Transformation and Persistence of Chlorsulfuron in Prairie Field Soils

Abstract

After 45 weeks, between 5 and 8% of the applied radioactivity from 14C-chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} applied to small sandy loam plots was recovered as chlorsulfuron and about 15% as 2-chlorobenzenesulfonamide. After 95 weeks, 2% of the original radioactivity remained as chlorsulfuron and 20% as the sulfonamide. The persistence of formulated chlorsulfuron was investigated using small field plots at two locations for three successive years. Between 3 and 16% of the herbicide applied during May was detected in the top 10-cm soil layers the following May using a corn-root (Zea mays L.) bioassay procedure.