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Soil mobility, octanol-water coefficients, and degradation of six sulfonylurea herbicides
Abstract
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 from 10 days at pH 6.1 to 85 days at an adjusted pH of 7.5. Organic matter content had less of an effect on persistence than soil pH and the effect was more variable. M6316 half-lives varied with organic matter content from 8 to 15 days at pH 6.1 and 8 to 22 days at pH 7.5.
Subject Area
Agricultural chemicals|Agronomy
Recommended Citation
Fredrickson, David Ray, "Soil mobility, octanol-water coefficients, and degradation of six sulfonylurea herbicides" (1988). ETD collection for University of Nebraska-Lincoln. AAI8914078.
https://digitalcommons.unl.edu/dissertations/AAI8914078