen storage and loss | 2001 | Organic Farming; Soil N Dynamics | Journal | Agric. Sys.; 68 (3); 253-268 | English | Hardcopy:Partial | Expt. to compare N accumulation and N losses in soil under different treatments - organic, low-input and conventional 2- [conv-2] and 4-year [conv-4] rotations. | Compared to the conv-2 system the organic and conv-4 systems showed 119 and 8% greater cumulative N balances respectively over the duration of the study. However, N balance in the low-input system was 19% less than in conv-2 system. After 10 years of differential management total N in the top 15 cm of soil was 1.46 g kg-1 in the organic, 1.26 g kg-1 in the low-input, 1.13 g kg-1 in the conv-4, and 1.1 g kg-1 in the conv-2 system. Compared to the conv-2 system, cumulative N losses for the organic, low-input and conv-4 systems were lower by 80, 92, and 10%, respectively. |
| 1486 | Powlson, D.S. | Understanding the nitrogen cycle | 1993 | Cover Crops; Soil N Dynamics | Journal | Soil Use Manag.; 9 (3); 86-94 | English | Hardcopy:Partial | Review of current knowledge of the N cycle in agricultural soils | .. some ammonia can be evolved from the foliage of arable plants.. in normal crops the quantities involved are probably less than 10 kg N/ha.; .. recovery of fertiliser N in the aboveground parts of the crop ranged from 46% to 87% with a mean of 68%. The proportion retained in the soil was .. averaging 18% where N was applied as ammonium nitrate, but less (7-14%) where it was applied .. as nitrate.. The proportion not recovered in either crop or soil varied .. from 2% to >35%.; .. dry deposition of gases .. giv[es] a net annual input of about 40 kg N/ha.; Incorporation of low-N crop residues, such as cereal straw, causes some immobilisation of N .., leaving slightly less at risk of leaching. |
| 1569 | Powlson, D.S., Smith, P., Coleman, K., Smith, J.U., Glendining, M.J., Körschens, M. & Franko, U. | A European network of long-term sites for studies on soil organic matter | 1998 | Soil Organic Carbon | Journal | Soil Tillage Res.; 47 (3-4); 263-274 | English | Hardcopy:Partial; Wordperfect:Full | Review of some long-term soil expt.s and their use in estimating potential sequestration of C in soil | [At Rothamsted] .. application of farmyard manure has more than doubled SOC content (compared to no fertilisation) over the course of the expt., whilst levels have remained stable on plots receiving no fertilisation. Plots receiving inorganic fertilisers only have shown very little change in SOC content over the course of the expt.. In the area allowed to naturally regenerate since 1882 SOC contents have trebled.; [At Bad Lauchstadt] .. 20 Mg ha-1 farmyard manure plus NPK has had virtually the same effect on total C as has 30 Mg ha-1 farmyard manure; NPK- fertilisation has increased soil C content at all organic manuring levels; at all farmyard manure levels without mineral N lower total C contents were found compared to treatments with mineral N.; 70-80% of SOC in the UK is contained in peat, mainly in Scotland and 47% of the total C in European soils is held within high OM soils (8% o.m.) that cover only 13% of Europe's area.; .. by 2010 20-30% of land currently under crops in Europe will be surplus to agricultural requirements.; .. standing woody biomass contains approximately three times the amount of C than does the soil under natural regeneration. |
| 914 | Prentice, K.C. & Fung, I.Y. | The sensitivity of terrestrial carbon storage to climate change | 1990 | Sustainability | Journal | Nature (Lond.); 346; 48-51 | English | Hardcopy:Full | Estimating the effect on soil C storage of doubling the present atmospheric CO2 content. The biomass and SOC content per unit area is given for 14 vegetation types. | For .. twice the present-day CO2 levels strong negative feedbacks appear which remove 235 Gt of C (128 ppm CO2) from the atmosphere. |
| 1066 | Prescott, C.E. | Does nitrogen availability control rates of litter decomposition in forests? | 1995 | Soil Organic Carbon; Soil N Dynamics | Journal | Plant Soil; 168-169; 83-88 | English | Hardcopy:Partial | Lab. expt. to study the influence of exogenous (from fertilisers or deposition) and endogenous (from N-rich litter) N on the rate of forest litter decomposition, which was shown to be independent of N supply, whatever the source. | |
| 523 | Preston, C.M., Shipitalo, S.E., Dudley, R.L., Fyfe, C.A., Mathur, S.P. & Levesque, M. | Comparison of 13C CPMAS NMR and chemical techniques for measuring the degree of decomposition in virgin and cultivated peat profiles | 1987 | Soil Organic Carbon | Journal | Can. J. Soil Sci.; 67; 187-198 | English | Hardcopy:Partial | Expt. to examine native and cultivated organic soils by chemical methods and by 13C CPMAS NMR, which can provide C fingerprints of different soil samples. It shows that the main effects of the cultivation of peat are a decrease in the carbohydrate intensity (mainly due to cellulose) and an increase in the aliphatic and methoxy intensities. Buried wood has been shown to give the same effect. | .. biological oxidation due to cultivation is largely confined to the plough layer, while changes in the subsurface layers are mainly due to physical processes, especially drying and compaction. |
| 524 | Preston, C.M., Trofymov, J.A. & Flanagan, L.B. | Decomposition, δ13C, and the 'lignin paradox' | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Can. J. Soil Sci.; 86; 235-245 | English | Hardcopy:Full | Lab. expt. to compare the change in 13C signature with decomposition in lignin and AUR (the acid-unhydrolysable residue fraction) | Plants discriminate against 13C during photosynthesis, so plant tissues are depleted in 13C compared with atmospheric CO2 (around -8K). C3 plants .. have a mean 13C discrimination against the atmosphere of 18.3K, so that 13C values of C3 foliage are typically -25K to -28K. Isotopic fractionation also occurs during subsequent biosynthesis.. Thus lignin .. is typically depleted by 3.0K-4.4K relative to cellulose .. plant lipids are even more depleted in 13C.; .. lignin, because of its grater recalcitrance, should accumulate with decomposition. This would lead to depletion of 13C in SOM relative to the starting litter inputs ..; .. increase in alkyl C (lipids) rather than lignin with increasing decompos'n .. should also cause depletion of 13C. |
| 192 | Pretty, J.N., Brett, C., Gee, D., Hine, R.E., Mason, C.F., Morison, J.I.L., Raven, H., Rayment, M.D. & Bijl, G. van der | An assessment of the total external costs of U.K. agriculture | 2000 | Sustainability | Journal | Agric. Sys.; 65 (2); 113-136 | English | Hardcopy:Partial | The environmental and health costs of U.K. agriculture are assessed. It is recommended that these external costs are internalised by redirecting public subsidies as to encourage positive externalities and by using advisory, economic, regulatory and legal measures to discourage the negative externalities | .. the total external cost of agriculture in the UK are substantial, comprising 2343 million or 89% of average net farm income for 1996. This aggregate is equivalent to 208/ha/year averaged across all 11.28 million ha of arable land and permanent grassland (but not rough grazing).; significant cost arise from contamination of drinking water with pesticides, nitrate, Cryptosporidium and phosphate and soil, from damage to wildlife, habitats hedgerows and dry-stone walls, from emissions of gases, from soil erosion and organic C losses, from food poisoning and from .. BSE. |
| 1450 | Puget, P. & Drinkwater, L.E. | Short-term dynamics of root- and shoot-derived carbon from a leguminous green manure | 2001 | Green Manure; Roots & Rhizodeposition | Journal | Soil Sci. Soc. Am. J.; 65 (3); 771-779 | English | Hardcopy:Full; Wordperfect:Full | A comparison of the rates of retention in the soil of C from root & shoot of a legume crop showed that root-derived C was retained to a greater extent. | Root-derived C was retained to a greater extent than was shoot-derived C .. The differences in decompos'n rates for root- & shoot-derived litter were partly due to differences in decomposability. Hairy vetch shoot litter, with a lignin/N of 1:1, was mineralised more rapidly and to a greater extent than was root litter, which had a lignin/N slightly greater than 6:1.; .. green manure residues are rapidly decomposed during the first few weeks after incorporation, resulting in significant net N mineralis'n..; By early Oct .. only 13% of the shoot-derived C remained in the soil, whereas nearly one half of the root-derived C was still present.. [thus] there was no difference in the amount of C remaining from each source by the end of the growing season, even though shoot-derived C was three times greater than root-derived C in May.; .. three mechanisms contributed to the increased retention of root-derived C: (i)the greater biochem. recalcitrance of root litter, (ii) increased physical protection of root-derived POM within aggregates & (iii) the continuous nature of root C inputs from exudates & fine root turnover .. leading to an increased retention of root C in the .. MB .. |
| 1331 | Puget, P., Angers, D.A. & Chenu, C. | Nature of carbohydrates associated with water-stable aggregates of two cultivated soils | 1999 | Soil (General); Tillage | Journal | Soil Biol. Biochem.; 31 (1); 55-63 | English | Hardcopy:Full; PDF:Full | Expt. to investigate the relationship between soil aggregates and soil carbohydrate content in ploughed and zero tillage. | Results showed the predominantly plant origin of the POM (>50 m) and the microbial origin of the clay+silt fraction (<50 m) carbohydrates.; Extracellular polysaccharides from bacteria or fungi and roots mucilages are typically a very labile SOM fraction which is important as binding agents of soil aggregates.; Stable macroaggregates (>250 m) contain more organic C, more microbial biomass, more POM, more labile SOM and more young SOM than the microaggregates (<250 m).; The NT sample had about 5 times more C as POM (73.8 g POM kg-1 soil) than the T sample (13.1 g POM kg-1 soil). The clay+silt fraction (<50 m) of NT sample was also richer in C & N (14.4 mg C g-1 fraction and 1.48 mg N g-1 fraction) than the T sample (7.6 mg C g-1 fraction and 0.82 mg N g-1 fraction).; .. 80% of the soil was in aggregates >50 m.; POM may have an indirect role as an energy source for microorganisms, which can contribute to binding and stabilising aggregates, through physical enmeshment by hyphae and through binding by extracellular polysaccharides. |
| 667 | Puget, P., Chenu, C. & Balesdent, J. | Total and young organic matter distributions in aggregates of silty cultivated soils | 1995 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 46; 449-459 | English | Hardcopy:Partial | An expt. in which 13C natural abundance measurement was used to calculate the amount of recently incorporated OM in different physical soil fractions. | Slaking-resistant macroaggregates were enriched in C as compared to dry-sieved macroaggregates or to microaggregates .. The larger C contents in stable macroaggregates were due to young [<6 to 23 years old] .. organic C and we concluded that young OM was responsible for macroaggregate stability. |
| 668 | Puget, P., Chenu, C. & Balesdent, J. | Dynamics of soil organic matter associated with particle-size fractions of water-stable aggregates | 2000 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 51 (4); 595-605 | English | Hardcopy:Partial | An expt. to investigate the association of C with different aggregates. The soil samples were fractionated, each fraction containing mineral and OM particles. | .. the fungal hyphae mechanically bind the soil particles that surround the organic resources and by extracellular poly-saccharides stick them to cells of bacteria and fungi. Stable aggregates are thus formed around POM.; Macroaggregation is very sensitive to changes in .. cultivation practices, whereas micro-aggregation is less so.; Stable macroaggregates (>200m) of cultivated soils .. are richer in organic C, and in young organic C in particular, than microaggregates (<200m). .. The stable macroaggregates were richer in total C and in young C (younger than .. 23 years ..) than the unstable ones. This young C comprised 50% POM, 20% associated with silt and 30% associated with clay particles.; .. the OM associated with macroaggregates was more easily mineralised than that in the microaggregate fractions.; We estimate the lifetime of stable macroaggregates to be a few years. |
| 706 | Pulido, F., Diaz, M. & Trucios, S.B. de | Size structure and regeneration of Spanish holm oak Quercus ilex forests and dehesas: effects of agroforestry use on their long-term sustainability | 2001 | Miscellaneous; Sustainability | Journal | For. Ecol. Manag.; 146; 1-13 | English | Hardcopy:Partial; PDF:Full | Field expt. to assess the factors determining the sustainability of the dehesa management system | .. the expansion of evergreen oaks at the expense of deciduous ones in the Mediterranean Basin was partially caused by the increasing intensity and prevalence of human-induced disturbances (specially fire) throughout the Neolithic period. .. Holm oak forests started to be transformed in the south-west of the Iberian Peninsula into a land-use system devoted to extensive livestock rearing [i.e. dehesa] from the early Middle Ages onwards; .. dehesa tree populations suffer from an acute lack of regeneration which is hampering its long-term sustainability .. it seems clear that this problem is inherent to their system of exploitation, i.e. it operates ever since each dehesa farm starts to be formed out from the original forests .. although it has been exacerbated by its recent intensification .. the dehesa system is unsustainable unless its long-term management includes periods of long-term exclusion of livestock (20 years or more).. |
| 749 | Pulleman, M.M. & Marinissen, J.C.Y. | Physical protection of mineralizable C in aggregates from long-term pasture and arable soil | 2004 | Soil Organic Carbon | Journal | Geoderma; 120 (3-4); 273-282 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare labile C protection in permanent pasture and arable land | Unprotected C fractions were not significantly different between the management systems and ranged from 1.9% to 2.4% of total organic C. In the arable soil 1.4% of total SOC was physically protected in macroaggregates. Crushing of macroaggregates did not significantly increase C mineralisation in the pasture soil. ... the protection in macroaggregates from the arable soil is not likely to be effective on the long-term because of the low water stability and the disrupting forces of cultivation under field conditions. A relatively high additional C mineralisation from ground compared to crushed soil material, especially in the upper layer of the pasture soil, suggests a more important C protection at the microstructural level. Higher C protection in microaggregates from the pasture soil was supported by a previous micromorphological study ... |
| 1451 | Pulleman, M.M., Bouma, J., Essen, E.A. van & Meijles, E.W. | Soil organic matter content as a function of different land use history | 2000 | Organic Farming; Tillage | Journal | Soil Sci. Soc. Am. J.; 64 (2); 689-693 | English | Hardcopy:Full; PDF:Full | A survey of available information from the past 63 years on 45 fields of the same loamy soil type to determine the effect on the SOM content of different land-use history, expressed as tillage, crop types, fertiliser and FYM use and biocide use. The land-use was grouped into four types: organic and conventional arable and grassland. | The SOM contents ranged between 17 and 88 g kg-1. .. SOM contents increased under long-term grass or, to a lesser extent, by organic farming, when compared with conventional-arable use. |
| 1487 | Pulleman, M.M., Jongmans, A.G., Marinissen, J.C.Y. & Bouma, J. | Effects of organic versus conventional arable farming on soil structure and organic matter dynamics in a marine loam in the Netherlands | 2003 | Organic Farming; Soil Organic Carbon | Journal | Soil Use Manag.; 19; 157-165 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the effects of conventional and organic farming on soil properties and SOM content | SOM content, mineralisation, earthworm activity and water-stable aggregation decreased as a result of tillage and arable cropping when compared with pasture, but were significantly greater under organic farming than under conventional farming. Total SOM contents between 0 and 20 cm depth amounted to 15, 24 and 46 g kg-1 for the conventional arable, organic arable and permanent pasture fields |
| 669 | Pulleman, M.M., Six, J., Breemen, N. van & Jongmans, A.G. | Soil organic matter distribution and microaggregate characteristics as affected by agricultural management and earthworm activity | 2005 | Organic Farming; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 56 (4); 453-467 | English | Hardcopy:Full; PDF:Full | Field expt. to investigate the effects of agricultural management and earthworm activity on the distributioon of SOM between the soil fractions | Despite a distinctly greater total SOM content and earthworm activity in the organic- versus the conventional-arable system, differences in microaggregate characteristics between both arable systems were small.; ... organic farming did not significantly affect microaggregate characteristics and OC stabilisation.; ... the great earthworm activity under permanent pasture is an important factor explaining the presence of very stable microaggregates that are relatively enriched in organic C and fine mineral particles. |
| 361 | Pulleman, M.M., Six, J., Uyl, A., Marinissen, J.C.Y. & Jongmans, A.G. | Earthworms and management affect organic matter incorporation and microaggregate formation in agricultural soils | 2005 | Soil (General) | Journal | Appl. Soil Ecol.; 29 (1); 1-15 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the effect of earthworms on soil aggregation in three long-term farming systems: a permanent pasture (PP), a conventional arable system (CA) and an organic arable system (OA). | ... the worm-made macroaggregates of the PP soil were considerably enriched in fine POM and microaggregates, in which large amounts of OM were intimately mixed with fine mineral material. By contrast, worm casts of the CA and OA soils were hardly enriched in POM and microaggregates. Our study demonstrated that earthworms can directly initiate the formation of microaggregates, which in turn affects the physical protection of SOM against microbial decay. |
| 1332 | Puri, G. & Ashman, M.R. | Relationship between soil microbial biomass and gross N mineralisation | 1998 | Mineralisation; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (2); 251-256 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the rate of N mineralsiation withthe size of the soil microbial biomass in a forest soil | Changes in the gross mineralisation rate were not reflected in the size of the soil microbial N pool, which remained essentially stable over 12 mo. .. The data suggested that only a fraction of the microbial biomass was involved in N mineralisation. Soil moisture and temperature were the most important factors influencing the gross rate of mineralisation. |
| 1330 | Pérez-Piqueres, A., Edel-Hermann, V., Alabouvette, C. & Steinberg, C. | Response of soil microbial communities to compost amendments | 2006 | Compost & Biocontrol; Soil Microorganisms | Journal | Soil Biol. Biochem.; 38; 460-470 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effect of composts on soil microorganisms | The addition of good quality composts may increase global microbial biomass & enhance soil enzyme activity.. Compost is effective in controlling diseases caused by soil-borne pathogens, such as Pythium, Phytophthora, Fusarium spp. or Rhizoctonia solani, both in fields and in potting mixtures in greenhouses. .. Compost amendments can modify the microbial community composition and .. enhance the competition &/or antagonism among microbes, leading to a decrease in plant pathogens activity.; All the soil biological props. evaluated in this study were modified after compost addition in microcosms. Modifications varied depending on the soil and the OM applied. The same amendment caused different effects in [different soils] and different amendments added to the same soil caused different effects. |
| 389 | Périé, F.H. & Gold, M.H. | Manganese regulation of manganese peroxidase expression and lignin degradation by the white rot fungus Dichomitus squalens | 1991 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 57 (8); 2240-2245 | English | Hardcopy:Partial | Lab. expt. to study the ability of D. squalens to degrade synthetic lignins under various conditions | .. Phanerochaete chrysosporium .. produces two extracellular heme peroxidases manganese peroxidase and lignin peroxidase - which, along with and H2O2generating system, constitute the major component of its lignin-degrading system.; In contrast to previous findings with Ph. chrysosporium, lignin degradation by D. squalens proceeded in the cultures containing excess C & N. |
| 525 | Qian, P. & Schoenau, J.J. | Availability of nitrogen in solid manure amendments with different C:N ratios | 2002 | Stockless Farming; Soil N Dynamics | Journal | Can. J. Soil Sci.; 82 (2); 219-225 | English | Hardcopy:Partial | Expt. to compare the availability of N in different kinds of animal manure [FYM] by testing them on a rape crop. The proportion of N mineralised in the manure was less than 1% in all cases except the poultry manure and the pelletised pig manure. | .. a significant negative correlation between manure C/N ration and N mineralisation was found for the manure-amended soils. .. cattle manures generally did not increase the short-term release of available N in the oil if the manure organic C/N ratio was in the range of 13-15 and tended to decrease N availability in the short term if the organic C/N ration was over 15. |
| 1067 | Quemada, M. & Cabrera, M.L. | Temperature and moisture effects on C and N mineralisation from surface applied clover residue | 1997 | Mulch; Soil Organic Carbon; Soil N Dynamics | Journal | Plant Soil; 189; 127-137 | English | Hardcopy:Full; PDF:Full | Lab. expt. to assess the effects of temperature and moisture on the rate of C and N mineralisation in clover residues. Total CO2 evolved from unamended soil increased linearly with log of the water potential, whereas total CO2 evolved from clover residue applied to the soil surface increased exponentially with water pot'l. In both cases the effect of water pot'l increased as T increased. | Apparent net mineralised N from the clover residue increased with water potential ..; The highest apparent net mineralised N from the clover residue was 28% of the N applied and it was obtained at -0.52 MPa and 35$C. Ammonia volatilisation increased with water potential .. |
| 1452 | Quemada, M. & Cabrera, M.L. | Carbon and nitrogen mineralised from leaves and stems of four cover crops | 1995 | Green Manure; Mineralisation | Journal | Soil Sci. Soc. Am. J.; 59; 471-477 | English | Hardcopy:Full | Lab. expt. to study the mineralisation of C & N in soil following surface application of leaves & stems from clover, wheat, rye & oats. When a mixture of both leaves & stems was applied, the CO2 emission and the N immobilisation were greater than would have been predicted from the sum of the two parts. | .. CO2 emission rates peaked 3 or 4 days after residue application and then decreased, to reach relatively low values after 16 or 30 days. |
| 844 | Quintern, M., Lein, M. & Joergensen, R.G. | Changes in soil-biological quality indices after long-term addition of shredded shrubs and biogenic waste compost | 2006 | Compost & Biocontrol; Soil Organic Carbon | Journal | J. Plant Nutr. Soil Sci.; 169; 488-493 | English | Hardcopy:Full; PDF:Full | Field expt. to test the effect on the soil of shredded shrubs and household-waste compost | The addition of compost and shredded shrubs to soil increased significantly all SOM-related properties. The effects of compost addition on soil chemical props were .. stronger than those of adding shredded shrubs ..; The increase in SOM was similar in the compost and shredded-shrubs treatments, although almost four times more C was supplied by the shredded shrubs than by the biogenic compost.; The microbial-biomass N/total N ratio can serve as an index for N availability to soil microorganisms. This suggests that the availability of N in the shredded -shrubs treatments was higher than in the compost and the control treatments, despite the large initial C/N ratio in the shredded shrubs. |
| 750 | Quénéa, K., Derenne, S., Largeau, C., Rumpel, C. & Mariotti, A. | Influence of change in land use on the refractory organic macromolecular fraction of a sandy spodosol (Landes de Gascogne, France) | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Geoderma; 136; 136-151 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the refractory fraction of the SOM in a forest soil cleared 22 yrs ago and since used for continuous maize cropping | The C of ROM [refractory OM] represents .. 20% of the TOC of the cropped soil.; .. almost two thirds of the refractory forest C was eliminated after 22 yrs... However, only limited input of maize .. occcurred in this ROM, so .. the refractory C in the cropped soil is still dominated (ca. 85%) by forest-inherited C.; Bulk lignin was substantially degraded, but a more resistant fraction was retained with partial alteration. |
| 698 | Rahman, M.A., Chikushi, J., Saifizzaman, M. & Lauren, J.G. | Rice straw mulching and nitrogen response of no-till wheat following rice in Bangladesh | 2005 | Mulch; Soil N Dynamics; Tillage | Journal | Field Crops Res.; 91 (1); 71-81 | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to study N cycling and the effect of mulch in zero-tillage wheat. Mulching increased soil water conservation, weed repression, wheat root development and wheat N uptake and recovery. A temporary mulch, which was removed 20 days after sowing the wheat, had a similar effect. | |
| 430 | Raich, J. & Tufekcioglu, A. | Vegetation and soil respiration: correlations and controls | 2000 | Roots & Rhizodeposition | Journal | Biogeochemistry (Dordr.); 48; 71-90 | English | Hardcopy:Full; PDF:Full | Review of factors affecting the rate of soil respiration | Factors such as temp, moisture availability & substrate properties, which simultaneously influence the production & consumption of OM, are more important in controlling the overall rate of soil respiration than is vegetation type in most cases. .. coniferous forests had ca. 10% lower rates of soil respiration than did adjacent broad-leaved forests growing on the same soil type & grasslands had .. ca.20% higher soil respir'n rates than did comparable forest stands |
| 1633 | Rajbhandari, N.K. & Upreti, H.K. | Monitoring of farm households | ? | Miscellaneous | Website | From internet? | English | Hardcopy:Full | Survey of farmers in the mid-hill region of Nepal | .. about 49% of the farm households in the study area have adopted improved paddy varieties.; About 53% .. use FYM on their rice fields. The average FYM application .. was 3.8 t/ha.; On average farmers use 64 kg/ha of nitrogenous fertiliser ..; The overall average yield of paddy .. was 5213 kg/ha ..; 90% of households use a bullock-driven plough for land preparation and 8% use tractors (power tiller).; .. FYM applied to wheat averaged 5.1 t/ha.; .. the average [wheat] yield [was] 3003 kg/ha .. |
| 532 | Ram, L., Nieto, R. & Lobley, G.E. | Tissue sequestration of C-labelled bicarbonate [HCO3-] in fed and fasted young sheep | 1999 | Greenhouse Gases | Journal | Comp. Biochem. Physiol. Part A Mol. Integr. Physiol.; 122; 323-330 | English | Hardcopy:Full | CO2 production and CO2 'entry rates' [?] in fed and fasted sheep were compared, using respiration chamber measurements and stable and radioactive isotope measurements respectively. Six-to-nine-month-old lambs averaging about 30 kg in weight produced about 10.5 moles CO2 per day when fed and about 5.5 moles per day when unfed (i.e. about 19 and 10 g per hour respectively). | |
| 1757 | Ramadhas, A.S., Jayaraj, S. & Muraleedharan, C. | Use of vegetable oils as I.C. engine fuels: a review | 2004 | Energy Resources; Rape and Biodiesel | Journal | Renew. Energ.; 29 (5); 727-742 | English | Wordperfect:Full | ||
| 1665 | Ramage, J. | Energy: a Guidebook | 1997 | Energy Resources | Book | Ramage, J.; Energy: a Guidebook; | English | Hardcopy:Partial | Figures for per capita energy consumption and for present and future energy sources | 12 TW divided equally between all the inhabitants of the world gives each of us .. 2 kW of primary power. .. each kilowatt of electric power delivered would probably need nearly 6 kW of primary input. |
| 60 | Ramakrishnan, P. | Agricultural systems in the north-eastern hills of India | 1990 | Energy in Agriculture | Book | Gliessman, S.R. (ed.); Agroecology - researching the ecological basis for sustainable agriculture; | English | Hardcopy:Partial | The energy budget of various agricultural systems is presented. The energy efficiency of land use patterns at different elevations is discussed. Figures are given for the output/input ratio of slash-and-burn, terraced and valley agriculture. | Jhum [slash-and-burn] is still the chief land use in the hill regions of northeast India .. One reason is the high energy efficiency of the system .. The only energy input into the system is manual labour ..; The efficiency of the terrace agro-ecosystem is very low due to heavy energy inputs for labour to prepare the terraces .. and maintain them .. [but it] is comparable to [that of] other sedentary and more modern Indian agricultural systems .. [and] better than most western agricultural systems, where the yield is one or two units of food energy per unit of energy input .. |
| 1743 | Randerson, J.T., Masiello, C.A., Still, C.J., Rahn, T., Poorter, H. & Field, C.B. | Is carbon within the global terrestrial biosphere becoming more oxidized? Implications for trends in atmospheric O2 | 2006 | Uncategorised | Journal | Glob. Change Biol.; 12; 260-271 | English | PDF:Full | ||
| 83 | Rao, A.R. & Singh, I.J. | Choice of foods to shorten food chains in India | 1977 | Stockless Farming; Sustainability | Book | Lockeretz, W. (ed.); Agriculture and Energy; | English | Hardcopy:Partial | The cost and land requirements of different food crops are compared. The figures on cost of energy and protein in different foods and on land required to provide the per capita food needs are given. Vegetarian diet cheaper and demanding less land. | Plants are better than animals as sources of human food .. Animal products .. are extravagant to produce. .. Animal products have no place in a poor man's budget.; Total land requirement: Vegetarians 0.4531 Non-vegetarians 0.4791 [hectares per capita] |
| 84 | Rao, A.R. & Singh, I.J. | Bullocks: the mainstay of farm power in India | 1977 | Energy in Agriculture; Labour and Animal Power | Book | Lockeretz, W. (ed.); Agriculture and Energy; | English | Hardcopy:Partial | An assessment of the extent to which the power needs of small and medium-sized holdings in India can be met by animal & human power. [conclusions not present] | Workers constituted 32.92% of the total population of India in 1971 .. About 69.6% of the work force was available for agriculture.; .. a man develops about 0.1 hp .. approximately 1 hp of power is needed per hectare of cropped land.; A pair of bullocks takes about 2.5 days to plough one hectare of land .. |
| 1165 | Rappaport, R.A. | The flow of energy in an agricultural society | 1971 | Energy in Agriculture; Sustainability | Journal | Sci. Am.; 225 (2); | English | Hardcopy:Partial | Study of the energetics of the swiddening agroecosystem of the Tsembaga tribe in New Guinea. Pig-keeping has an output/input ratio < 1, but is practised as part of a means for regulating relations between local tribal groups, for recycling waste and for converting vegetable carbohydrate into protein. | .. the regular protein intake of the Tsembaga is marginal, their antibody production is .. low and their rate of recovery from .. illness is slow.; Both in .. the small numbers of species present and the lack of ecological complexity a farm .. more closely resembles an immature stage of succession than .. a mature stage. .. in man's quest for higher plant yields he has devised some of the most delicate and unstable ecosystems ever to have appeared on the face of the earth.; Information feedback from the environment is sensitive and rapid in small autonomous ecological systems and such systems are likely to be rapidly self-correcting.; .. economic development surely accelerates ecological simplification; it inevitably encourages a shift from more diverse subsistence agriculture to the cultivation of a few crops for sale in a world market.; .. some aspects of what we have called progress or social evolution may be maladaptive. |
| 1333 | Rasmussen, J., Eriksen, J., Jensen, E.S., Esbensen, K. & Hřgh-Jensen, H. | In-situ carbon and nitrogen dynamics in ryegrass-clover mixtures: transfers, deposition and leaching | 2007 | Green Manure; Soil Organic Carbon; Soil N Dynamics | Journal | Soil Biol. Biochem.; 39; 804-815 | English | Hardcopy:Full; PDF:Full | Field expt. to study the N dynamics in a grass-clover ley | Transfer of 14C occurred mainly from ryegrass to clover, whereas the largest transfer of 15N was in the opposite direction. The average transfer of N from clover was 40% of N in ryegrass, whereas the fraction of N in clover donated by ryegrass was 5%. The amount of 14C transferred from ryegrass to clover was 1.7% of the 14C-activity in the total above-ground plant biomass found in the unlabelled clover & with a transfer from clover to ryegrass being 0.4% 15N-enriched compounds were not detected in percolating pore water... 14C was found solely as 14CO2 in the pore water, indicating that DOC did not originate from fresh root deposits. .. part of the N transfer occurred in non-leachable Nforms. The amount of N transferred between the 2 species was found to depend on the ratio between DM accumul'd in the donating & receiving spp., the 14C-alloc'n within the receiving species & the root turnover rate in the soil. |
| 168 | Rasmussen, P.E. & Collins, H.P. | Long-term impacts of tillage, fertiliser and crop residue on soil organic matter in temperate semi-arid regions | 1991 | Soil Organic Carbon; Tillage | Journal | Adv. Agron.; 45; | English | Hardcopy:Partial | A review of the work done on studying and modelling changes in SOM | Grassland soils have higher OM content than forest soils.; The loss of OM with cultivation is usually exponential, declining rapidly in the first 10-20 years, then more slowly and finally approaching a new equilibrium in 50-60 years.; Loss of C & N is a combination of increased oxidation due to more cultivation, lower residue return to soil and, frequently, increased wind and water erosion.; .. conservation tillage increases organic C & N .. compared to conventional methods .. the increase averages from 1 to 2% per year for both C & N ..; .. soil erosion surpasses accelerated mineralisation as the dominant factor affecting OM loss from soil ..; Estimates of atmospheric content of C range from 690-700 x 109 tons, whereas SOM contains approximately twice this amount. Cultivated soils account for slightly less than 10% of the earth's surface but maintain over 12% of the world's total C .. Estimates set annual C fixation in grasslands and cultivated lands at 10 and 5 x 109 tons of C respectively.; Halflives of these SOM fractions range from a few months for easily decomposable plant material to nearly 2000 years for chemically stabilised fractions.; The [Century] model assumed that all transformations of organic C were the result of microbial activity, with 55% of the C lost due to microbial respiration. |
| 1570 | Rasmussen, P.E., Albrecht, S.L. & Smiley, R.W. | Soil C and N changes under tillage and cropping systems in semi-arid Pacific Northwest agriculture | 1998 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 47 (3-4); 197-205 | English | Hardcopy:Partial; Wordperfect:Full | Evaluation of tillage and crop rotation effects on SOM in long-term expts, some lasting from the early twentieth century. | .. most of the SOM loss was due to high biological oxidation and absence of C input during the fallow year rather than resulting from erosion. Decreasing tillage intensity reduced SOM loss, but the effect was not as dramatic as eliminating summer-fallow. Crop management practices such as N fertilisation increased residue production and improved C & N levels in soil.; .. erosion rates of 5-10 Mg ha-1 yr-1 and 1-2 Mg ha-1 yr-1 [were reported at one site] for W/F [wheat/fallow] and W/W [wheat/wheat] rotations respectively .. Estimated yearly erosion for the wheat/fallow study at Pendleton is less than 2 Mg ha-1 using the RUSLE soil loss equation.; Converting from ploughing to mulch (non-inversion) tillage at Pendleton conserved C & N in both wheat/fallow rotation and annual cropping .. |
| 1334 | Rasmussen, P.E., Douglas, C.L., Collins, H.P. & Albrecht, S.L. | Long-term cropping system effects on mineralizable nitrogen in soil | 1998 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (13); 1829-1837 | English | Hardcopy:Partial; PDF:Full | Field expt. to study long-term changes in N mineralisation potential | Soil N mineralisation from wheat-summer fallow, wheat-pea and wheat-wheat crop rotations was 32, 42 & 51% of that mineralised from non-cultivated pasture soil. N mineralised, as a fraction of the total N present, increased with increasing N application, reduction in tillage intensity & higher frequency of cropping. Stubble-mulch soils mineralised 10-20% more N than ploughed soils. The fraction of total N mineralised increased with increasing soil org. N content, indicating that org. N added through recent crop mgmnt practices is more labile than N in the native soil matrix. N mineralisation in situ increased linearly as a function of past N fertiliser application, which implies that a substantial portion of previously applied N may be recovered slowly over time in subsequent crops. |
| 1138 | Rasmussen, P.E., Goulding, K.W.T., Brown, J.R., Grace, P.R., Janzen, H.H. & Körschens, M. | Long-term agroecosystem experiments: assessing agricultural sustainability and global change | 1998 | Soil (General) | Journal | Science; 282; 893-896 | English | Hardcopy:Full | Review of the results of long-term field expts. world-wide | Belowground material makes up a substantial portion of net annual production in most crops, approaching nearly 40% in modern wheat varieties.; A combination of inorganic fertiliser and organic manure has given the best yields in many parts of the world.; Legume-wheat rotations in Australia acidified the soil through N-fixation to the extent that legume growth could no longer be maintained without regular liming.; Agriculture research has, in the past, been fragmented, production-oriented and territorial. .. This situation is changing, however, .. |
| 670 | Rasse, D.P., Dignac, M.F., Bahri, H., Rumpel, C., Mariotti, A. & Chenu, C. | Lignin turnover in an agricultural field: from plant residues to soil-protected fractions | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 530-538 | English | Hardcopy:Full; PDF:Full | Modelling the decay of lignin in arable soil | Lignin has long been suspected to be a major source of stable carbon in soils .. However, lignin turnover studies have produced conflicting results, most of them suggesting that large prop'ns of plant-residue lignin decompose within a year of incorp'n into soils. Here we propose a two-reservoir model where lignin in undecomposed plant residue (Lp) can either reach soil fractions, where it is somewhat protected from further decompos'n (Ls), or is transformed to non-lignin products.; In the present study not only have we confirmed the hypothesis of the transformation of plant-residue VSC-lignin into slow-turnover soil-protected VSC-lignin, but we have also quantified the respective sizes and turnover rates of these lignin pools in a loamy temperate soil: about 1.9 year-1 for Lp and about 0.05 year-1 for Ls. |
| 1068 | Rasse, D.P., Rumpel, C. & Dignac, M.F. | Is soil carbon mostly root carbon? Mechanisms for a specific stabilisation | 2005 | Roots & Rhizodeposition; Soil Organic Carbon | Journal | Plant Soil; 269 (1/2); 341-356 | English | Hardcopy:Full; PDF:Full | Review of current knowledge of the contribution of plant roots to SOM | .. the mean residence time in soils of root-derived C is 2.4 times that of shoot-derived C.; .. the higher chemical recalcitrance of root tissues as compared to that of shoots is responsible for only a small portion, i.e. about one fourth, of the difference in mean residence time in soils of root-derived vs. shoot-derived C. This suggests that SOM protection mechanisms other than chemical recalcitrance are also enhanced by root activities ..; Cutins and suberins are among the most recalcitrant plant molecular structures in soils. Cutin is a polyester-like biopolymer that constitutes an integral part of the protective covering layer of above-ground vascular-plant tissues. Suberin is an analogous biopolyester, containing polyphenolic & polyaliphatic domains, that is mostly found in root tissues, but is also present in the above-ground organs of woody species that undergo secondary thickening. Therefore, while cutin is a shoot-specific cpd, suberin is a good tracer of root activities only in ecosystems dominated by non-woody species. Both cutin and suberin polymers have a high potential for preservation within the mineral soil. |
| 1453 | Rasse, D.P., Smucker, A.J.M. & Santos, D. | Alfalfa root and shoot mulching effects on soil hydraulic properties and aggregation | 2000 | Green Manure; Mulch | Journal | Soil Sci. Soc. Am. J.; 64 (2); 725-731 | English | Hardcopy:Partial; PDF:Full | 2-year field expt. to study the effect of lucerne on soil properties | Alfalfa root systems increased saturated hydraulic conductivity by 57%, total and macroporosities by 1.7 and 1.8% respectively and water recharge rate of the soil profile by .. 5.4% per day.; Mean weight diameter (MWD) of aggregates from bare fallow soils was 20% higher when alfalfa shoot mulch was applied.; Improved soil structural stability under alfalfa stands has been reported by several authors ..; Our results suggest that aggregate stability was more affected by C sources from shoot mulch and root turnover than by factors specific to root activities such as phys. enmeshment of aggregates.. |
| 299 | Rasse, D.P., Smucker, A.J.M. & Schabenberger, O. | Modifications of soil nitrogen pools in response to alfalfa root systems and shoot mulch | 1999 | Green Manure; Soil N Dynamics | Journal | Agron. J.; 91 (3); 471-477 | English | Hardcopy:Partial; PDF:Full | Field expt. to determine the contribution of above- and belowground lucerne biomass to soil N pools | Living alfalfa stands kept soil inorganic N at very low levels, whether shoot mulch was applied or not. ... alfalfa shoot mulch contributed little to ... soil N pools, while crowns and roots contributed larger quantities ... |
| 1571 | Raun, W.R., Johnson, G.V., Phillips, S.B. & Westerman, R.L. | Effect of long-term N fertilisation on soil organic carbon and total nitrogen in continuous wheat under conventional tillage in Oklahoma | 1998 | Soil Organic Carbon; Soil N Dynamics | Journal | Soil Tillage Res.; 47 (3-4); 323-330 | English | Hardcopy:Partial; Wordperfect:Full | Study of the effect of N addition on C sequestration in soil at the sites of four long-term field expt.s | C/N ratios increased at the low rates of applied N and then decreased to levels below that found in check plots at high N rates (134 kg N ha-1 yr-1).; When N was applied at rates > 90 kg ha-1 yr-1, surface SOC was either equal to that of the control (no N applied) or slightly greater. Total soil N (0-30 cm) increased at the high N rates at all locations. However, at two locations total soil N decreased at low N rates, indicating the presence of priming (increased net mineralisation of organic N pools when low rates of fertiliser N are applied). At these same two sites, soil-plant inorganic N buffering (amount of N that could be applied in excess of that needed for maximum yield without resulting in increased soil profile inorganic N accumulation) was greater compared to the other two sites, where no evidence of priming was found.; .. 81.9% of the fertiliser N remaining in a 0-150 cm soil profile had been immobilised by harvest time in a winter wheat expt. .. [so] only 18% of the fertiliser N .. was present as inorganic N. |
| 125 | Raupp, J. | Quality investigations with products of the long-term fertilisation trial in Darmstadt | 1996 | Biodynamic Farming; Organic Farming | Book | Raupp, J. (ed.); Quality of plant products grown with manure fertilisation, Proc. 4th mtg (concerted action AIR3-CT94-1940); | English | Hardcopy:Partial; Wordperfect:Full | Long-term field expt. to compare the quality of produce from conventional, organic and biodynamic farming. The crop yields from the biodynamic treatment were, on average, 4% higher than those from the organic treatment. | Mineral fertilisation increased the parameters of rising number, maltose and crude protein content a little, which is assessed positively for baking.; Protein content was also increased by mineral fertilisation, 13.8% in MIN instead of 10.8% in CM [organic]; manure with the biodynamic prep'ns gave more protein, 11.2%. In contrast to spring wheat the gluten content in winter wheat was much higher with mineral (38.6%) compared to manure fertilisation (28.7 and 28.1%) |
| 143 | Raupp, J. | Manure fertilisation for soil organic matter maintenance and its effects upon crops and the environment, evaluated in a long-term trial | 2001 | Biodynamic Farming; Soil Organic Carbon; Stockless Farming | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Long-term field expt. on a sandy soil to compare crop yields & SOM accumul'n in soils fertilised with chemical fertilisers, FYM and FYM+biodynamic prep'ns | Whereas spring wheat gave the same yield with all types of fertiliser,winter rye had 33% & potatoes 10% higher yields with mineral than with manure fertilisation.. The biodynamic prep'ns increased potato yields by 15 dt ha-1 (6%) on average over all years. Higher levels of fertilisation influenced yields positively with all crops.; The manure treatments in our trial contain 3.6- 8.4 t ha-1 more C in the topsoil than the corresponding minerally fertilised plots. These differences are several times higher than those reported [by Drinkwater etal (1998)]. However, .. the Corg differences in our trial are the outcome of varying degrees of [humus] reduction, not of humus accumulation. Even the soil fertilised with FYM was a C source, though to a much lesser extent than the minerally fertilised soil. C losses could only be avoided when FYM application was combined with the biodynamic preparations. |
| 1335 | Rawlins, A., Bull, I., Poirier, N., Ineson, P. & Evershed, R.P. | The biochemical transformation of oak (Quercus robur) leaf litter consumed by the pill millipede (Glomeris marginata) | 2006 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 38; 1063-1076 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the products of oak leaf consumption by pill millipedes | the conc'ns of short-chain (<C20) n-alkanoic acids, sterols & triacylglycerols reduced dramatically in the millipede faeces relative to the leaf litter. Hydrolysable carbohydrates & proteins both decreased in conc'n in the faeces, whereas similar yields of phenolic components were observed for the cupric oxidation products of lignin, although the oxygenated functionalities were affected by passage through the millipede gut, yielding a more highly condensed state for lignin. .. the chemical composition of fresh OM entering the soil is directly controlled by invertebrates feeding upon the leaf litter and .. they are key contributors to the early stages of diagenesis in terrestrial soils. |
| 1391 | Rawls, W.J. | Estimating soil bulk density from particle size analysis and organic matter content | 1883 | Soil (General) | Journal | Soil Sci.; 135 (2); 123-125 | English | Hardcopy:Full | Study of 2721 soil samples to derive a method of calculating the BD. Their OM content ranged from 0.1% to 12.5% (average 0.66%) and their bulk densities ranged from 0.7 to 2.09 (average 1.42) g/cm3. The average density of the OM was 0.224 g/cm3. | Soil BD = 100/(%OM/OM BD+(100-%OM)/mineral BD) |
| 1337 | Recous, S. & Mary, B. | Microbial immobilisation of ammonium and nitrate in cultivated soils | 1990 | Soil N Dynamics | Journal | Soil Biol. Biochem.; 22 (7); 913-922 | English | Hardcopy:Partial | Lab. study of the comparative immobilisation of ammonium and nitrate by the incubation of soils after the addition of ammonium and nitrate with and without glucose. In a separate expt. on 54 isolated strains of bacteria their response to ammonium and nitrate was observed. All of them cold grow on ammonium sulphate. 47 of them could also grown on nitrate, although 16 of these showed a lower growth rate. | The immobilisation ratio, immobilised N/decomposed C, was calculated for glucose .. It was independent of the form of N applied and was similar between soils, c. 45-48 mg N/g C.; .. the immobilisation of nitrate is negligible when the ammonium pool is large enough to satisfy the microbial needs.; NO3 uptake by microorganisms is inhibited when NH4 [is] present. |
| 1336 | Recous, S., Aita, C. & Mary, B. | In situ changes in gross N transformations in bare soil after addition of straw | 1999 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 31; 119-133 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the effect of incorporating wheat straw at 8 tons per hectare into the soil | The mean rate of gross mineralisation was 0.42 mg N kg-1 soil normalised d-1 and for immobilisation it was 0.13 mg N kg-1 soil normalised d-1, resulting in net mineralisation of 0.29 mg N kg-1 soil normalised d-1. Gross mineralisation and immobilisation were both increased by straw addition, with rates of 0.99 and 1.98 mg N kg-1 soil d-1 respectively ..; On average the immobilisation from nitrate represented 30% of total immobilisation (ammonium+nitrate).; The ratio between gross mineralisation and net mineralisation was approximately 3:2.; .. residue-N also contributes to the N requirements of the microbial biomass developing during decomposition. .. straw-derived N contributed to 25% of the zymogenous biomass-N and to 5- 8% of total biomass N.; The higher gross mineralisation observed in straw-amended soil .. may be due .. to extra mineralisation of SOM and, later on, to re-mineralisation of previously immobilised N. .. The net difference in accumulated N between the two treatments was up to 30 kg N ha-1, consistent with re-mineralisation of N which had been immobilised during decomposition of straw.; [7 d after incorporation] .. part of residue-N could be assimilated by the microflora without first entering the inorganic N pool. .. the direct assimilation of residue-N occurred during decomposition of simple amino acids and probably in parallel with the MIT (mineralisation-immobilisation turnover) route for N assimilation. For the other 7 measurement dates, the relationship between mineralised C and immobilised N was constant at 0.126. |
| 1069 | Recous, S., Machet, J.M. & Mary, B. | The partitioning of fertiliser-N between soil and crop: comparison of ammonium and nitrate applications | 1992 | Soil N Dynamics | Journal | Plant Soil; 144; 101-111 | English | Hardcopy:Partial | Field expt. to study the immobilisation and uptake of different forms of N in a soil cropped with winter wheat. | The initial rate of N immobilisation following application was 3 to 4 times higher when N was applied as ammonium or urea that as nitrate.. [showing] preferential assimilation of ammonium by soil microflora .. During the 0-26-day period following N application ammonium was more immobilised and less taken up by the crop than was nitrate. |
| 1338 | Recous, S., Robin, D., Darwis, D. & Mary, B. | Soil inorganic N availability: effect on maize residue decomposition | 1995 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 27 (12); 1529-1538 | English | Hardcopy:Full | Lab. expt. to test the effect of inorganic N availability on the decompos'n of maize straw (42.5% C) in soil. For all treatments the ratio of gross immobilised N to mineralised C falls at about the same rate in relation to mineralised C as a %age of added C. This implies a diminishing demand for N, which could be:1. because the C/N ratio of the decomposing microbes increases as the microbial population changes; 2. because the growth efficiency of the decomposing microorganisms decreases when more recalcitrant components of the residue are decomposed; and/or 3. because the decomposing microorganisms increasingly get N from the recycling of biomass. | ..there was no non-productive (or luxury) N consumption by microbial decomposers and .. the heterotrophic soil microflora is not a sink for excess soil N.; .. the production .. of the .. enzymes required for cellulose and lignin degradation imply an additional energy cost for the decomposer organisms ..; .. it is possible to define a critical level of N availability, below which N will drive C decomposition and above which C will drive N dynamics. |
| 1572 | Reeder, J.D., Schuman, G.E. & Bowman, R.A. | Soil C and N changes on conservation reserve programme lands in the Central Great Plains | 1998 | Soil Organic Carbon; Tillage | Journal | Soil Tillage Res.; 47; 339-349 | English | Hardcopy:Partial; PDF:Full | Field expt. to compare the SOC & N in plots cultivated for 60+ years and 6 years with that in adjacent native grassland. | After 60 years of cultivation, surface soils at both study sites were 18-26% lower .. in total organic C and N than in .. adjacent native range. Six years after ploughing and converting native rangeland to cropland .. both total and potential net mineralised C and N in the surface soil had decreased and NO3-N at all depths had increased to levels found after 60 years of cultivation. .. mixing of the surface and sub-surface soil with tillage accounted for 40-60% of the decrease in surface soil C and N in long-term cultivated fields. In the short-term cultivated fields mixing with tillage may have accounted for 60-75% of the decrease in C and 30-60% of the decrease in N. |
| 319 | Reekie, E.G. & Bazzaz, F.A. | Reproductive effort in plants: 1. carbon allocation to reproduction 2. Does carbon reflect the allocation of other resources? 3. Effect of reproduction on vegetative activity | 1987 | Miscellaneous | Journal | Am. Nat.; 129 (6); 876-919 | English | Hardcopy:Partial | Lab. expt. to study the allocation of resources to reproduction in plants | ... carbon ... tends to integrate the allocation patterns of other resources and can therefore be used as a common currency to assess allocation patterns.; ... biomass allocation to flowers and fruits may not reflect the carbon cost of reproduction.; ... it will be necessary to consider not only reproductive output but also total resource allocation to reproduction and its effect on vegetative growth.; In a plant that allocates resources to reproduction, the decrease in vegetative activity would depend not only on the quantity of resources diverted to reproduction but also on the ability of the plant to compensate for this diversion through photosynthesis by the reproductive parts.; Reproduction was much less costly than the resources allocated to reproduction would indicate. ... reproduction had little detrimental effect on total growth ... |
| 103 | Reents, H.J. & Möller, K. | Strategies to avoid nitrate leaching after potato crops by applying different cultivation methods to the following cereals | 1999 | Soil N Dynamics | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | Field expt. to test the effect on nitrate leaching of different sowing methods | The results showed .. distinct effects of the cultivation methods on nitrate leaching during winter. Early sowings (mid Sept), especially when intercropped with white clover, reduced nitrate leaching to a level equal to that of a mustard cover-crop. The yields of early sowings were almost as high as for October sowings, but the grain quality was slightly reduced. Intercropping with white clover decreased the yield and the grain quality of winter rye and winter wheat .. The effects of a mustard cover crop were lower yields and grain quality .. |
| 112 | Rees, W.E. | Patch disturbance, ecofootprints and biological integrity: revisiting the limits to growth (or why industrial society is inherently unsustainable) | 2000 | Miscellaneous; Sustainability | Book | Pimentel, D., Westra, L. & Noss, R.F. (eds.); Ecological Integrity: Integrating Environment, Conservation & Health; | English | Hardcopy:Partial; Wordperfect:Full | Review of the sustainability of industrial society | .. almost everyone in the mainstream shares the perception that we are confronting an environmental crisis rather than a human ecological crisis. This distinction is not a trivial one. The former term externalises the problem, effectively blaming it on an environment gone wrong or on defective resource systems that need to be fixed. By contrast, the latter term places blame squarely where it belongs, on the nature and behaviour of people themselves, and suggests that it is human wants which should be better controlled ... The Cartesian dualism that underpins Western scientific culture has created a psychological barrier between humans and the rest of nature, a barrier that prevents us from understanding ourselves as ecological beings. |
| 116 | Rees, W.E. | The ecology of sustainable development | 1989 | Sustainability | Book | ; Proc. 9th Commonwealth Conference on Human Ecology, Edinburgh; | English | Hardcopy:Full | The thermodynamics of growth, consuming the ecological capital, the need to face up to the real meaning of sustainability. | True sustainability demands a radically different economics which fully recognises the processes and limits of the biosphere.; ..all material economic production is in fact consumption and contributes to increasing entropy.; .. our continuing belief in the possibility of sustainable development based on the growth-oriented assumptions of neo-classical economics is illusory.; Ecosystems are inherently self-sustaining and self-organising and therefore contribute to a reduction in global net entropy.; .. photosynthesis is the .. ultimate source of all renewable resources used by the human economy.; .. any human activity dependent on the consumptive use of ecological resources cannot be sustained indefinitely if it uses not only the annual production of the biosphere (the `interest') but also cuts into the standing stock (the `capital'). |
| 1573 | Reeves, D.W. | The role of soil organic matter in maintaining soil quality in continuous cropping systems | 1997 | Soil (General) | Journal | Soil Tillage Res.; 43; 131-167 | English | Hardcopy:Partial | A review of the literature on SOM | SOC .. is chosen as the most important indicator of soil quality and agronomic sustainability, because of its impact on other physical, chemical and biological indicators of soil quality. .. even with crop rotation and manure additions continuous cropping results in a decline in SOC .., although the rate and magnitude of the decline is climate and soil dependent and can be ameliorated by wise soil management practices [which] include manure additions, adequate fertilisation, return of crop residues to the soil and, most importantly, conservation tillage coupled with intensive cropping systems and rotations which include pasture or ley periods. .. within climatic limits conservation tillage can sustain or increase SOC when coupled with intensive cropping systems. However, the need for sound rotation practices in order to maintain agronomic productivity and economic sustainability is even more critical in conservation tillage systems than conventional [ones]. |
| 193 | Refsgaard, K., Halberg, N. & Kristensen, E.S. | Energy utilisation in crop & dairy production in organic and conventional livestock production systems | 1998 | Energy in Agriculture; Organic Farming | Journal | Agric. Sys.; 57(4); 599-630 | English | Hardcopy:Partial | The energy utilisation in the production of fodder for dairy cattle is estimated. A comparison is made between conventional and organic farms in respect of the energy cost of producing fodder. Tables of energy values for farming inputs and operations are given. | Conventional crop yields were higher but they also used more indirect energy with input factors, especially fertilisers. The conventional yields were not sufficiently higher to compensate for the extra use of energy compared with the organic crops.; .. organic fodder crops show clearly lower energy prices than conventional crops.; .. the most energy efficient crop [is] clover-grass .. |
| 390 | Regalado, V., Rodriguez, A., Perestelo, F., Carnicero, A., Fuente, G. de la & Falcon, M.A. | Lignin degradation and modification by the soil-inhabiting fungus Fusarium proliferatum | 1997 | Lignin and CBW | Journal | Appl. Environ. Microbiol.; 63 (9); 3716-3718 | English | Hardcopy:Full; PDF:Full | Study of the degradation of lignin by a soil inhabiting fungus imperfectus | .. 33.7% of 14C-labelled milled wood lignin (14C-MWL) from wheat straw was mineralised after 30 days of incubation. .. However, the amounts of 14CO2 recovered from pine 14C-MWL and [14C-lignin]lignocellulose and from spruce [14C- lignin] lignocellulose were very low.; Differences in the biodegradability of lignins from different plant sources have been demonstrated, with pine wood being highly refractory to biodegradation and herbaceous agricultural residues being degraded to a much greater extent during the same incubation period.; maximal rates of 14CO2 release occurred between days 5 and 10 of incubation, correlating over time with glucose consumption and mycelial growth. Lignin degradation in the early stages of the vegetative growth period was previously reported for other soil-inhabiting fungi imperfecti. Occasionally, the production of ligninolytic enzymes by some white rot fungi was also detected during primary metabolism, although it is well known that ligninolysis occurs mainly during the secondary metabolic growth phase in response to nutrient depletion.; F. proliferatum produced limited mineralisation together with residual products with higher molecular mass than the original lignins, indicating that both depolymerisation and polymerisation occurred. .. Repolymerisation of degradation products and recondensation of lignin could be related to detoxification of phenolic products from lignin decay and the formation of humic substances in soils. |
| 39 | Reganold, J.P. | Soil quality and farm profitability studies of biodynamic and conventional farming systems | 1995 | Organic Farming; Soil (General) | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; | English | Hardcopy:Partial | Review of research comparing the soil quality of organic and conventional farms | These studies indicated that the biodynamic farming systems generally had better soil quality than their conventional counterparts. |
| 915 | Reganold, J.P., Elliott, L.F. & Unger, Y.L. | Long-term effects of organic and conventional farming on soil erosion | 1987 | Organic Farming; Soil (General) | Journal | Nature (Lond.); 330; 370-373 | English | Hardcopy:Full | Soil erosion is compared on organic and conventional farms. Organic farming is more effective than conventional farming in reducing soil erosion and maintaining soil productivity. | The organically farmed soil had significantly higher OM content, thicker topsoil depth, higher polysaccharide content, lower modulus of rupture and less soil erosion than the conventionally farmed soil.; The difference in erosion rates between the organic and conventional farms was most probably due to their different crop rotation systems. Only the organic farm included a green manure legume crop in the .. rotation. |
| 1139 | Reganold, J.P., Palmer, A.S., Lockhart, J.C. & MacGregor, A.N. | Soil quality and financial performance of biodynamic and conventional farms in New Zealand | 1993 | Organic Farming; Soil (General) | Journal | Science; 260; 344-349 | English | Hardcopy:Full | Soil properties and economic profitability of adjacent commercial biodynamic and conventional farms were compared. Biodynamic farms had better soil quality than the neighbouring conventional farms and were just as financially viable | the biodynamically farmed soils had better structure and broke down more readily to a good seedbed ..; The surface soil BD was significantly less on four of the biodynamic farms ..; Earthworms were counted on the two market gardens .. we found the biodynamically farmed soil to average 175 earthworms per square metre compared with 21 earthworms per square metre on the conventionally farmed soil. |
| 1634 | Regmi, A.P. | Effects of long-term application of mineral fertilisers and manure on rice-rice-wheat system | ? | Miscellaneous | Website | From internet? | English | Hardcopy:Full | Field expt. to compare 9 different fertiliser and manure treatments on a ricerice-wheat rotation in Nepal | The total grain production .. decreased in all treatments ..; Yields declined most slowly in [treatment] 8 (50:20:0 NPK + 30 cm straw). The incorporation of straw into the soil might have supplied K ...; .. available P limits grain yield, followed by K.; Where P was not applied, grain yields fell to zero by year 5 ..; FYM improved .. all soil props. except exchangeable K. |
| 1635 | Regmi, A.P. | Long-term soil fertility experiment in the rice-wheat system, Nepal | ? | Miscellaneous | Website | From internet? | English | Hardcopy:Full | Field expt. to study the effect of different fertiliser and manure treatments on a rice-wheat rotation. The treatments included FYM, green manure and N, P and K in various combinations. | ... FYM in combination with N and P resulted in better wheat yields than applications of mineral fertilisers only.; ... a green manure, sesbania, increased the rice yield but had no residual effect on wheat.; Olsen P was below the critical level of 5 g/g soil where P was not applied. Exchangeable K was ... below the critical level of 78 g/g soil in all treatments, including the FYM treatment. |
| 959 | Reicosky, D.C. | Tillage-induced CO2 emission from soil | 1997 | Tillage | Journal | Nutr. Cycl. Agroecosyst.; 49; 273-285 | English | Hardcopy:Partial; PDF:Full | Expt.s to measure the rate of CO2 emission from soil immediately following the tillage of wheat stubble using four different methods - ploughing, ploughing and disc-harrowing, disc harrowing alone and chisel ploughing - and to compare it with zero tillage. | The .. CO2 losses 5 hours after .. conservation tillage .. was only 31% of that of the mouldboard plough. The mouldboard plough lost 13.8 times as much CO2 as the soil are not tilled .. |
| 1574 | Reicosky, D.C., Dugas, W.A. & Torbert, H.A. | Tillage-induced soil CO2 loss from different cropping systems | 1997 | Tillage | Journal | Soil Tillage Res.; 41 (1-2); 105-118 | English | Hardcopy:Partial | Expt. to measure short-term tillage-induced CO2 loss from soil under different cropping systems. Soil inorganic N was also measured. | The CO2 flux over a 24 h period .. was greatest immediately after tillage ..; Fluxes in the mouldboard plough treatment were usually the greatest, and fluxes in the untilled treatment were considerably smaller than fluxes from either tillage treatment.; For the first 24 h after tillage there was no relationship between cumulative CO2 flux and the change of inorganic N. Thus, to the extent that these inorganic N content changes reflect microbial activity, the shortterm CO2 flux from tilled soils is controlled more by mass flow processes related to a tillage-induced change in porosity than to immediate microbial activity. |
| 869 | Reicosky, D.C., Evans, S.D., Cambardella, C.A., Allmaras, R.R., Wilts, A.R. & Huggins, D.R. | Continuous corn with moldboard tillage: residue and fertility effects on soil carbon | 2002 | Greenhouse Gases; Soil Organic Carbon; Tillage | Journal | J. Soil Water Conserv.; 57 (5); 277-284 | English | Hardcopy:Partial | The results of an expt. to measure the SOC changes over a 30-year period of continuous ploughed maize cropping under four different treatments - silage removal or grain removal, each with two different rates of N-fertiliser application. | Total C, total N and C/N ratio in the soil remained virtually unchanged after 30 years .. all four treatments produced the same SOC content .. (2.2%) in the 0-20 cm. depth. .. plough tillage caused rapid soil degassing that masked fertiliser and stover removal and/or return effects on SOC. .. the soils were sources of CO2, regardless of other agronomic practices, as long as .. plough tillage was used.; .. the potential beneficial effects of C input through aboveground stover management were negated by intensive tillage. |
| 870 | Reicosky, D.C., Kemper, W.D., Langdale, G.W., Douglas, C.L. & Rasmussen, P.E. | Soil organic matter changes resulting from tillage and biomass production | 1995 | Soil Organic Carbon; Tillage | Journal | J. Soil Water Conserv.; 50 (3); 253-261 | English | Hardcopy:Full | Review of expt'l work on the effects of tillage on SOM | In general it is practically impossible to increase OM where mouldboard ploughing is taking place.; .. soil cultivation caused a decline in organic C content .., even with heavy manure treatment, as long as conventional tillage continued.; Mouldboard ploughing not only fractures, inverts and opens the soil, allowing rapid O2 and CO2 exchange, but also incorporates crop residues into the soil, which feeds a microbial population explosion.; Some biological oxidation is needed to get other benefits or microbial activity, e.g. mucilage, gels for stabilised aggregate formation, controlled release of nutrients through mineralisation.; .. the detrimental effects of tillage on OM were not just in the reduction in total OM, but were associated with mixing the OM that had been concentrated in the top 15 mm of soil. This mixing moved most of the OM out of the top [15 mm] of soil,where it could substantially affect infiltration and evaporation, to greater depths in the soil, where it does not appreciably affect water-use efficiency. |
| 501 | Reid, I.D. | The influence of nutrient balance on lignin degradation by the white-rot fungus Phanerochaete chrysosporium | 1979 | Lignin and CBW | Journal | Can. J. Bot.; 57; 2050-2058 | English | Hardcopy:Partial | Lab. expt. to study the study the effect of nutrient availability on the fungal decomposition of lignin, using 14C-labelled wood as lignin source and glucose as source of available C. | The most lignin degradation occurred in the medium containing sufficient sulphate and phosphate and low N.; .. carbohydrate depletion terminated lignin degradation ..; N limited cultures released radioactive CO2 [from lignin] earlier, at a higher maximum rate and over a longer period that high-N cultures.; Abundant C causes the available N to be tied up in cell constituents, so that it does not repress ligninolysis. Abundant N increases the amount of C incorporated into cell constituents .. Thus increasing the N supply inhibits lignin degradation in 2 ways. Repressive concentrations of N delay the appearance of and limit the maximum rate of lignin degradation. They also increase the rate of carbohydrate depletion and thereby shorten the period of lignin metabolism. |
| 1575 | Reilly, J.M. & Fuglie, K.O. | Future yield growth in field crops: what evidence exists? | 1998 | Energy Resources; Sustainability | Journal | Soil Tillage Res.; 47 (3-4); 275-290 | English | Hardcopy:Partial; PDF:Full | Modelling the growth rate in the yield of crops in the U.S.A. and using the model to predict future growth. There is no evidence of a levelling off and the historical rate of growth (1-3% p.a.) is likely to continue for the next 20 years. | Whether and the extent to which, an increased focus on the environment implies a trade-off with yield growth is unclear and will depend on the type of environmental incentives put in place. |
| 71 | Reinhardt, T. | Organic acids as a decisive limitation to process dynamics during composting of organic matter | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the effect of organic acids on the development of microbial activity and temperature during composting | .. during the initial stages of the composting process a significant drop in pH, due to the microbial formation of organic acids, may .. occur.; .. the limitations of oxygen transport from the free air space into the heterogeneous solid particles of the OM, making this process more likely to be an anaerobic/aerobic co-process than a solely aerobic process.; .. an intimate correlation of the development of the pH-value, the concentration of acetic acid, the temperature and the microbial metabolic activity could be demonstrated.; Due to the emitted heat in the course of the developing microbial activity, a rise in temperature can be detected throughout the heap after the start .. The development of intensive microbial activity .. was detected only in sections of the heap where acetic acid conc'ns had already .. diminished; |
| 1339 | Reiter, K., Schmidtke, K. & Rauber, R. | Estimation of symbiotic N2 fixation by a low-level large-scale 15N application technique | 2002 | Green Manure; Soil N Dynamics | Journal | Soil Biol. Biochem.; 34 (3); 303-314 | English | Hardcopy:Partial; PDF:Full | An expt. to test a new method of estimating the proportion of plant N derived from the atmosphere. The method is said to be easier to use and more accurate than the established isotope dilution method. | |
| 1140 | Renwick, W.H., Smith, S.V., Sleezer, R.O. & Buddemeier, R.W. | Comment on 'Managing soil carbon' (II) | 2004 | Soil Organic Carbon | Journal | Science; 305; 1567 | English | Hardcopy:Full; PDF:Full | Comment on the assertion of Lal et al. (2004) that soil erosion represents a CO2 source of about 1 Gt/year. The authors reckon that it is actually a sink for about the same amount, due to the fact that soil is deposited in depressions, flood plains and reservoirs (buried, submerged, waterlogged or very dry environments), where the oxidation rate of the OM is less than in the original soil, moistened to field capacity. | |
| 478 | Requena, N., Baca, T.M., Azcón, R. | Evolution of humic substances from unripe compost during incubation with lignolytic or cellulolytic microorganisms and effects on the lettuce growth promotion mediated by Azotobacter chroococcum | 1997 | Compost & Biocontrol; Lignin and CBW | Journal | Biol. Fertil. Soils; 24; 59-65 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effect of incubation with ligno-cellulolytic microorganisms on unripe compost, particularly in respect of its influence on the plant growth effects on lettuce exerted by Azotobacter chroococcum | Organic matter not completely stabilised, that is, that may undergo further important chemical changes, can result in phytotoxicity if it is added to soil.; Some recalcitrant organic wastes that contain a large proportion of lignin or cellulose are not changed much by composting and thus the effectiveness of the compost as fertiliser is usually low. In this study incubation of unripe compost with ligno-cellulolytic microorganisms was investigated to increase the degree of humification of the OM present.; Bacteria use the root exudates .. and provide the plant with hormone-like substances that enhance plant growth.. it seems that control incubation mixtures of 30% compost provide Azotobacter with enough energy to enhance plant growth... incubation of such mixtures with Trichoderma or Bacillus may .. provide sufficient energy with an incubation of only 35days. |
| 941 | Requena, N., Jimenez, I., Toro, M. & Barea, J.M. | Interactions between plant-growth-promoting rhizobacteria (PGPR), arbuscular mycorrhizal fungi and Rhizobium spp. in the rhizosphere of Anthyllis cytisoides, a model legume for revegetation in mediterranean semi-arid ecosystems | 1997 | Soil Microorganisms | Journal | New Phytol.; 136; 667-677 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the interactive effects of PGPR, AM fungi & symbiotic N-fixing bacteria on the growth of a woody legume | .. PGPR can influence plant development not only directly (hormone production, P solubilisation or asymbiotic N2-fixation), but also indirectly through modifications to the activity of other plant-microbe interactions, such as the mycorrhizal or the Rhizobium symbioses, or by inducing changes in the microbial population balance, for instance, exerting biological control against plant pathogens.; .. P deficiency has been described as a main factor in restricting not only plant development but other biological processes such as the biological N fixation, owing to the high requirement of P (as ATP) for the N2 fixation process. .. the role of the AM fungi as P suppliers to the plant, and particularly to the nodule, appears to be of great relevance. |
| 944 | Rethemeyer, J., Grootes, P.M., Bruhn, F., Andersen, N., Nadeau, M.J., Kramer, C. & Gleixner, G. | Age heterogeneity of soil organic matter | 2004 | Soil Organic Carbon | Journal | Nucl. Instrum. Methods Phys. Res., Sect. B; 223/224; 521 | English | Hardcopy:Partial | Field expt. to study the age-heterogeneity of SOM by accelerator mass spectrom | At the field expt .. located in a heavily industrialised area, an increase of 14C content with increasing depth was observed, even though the input of modern plant debris should be highest in the topsoil. This is attributed to a significant contribution of old C (of up to 50% in the topsoil) to SOM.; .. 14C data of other field trials distant from industrial areas indicate that there inputs of old C to the soil are lower or even absent. |
| 751 | Rethemeyer, J., Kramer, C., Gleixner, G., John, B., Yamashita, T., Flessa, H., Andersen, N., Nadeau, M.J. & Grootes, P. | Transformation of organic matter in agricultural soils: radiocarbon concentration versus soil depth | 2005 | Soil Organic Carbon | Journal | Geoderma; 128; 94-105 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the origins of OC in different SOM fractions at different depths, using C-14 radiocarbon measurments | .. the humin fraction .. yielded 14C decreases of about 30% to 54% from the surface soil to ca. 65 cm depth. These results indicate a progressive enrichment of stable organic compounds with increasing soil depth. .. a minor decline in 14C concentrations of the humic acid fraction, which mostly showed higher 14C values than the humin, reflect the translocation of modern OC towards greater depth. Low radiocarbon levels of the light occluded particulate OM (<1.6 g/cm3), obtained by density separation, suggest stabilisation of OC in soil aggregates. |
| 1141 | Reynolds, J.D. & Freckleton, R.P. | Population dynamics: growing to extremes | 2005 | Miscellaneous | Journal | Science; 309; 567-568 | English | Hardcopy:Partial; Wordperfect:Full | Modelling the population growth of vertebrate animals and insects in the wild. The growth rate was found to conform to a concave curve. | The linear .. model .. assumes that the absolute negative effect of each additional individual on population growth is the same. This implies scramble competition, whereby each individual requires a fixed amount of resource to survive and reproduce.; . plots of population growth rate against population size are concave. This implies that populations experience strong density dependence early in their growth, with a weaker effect as they approach and exceed their carrying capacity.; .. the net reduction in population growth per individual is greater at low densities than at high densities .. |
| 1454 | Rhoton, F.E. | Influence of time on soil response to no-till practices | 2000 | Tillage | Journal | Soil Sci. Soc. Am. J.; 64 (2); 700-709 | English | Hardcopy:Partial; PDF:Full | 8-year field expt. to assess how long is required for conversion to zero tillage to take effect | Within 4 years no-till resulted in .. significant differences compared to conventional tillage. The surface 2.5 cm of the NT treatments had higher levels of SOM, exchangeable Ca and extractable P, Mn and Zn, but lower extractable K, Fe and Cu. Tillage had no effect on exchangeable Mg and pH. No-till also resulted in higher AS [aggregate stability] and lower MR [modulus of rupture], WDC [water-dispersible clay] and TC [total clay] in the top 2.5 cm relative to CT.; .. all the changes that occurred in the soil properties at the 0-to 2.5-cm depth are the result of gains or losses in the SOM contents. |
| 871 | Ribaudo, M.O., Gollehon, N.R. & Agapoff, J. | Land application of manure by animal feeding operations: is more land needed? | 2003 | Stockless Farming | Journal | J. Soil Water Conserv.; 58 (1); 30-38 | English | Hardcopy:Partial | Review of recent developments in livestock farming with particular reference to the area of land available for disposal of FYM | .. the average AU [animal unit] per farm has increased significantly.; While animal numbers were increasing, available cropland and pastureland operated by confined operations on which to spread manure declined from an average of 1.4 hectares per AU in 1982 to 0.9 hectares per AU in 1997.; An animal unit is defined as 1000 pounds liveweight. .. the number of animals per animal unit are as follows: feedlot beef - 1.14; dairy cows - 0.74; swine for breeding - 2.67; swine for slaughter - 9.09; laying hens and pullets > 3 months - 250; broilers and pullets , 3 months - 455; turkeys for breeding - 50; turkeys for slaughter 67. |
| 1392 | Rice, J.A. | Humin | 2001 | Soil Organic Carbon | Journal | Soil Sci.; 166 (11); 848-857 | English | Hardcopy:Partial | Review of the current state of knowledge abut humin, which is the fraction of humic substances that is insoluble in aqueous solution at any pH. It typically constitutes >50% of SOC. Its nature is still unknown, but appears to consist of a bound humic acid component (aromatic and carbohydrate) and a lipid component (aliphatic). It binds irreversibly to a wide range of chemicals, such as pesticides and PCBs. It is the oldest part of the humic substances, being typically >1000 years old. It is quite recalcitrant, possibly because it is an amorphous and heterogeneous mixture, the microbial decomposition of which would require a very large assemblage of enzymes or one uncharacteristically versatile enzyme. It is believed to be a precursor of coal and kerogen, which itself is a precursor of petroleum. | |
| 1092 | Richardson, A.E., Hadobas, P.A. & Hayes, J.E. | Acid phosphomonoesterase and phytase activities of wheat roots and utilisation of organic phosphours substrates by seedlings grown in sterile culture | 2000 | Phosphorus Cycling; Roots & Rhizodeposition | Journal | Plant Cell Environ.; 23; 397-405 | English | Hardcopy:Partial; PDF:Full | Expt. to investigate the effects of enzymes secreted by plant roots on their uptake of phosphorus from soil containing organic phosphates. Phosphatase enzymes with various substrate specificities show increased activity in the rhizosphere in response to soil available P deficiency. Whereas glucose phosphate, phospoglycerate, RNA, ATP and AMP all met crop P requirements as well as inorganic P did, inositol phosphate (phytate) did not. This was due to the limited activity of phytase (phosphatase specific to phytate) in wheat roots. Phytases in maize roots are located predominantly in the endodermis rather than in the rhizodermis and are involved mainly in the internal re-mobilisation of phytates, rather than the mineralisation of external phytates. The addition to the soil of a bacterium with phytase activity significantly improved the plant uptake of P from phytate. | Some 50-80% of the total P in soil occurs in organic forms .. around 25% of soil Po may occur as phytate. |
| 996 | Riederer, M., Matzke, K., Ziegler, F. & Kögel-Knabner, I. | Occurrence, distribution and fate of the lipid plant biopolymers cutin and suberin in temperate forest soils | 1993 | Soil Organic Carbon | Journal | Org. Geochem.; 20 (7); 1063-1076 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the distribution and fate of cutin and suberin in the soils of beech and spruce forests | Cutin and suberin are lipid polymers consisting of mainly hydroxy- and epoxysubstituted alkanoic acids, which are cross-linked to form a three-dimensional amorphous network. Suberin very likely additionally contains a lignin-like fraction of predominantly aromatic nature. Wax-like lipids are associated with both polymers endowing them with a very low permeability to water and solutes.; This study provided evidence for the occurrence of considerable amounts of the lipid biopolymers cutin and suberin in the soils of two important types of European forests... indicating a fairly good preservation of this type of plant material under soil conditions. |
| 245 | Riffaldi, R., Levi-Minzi, R., Saviozzi, A. & Benetti, A. | Adsorption on soil of dissolved organic carbon from farmyard manure | 1998 | Soil Organic Carbon; Stockless Farming | Journal | Agric. Ecosyst. Environ.; 69 (2); 113-119 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to study the adsorption on soil of dissolved OM from FYM | The dissolved organic C (DOC) in soil, composed mainly by organic acids is usually less than 1% of the total organic C. It plays an important role, both in natural and modified ecosystems. [There is] a strong relationship between DOC concentration and CO2-C mineralisation and denitrification capacities in a wide variety of soils. DOC movements from surface to deep horizons represent the main way for translocation of nutrients and energy compounds through ecosystem compartments, so controlling the nutrient turnover and the development of microbial populations.; The soil DOC content varies from 3.33 to 23.67 mg l-1, in the range of the values observed in soil solutions (0-44 mg l-1) .., and represents from 0.48 to 7.37 of the total organic C (mean 2.19%), similar to an average of 3.2% reported for a series of soils ..; .. the soils buffered the DOC solution pH such that final pH values were within one pH unit.; Organic C in the water extract of FYM represents about 6% of the total organic C content of the original material. |
| 194 | Rigby, D. & Cáceres, D. | Organic farming and the sustainability of agricultural systems | 2001 | Organic Farming; Sustainability | Journal | Agric. Sys.; 68 (1); 21-40 | English | Hardcopy:Partial; PDF:Full | Sustainability is considered in relation to organic farming. There is no consensus as to exactly what organic and sustainable mean. Sustainability in agriculture is discussed in the context of energy efficiency, use or otherwise of synthetic chemicals, food miles and scale of production. | The extent to which any farming system which is intended to be sustainable should be linked to an unsustainable society is one such issue. .. there are important questions as to whether sustainable farming should aspire to as great a degree of self-sufficiency and self reliance as possible ..; For those who seek a closing of the gap between producer and consumer, .. falling into the same patterns of scale, distance and control as the conventional food system poses major problems. |
| 1576 | Riley, H.C.F., Bleken, M.A., Abrahamsen, S., Bergjord, A.K. & Bakken, A.K. | Effects of alternative tillage systems on soil quality and yield of spring cereals on silty clay loam and sandy loam soils in the cool, wet climate of central Norway | 2005 | Tillage | Journal | Soil Tillage Res.; 80 (1-2); 79-93 | English | Hardcopy:Partial; Wordperfect:Full | 12-year field expt. to compare 4 tillage systems: autumn and spring ploughing and deep and shallow harrowing | In treatments without ploughing, average yields on the silty loam over clay were 93% of those obtained with ploughing, and on the sandy loam over sand they were 81%.; The reduction of 19% on sandy loam .. represents an economically unacceptable loss to the farmer. It thus appears that shallow ploughless tillage is problematic under the cool and wet growing seasons that frequently occur in central Norway and that the problems are the greatest on compactable soil with low aggregate stability, such as sandy loam with low OM content.; .. increases in penetrometer resistance occurred in the topsoil of unploughed treatments. .. observations of greater earthworm activity on unploughed soil. .. mineral N and plant-available P and K accumulated in the upper horizon under ploughless tillage. |
| 942 | Rillig, M.C. & Mummey, D.L. | Mycorrhizas and soil structure | 2006 | Soil Microorganisms | Journal | New Phytol.; 171; 41-53 | English | Hardcopy:Full; PDF:Full | Review of the contribution of mycorrhizas to soil structure | .. mycorrhizal fungi can influence soil aggregation at .. various scales. |
| 1070 | Rillig, M.C., Ramsey, P.W., Morris, S. & Paul, E.A. | Glomalin, an arbuscular-mycorrhizal fungal soil protein, responds to land-use change | 2003 | Soil Microorganisms | Journal | Plant Soil; 253 (2); 293-299 | English | Hardcopy:Partial | Lab. expt. to study the decomposability and concentrations of glomalin in forest and arable soils. Glomalin is an iron-containing glycoprotein produced by AM fungi. It is quite recalcitrant - 25% decomposed in 5 months and 50% in 14 months. Its concentration is higher in forest than in arable soils and is highly correlated with soil aggregate stability. | |
| 1071 | Rillig, M.C., Wright, S.F. & Eviner, V.T. | The role of arbuscular mycorrhizal fungi and glomalin in soil aggregation: comparing effects of five plant species | 2002 | Soil Microorganisms; Soil (General) | Journal | Plant Soil; 238; 325-333 | English | Hardcopy:Full | Field expt. to study the effect of five plant species - 3 grasses and 2 nongrasses, including a legume - on glomalin concentration and soil aggregation | .. the identity of the species does not matter, but rather the relative productivity .. For example, root length was a good predictor of hyphal length, which in turn was a good predictor of glomalin concentration.; .. the indirect effects of hyphae via the production of glomalin were stronger than the direct effect of hyphae, which .. were rather weak .. |
| 1072 | Rillig, M.C., Wright, S.F., Nichols, K.A., Schmidt, W.F. & Torn, M.S. | Large contribution of arbuscular mycorrhizal fungi to soil carbon pools in tropical forest soils | 2001 | Soil Microorganisms | Journal | Plant Soil; 233 (2); | English | Hardcopy:Partial | Expt. to quantify and carbon-date the glomalin in various tropical soils | Arbuscular mycorrhizal fungi (AMF) are recognised as indirect contributors through their influence on soil aggregation, plant physiology and plant community composition. Here we present evidence that AMF can also make large direct contributions to SOM. Glomalin, a recently discovered glycoprotein produced by AMF hyphae, was detected in tropical soils in concentrations of over 60 mg cm-3. .. a pattern of glomalin concentrations is consistent with the hypothesis that this protein accumulates in soil. Carbon dating of glomalin indicated turnover at time scales of several years to decades, much longer than the turnover of AMF hyphae (which is assumed to be on the order of days to weeks). .. The amount of C & N in glomalin represented a sizeable amount (ca. 4-5%) of total soil C & N in the oldest soils. .. microbial (fungal) C that is not derived from above- or belowground litter can make a significant contribution to soil C & N pools and can far exceed the contributions of soil microbial biomass (ranging from 0.08 to 0.2% of total C forthe oldest soils). |
| 671 | Rimmer, D.L. | Free radicals, antioxidants, and soil organic matter recalcitrance | 2006 | Mineralisation; Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 57; 91-94 | English | Hardcopy:Full; PDF:Full | Review of the possible role of anti-oxidants in the protection of OM in soils | .. humic materials contain stable semi-quinone free radicals .. These .. species are most likely to be derived from the reaction of phenolic cpds. with reactive radicals .. the phenolics are acting as anti-oxidants, because they are scavenging the reactive free radicals and terminating the oxidative chain reaction responsible for SOM degradation. Thus the soil's anti-oxidant capacity .. could provide a chemical mechanism for the recalcitrance of SOM. |
| 144 | Ritz, K. & Griffiths, B.S. | Implications of soil biodiversity for sustainable organic matter management | 2001 | Soil Organic Carbon; Soil Microorganisms | Book | Rees, R.M., Ball, B.C., Campbell, C.D. & Watson, C.A. (eds.); Sustainable Management of Soil Organic Matter; | English | Hardcopy:Partial; Wordperfect:Full | Review of the effects of soil microbial and faunal diversity on SOM turnover and plant development | .. under most non-extreme conditions the biodiversity of soils is probably not the primary regulator of SOM dynamics. This is not because diversity has little impact on C dynamics, but rather that the prevailing levels of diversity in most systems are sufficiently high that the repertoire is complete, .. and there is a significant degree of redundancy in the decomposer communities. .. It is unclear whether there are actual diversity thresholds below which OM dynamics are impaired and which occur outside of the laboratory or field experiment.; .. a general reduction in biodiversity may have implications for the susceptibility & resilience of soils to stresses. |
| 1340 | Rizhiya, E., Bertora, C., Vliet, P. van, Kuikman, P.J., Faber, J., Groenigen, J.W. van | Earthworm activity as a determinant for N2O emission from crop residue | 2007 | Greenhouse Gases; Mulch; Soil N Dynamics | Journal | Soil Biol. Biochem.; 39; 2058-2069 | English | Hardcopy:Full; PDF:Full | Lab. expt. to study the effect of earthworm activity on CO2 and N2O emissions from arable soil amended with grass mulched or incorporated into the soil | .. earthworm activity has the potential to increase N2O emissions from crop residues up to 18-fold; .. earthworm species specifically affect N2O emissions and residue stabilisation in SOM. However, earthworm-mediated emissions of N2O mostly resulted from residue incorporation into the soil and disappeared when ploughing of residue into the soil was simulated.. farmers may decrease direct N2O emissions from crop residues with a relatively low C/N ratio by leaving it on top for a few weeks before ploughing it into the soil. |
| 1455 | Roberson, E.B., Sarig, S. & Firestone, M.K. | Cover crop management of polysaccharide-mediated aggregation in an orchard soil | 1991 | Soil (General) | Journal | Soil Sci. Soc. Am. J.; 55; 734-739 | English | Hardcopy:Full | Study of soil carbohydrate content and aggregation in a soil under four treatments - permanent grass, cereal sown after autumn tillage, cereal sown after autumn tillage and killed the following May with glyphosate and fallow with occasional discing to control weed | Cover crops significantly increased .. heavy-fraction carbohydrates (those in soil denser than 1.7 g/ml) .. heavy-fraction carbohydrates are probably mainly compose of microbial extracellular polysaccharides produced in response to cover-crop inputs .. [and] were significantly correlated with aggregate stability ..; In soils that contain large amounts of clay, humified OM or Fe oxides these aggregating agents may overshadow carbohydrates. .. other organicmatter fractions, such as the aliphatic fraction, may be important in other soils, where interaction with clays or metallic oxides is important ..; .. fungal hyphae as well as microbial and plant mucilages are largely responsible for the changes in aggregate stability .. fungal hyphae have been observed to stabilise soil aggregates and fungal biomass increases dramatically under notill management. |
| 1456 | Roberson, E.B., Sarig, S., Shennan, C. & Firestone, M.K. | Nutritional management of microbial polysaccharide production and aggregation in an agricultural soil | 1995 | Soil (General) | Journal | Soil Sci. Soc. Am. J.; 59 (6); 1587-1594 | English | Hardcopy:Full | Expt. to study extracellular polysaccharide (EPS) production and aggregation under tomatoes with five different treatments: woolly vetch, oats and three different rates of nitrogenous fertiliser. High N fertilisation depresses EPS production and so reduces aggregate stability. | .. cover crop inputs of microbially available C stimulated rapid production of HF [heavy fraction = > 1.74 g ml-1] carbohydrate and improved soil structure. .. The N2-fixing vetch cover crop was also the most effective treatment .. in increasing .. microbial biomass and SOC. .. [It] added C to the soil both through root exudation and turnover .. and through residue decomposition ..; carbohydrates .. may have been used .. by microorganisms as they assimilated N, reducing polysaccharide-mediated aggregate stability.; Microbial biomass was not well correlated with aggregate slaking resistance .. this suggests that fungal hyphae are not important aggregating agents ..; .. fungi make up a larger proportion of microbial biomass and play a greater role in soil structure in reduced tillage systems than under conventional tillage.; .. changes in management practices may be quickly reflected in changes in microbial EPS production. Other organic aggregating agents, such as humic acids, may take mor time to form. .. Tillage disrupts aggregates and exposes organic aggregating agents to microbial attack. .. The EPS, therefore, may be more important as a aggregating agent in tilled systems than in less mechanically disturbed soils. |
| 550 | Robertson, G.P., Klingensmith, K.M., Klug, M.J., Paul, E.A., Crum, J.R. & Ellis, B.G. | Soil resources, microbial activity, and primary production across an agricultural ecosystem | 1997 | Soil (General) | Journal | Ecol. Appl.; 7 (1); 158-170 | English | Hardcopy:Full | Expt. to measure the spatial variability of soil attributes on a 48 ha. site that had been cultivated for decades | Visually the site appears to be as homogeneous as any agricultural field in the region. [And yet they found] differences of up to two orders of magnitude in important soil properties and resources across the site. Spatial variability was high for virtually all soil, plant and microbial properties that we examined. .. For most soil physical and chemical properties .. 50-90% of apparent sample variance was spatially structured. For most biological properties spatial structure .. accounted for 35-55% of total sample variance.; [These results also showed] the relatively short range over which spatial dependence occurred in this field... in all but three cases - elevation, soil pH and inorganic P - structural variance was limited to separation distances of < 100 m. .. Microbial properties were auto-correlated at even smaller scales: for microbial biomass, nitrification and N-mineralisation, model ranges were of the order of 20-30 m.; [The results showed] little correlation between biological processes (soya bean productivity, soil N turnover, soil respiration) and static soil properties. The best prediction of soya bean biomass at late reproductive stages .. was a combination of nitrate N, BD, inorganic P, N-mineralisation rates and pH. |
| 1142 | Robertson, G.P., Paul, E.A. & Harwood, R.R. | Greenhouse gases in intensive agriculture: contributions of individual gases to the radiative forcing of the atmosphere | 2000 | Greenhouse Gases; Green Manure; Tillage | Journal | Science; 289; 1922-1925 | English | Hardcopy:Full; Wordperfect:Full | Expt. to measure soil C sequestration, CH4 oxidation and N2O production in several agricultural and unmanaged ecosystems [useful tables included]. All the annual crop systems gave a net annual emission of CO2 equivalents, but the zero tillage system gave the lowest figure (lower even than the organic with leguminous green crop), showing that tillage is the overriding factor. A perennial lucerne crop gave a net mitigation of the greenhouse effect, thanks to high C sequestration, but its N2O emission was as high as that of the annual crops at about 3.5 g N2O-N per ha per day. The unmanaged areas gave an average N2O emission rate of only 1.0 g N2O-N per ha per day. The cropped areas gave a uniformly low rate of CH4 oxidation, averaging -1.80 g CH4-C per ha per day, while the forest areas gave a much higher rate, averaging -9.17 g CH4-C per ha per day. | .. it is neither fertiliser per se nor tillage that leads to accelerated N2O fluxes from cropping systems, but rather high soil N availability. |
| 72 | Robertsson, M. | Effects of interrupted air supply on the composting process: composition of volatile organic acids | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to test the effect of interrupted air supply on the composting process and the production of volatile organic acids | The fate of potentially phytotoxic lactic acid, acetic acid, propionic acid and butyric acid during composting has been studied in self-heating bench scale bioreactors.; The terms stability and maturity often appear in the literature. .. stability is a stage in the decomposition of organic matter and is a function of biological activity. Maturity is an organo-chemical condition of the compost which indicates the presence, or lack of, phytotoxic organic acids.; .. the composting process requires oxygen and that the temperature declines immediately if oxygen is absent. .. if aeration is resumed, the composting process starts again. The extension and maximum temperature of re-activated compost will be decided by how much microbial available energy is left in the compost material when the air supply is turned off. It is also interesting to notice that there is no observable change from mesophilic to thermophilic populations after restored aeration. .. The highest total content of VOA was found in the composts where the air supply was turned off at the mesophilic maximum temperature.; No VOA could be detected in any treatment two days after aeration was restored. |
| 198 | Robinson, D. | A comparison of soil-water distribution under ridge and bed cultivated potatoes | 1999 | Potato Growing | Journal | Agric. Water Manag.; 42; 189-204 | English | Hardcopy:Partial; PDF:Full | Field expt. to study effect of irrigation on ridge- and bed-cultivated potatoes | .. most of the water by-passed the potatoes planted in ridges, as irrigation water .. was shed off the ridges, infiltrating in the furrows. This was due to the water repellent nature of the sandy soil and meant that the irrigation water by-passed the potatoes. A soil water deficit built up in the core of the ridge .. and was not replenished by irrigations. A .. potato crop planted in beds was more successful at capturing water, as the flat bed increased water infiltration around the crop. |
| 1457 | Rochette, P., Flanagan, L.B. & Gregorich, E.G. | Separating soil respiration into plant and soil components using analyses of the natural abundance of C-13 | 1999 | Roots & Rhizodeposition | Journal | Soil Sci. Soc. Am. J.; 63; 1207-1213 | English | Hardcopy:Partial; PDF:Full | Field expt. to study the contribution of rhizosphere respiration to total soil respiration and its variation with time | The maximum contrib'n of Rrh [rhizosphere respir'n] to total respir'n was 45%, observed in August. Estimates of Rrh increased from zero 30 d after planting to [a max.] 70 d after planting, remained relatively constant at that level in Aug. and then decreased until the end of the growing season. Values of Rs gradually declined from [a max] in late June to .. the end of the season. |
| 752 | Roder, W., Phengchanh, S. & Maniphone, S. | Dynamics of soil and vegetation during crop and fallow period in slash-and-burn fields of northern Laos | 1997 | Soil (General); Sustainability | Journal | Geoderma; 76 (1/2); 131-144 | English | Hardcopy:Partial | Soil C, N, P and K were monitored over a three-year period on four plots subject to slash-and-burn treatment in northern Laos. The soil C & N pools declined during the cropping and fallow periods. | Slash-and-burn agriculture remains a dominant land use system in many parts of the tropics. .. slash-and-burn systems are sustainable with long fallows, but .. the system will collapse due to insufficient restoration of soil fertility levels if fallows are reduced.; Mineralisation of OM, occurring at high rates after the initial burning of the plant biomass, is an important source for N and other nutrients. [One author] estimated a loss of 13 t. OM per ha in the first year after burning .. OM losses of 10 t per ha during the cropping period after burning were reported from [another] study.; Upland rice is generally cultivated on sloping land using slash-and-burn methods without tillage and without inputs of fertilisers. .. Rice is planted in hills with the help of a dibble stick. A single crop of rice is followed by fallow periods of 2-10 years.; .. the time for recovery of soil C during succession would be about 4050 years. |
| 683 | Rodriguez, A., Perestelo, F., Carnicero, A., Regalado, V., Perez, R., Fuente, G. de la & Falcon, M.A. | Degradation of natural lignins and lignocellulosic substrates by soil-inhabiting fungi imperfecti | 1996 | Lignin and CBW | Journal | FEMS Microbiol. Ecol.; 21 (3); 213-219 | English | Hardcopy:Partial | A study of the lignin degrading fungi in the soil | The most powerful lignin-degraders among the 82 microbial strains isolated during a screening of ligninolytic microorganisms from forest soil were identified as Penicillium chrysogenum, Fusarium oxysporum and Fusarium solani. These fungi imperfecti mineralised 27.4%, 23.5% and 22.6% of 14C-labelled milled wood lignin (MWL) from wheat straw after 28 days of incubation .. |
| 1143 | Rojstaczer, S., Sterling, S. & Moore, N. | Human appropriation of photosynthesis products | 2001 | Miscellaneous; Sustainability | Journal | Science; 294; 2549-2552 | English | Hardcopy:Full; PDF:Full | Calculation of global human appropriation of net primary product | Previous global estimates of the human impact on terrestrial photosynthesis products depended heavily on extrapolation from plot-scale measurements. Here we estimated this impact with the use of recent data, many of which were collected at global and continental scales. .. We estimate that humans appropriate 10 to 55% of terrestrial photosynthesis products. This broad range reflects uncertainty in key parameters and makes it difficult to ascertain whether we are approaching crisis levels in our use of the planet's resources. |
| 199 | Romic, D., Romic, M., Borosic, J. & Poljak, M. | Mulching decreases nitrate leaching in bell pepper (Capsicum annum L.) cultivation | 2003 | Mulch | Journal | Agric. Water Manag.; 60; 87-97 | English | Hardcopy:Partial | Study of the effects of different mulching materials (black polythene and biodegradable cellulose sheet) on nitrate leaching | .. mulched surfaces showed lower quantities of nitrate leached in comparison with the treatment without mulching. |
| 531 | Rosenberg, N.J. & Izaurralde, R.C. | Storing carbon in agricultural soils to help head off a global warming | 2001 | Greenhouse Gases; Soil Organic Carbon | Journal | Clim. Change; 51 (1); 1-10 | English | Hardcopy:Partial; PDF:Full | Review of the possibilities for increased sequestering of carbon in agricultural soils | Depending on its type - humus, manure, stubble or litter - organic matter contains between 40 and 60% carbon.; ... it might be possible over the course of the next 50 to 100 years to sequester 40 and 80 Pg of C in cropland soils.; Schlesinger's calculations show that the energy costs of soil carbon sequestration could be substantial and effectively negate any net carbon sink. Other analysts (Smith & Powlson, 1999; Izaurralde etal, 2000) have challenged the details of Schlesinger's calculations and assert that the practices that foster C sequestration will demand little extra or may actually reduce the need for energy consuming inputs. |
| 1393 | Rosenzweig, C. & Hillel, D. | Soils and global climate change: challenges and opportunities | 2000 | Greenhouse Gases; Soil (General) | Journal | Soil Sci.; 165; 47-56 | English | Hardcopy:Partial | A review of the subject of C storage in the soil and its effect on climate change | .. our management of the soil should be aimed at enhancing SOM for the multiple complementary purposes of improving soil fertility and soil structure, reducing erosion and helping to mitigate the greenhouse effect. |
| 800 | Roslon, E. & Fogelfors, H. | Crop and weed growth in a sequence of spring barley and winter wheat crops established together from a spring sowing (relay cropping) | 2003 | Miscellaneous | Journal | J. Agron. Crop Sci.; 189; 185-190 | English | Hardcopy:Full | 2-year expt. in the relay cropping of barley and wheat. Yields of both barley and wheat were slightly higher than normal for the region. | Winter wheat has a vernalisation requirement that prevents plants from flowering until their cold requirement has been met. In a northern climate May sowing avoids vernalisation of the wheat. .. in Southern Europe, where spring barley is sown much earlier, it is possible that wheat may vernalise during the first growth season .. |
| 1342 | Ross, D.J., Tate, K.R., Scott, N.A. & Feltham, C.W. | Land-use change: effects on soil carbon, nitrogen and phosphorus pools and fluxes in three adjacent ecosystems | 1999 | Phosphorus Cycling | Journal | Soil Biol. Biochem.; 31 (6); 803-813 | English | Hardcopy:Partial; PDF:Full | Field study of C, N, and P cycling in the soil of native broad-leaved forest, coniferous plantation and introduced pasture | Total P, organic P and extractable inorganic P concentrations .. were .. lowest in the indigenous forest.; .. P availability appears to be less important than other factors in our pine and forest mineral soils which, in spite of very different extractable Pi concentrations, had similar microbial C/P ratios. |
| 753 | Rovira, P. & Vallejo, V.R. | Labile and recalcitrant pools of carbon and nitrogen in organic matter decomposing at different depths in soil: an acid hydrolysis approach | 2002 | Green Manure; Soil Organic Carbon | Journal | Geoderma; 107 (1-2); 109-141 | English | Hardcopy:Partial; Wordperfect:Full | 2-year field incubation expt. to study the change in OM quality during decomposition of mixtures of four plant materials (whole lucerne plants and litter from eucalyptus, oak, pine), using chem. fraction'n into 3 pools: 2 labile & 1 recalcitrant. The recalcitrance index for C (RIC) for undecomposed materials varied between 25% (for lucerne) and 60% (for pine). 60-65% was the absolute maximum value for RIC. Initial RIN values were much lower (15-30%), but .. increased strongly during decompos'n. The recalcitrant pool was relatively poor in aromatic C & rich in alkyl C (up to 50% of the pool). | .. the cellulose/total carbohydrates ratio (Pool II/Pools I+II) decreased as decompos'n proceeded .. Transfer of carbohydrates from Labile Pool II to Labile Pool I, probably monosaccharides or oligosaccharides resulting from the degradation of lignocellulose, would account for that decrease and for the maintenance of the C quality (carbohydrate C/polyphenol C ratio) in Labile Pool I, despite the biodegradability of carbohydrates, much higher than that of polyphenols. |
| 825 | Rowell, D., Prescott, C.E., Preston, C.M. | Decomposition and nitrogen mineralisation from biosolids and other organic materials: relationship with initial chemistry | 2001 | Mineralisation; Soil Organic Carbon; Soil N Dynamics | Journal | J. Environ. Qual.; 30 (4); 1401-1410 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the decomposition in soil of materials of varying compos'n | Decomposition rates were best predicted by a model incorporating the ratio of carbon to OM. .. There was a weak relationship between rates of decomposition and net N mineralisation. Rates of net N mineralisation were best predicted by a model incorporating the initial org. N conc'n and the proportion of phenolic C .. Among the four biosolids there was a strong correlation between organic N conc'n and indices of protein determined from 13C NMR, suggesting that these protein indices may be useful for predicting N mineralisation from biosolids. |
| 362 | Ruiter, P.C. de, Neutel, A.M., Moore, J. | Biodiversity in soil ecosystems: the role of energy flow and community stability | 1998 | Soil Microorganisms | Journal | Appl. Soil Ecol.; 10; 217-228 | English | Hardcopy:Partial; PDF:Full | Modelling the food webs in soils under different agricultural management systems | .. some interactions had a relatively strong impact on stability, whereas other interactions had only a small impact. These impacts on stability were correlated neither with energy flow nor with interaction strength. Comparison of the seven food webs showed that these impacts were sometimes connected to particular groups of organisms involved in the interaction, but sometimes they were not, which might be due to different trophic positions in the food webs. |
| 943 | Ruiz-Lozano, J.M., Collados, C., Barea, J.M. & Azcón, R. | Arbuscular mycorrhizal symbiosis can alleviate drought-induced nodule senescence in soybean plants | 2001 | Soil Microorganisms | Journal | New Phytol.; 151; 493-502 | English | Hardcopy:Partial; PDF:Full | Field expt. to find out whether AM fungi, which can protect host plants against some effects of drought, can also lessen drought-induced nodule senescnence in leguminous plants | ... results from this study show that AM symbiosis can protect legume plants against the detrimental effects of premature nodule senescence induced by drought stress. The exact mechanisms by which the AM symbiosis promote such an effect remain to be elucidated. It could be thought that mycorrhizal plants were simply better hydrated than non-mycorrhizal ones, due to direct fungal water uptake and its transport to plant. However, it is unlikely that this was the only mechanism involved. |
| 1343 | Rumpel, C., Eusterhues, K. & Kögel-Knabner, I. | Location and chemical composition of stabilised organic carbon in topsoil and subsoil horizons of two acid forest soils | 2004 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 36 (1); 177-190 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to study the stabilisation of organic compounds in the whole soil profile | These results are .. showing that cutin/suberin-derived hydroxyalkanoic acids are preserved in the fine particle-size fractions of the B horizons. The OM composition in particle size fractions of the top- and sub-soil horizons of the Haplic Podzol shows that this soil is acting like a chromatographic system, preserving insoluble alkyl C in the fine particle size fractions of the A horizon. Small molecules, most probably organic acids, dominate in the fine particle size fractions of the C horizons, where they are stabilised in clay-sized fractions, most likely due to the interaction with the mineral phase. The characterisation of lignin-derived phenols indicated, in accordance with the NMR measurements, that these compounds are not stabilised in the mineral soil horizons. |
| 997 | Rumpel, C., Kögel-Knabner, I. & Bruhn, F. | Vertical distribution, age and chemical composition of organic carbon in two forest soils of different pedogenesis | 2002 | Soil Organic Carbon | Journal | Org. Geochem.; 33 (10); 1131-1142 | English | Hardcopy:Full; PDF:Full | Lab. expt. to analyse two forest soils (under beech and spruce) & compare the quantities & qualities of the SOM in the topsoil and the sub-soil. About half of the OM in the mineral soil under beech and three quarters of that under spruce were stored in the sub-soil. The C in the sub-soils has a radiocarbon age between 2000-4000 years. The OM contains a high proportion of alkyl carbon. | Alkyl structures may originate from the contribution of plant-derived hydroxyalkanoic acids, indicating the presence of cutin/suberin, which may have been preserved preferentially compared to phenolic units ..; In the C horizons most OM seems to be adsorbed to the mineral surfaces .. different stabilisation processes operate in the subsoil (B & C horizons) compared to the topsoil and litter layers. Root litter input as well as soil forming processes have a high impact on the composition of OM in subsoils.; Lignin may be decomposed preferentially in comparison to hydroxyalkanoic acids in B horizons .. and is probably not as stable as previously thought. |
| 1344 | Ruser, R., Flessa, H., Russow, R., Schmidt, G., Buegger, F. & Munch, J.C. | Emission of N2O, N2 and CO2 from soil fertilised with nitrate: effect of compaction, soil moisture and rewetting | 2006 | Greenhouse Gases; Soil N Dynamics | Journal | Soil Biol. Biochem.; 38; 263-274 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effect of soil moisture and compaction on N2O emissions | N2O is primarily derived from nitrification at low and moderate soil moistures, with denitrification becoming more important at soil moisture contents greater than 60% water-filled pore space, due to a decreased O2 supply. BSoil moisture, soil respiration, soil aggregation & soil compaction are key factors determining the aeration of soils & the formation of anoxic microsites.; High N2O emissions were a result of denitrification and occurred at a WFPS >= 70% in all compaction treatments. N2 production occurred only at the highest soil moisture level (>= 90% WFPS) but it was considerably smaller than the N2O-N emission in most cases. |
| 431 | Rustad, L.E., Huntington, T.G. & Boone, R.D. | Controls on soil respiration: implications for climate change | 2000 | Greenhouse Gases; Roots & Rhizodeposition | Journal | Biogeochemistry (Dordr.); 48; 1-6 | English | Hardcopy:Full; PDF:Full | Review of factors affecting the rate of soil respiration | Soil respiration represents the combined respiration of roots & soil micro- and macro-organisms. Estimates of the magnitude of this flux range from 68 Pg C yr-1 to 100 Pg C yr-1, which makes soil respiration one of the major pathways of flux in the global C cycle, second only to gross primary productivity, which is estimated to range from 100 to 120 Pg C yr-1.; Critical factors reported to influence rates of soil respiration include (1) temp., (2) soil moisture, (3) vegetation & substrate quality, (4) net ecosystem productivity, (5) the relative allocation of NPP above- and belowground, (6) population & community dynamics of the aboveground vegetation & belowground flora & fauna and (7) land-use and/or disturbance regimes, including fire. |
| 316 | Ruttan, V.W. | Sustainability is not enough | 1988 | Sustainability | Journal | Am. J. Alternative Agr.; 3 (2-3); | English | Hardcopy:Partial | Sustainability and the satisfaction of growing demand for farm produce are compared. Sustainability research has not shown sufficient recognition of the challenge that modern rates of growth in demand impose on agriculture. | .. none of the traditional systems, while sustainable under conditions of slow growth in demand, has the capacity to respond to modern rates of growth in demand generated by some combination of rapid increase in population and in growth of income.; In the United States the capacity to sustain the necessary increases in agricultural production will depend largely on our capacity for institutional innovation [of agricultural commodity programmes].; (my emphasis!); .. scientific and technical knowledge is not yet available that will enable farmers in most tropical countries to meet the current demand their societies are placing on them .. |
| 121 | Ryan, M.H., Angus, J.F. & Kirkegaard, J.A. | Effect of Brassicas on VAM fungi in following crops | 1999 | Rape and Biodiesel; Soil Microorganisms | Book | ; Proceedings of the Tenth International Rapeseed Conference; | English | Hardcopy:Full | Field expt. to study the effect of Brassicas on VAM fungi in followingnon-Brassica crops | Brassicas are generally regarded as non-hosts for VAM fungi. .. colonisation by VAM fungi may substantially increase growth of many crops ..; Plants with finely-branched root systems and copious root hairs (eg cereals and grasses) generally do not rely heavily on VAM fungi to access and absorb nutrients, while plants with relatively coarse, poorly-branched root systems and few root hairs (eg many legumes) may acquire a substantial portion of their nutrients through the actions of VAM fungi; .. Brassica crops .. may enhance yields of following cereal crops through reducing the incidence of root diseases .. This effect has been termed biofumigation and is thought to result from biocidal compounds .. released when glucosinolates (GSLs) in Brassica tissues are hydrolysed to form compounds including isothiocyanates.; .. the non-mycorrhizal nature of the brassicas resulted in a reduced level of VAM colonisation in following crops. .. The reduction in VAM colonisation in crops grown after brassicas did not reduce uptake of P or Zn or negatively affect crop yield. |
| 1074 | Ryan, M.H., Chilvers, G.A. & Dumaresq, D.C. | Colonisation of wheat by VA-mycorrhizal fungi was found to be higher on a farm managed in an organic manner than on a conventional neighbour | 1994 | Organic Farming; Soil Microorganisms | Journal | Plant Soil; 160; 33-40 | English | Hardcopy:Partial | Field study of mycorrhizal fungi on the roots of wheat grown organically and conventionally | Wheat grown on the organic farm was found to have VAM colonisation levels consistently 2 to 3 times higher than wheat on the conventional farm. .. lower colonisation levels on the conventional farm were due to continual use of fertiliser containing soluble P.; Total P levels in soil are similar for both farms. However the Olsen test showed extractable P level to be three times higher on the conventional farm. |
| 73 | Ryckeboer, J., Cops, S. & Coosemans, J. | The fate of plant pathogens and seeds during backyard composting of vegetable, fruit and garden wastes | 2002 | Compost & Biocontrol | Book | Insam, H., Riddech, N. & Klammer, S. (eds.); Microbiology of Composting; | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the effect of composting on plant pathogens & weed seeds | Of the four test organisms (TMV, P.brassicae [club-root], H.schachtii [beet- cyst nematode] and tomato seeds) used in this study, only TMV was eliminated within the test period. Although viruses can be very heat-resistant, they are sensitive to enzymatic degradation.; .. tomato seeds were almost entirely eliminated during 184 days of composting. .. Temp. seemed to play an important role in the elimination of tomato seeds... Lethal temperatures are severely limited spatially in small compost piles; they appear mostly in the centre of the pile. Tomato seeds that survived composting .. possibly did so as result of localised cool spots e.g. the edge of compost piles or vessels.; Biotrophic fungi, such as Plasmodiophora brassicae, are highly resistant to conditions that prevail during composting... backyard composting in small vessels is not sufficient for the destruction of P. brassicae. Consequently dissemination of club root with compost originating from small vessels is possible... the resting spores of these fungi need to be composted for at least several hours at 60$C under humid circumstances to be eliminated. |
| 1577 | Rydberg, T. | Ploughless tillage in Sweden. Results and experiences from 15 years of field trials | 1992 | Rape and Biodiesel; Tillage | Journal | Soil Tillage Res.; 22; 253-264 | English | Hardcopy:Partial | Review of 140 field trials in Sweden comparing ploughless with conventional tillage for rape, wheat barley, potatoes and sugar beet. OSR yielded an average of 3.17 t/ha under conventional tillage. Under ploughless tillage the yields were on average about 10% lower. | .. use of ploughless tillage reduced yields of winter wheat, spring barley, winter and spring OSR and sugar beet and somewhat improved yields of oats and potatoes. .. The incidence of annual weeds increase .. by 25% and stoloniferous weeds by 100%. |
| 557 | Rydberg, T., Jansén, J. | Comparison of horse and tractor traction using emergy analysis | 2002 | Energy in Agriculture | Journal | Ecol. Eng.; 19 (1); 13-28 | English | Hardcopy:Full; PDF:Full | Calculation of the energy consumed in horse-powered and tractor-powered farming | Horse traction in ... Sweden 1927 and tractor traction in ... Sweden 1996 were compared in terms of their resource requirements. ... The main difference between the systems was found in their energy signature. 60% of the horse inputs were renewable, compared with only 9% renewable inputs for the tractor.; ... the total amount of emergy required behind a unit of traction energy was somewhat larger for the horse than for the tractor system. However, since the traction energy input/ha in typical 1996 farming was 67% larger than in 1927, more emergy was required per ha in the tractor case.; ... the increased productivity from agriculture was a result of an increased input of nonrenewable resources. ... This type of agricultural activity is possible only in situations of access to concentrated stocks of natural resources. When such stocks are used up, or if environmental disturbances from their use restricts the use of them, we will have to organise our agriculture and other societal activities to the flow of limited renewable resources. |
| 1341 | Röver, M., Heinemeyer, O. & Kaiser, E.A. | Microbial induced nitrous oxide emissions from an arable soil during winter | 1998 | Greenhouse Gases; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 30 (14); 1859-1865 | English | Hardcopy:Full; PDF:Full | Field expt. to study the emission of N2O from soil in winter | The application of 220 kg N to the soil induced significantly higher N2O losses throughout the cropping season compared to the unfertilised soil. No significant differences were found during winter, where 70% of the annual N2O emissions were found.; .. microbial processes were responsible for N2O production in thawing and even frozen soils. |
| 1073 | Rühlmann, J. | A new approach to estimating the pool of stable organic matter in soil using data from long-term field experiments | 1999 | Soil Organic Carbon | Journal | Plant Soil; 213 (1/2); | English | Hardcopy:Partial | Modelling the size and turnover of the stable SOM pool | .. the organic C content of long-term bare fallow soils was used as an indicator of the size of the stable SOM pool.; .. over 50 yr, under bare fallow conditions, the relative decrease in the amount of C (C) for the most stable pools ranged between 2 and 12%. In comparison, for the less stabilised pools the relative decrease was calculated from 50 to 100%. This indicates that the organic C content of long-term bare fallow soils should be very similar to the size of the most stable C pool.; .. the amounts of C associated with primary particles <20 m for numerous soils .. showed a lower and an upper limit. Both these limits and the C content of long-term bare fallow soils .. were related to the content of primary particles <20 m in the soil.; the stable pool may be defined as the capacity of soils to sorb C. The upper limit of C content associated with primary particles <20 m may be interpreted as the capacity of soil to protect C. |
| 1744 | Saggar, S. & Hedley, C.B. | Estimating seasonal and annual carbon inputs, and root decomposition rates in a temperate pasture following field 14C pulse-labelling | 2001 | Uncategorised | Journal | Plant Soil; 236; 91-103 | English | PDF:Full | ||
| 479 | Saggar, S., Hedley, C. & Mackay, A.D. | Partitioning and translocation of photosynthetically fixed 14C in grazed hill pastures | 1997 | Roots & Rhizodeposition | Journal | Biol. Fertil. Soils; 25 (2); 152-158 | English | Hardcopy:Full; PDF:Full | 35-day field expt. to study the partitioning and translocation of recent C in grasses in pastures of differing fertility. The proportion of photosynthate translocated to the roots ranged from 25% to 35% (most in the least fertile pasture). 35%-40% was respired, 2%-3% was stored in the soil and 25%-30% remained in the shoot. | Allocation of the 14C-labelled assimilate below-ground was rapid .. with 23-39% detected in the roots within 4 h of pulse application. .. the proportion of net assimilated 14C that remained in the shoots decreased with time. At day 35 only 26-31% of the 14C was found in the shoot. |
| 1345 | Saggar, S., Parshotam, A., Hedley, C. & Salt, G. | 14C-labelled glucose turnover in New Zealand soils | 1999 | Mineralisation; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 31; 2025-2037 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the influence of the mineral soil on organic C turnover, using glucose as a substrate | The 14CO2 respired after 35 d incubation accounted for 51 to 66% of the glucose 14C input .. The extent of mineralisation of 14C-labelled glucose was influenced by .. clay content & .. surface area. Soils of low clay content (3-12%) had high biophysical quotients (respired/residual 14C); the highest (1.93) was in the soil with least clay (3%) and lowest mineral surface area, suggesting that clay is effective in C stabilisation immediately after substrate assimilation. MRTs for microbial biomass 14C were correlated with clay content, surface area .. & pH. .. the MRTs of microbially assimilated 14C are similar despite differences in the chemical nature of the applied 14C-labelled substrate. However, the MRT for humus 14C differed with the chemical nature of the applied substrate. Clay and surface area played a major role in controlling the decomposition of added substrate through the stabilisation and protection of the microbial biomass. |
| 565 | Salamanca, E.F., Kaneko, N., Katagiri, S. & Nagayama, Y. | Nutrient dynamics and lignocellulose degradation in decomposing Quercus serrata leaf litter | 1998 | Lignin and CBW | Journal | Ecol. Res.; 13; 199-210 | English | Hardcopy:Partial; PDF:Full | 3-year field experiment to study the decomposition of oak leaf litter | During the first 12 months N and P had accumulated but tended to decline thereafter. .. The release pattern of the masses of lignin and nitrogen were different during the first 12 months but seemed to follow the same trend afterwards.; The by-products of lignin degradation have been reported to react with ammonia or amino acids and form complexes. The incorporation of N into the humic substances may partly explain the close relationship between N and lignin dynamics after 1 year. |
| 1459 | Salas, A.M., Elliott, E.T., Westfall, D.G., Cole, C.V. & Six, J. | The role of particulate organic matter in phosphorus cycling | 2003 | Phosphorus Cycling | Journal | Soil Sci. Soc. Am. J.; 67; 181-189 | English | Hardcopy:Partial; PDF:Full | Expt. to study the immobilisation of P on incorporation of plant residues into the soil. An initial rapid release of P from the residues in the first 5 days was followed by an immobilisation of up to 30% of the plant P in the residues. The mechanism of his immobilisation is not known. | |
| 998 | Salmon, V., Derenne, S., Lallier-Vergčs, E., Largeau, C. & Beaudoin, B. | Protection of organic matter by mineral matrix in a Cenomanian black shale | 2000 | Soil Organic Carbon | Journal | Org. Geochem.; 31 (5); 463-474 | English | Hardcopy:Partial; Wordperfect:Full | Expt. to study the protection of OM in a shale | .. the dominant protective process likely involves physical protection by minerals, resulting from alternation of organic and clay nanolayers of approximately 100 nm in thickness, rather than OM adsorption as molecular monolayers .. |
| 1699 | Samson, R., Zan, C., Hanley, A. & Mailhot, S. | Analyse stratégique des régions du Québec pour la valorisation agricole des Bois Raméaux Fragmentés (BRF) par leur digestion au sol | 2000 | Uncategorised | Book | Samson, R., Zan, C., Hanley, A. & Mailhot, S.; Analyse stratégique des régions du Québec pour la valorisation agricole des Bois Raméaux Fragmentés (BRF) par leur digestion au sol; 1-21 | French | Word:Full | ||
| 707 | San Jose, J.J., Montes, R.A. & Farińas, M.R. | Carbon stocks and fluxes in a temporal scaling from a savanna to a semideciduous forest | 1998 | Greenhouse Gases; Soil Organic Carbon | Journal | For. Ecol. Manag.; 105 (1/3); 251-262 | English | Hardcopy:Partial; PDF:Full | Field expt. to assess the amount of carbon fixed in protected savanna, returned to deciduous forest, over a period of 51 years | ... the carbon stock in the vegetation increased from 207 to 9215 g C m-2, whereas in the soil it varied from 6680 to 12,196 g C m-2. The carbon stock accumulation was mainly related to increases in the woody layer from 36 to 9215 g C m-2 (255-fold) and in the soil from 1341 to 12,196 g C m-2 (nine-fold) respectively. The estimated pool of C sequestered in the Orinoco Llanos by the restored forest in 51 yrs was 5.69 Pg C.; ... in a forest patch the difference between soil respiration and litter production might be up to 124 g C m-2 yr-1. Such results demonstrate the potential of the forest to act as a carbon source. If all the forest of the Orinoco Basin (0.28 x 1012 m2) were behaving in the same way as the semi-deciduous forest, the carbon source in the basin would be 0.034 Pg C yr-1. On the other hand the undisturbed tropical forest accumulated 0.56 Pg yr-1 in south-west Amazonia. |
| 1705 | Sanchez, P.A. & Leakey, R.R.B. | Land use transformation in Africa: three determinants for balancing food security with natural resource utilization | 1997 | Uncategorised | Journal | Eur. J. Agron.; 7; 15-23 | English | PDF:Full | ||
| 812 | Sanger, L.J., Cox, P., Splatt, P., Whelan, M.J. & Anderson, J.M. | The characterisation of a lignin-derived organic matter fraction in soils developed under different vegetation types | 1997 | Lignin and CBW; Soil Organic Carbon | Journal | J. Appl. Ecol.; 34 (1); 14-20 | English | Hardcopy:Full | Study of the lignin-derived fractions in soil from different horizons under beech forest, spruce forest, pasture and arable land to determine the origin of the OM. Except in the mixed soil of the arable land, the BD increased with depth. The forest soils had an organic horizon (SOC content > 35%) in the top 18 cm and 1 cm respectively. | Generally the less biodegradable compounds in soils are associated with microbial secondary products, although a resistant fraction primarily derived from lignin can retain biochemical integrity for extended periods of time.; .. a lignin-derived fraction was a major source of accumulated C in this [the beech forest] profile.; .. the lignin-derived fraction was more oxidised and decomposed in the surface layers of the pasture and arable soils .. compared with both of the forest soils. |
| 1346 | Sariyildiz, T. & Anderson, J.M. | Interactions between litter quality, decomposition and soil fertility: a laboratory study | 2003 | Lignin and CBW; Soil Organic Carbon | Journal | Soil Biol. Biochem.; 35 (3); 391-399 | English | Hardcopy:Partial; Wordperfect:Full | Rather inconclusive results of the lab. incubation of leaf litter from oak and beech trees. | Pooled data for litter species and origin showed linear relationships between initial litter quality variables and mass losses at 4, 8 and 12 months. Initial lignin concentrations explained most of the variation in decomposition rates within and between oak and beech, and for the two soil treatments. |
| 876 | Saroa, G.S. & Lal, R. | Soil restorative effects of mulching on aggregation and carbon sequestration in a Miamian soil in central Ohio | 2003 | Mulch; Soil Organic Carbon | Journal | Land Degrad. Dev.; 14 (5); 481-493 | English | Hardcopy:Partial | Field expt. to test the effect of mulching - at rates of 0, 8 and 16 Mg ha-1 yr-1 - on soil composition and texture | Mulch rate significantly increased SOC and TSN [total soil N] concentrations in the 0-5 cm soil layer only. The variation in the SOC concentration .. was 41% after 4 yrs mulching and 52% after 11 yrs. |
| 40 | Sarrantonio, M. | Microbial activity and nitrogen dynamics following a winter annual green manure | 1995 | Green Manure; Soil N Dynamics | Book | Cook, H.F. & Lee, H.C.; Soil Management in Sustainable Agriculture; 300-307 | English | Hardcopy:Full | Long-term field expt. to study the release of N from surface green manure residues and the soil microbial activity. Following spring mowing of winter annual green manures three phases of N availability were observed: 1. a flush of nitrate in the first 2 weeks; 2. a drop in nitrate levels in mid June, coinciding with high soil respiration levels, indicating that the soil microbial biomass is immobilising part of the released nitrate; 3. a second peak in nitrate 1-3 weeks after the preceding decrease. | N can be released ... in large flushes - as much as 140 kg/ha -... within one week after a green manure crop is killed. The presence of high carbon material might serve to immobilise a portion of this nitrogen until later in the cropping season. |
| 480 | Sarrantonio, M. | Soil response to surface-applied residues of varying carbon-nitrogen ratios | 2003 | Mineralisation; Mulch; Soil N Dynamics | Journal | Biol. Fertil. Soils; 37; 175-183 | English | Hardcopy:Partial; PDF:Full | 5-year study of nitrate accumulation in soils mulched with plant residues of varying C/N ratio (vetch, wheat straw and vetch/straw) | The total available N in most years was sufficient for most annual crop needs .. The presence of 4 Mg ha-1 of straw reduced NO3- concentrations by 20% relative to vetch alone, but the reduction lasted throughout the season. The C/N ratio of the mixed residue was borderline to the 20-30:1 ratio commonly considered the threshold for measurable immobilisation of N but it is unclear from this data whether the reduction in NO3- was due to immobilisation, to decreased mineralisation and/or nitrification, to gaseous N loss or to a combination of these. Neither respiration rates nor anaerobic incubation strongly indicated a larger microbial community in the vetch-straw treatment than in the vetch treatment. |
| 1075 | Sarwar, M. & Kirkegaard, J.A. | Biofumigation potential of brassicas: II. Effect of environment and ontogeny on glucosinolate production and implications for screening | 1998 | Miscellaneous; Rape and Biodiesel | Journal | Plant Soil; 201; 91-101 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the effectiveness of glasshouse testing of Brassicas to assess their glucosinolate biofumigation potential. [Part I was published as Kirkegaard & Sarwar (1998)] | Brassica green manure, rotation crops or seed meal amendments have been reported to suppress pest and disease organisms when grown or incorporated in the soil. These effects are generally attributed to biocidal compounds released into the soil when glucosinolates ... are hydrolysed.; Total glucosinolate concentration generally declined from buds-raised to flowering .. and was lowest at maturity.; .. vernalisation-requiring winter rape .. grown in the spring environment failed to vernalise and continued to produce vegetative biomass of high GSL concentration .. These winter types may provide an excellent biofumigation option .. |
| 1706 | Sarwar, M., Kirkegaard, J.A., Wong, P.T.W. & Desmarchelier, J.M. | Biofumigation potential of brassicas III. In vitro toxicity of isothiocyanates to soil-borne fungal pathogens | 1998 | Uncategorised | Journal | Plant Soil; 201; 103-112 | English | PDF:Full | ||
| 491 | Sastre, I., Vicente, M.A. & Lobo, M.C. | Influence of the application of sewage sludges on soil microbial activity | 1996 | Soil Organic Carbon; Soil Microorganisms | Journal | Bioresour. Technol.; 57; 19-23 | English | Hardcopy:Full; PDF:Full | Field expt. to study the effect of amendment with sewage sludges on SOM and SMB | The application of sewage sludge introduces a large number of microorganisms. However, the natural populations of the soil try to remain homeostatic; thus, alien microorganisms introduced into the soil die rapidly. The death of microorganisms increases the level of OM in the soil, as well as the enzymic content. |
| 960 | Sauerbeck, D.R. | CO2 emissions and C sequestration by agriculture - perspectives and limitations | 2001 | Greenhouse Gases | Journal | Nutr. Cycl. Agroecosyst.; 60; 253-266 | English | Hardcopy:Full; PDF:Full | Review of the mechanisms of C emission and sequestration in agriculture | The combined losses from the earth's native biomass & from soils due to cultivation between .. 1700 & today amount to about 170 Gt C..; ..the global historical loss [is] about 42 Gt former soil C from mineral soils.; .. the .. 0.4-0.9 Gt C yr-1 mitigation potential from increased soil C sequestration .. would only be effective during a few decade's time period ..; the humus enrichment in crop soil always follows a saturation curve, approaching a new equilibrium level after not more than 50-100 years. .. this new soil C level drops rapidly again as soon as the required most careful management can no longer be sustained. |
| 1347 | Savin, M.C., Görres, J.H., Neher, D.A. & Amador, J.A. | Biogeophysical factors influencing soil respiration and mineral nitrogen content in an old field soil | 2001 | Mineralisation; Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 33 (4/5); 429-438 | English | Hardcopy:Partial; PDF:Full | Field expt. to test the validity of the exclusion and enclosure hypotheses to explain the effect of water restriction on microbivory. When soil moisture was low, microbivory and predation of nematodes on other nematodes was found to be greater, thus supporting the enclosure hypothesis, which predicts that the confining of nematodes in limited pore space will bring the nematodes closer to their prey and give an increase in microbivory and predation. C & N mineralisation in soil is normally coupled by the C/N ratio of the microorganisms and the residues they are eating. Microbivory uncouples them by preferentially increasing N mineralisation rates by up to 30%, due to the excretion of excess N by the grazing nematodes. | |
| 1348 | Savin, M.C., Görres, J.H., Neher, D.A., Amador, J.A. | Uncoupling of carbon and nitrogen mineralisation: role of microbivorous nematodes | 2001 | Mineralisation; Soil N Dynamics | Journal | Soil Biol. Biochem.; 33 (11); 1463-1472 | English | Hardcopy:Partial; PDF:Full | Expt. to evaluate temporal changes in the relationships between C & N mineralisation, abundance and distribution of nematode trophic groups and matric potential | .. N mineralisation is generally considered to be coupled to C mineralisation by the C/N ratios of specific substrate and microbial pools. In other words, microbes mineralise N at a rate proportional to respiration when growing on a substrate with a C/N ratio less than the microbial C/N ratio.; Microfauna can affect nutrient mineralisation directly, by excreting mineral nutrients, and indirectly, by causing shifts in the microbial community structure and growth rates.; . the accessibility of microbial food resources to microfauna depends on matric potential because microfauna require water to move.; The general relationship between C & N mineralisation for all data points did not hold among sampling periods. Differences in this relationship may have been a result of microbivorous grazing. |
| 246 | Schaller, N. | The concept of agricultural sustainability | 1993 | Sustainability | Journal | Agric. Ecosyst. Environ.; 46; 89-97 | English | Hardcopy:Partial | Sustainable agriculture is defined and examined. Two opposing views are set out: one that it is simply a question of fine-tuning conventional agriculture and the other that it involves fundamental changes in agriculture and in societal values. Sustainable agriculture is examined from the point of view of profitability and whether it can feed the rapidly growing world population. | We cannot expect to have a sustainable agriculture unless all of us adopt a fundamentally different way of thinking about agriculture, which will require major changes in personal beliefs, values and lifestyles.; Resource conservation, environmental protection and health and safety are just as important as profitable production.; As currently defined .. profit .. automatically favours conventional agriculture and penalises sustainable agriculture .. because its calculation excludes many of the benefits of sustainable farming .. [and] the costs associated with conventional farming such as soil erosion and groundwater contamination.; .. diets might change in ways that would reduce substantially the mounting pressure on available agricultural resources [i.e. less livestock products]; If farmers adopt .. sustainable practices, but the processing & transport of food beyond the farmgate are highly industrialised .., what does that say about the sustainability of agriculture as a whole? |
| 14 | Scheller, E. | Soil fertility and soil examination | 1996 | Soil N Dynamics; Soil (General) | Book | ; Book of Abstracts, 11th IFOAM Scientific Conf., Copenhagen; | English | Hardcopy:Partial | Review of the factors affecting soil weathering and C & N turnover in soil | Increasing intensity of agriculture ... intensify[s] the weathering of primary silicates, the release of nutrients ... potassium release ranges from 5 kg/ha/yr in a pine forest to 900 kg/ha/year in a field of sugar beet.; Crops with N deficiency have also an energy deficiency in the rhizosphere. They are only able to take up sol. nutrients, .. not to mobilise insoluble nutrients. Normally 2/3 of crop N uptake in conv'l agriculture is delivered from the humus N-reserve.; Net N mineralisation is influenced by C turnover to soil and by the SMB and can be additionally stimulated by green manure up to 10 kg NO3-/ha/day. |
| 1014 | Scheuerell, S.J. & Mahaffee, W.F. | Compost tea as a container medium drench for suppressing seedling damping-off caused by Pythium ultimum | 2004 | Compost & Biocontrol | Journal | Phytopathology; 94; 1156-1163 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to test the efficacy of compost teas in suppressing damping-off | Drench application of compost tea can suppress P.ultimum damping-off of cucumber in soilless container media... both ACT and NCT [aerated & non-aerated compost tea] significantly reduced disease; but consistent disease reduction was only attained with ACT produced with specific additives (i.e. kelp and humic acid).; The most consistent formulation for damping-off suppression was ACT fermented with kelp,humic acids & rock dust (termed fungal additive). The suppressiveness of this formulation was significantly reduced by heat treatment or dilution with tap water. Further characterisation indicated that the rock dust component was not necessary for damping-off suppression. |
| 1144 | Schimel, D.S. | Climate change and crop yields: beyond Cassandra | 2006 | Greenhouse Gases; Miscellaneous | Journal | Science; 312; 1889-1890 | English | Hardcopy:Partial; PDF:Full | Review of research assessing the effect of climate change on crop yields | ... previous studies overestimated the positive effects of higher CO2 concentrations on crop yields.; ... most current models are based on literature suggesting 20 to 30% increases in photosynthesis and yield.; Long etal synthesised the results from agronomic FACE studies and find the effects of increased CO2 concentrations on crop yields to be no more than half of the levels expected from earlier laboratory ... studies.; The observed effect on yield is typically closer to 20%, with effects on biomass and yield being even smaller (20 and 13% respectively). |
| 1145 | Schimel, D.S., Melillo, J.M., Tian, H., McGuire, A.D., Kicklighter, D., Kittel, T., Rosenbloom, N., Running, S., Thornton, P., Ojima, D., Parton, W., Kelly, R., Sykes, M., Neilson, R. & Rizzon, B. | Contribution of increasing CO2 and climate to carbon storage by ecosystems in the United States | 2000 | Greenhouse Gases | Journal | Science; 287; 2004-2006 | English | Hardcopy:Full; PDF:Full | Review of data on the relative influence of different factors affecting the magnitude of the carbon sink. About two thirds of the annual C sink in the U.S. is due to re-growth on abandoned agricultural land and harvested forest. The remaining third is down to N deposition, soil erosion and sedimentation and changes in atmospheric CO2, climate and land use. The annual net C storage per unit area in the U.S. ranges from 100 to 150 kg/ha. | |
| 1745 | Schimel, J.P. & Weintraub, M.N. | The implications of exoenzyme activity on microbial carbon and nitrogen limitation in soil: a theoretical model | 2003 | Uncategorised | Journal | Soil Biol. Biochem.; 35; 549-563 | English | PDF:Full | ||
| 1349 | Schimel, J.P., Jackson, L.E. & Firestone, M.K. | Spatial and temporal effects on plant-microbial competition for inorganic nitrogen in a California annual grassland | 1989 | Soil Microorganisms; Soil N Dynamics | Journal | Soil Biol. Biochem.; 21 (8); 1059-1066 | English | Hardcopy:Partial | Field expt. to study the uptake of N by plants and microorganisms in grassland after the start of autumn rain following a long summer drought | .. microbes took up more of both NH4+ and NO3- than did plants. The ratios of microbial-to-plant uptake .. were greater for NH4+ than for NO3-, indicating that microbes competed more effectively for NH4+ than for NO3-. Microbes too up NH4+ significantly faster, while plant uptake of the two N forms was more closely balanced.; Ammonium is relatively immobile is soils and the ubiquitous distribution of microbes may therefore give them an advantage over comparatively sparsely distributed roots in acquiring NH4+. Nitrate is mobile in soil, making it more available to plant roots. .. Low microbial competitiveness for NO3- would also be expected, because NO3- assimlation is repressed by NH4+ ..; Nitrification accounted for roughly a third of the ammonified N.; Denitrification rates .. were negligible relative to the other N-flows.; .. the thin surface organicrich zone was a key component in the overall N-cycling, accounting for a large fraction of both N-mineralised and N taken up by plants. |
| 1578 | Schjřnning, P. & Rasmussen, K.J. | Soil strength and soil pore characteristics for direct drilled and ploughed soils | 2000 | Soil (General); Tillage | Journal | Soil Tillage Res.; 57 (1-2); 69-82 | English | Hardcopy:Partial; Wordperfect:Full | Almost inconclusive field expt. carried out on 3 texturally differing soils that had been under direct drilling for 4-6 years | When compared with continuously ploughed soil, 4-6 years with direct drilling caused the upper soil layer (0-20 cm) to be more dense and display higher strength .. [and] display a reduced continuity of pores when drained to a matric potential of -100 hPa. |
| 672 | Schjřnning, P., Christensen, B.T. & Carstensen, B. | Physical and chemical properties of a sandy loam receiving animal manure, mineral fertiliser or no fertiliser for 90 years | 1994 | Organic Farming; Stockless Farming; Soil (General) | Journal | Eur. J. Soil Sci.; 45; 257-268 | English | Hardcopy:Partial | Tests carried out on soil from 90-year expts under three different fertiliser treatments - FYM, chemical and no fertiliser - showed that the SOC, CEC, water retention, shear strength and penetrability decreased in the order animal manure > chemical fertiliser > no fertiliser. | |
| 247 | Schjřnning, P., Elmholt, S., Munkholm, M.J. & Debosz, K. | Soil quality aspects of humid sandy loams as influenced by organic and conventional long-term management | 2002 | Organic Farming; Soil (General) | Journal | Agric. Ecosyst. Environ.; 88; 195-214 | English | Hardcopy:Partial; PDF:Full | Comparative study of the soil quality on organic and conventional farms. The organic farms used FYM as a fertiliser. | .. the results highlight the paramount influence of soil tillage and traffic in agriculture. Further, the results confirm the positive effects of organic manures and diversified crop rotations on soil quality aspects. Microbial biomass C was found to be higher in organically than in conventionally managed dairy farm soils ..; .. a long-time increase in OM inputs (manure, crop residues) and/or a diversified crop rotation significantly increased the Cbiom:Corg ratio (ranging from 0.9 to 3%).; .. the aggregating mechanisms are related to polysaccharide bonding rather than enmeshment by hyphae.; Regardless of management system, the results emphasise that extensive traffic and tillage are likely to reduce soil quality. |
| 754 | Schjřnning, P., Thomsen, I.K., Mřberg, J.P., Jonge, H. de, Kristensen, K. & Christensen, B.T. | Turnover of organic matter in differently textured soils: I. Physical characteristics of structurally disturbed and intact soils | 1999 | Soil Microorganisms; Soil (General) | Journal | Geoderma; 89 (3-4); 177-198 | English | Hardcopy:Partial; PDF:Full | [For part II, see Thomsen (1999)] Lab. expt. to compare the physical properties of disturbed and undisturbed soils. Compared with undisturbed soils, disturbed soils are structurally weaker, have a greater volume of large pores (>100m), have a less continuous and more tortuous pore system and have a lower waterfilled pore space at a critical level of air diffusion potential. | An increase in the soil water content has two consequences: substrate diffusion becomes less limiting whereas O2 diffusion becomes more limiting for microbial activity.; [for disturbed soils] .. biological activity peaked at approximately 60% of the water-holding capacity.; For .. structurally intact soils the WFPS ranged from 58% for the most sandy soil t more than 80% for the most clayey soil. |
| 1076 | Schjřrring, J.K., Bock, J.G.H., Gammelvind, L., Jensen, C.R. & Mogensen, V.O. | Nitrogen incorporation and remobilisation in different shoot components of field-grown winter oilseed rape (Brassica napus L.) as affected by the rate of nitrogen application and irrigation | 1995 | Rape and Biodiesel | Journal | Plant Soil; 177; 255-264 | English | Hardcopy:Partial | Field trial to study the uptake and translocation of N in rape grown under different rates of N fertilisation | .. recoveries [in the aboveground plant parts?] varied from a maximum of 67% at low rates of N application (60 kg N/ha) .. to about 35-40% at higher N application (>250 kg N/ha). In cereal crops about 60-70% of applied N is normally recovered in aboveground parts, thus making OSR a relatively N-inefficient crop.; The high-N plants lost up to about 20 kg N/ha by leaf drop. .. Losses of N by ammonia volatilisation from the high-N oilseed canopies amounted to 8 kg N/ha.; About 70% of the N present in stems and pod walls at mid-flowering is remobilised before maturity and leaves, stems and pod walls each contribute about one third of the final seed N content in high-N plants. |
| 363 | Schlecht-Pietsch, S., Wagner, U. & Anderson, T.H. | Changes in composition of soil polysaccharides and aggregate stability after carbon amendments to different textured soils | 1994 | Soil Organic Carbon; Soil (General) | Journal | Appl. Soil Ecol.; 1 (2); 145-154 | English | Hardcopy:Partial | 220-day expt. to compare the effects on aggregate stability and saccharide content of amending soil with glucose and ground wheat straw | At the end of the expt. .. the saccharide concentrations of both treatments had approached those of the unamended control soils. .. Mannose apparently was synthesised by soil microorganisms. Glucose and straw metabolism led to a significant increase in aggregate stability in the three soils during the incubation time. .. Polysaccharide production seemed to be related to Cavailability or C over-supply. |
| 157 | Schlesinger, W.H. | Soil organic matter: a source of atmospheric CO2 | 1984 | Greenhouse Gases; Soil Organic Carbon | Book | Woodwell, G.M. (ed.); The Role of Terrestrial Vegetation in the Global Carbon Cycle: Measurement by Remote Sensing; | English | Hardcopy:Partial | Review of the literature on SOC and its release into the atmosphere | Estimates suggest that between 10 and 40 x 1015 g C have been transferred to the atmosphere as CO2.; Each year OM enters the soil from plant debris derived from above- and belowground sources. World wide this input is estimated at 37.5 x 1015 g C per year.; The total steady state C output from soils may be as much as 75 x 1015 g C per year.; When temperate forest are cleared for farmland the losses of soil C also range up to 50%. |
| 248 | Schlesinger, W.H. | Carbon sequestration in soils: some cautions amidst optimism | 2000 | Greenhouse Gases; Soil Organic Carbon; Stockless Farming | Journal | Agric. Ecosyst. Environ.; 82 (1/3); 121-127 | English | Hardcopy:Full; PDF:Full | The author questions the wisdom of three recommended techniques for increasing the C sequestration of the soil, namely, the use of nitrogenous fertiliser, the irrigation of arid and marginal lands and the application of FYM. In each case the emissions entailed in the application of the method will reduce, or even fully cancel out, the increased C storage. | The data of Drinkwater et al. (1998) show that 71% of the C sequestration in fields with conventional tillage and N fertiliser is offset by CO2 emissions associated with fertiliser production. .. the large C cost of N fertiliser is avoided by agronomic systems that include leguminous crops that fix N.; .. the CO2 emissions associated with the supply of water and from the equilibration of those waters in the surface environment must be subtracted from the apparent net sequestration of C in dry-land soils.; The myth of manure .. manure is not likely to yield a net sink for C in soils .. The entire aboveground plan production on 3 ha. of land would be required to supply the manure to each hectare of manured land. .. Manuring has a number of practical applications in agronomy, but net C sequestration does not appear to be one of them. |
| 916 | Schlesinger, W.H. | Evidence from chronosequence studies for a low carbon-storage potential of soils | 1990 | Greenhouse Gases; Soil Organic Carbon | Journal | Nature (Lond.); 348; 232-234 | English | Hardcopy:Full | Using pedological chronosequence data to calculate the long-term C storage potential of soil. 30 g C m-2 yr-1 is given as an estimate of the rate of accumulation of SOM in 40-50-year-old soils (on abandoned farmland in the US). | During soil development OM often shows an initial period of rapid increase for up to 3000 years, followed by a lower rate of accumulation that may continue for millenia.; .. most soils are at least 3000 years old ..; In upland ecosystems the long-term rate of C storage varies from 0.2 g C m-2 yr-1 in some polar deserts to > 10 g C m-2 yr-1 in some forests.; .. the total storage of SOM (0.40 x 1015 g C yr-1) is ca. 0.7% of recent estimates of net primary production (60 x 1015 g C yr-1) ..; OM does not accumulate in upland soils for ever; eventually a steady-state profile content is achieved. In many forests the soil profile contains ca. 10-20 kg C m-2, implying that > 6000 years are required to establish a stable distribution of C in the soil. At this point the production of humic compounds in excess of decomposition must equal the removal of these substances by erosion.; .. the amount of C that can be stored in soils is likely to be only a small fraction of the annual release from fossil fuels (5.3 x 1015 g C yr1) ..; Under human influence the loss of humic materials from cultivated lands is greatly in excess of the rate of formation of humus in undisturbed lands, transforming the soil pool from a small sink to a large source of atmospheric CO2. |
| 1146 | Schlesinger, W.H. | Carbon sequestration in soils | 1999 | Greenhouse Gases; Soil Organic Carbon; Stockless Farming | Journal | Science; 284; 2095 | English | Hardcopy:Partial; Wordperfect:Full | Review showing that increasing
crop yields & soil C-content by use of fertilisers, irrigation & FYM
do not necessarily increase global C sequestr'n because of C-costs incurred
in the production of the FYM & fertilisers and in pumping the irrigation
water. [Smith & Powlson argue that FYM is a by-product of agriculture
& therefore its production C-cost can be ignored. Izaurralde etal (2000)
& Izaurralde etal (2001) (q.v.) also provide arguments in contradiction
to Schlesinger's points about FYM and fertilisers.] Plus comment by Smith & Powlson |
Additional C emissions are incurred in the manufacture, transport and application of fertiliser. A factor of 1.436 moles of CO2-C released per mole of N .. reflects the full C cost of N fertiliser. This factor would effectively negate any net C sink as a result of the application of the fertiliser.; The .. energy used in pumping irrigation water amounts to 22 to 83 g C/m2 per year for irrigated lands in the United States. This emission is likely to exceed any net C sequestration on irrigated agricultural lands.; Manure was applied at an annual rate of 1340 g/m2 .. assuming the digestive efficiency of livestock is 60% .. the entire aboveground plant production on 3.0 ha of land was required to supply the manure to each hectare of manure land. .. Manuring has a number of practical applications, but net C sequestr'n is not one of them. |
| 1614 | Schlesinger, W.H. | Global change ecology | 2006 | Miscellaneous | Journal | Trends Ecol. Evol.; 21 (6); 348-351 | English | Hardcopy:Partial; PDF:Full | Review of recent research on human impact on natural ecosystems | ... Gaia has few followers now ...; In 1986 Peter Vitousek and colleagues estimated that humans use or dominate approximately 40% of the terrestrial net primary production on Earth. |
| 432 | Schlesinger, W.H. & Andrews, J.A. | Soil respiration and the global carbon cycle | 2000 | Greenhouse Gases; Soil Organic Carbon | Journal | Biogeochemistry (Dordr.); 48 (1); 7-20 | English | Hardcopy:Partial | Review of the part played by soil microbial respiration in the global C cycle | Soil respiration is the primary path by which CO2 fixed by land plants returns to the atmosphere. Estimated at approximately 75 x 1015 g C/yr, this large natural flux is likely to increase due changes in the Earth's condition. .. Traditional tillage cultivation and rising temperature increase the flux of CO2 from soils without increasing the stock of SOM. .. but a large increase in the soil C pool seems unlikely to moderate the rise in atmospheric CO2 during the next century. |
| 1147 | Schlesinger, W.H., Reynolds, J.F., Cunningham, G.L., Huenneke, L.F., Jarrell, W.M., Virginia, R.A. & Whitford, W.G. | Biological feedbacks in global desertification | 1990 | Agricultural Ecology | Journal | Science; 247; 1043-1047 | English | Hardcopy:Full | Soil resource heterogeneity is linked to desertification. Spatial and temporal heterogeneity of water, N and other soil resources leads to the desertification of formerly productive land. | Conversion of semi-arid grasslands to row-crop agriculture adds to the local heterogeneity and is likely to lead to permanent desertification ..; The impact of nomadic herders .. are spread evenly and at low levels across the landscape. When people and livestock are concentrated into small areas in which their impact leads to an increased heterogeneity of soil resources, permanent degradation .. occurs. |
| 249 | Schloter, M., Dilly, O. & Munch, J.C. | Indicators for evaluating soil quality | 2003 | Soil (General) | Journal | Agric. Ecosyst. Environ.; 98 (1-3); | English | Hardcopy:Partial | A review of the possibilities of using bacterial, fungal and nematode populations as an indicator of soil quality | |
| 435 | Schmidt, H. | Viehlose Fruchtfolge ist tragfaehig | 1998 | Stockless Farming | Journal | Bioland; 4; | German | Hardcopy:Partial | A very brief summary of the author's doctoral thesis at Kassel University on stockless organic rotations. His conclusion is that such rotations are feasible with one course of grass/clover ley and the application of small quantities of organic fertilisers - in his case, municipal compost and vinasses (a by-product of the sugar industry) | |
| 104 | Schmidt, H. & Fragstein, P. von | Importance of varying management and environmental conditions in a long-term crop rotation trial: effects on plant development, crop yield and nitrogen dynamics | 1999 | Green Manure; Miscellaneous; Soil N Dynamics | Book | Olesen, J.E., Eltun, R., Gooding, M.J., Jensen, E.S & Köpke, U. (eds); Designing & testing crop rotations for organic farming. Proceedings from an international workshop; | English | Hardcopy:Partial; Wordperfect:Full | 4-yr field expt. to study the factors determining crop yield variations | Annual variations in plant development and soil nutrient dynamics are governed largely by environmental conditions.; .. annually varying weather conditions have an overriding effect on biomass production and crop yields as well as on N supply .. that 70% of variance of crop yields was caused by varying weather conditions, while only 2% of yield variance was caused by different preceding crops .. This is confirmed by our results, which showed that preceding crops had very little effect on the yield of wheat and barley. Plant and yield development of these crops was hardly influenced by a preceding green manure crop. |
| 442 | Schmidt, H., Philipps, L., Welsh, J.P. & Fragstein, P. von | Legume breaks in stockless organic farming rotations: nitrogen accumulation and influence on the following crops | 1999 | Green Manure; Stockless Farming | Journal | Biol. Agric. Hortic.; 17; 159-170 | English | Hardcopy:Full | N cycling in two long-term field trials at Elm Farm and at Witzenhausen was evaluated. | .. the influence of N accumulated by the green manure can hardly be separated from other factors on the N-uptake of the succeeding crops.; In the individual rotations the influence of varying green manure N-accumulation on N-uptake of the cash crops was not significant. However, combining the rotations using partial correlation analysis revealed significant correlations in some groupings. In particular, the N-uptake of potatoes as the first crop following the green manure reacted clearly to N-differences in the green manure biomass; this was not true for wheat following clover.; One reason [for this] could be the lower N-mineralisation in winter wheat because of a lower tillage intensity compared with potatoes. |
| 845 | Schmidt, L., Warnstorff, K., Dörfel, H., Leinweber, P., Lange, H. & Merbach, W. | The influence of fertilisation and rotation on soil organic matter and plant yields in the long-term Eternal Rye trial at Halle (Saale), Germany | 2000 | Soil Organic Carbon | Journal | J. Plant Nutr. Soil Sci.; 163 (6); 639-648 | English | Hardcopy:Partial | Long-term field expt. to study the effect of different fertiliser regimes on SOM | The establishing of new steady states in the turnover of SOM took about 50 years after changes in fertilisation. Contrary to what happened with rye monoculture, both silage-maize monoculture and potato alternating with winter rye caused considerable decomposition of SOM. |
| 917 | Schmidt, M.W.I. | Carbon budget in the black | 2004 | Soil Organic Carbon | Journal | Nature (Lond.); 427; 305-307 | English | Hardcopy:Full; PDF:Full | Review of recent research into the origin and fate of black carbon | As much as half of the organic carbon [in marine sediments] previously identified as black carbon instead appears to be fossil graphitic black carbon, that is, carbon derived from the weathering of rocks.; But, if much less black C is ending up in marine sediments than we had thought, where is the excess? Possibilities include retention in the marine water column or in rivers, soils or the atmosphere. If it is not stored in these sinks, it might be degraded before it reaches them, possibly both mechanically and chemically. .. forests burn quite often, but the amounts of black carbon on the forest floor & underlying soil can be surprisingly small6. Is the black carbon re-burnt during subsequent fires? Do freezing and thawing break it up into smaller particles, thus making it more susceptible to chemical degradation? There is evidence that atmospheric black carbon can be oxidised and become water-soluble7, a fate to which terrestrial black carbon might also succumb. |
| 673 | Schmidt, M.W.I. & Kögel-Knabner, I. | Organic matter in particle-size fractions from A and B horizons of a Haplic Alisol | 2002 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 53; 383-391 | English | Hardcopy:Partial | Expt. to study the extent to which SOM may be stabilised by its interaction with minerals | In the Ah horizon most of the OM was present in polysaccharide (O-alkyl) and methylene structures, each contributing one third to the bulk OM. .. the C/N ratios and the yields for lignin and hydrolysable amino-acids decreased as the particle size decreased. .. potentially labile OM, such as O-alkyl typically present in polysaccharides, may be stabilised against further degradation in organo-mineral complexes.; .. in a Bvt horizon .. clay and OM are intimately associated with metal oxy-hydroxides, typically forming clay skins or cutans. such soils may contain large proportions of natural organo-mineral complexes ..; .. soil polysaccharides can originate from plants or microorganisms ..; The increasing proportion of potentially labile polysaccharides from coarse to fine fractions .. was unexpected and described here for the first time .. Small microbial-like C/N ratios .. suggest that plant material was decomposed, thus favouring a microbial origin for the polysaccharides. .. Sorptive organo-mineral interactions with clay-sized minerals with large surface areas could protect these polysaccharides against further degradation. |
| 999 | Schmidt, M.W.I., Knicker, H. & Kögel-Knabner, I. | Organic matter accumulating in Aeh and Bh horizons of a Podzol: chemical characterisation in primary organo-mineral associations | 2000 | Soil Organic Carbon | Journal | Org. Geochem.; 31 (7-8); 727-734 | English | Hardcopy:Partial; PDF:Full | Lab. expt. to study the nature and distribution of OM in the soil of a pine forest. In the topsoil the alkyl C/O-alkyl C ratio increased with increasing particle size, indicating increasing decomposition of polysaccharides. In the sub-soil the aromatic fraction was the largest, because it had a high content of Fe and Al oxides, which preferentially bound and stabilised aryl before alkyl and polysaccharide structures. | .. [in] agricultural soils in Australia (Baldock etal, 1992, 1997) .. sand- size separates were dominated by O-alkyl C, probably mainly due to polysaccharides in plant residues. Clay fractions were dominated by alkyl C, which is considered to relate to a gradual accumulation of plant-derived waxes and microbial methylene type structures. Contributions from aromatic C reached a maximum in the silt size separate and decreased in the fine separate .. |
| 674 | Schmidt, M.W.I., Skjemstad, J.O., Gehrt, E. & Kögel-Knabner, I. | Charred organic carbon in German chernozemic soils | 1999 | Soil Organic Carbon | Journal | Eur. J. Soil Sci.; 50; 351-365 | English | Hardcopy:Partial | Expt. to study the charred organic C in soils | Burning vegetation produces large amount of highly refractory OM consisting of charcoal and partly charred plant material .. The COC can have a major impact on .. SOM. It may increase the amount of aromatic C and contribute a relatively inert type of C to the SOM pool.; .. the COC can be a major contributor to the organic C but the origin of this fire-induced from of organic C remains unclear. .. it could have originated from fires in the post-glacial vegetation .. [it] could also originate from post-mesolithic human use of fire for the clearing of forests and subsequent agriculture.; In .. northern Eurasian soils humic acid contents increased in the order grey forest soils < dark grey forest soils < chernozems.; .. Australian grassland soils, which were under aboriginal fire management presumably for thousands of years, are characterised by black A horizons with up to 30% of the soil C present as COC ..; .. COC is restricted to chernozemic soils ..; The COC contributes up to about 45% of the bulk organic C, which is equivalent to about 8 g kg-1 of the bulk soil.; [SOC content = about 18%] |
| 5 | Schmitt, L. & Dewes, T. | N2-Fixierung und N-Flüsse in und unter Kleegrasbeständen bei viehloser und viehhaltender Bewirtschaftung | 1997 | Green Manure; Stockless Farming | Book | ; Beitraege zur 4. Wissenschaftstagung zum oekologischen Landbau, Bonn; 258-264 | German | Hardcopy:Partial | An expt. to compare the N fixing in a grass/clover crop under three regimes: harvesting and cut-and-mulching (twice and three times per year). The N fixing was determined by an isotope method - the 15N-natural-abundance technique, which is much more accurate than older approaches such as the determination of nitrogenase activity or difference methods. The results showed significantly more atmospheric N in the harvested clover than in the cut-and-mulched. The cutand-mulched grass, on the other hand, contained more atmospheric N than the harvested, especially at the third cut. The weight of grass from the third cutand-mulched crop was greater, whereas the weight of clover was less, compared with the harvested crop. This shows that the grass in the cut-and-mulched crop was benefitting from the N liberated from the mulched material, which was at the same time inhibiting the N-fixing and general development of the clover. | Kleegras bestaende sind im oekologischen Landbau obligatorisch. .. Bei viehlosen Betrieben .. wird der Aufwuchs als Gruenduengung gemulcht und verbleibt damit auf der Flaeche.; Bei viehloser Nutzung wird ein erheblicher Teil des im Aufwuchs befindlichen N im System recycliert .. Mit den bisher gegebenen methodischen Moeglichkeiten koennen verlaeliche N-Bilanzen deshalb am ehesten bei Abfuhr des Aufwuchses, d.h. unter viehhaltender Nutzung erwartet werden. |
| 755 | Scholes, M.C., Powlson, D. & Tian, G.L. | Input control of organic matter dynamics | 1997 | Soil Organic Carbon | Journal | Geoderma; 79; 25-47 | English | Hardcopy:Partial; PDF:Full | Review of the ways in which inputs to plants and the soil influence the fate of carbon in the soil and the possible effects on this of rising atmospheric CO2 | Soil C pools & fluxes are influenced by several factors including C inputs (amount & quality of residues) & climatic (rainfall & temp) & edaphic (texture, structure & pH) conditions.; The most important chem. characteristics influencing litter decompos'n, nutrient release & SOM dynamics are C/N ratio, lignin & polyphenols.; Changes in lignin, tannin & polyphenol levels are more important in the decomposability of tropical litters than changes in the C/N ratios.; .. the decline in soil C was less when mulches were returned to the soil. |
| 1077 | Scholl, L. van, Leffelaar, P.A. & Dam, A.M. van | Mineralisation of nitrogen from an incorporated cover crop at low temperatures: experiment and simulation | 1997 | Cover Crops; Mineralisation; Soil N Dynamics | Journal | Plant Soil; 188; 211-219 | English | Hardcopy:Partial; Wordperfect:Full | Lab. expt. to study the mineralisation of N from incorprated cover crops | At 1$C, 20% of total organic N in the crop material had been mineralised after ten weeks, indicating that mineralisation at low temps is not negligible. Max. mineralisation occurred at 15$C; after ten weeks it was 39% of total applied organic N from shoot and 35% from root material. The relative decomposition rate was influenced by soil temp. and soil moisture content and the mineralisation of N was calculated from the decomposition of C, the C/N ratio of the catch crop material and the C/N ratio of the microbial biomass.; Incorporation before winter or the use of non-persistent crops can lead to early mineralisation of plant N and subsequent leaching from the soil profile. Late winter N uptake by the catch crop when incorporating in spring will lead to a temporary loss of easily available soil mineral N into an unavailable form, only some of which will become mineralised in time to be used by the succeeding crop. |
| 763 | Schrope, M.K., Chanton, J.P., Allen, L.H. & Baker, J.T. | |||||||||