Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2004
Publication Date: 11/1/2004
Citation: Stubbs, T.L., Kennedy, A.C., Hansen, J.C., Reisenauer, P.E., Burns, J.W., Campbell, K. 2004. Composition of straw from cereal cultivars in dryland ecosystems. Abstract. ASA, CSSA, and SSSA, Madison, WI. Paper # 4067. Interpretive Summary:
Technical Abstract: Conservation tillage (CT) and no-tillage (NT) systems are needed in the inland Pacific Northwest to reduce soil erosion, maintain soil quality, enhance crop yields and improve farm profitability. Impacts of management practices on soil biotic and abiotic properties need to be considered before adoption of changes in those practices. We investigated soil aggregation and distribution of carbon and microbial communities in aggregates under various management systems in several long-term cropping systems studies. Soil aggregate size distribution was determined using dry sieving (1 mm, 0.25 mm, and 53 micron fractions). Soil microbial communities were assessed using substrate utilization, fatty acid methyl ester and phospholipid fatty acid methyl ester analyses. Organic carbon was higher in CT and NT compared to traditional tillage methods. With less disturbance, the proportion of aggregates in the larger size fractions (greater than 53 micron) increased. The CT and NT systems also had a greater percentage of the carbon protected in the larger aggregates and thus were less susceptible to loss do to erosion. Microbial communities varied with tillage and aggregate size. These data will provide growers and scientists with knowledge of management practices that retain soil carbon and improve soil quality.