Soil mobility, octanol-water coefficients, and degradation of six sulfonylurea herbicides

TL;DRAbstract

Octanol-water partition coefficients (K$\sb{\rm ow}$) for the sulfonylurea herbicides chlorsulfuron, metsulfuron, DPX-M6316 (M6316), sulfometuron, chlorimuron and bensulfuron were pH dependent and ranged from $<$0.005 to 3.46 at pH 7.0, and 6.51 to 147 at pH 5.5. The pyrimidine sulfonylureas had higher K$\sb{\rm ow}$ values than the triazine sulfonylureas. Mobility determined by soil thin layer chromatography ranged from immobile (R$\sb{\rm f}$ = 0.0) to highly mobile (R$\sb{\rm f}$ = 0.88) depending on herbicide, soil pH, and organic matter content. Mobility was greatest at high pH and low organic matter content, and the triazine sulfonylureas were generally more mobile than the pyrimidine sulfonylureas. Chlorsulfuron was the most persistent sulfonylurea at pH 7.5 (94 days), while bensulfuron was the most persistent at pH 6.1 (26 days). The persistence of all the sulfonylureas, except M6316, increased with pH. Chlorsulfuron degradation was affected most by pH as half-life increased fr

Chat with Paper

AI Agents for this Paper