Crop yield, soil erosion, and net returns from five tillage systems in the Mississippi Blackland Prairie

Abstract

ABSTRACT: Five tillage systems were used on two Blackland Prairie soils in Mississippi. Monocrop soybeans were grown with four systems ranging from zero tillage to conventional tillage plus fall chisel plowing. A double-crop of soft red winter wheat and soybeans was the fifth system. One soil was a Leeper silty clay loam with less than 1% slope, the other an upland soil, Brooksville silty clay, with a 3% slope. Relative crop yields as a function of tillage were similar on both soils. There was no soybean yield response to fall chisel plowing. Minimum tillage and zero tillage reduced soybean yields significantly. The double-crop treatment produced the highest net return and was the most soil-conserving practice on the upland soil. Soil loss with the double-crop treatment averaged 2.48 tons/ha/year, compared to 6.53 and 40.13 tons/ha/year for the zero tillage and bare fallow reference plot, respectively. The double-crop treatment also produced the least runoff (11.48 cm/year), which was 10% of the average annual rainfall. Of the five tillage systems studied, only the fall chisel treatment resulted in erosion rates greater than the soil loss tolerance of 9.1 tons/ha/year for the Brooksville soil.