Wednesday, November 7, 2007
328-14
Compaction and Tillage Effects on Soil Carbon Sequestration.
Randall Reeder, Food, Agricultural and Biological Engineering, The Ohio State University, 590 Woody Hayes Drive, Columbus, OH 43210, Alan Sundermeier, Ohio State University Extension, 639 S Dunbridge Road Ste 1, Bowling Green, OH 43402, Y. Raut, The Ohio State University South Centers, 1864 Shyville Road, Piketon, OH 45661, and Khandakar Islam, Ohio State University - OARDC, OSU South Centers, 1864 Shyville Rd, Piketon, OH 45661-9749.
Compaction induced by agricultural machinery is often affects soil properties and crop production. The impact of compaction and tillage on concentration and stocks of various C fractions in corn-soybean rotation was evaluated. The experiment was established on Hoytville clay loam in randomized complete block design with 2 compaction levels (Control vs. 20 tons) and 2 tillage systems (no-till vs. annual tillage) at the Northwest Agricultural Experiment Station, Wood County, northern Ohio. Composite soil samples at 0-15 and 15-30 cm depth were collected were randomly collected; 2-mm sieved, and analyzed for bulk density (rb), porosity (¦t), pH, electrical conductivity (Ec), total N, and various C fractions, such as microbial biomass C (Cmic), total C (CT), active C (CAC), particulate organic matter (POM), and extractable (CExt) C pools. Increasing compaction and depth of soil have decreased ft with a significant interaction. The concentration and stocks of Cmic, Cmic:CT ratios, and CAC distribution were affected by compaction, tillage, and soil depth without a significant interaction. Averaged across tillage and soil depth, the Cmic decreased by >20%, Cmic:CT ratios by >35%, and CAC by 5% with increasing compaction. However, the concentration and stocks of Cmic (17%), Cmic:CT (14%), CAC (5%) and POM (31%) significantly increased by NT compared to CT. Significant interaction of compaction and tillage increased CAC in NT soil without compaction. Among the various C fractions, Cmic, Cmic:CT, CAC and POM acted as early indicators of C sequestration in response to compaction and tillage operations.