Browse on keywords: organic matter carbon
Search results on 05/20/13
3670. Knapp, E.B., L.F. Elliott, and G.S. Campbell. 1983. Carbon, nitrogen, and microbial biomass interrelationships during the decompostion of wheat straw: a mechanistic simulation model.. Soil Biol. Biochem. 15:455-461.
The effect of N on the disappearance of C from a wheat straw system, and the response of the biomass to N additions, was simulated using microbial growth and maintenance terms from the literature. Straw decomposition rate was shown to be strongly dependent on available C and N during initial decomposition. When N is limiting, excess available C apparently is immobilized as polysaccharides.
5715. Rasmussen, P.E., R.R. Allmaras, C.R. Rohde and N.C. Roager, Jr.. 1980. Crop residue influences on soil carbon and nitrogen in a wheat-fallow system.. Soil Sci. Soc. Am. J. 44(3):596-600.
Seven crop residue treatments were initiated in 1931 to measure long-term residue managements effects on soil organic matter in a wheat-fallow cropping system on Pacific Northwest semiarid soils. Organic carbon and total N were measured at approximately 11-yr intervals over a 45-yr period to determine residue effects on the rate of change in soil OM content. Only the addition of 22.4 metric tons of manure/ha to straw residue before incorporating prevented a decline in soil N and C. The addition of 45 or 90 kg fertilizer N or of 22.4 metric tons of pea vines/ha to straw residue before incorporation reduced N and C loss when compared to straw only incorporation. Burning of straw in the fall following wheat harvest accelerated the loss of N, but not C. Burning of straw in the spring just prior to tillage had no effect on N or C loss.
6001. Russell, J.S. and C.H. Williams. 1982. Biogeochemical interactions of carbon, nitrogen, sulfur, and phosphorus in Australian agroecosystems.. IN: J.R. Freney and I.E. Galbally (eds.). Cycling of C,N,S, and P in terrestrial/aquatic ecosystems..
An excellent review article looking at nutrient cycling and gains and losses over time under different agricultural management. Estimates that over 3 million tons C are tied up in soil organic matter additions each year in Australian farmland. SOM levels are higher now than the native condition under systems that have used a legume pasture in the rotation. There was a generally downward trend in the soil C:N over the first 25 yr of OM accumulation. A WWPP rotation slightly increased SOM, while WWWP decreased it slightly, and fallow systems decreased it significantly. Increases in SOM increased the water-stable aggregates in the soil and improved infiltration. Leguminous pastures had an acidifying effect on the underlying soil.
7712. Young, A., R.J. Cheatle, and P. Muraya. 1987. The potential of agroforestry for soil conservation. Part 3. Soil changes under agroforestry (SCUAF): a predictive model.. ICRAF working paper no. 44..
Predicts soil carbon changes in different climatic zones under various agroforestry management schemes. Can be used for prediction of changes under other land use as well.