Soil Erosion from Tillage and Planting Systems Used in Soybean Residue: Part II - Influences of Row Direction

A rainfall simulator was used to compare soil losses from tillage and planting systems used in residue from soybeans. The study was conducted on a silty clay loam soil in the Wymore Series with a 5% slope and on a silt loam soil in the Nora Series with a 10% slope. Tillage and planting treatments, ranging from a moldboard plow system to no-till planting, were evaluated both up and- down hill and on the contour using replicated plots. For the first rainfall event after tillage and planting, the average soil loss for all systems on the contour was 3.0 t/ha which was a 74% reduction from the average soil loss of 11.5 t/ha for tillage and planting conducted up-and-down hill. Similarly, the average soil erosion rate for systems on the contour was 9.5 t/(ha·h), a 65% reduction from the 26.2 t/(ha·h) average soil erosion rate for up-and-down hill tillage systems. All tillage systems compared showed a significant reduction in soil erosion, soil erosion rate, and sediment concentration for row direction on the contour rather than with the slope