ABSTRACT

Continued cotton production on highly erodible land will require systems which minimize soil loss and are sustainable from economic and environmental standpoints. The overall objective of this study was to determine the effects of winter cover and fertilizer N management on cotton growth and N uptake. Winter cover treatments included hairy vetch (Vicia villosa Roth.) seeded at 27 lb/acre, rye (Secale cereale L.) seeded at 53 lb/acre, and winter fallow. These cover treatments were arranged in factorial combination with N treatments of 0, 45, 90, and 135 lb/acre. Fertilizer N treatments were applied half at planting and half at early square. The soil at this site was a Caledonia loam. The research was conducted from 1989 through 1992 and the cotton variety DES 119 was used each year. Cotton stand reduction occurred 3 of 4 years with hair vetch and 1 of 4 years with rye; however, stands were uniform and yields were not adversely affected. Cotton N uptake was greatest following hairy vetch with N rates up to 90 lb/acre. Cotton N uptake following rye and winter fallow was very similar. With no applied N, cotton N uptake following vetch was predicted to be equivalent to winter fallow with fertilizer N applied at 50 lb/acre. Lint yield response to vetch was greatest with no applied N and was evident with up to 45 lb/acre of fertilizer N. With no N, lint yield following vetch was predicted to be equivalent to winter fallow with 70 lb N/acre. Maximum lint yield following either rye or winter fallow was predicted at about 110 lb N/acre. Overall, the highest average lint yield occurred with a vetch cover crop and 45 lb N/acre.