ABSTRACT

Soil erosion is a major environmental problem in the U.S. and worldwide and one of the primary pollutants in agricultural runoff is the eroded soil. Large areas of eroded and degraded soils exist in the southeast U.S.A. because of poor row crop production practices and due to intensive tillage practices. The objectives of this study are to evaluate the effects of tillage systems (no-till, mulch-till, conventional till); cropping systems (cotton-winter rye (secale cereale L.) and cotton-winter fallow); and nitrogen source (poultry litter, ammonium nitrate) on soil erosion estimates using the RUSLE computer model. The study is being conducted using existing plots and treatments that were established in 1996 at Alabama Agricultural Experiment Station, Belle Mina, AL. Data collected to calculate the cover management factor (C), which is an important component of RUSLE were surface residue cover, effective fall height, canopy cover, root mass, and shoot mass. Percent residue cover in no-till and mulch-till were 63% and 26% higher than that under conventional till system, respectively. No-till plots had higher canopy cover and root mass compared to mulch-till and conventional till systems. Cotton effective fall height, canopy cover, and root mass were higher under cotton-winter rye than cotton-winter fallow cropping system. Cotton plant growth parameters were higher under 200 Kg N ha^-1 poultry litter compared to 100 Kg N ha^-1. The data will be entered in to the RUSLE computer program to calculate C values and soil erosion estimates in cotton plots. Our study demonstrates that cotton under no-till and mulch-till in combination with rye cover crop and poultry litter at 200 Kg N ha^-1 will increase cotton growth parameters. This may reduce the soil erosion making cotton production in the southeast U.S.A. more sustainable.