NITROGEN AND PHOSPHORUS LOSSES FROM NO-TILL COTTON FERTILIZED WITH POULTRY LITTER IN THE SOUTHERN PIEDMONT

Abstract. Adoption of conservation tillage and use of poultry litter as fertilizer in major crops is increasing in the southeastern USA. The water quality impact of these alternative cropping methods needs investigation. In a study near Watkinsville, GA, nitrate loss through drainage was similar between no-till (NT) and conventional tillage (CT) cotton (mean 8.9 vs 8.2 kg ha-1). Cotton fertilized with poultry litter (PL) had higher nitrate loss than that fertilized with ammonium nitrate as conventional fertilizer (CF) (10.3 vs 6.5 kg ha-1). Peak nitrate concentrations reached 30 mgL-1 from CT and 15 mgL-1 from NT. Cotton under PL had about 5 mgL-1 higher peak concentration than CF cotton. Losses of dissolved reactive phosphorus in runoff were: 0.24, 0.25, 0.45 and 0.72 kg ha-1 respectively, fo