Browse on keywords: organic matter Australia
Search results on 05/23/13
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.
10436. Haines, P.J. and N.C. Uren. 1990. Effects of conservation tillage farming on soil microbial biomass, organic matter and earthworm populations, in northeastern Victoria.. Austral. J. Expt. Agric. 30:365-371.
Wheat was grown continuously for 7 years with conventional tillage and direct drilling (no-till). There was a significant gradient of organic matter under no-till. In the surface 2.5 cm, biomass C and N, and N mineralization were 35, 30, and 62% greater, respectively, than under conventional tillage. No-till did not significantly increase soil organic C or N. Of the estimated 7.8 t/ha of C added to the soil from crop residues, 4% was retained in the top 7.5 cm at the time of sampling. Microbial biomass varied considerably with season. The biomass of earthworms in the top 10 cm under no-till was more than twice that of conventional tillage, while total worm numbers increased significantly when wheat residue was retained versus burned.