Soil erosion estimation in conservation tillage systems with poultry litter application using RUSLE 2.0 model

Soil erosion is a major threat to global economic and environmental sustainability. This study evaluated long-term effects of conservation tillage with poultry litter application on soil erosion estimates in cotton (Gossypium hirsutum L.) plots using RUSLE 2.0 computer model. Treatments consisting of no-till, mulch-till, and conventional tillage systems, winter rye (Secale cereale L.) cover cropping and poultry litter, and ammonium nitrate sources of nitrogen were established at the Alabama Agricultural Experiment Station, Belle Mina, AL (34 degrees 41'N, 86 degrees 52W), beginning fall 1996. Soil erosion estimates in cotton plots under conventional tillage system with winter rye cover cropping declined by 36% from 8.0 Mg ha(-1) year(-1) in 1997 to 5.1 Mg ha(-1) year(-1) in 2004. This result was largely attributed to cumulative effect of surface residue cover which increased by 17%, from 20% in 1997 to 37% in 2004. In conventional tillage without winter rye cover cropping, soil erosion estimates were 11.0 Mg ha(-1) year(-1) in 1997 and increased to 12.0 Mg ha(-1) year(-1) in 2004. In no-till system, soil erosion estimates generally remained stable over the study period, averaging 0.5 and 1.3 Mg ha(-1) year(-1) with and without winter rye cover cropping, respectively. This study shows that cover cropping is critical to reduce soil erosion and to increase the sustainability of cotton production in the southeast U.S. Application of N in the form of ammonium nitrate or poultry litter significantly increased cotton canopy cover and surface root biomass, which are desirable attributes for soil erosion reduction in cotton plots. (C) 2006 Elsevier B.V. All rights reserved.