Effects of soil pH and soil water content on prosulfuron dissipation

Ryan P. Hultgren, Robert J M Hudson, Gerald K. Sims

Research output: Contribution to journalArticlepeer-review

Abstract

The sulfonylurea herbicide prosulfuron, 1-(4-methoxy-6-methyltriazin-2-yl)-3-[2-(3,3,3-trifluoropropyl) -phenylsulfonyl]urea, is used for the selective control of broadleaf weeds in corn, sorghum, and cereal grains. To investigate its fate in soils, this study examined the effects of soil pH and water content on the rates of dissipation processes and the products formed under aerobic conditions. Radiometry and chromatography analyses were used to quantify the degradation products and bound residues formed in incubations of 10 different soils. The pH-dependent hydrolysis of the sulfonylurea bridge to form phenyl sulfonamide was the primary transformation process. Significant microbial degradation of prosulfuron occurred in 2 of the 10 soils, yielding 14CO2 and desmethyl prosulfuron among the major products. The time required for 50% dissipation of the herbicide (DT50) was determined for each soil and water content treatment. At equivalent water contents, prosulfuron DT50 values were positively correlated with soil pH (P < 0.0001), varying from 6.5 days at pH 5.4 to 122.9 days at pH 7.9. Soil pH and water content strongly influence the fate of sulfonylurea herbicides in agricultural fields. Differences in the effect of soil water content on dissipation kinetics in a comparison of two soils were attributed to differences in soil pH, texture, and the ability of indigenous microorganisms to transform the herbicide.

Original languageEnglish (US)
Pages (from-to)3236-3243
Number of pages8
JournalJournal of Agricultural and Food Chemistry
Volume50
Issue number11
DOIs
StatePublished - May 22 2002

Keywords

  • Aerobic dissipation
  • DT
  • Environmental fate
  • Prosulfuron
  • Soil pH
  • Soil water content

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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