Herbicide surface runoff and leaching from a cotton-rye cropping system under contrasting tillage and nutrient management levels

Field studies were conducted in 1997 and 1998 to examine fluometuron and pe ndimethalin surface runoff and leaching after application to cotton under t wo tillage (conventional- and no-tillage) and fertility regimes (synthetic fertilizer and broiler litter). Fluometuron was detected in surface runoff and leachate for approximately 40 days after application. Fluometuron was d etected at higher levels in no-tillage than conventional-tillage cotton and cotton treated with broiler litter. Differences in fluometuron concentrati on in leachate amongst tillage and fertility treatments were not observed, The desmethyl metabolite was identified in all water samples containing flu ometuron. Pendimethalin was not detected in surface runoff or leachate. Due to extended dry conditions, surface runoff and leachate samples were not c ollected in 1998.