Foliar Washoff Potential and Simulated Surface Runoff Losses of Trifloxysulfuron in Cotton

• Published in: Journal of agricultural and food chemistry Vol. 54; no. 15; pp. 5498 - 5502
• Main Authors: Matocha, Mark A, Krutz, L. Jason, Reddy, Krishna N, Senseman, Scott A, Locke, Martin A, Steinriede, Robert W, Palmer, Eric W
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 26.07.2006
• Subjects: Adsorption; agricultural runoff; Biological and medical sciences; Chromatography, High Pressure Liquid; cotton; foliar spraying; foliar washoff; Food industries; Fundamental and applied biological sciences. Psychology; Gossypium - growth & development; Gossypium hirsutum; herbicide residues; Herbicides - administration & dosage; Herbicides - chemistry; leaves; losses from soil; pesticide application; Plant Leaves; Pyridines - administration & dosage; Pyridines - chemistry; Rain; rainfall simulation; Soil - analysis; soil treatment; sorption; Sulfonamides - administration & dosage; Sulfonamides - chemistry; sulfonylurea herbicides; trifloxysulfuron; Sorption; sulfonylurea; foliar washoff; Mobility; cotton; Surface runoff; Surface
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf060511q

The surface runoff potential of trifloxysulfuron {N-[(4,6-dimethoxy-2-pyrimidinyl)carbamoyl]-3-(2,2,2-trifluoroethoy)-pyridin-2-sulfonamide sodium salt} in cotton (Gossypium hirsutum L.) production systems has not been evaluated. The objectives of this study were to (i) determine sorption/desorption coefficients for trifloxysulfuron; (ii) quantify foliar washoff of trifloxysulfuron when applied to cotton at the five-leaf stage; and (iii) determine the surface runoff potential of trifloxysulfuron when applied to cotton at the five-leaf stage and to bare soil. Freundlich sorption and desorption coefficients were 1.15 and 1.22, respectively. Sorption data indicated that trifloxysulfuron was moderately sorbed to soil and that it will be transported primarily in the dissolved phase of surface runoff. Foliar washoff studies revealed that approximately 91% of trifloxysulfuron applied to cotton at the five-leaf stage was available for washoff 72 h after application. Simulated rainfall (7.5 cm h-1) applied 1 day after herbicide application (7.9 g ha-1) resulted in average concentrations of trifloxysulfuron in surface runoff water of 0.8 μg L-1 for bare plots and 1.3 μg L-1 for cotton plots. Cumulative trifloxysulfuron losses in surface runoff from bare plots and cotton plots were 0.13 and 0.21 g ha-1, respectively. These values correspond to fractional losses of 1.7% for bare plots and 2.7% for cotton plots. Greater runoff losses of trifloxysulfuron from cotton plots were attributed to foliar washoff. Trifloxysulfuron runoff losses may be curtailed if the herbicide is applied early postemergence when canopy coverage is minimal, thereby reducing the potential for foliar washoff. Keywords: Surface runoff; foliar washoff; sulfonylurea; sorption; mobility; cotton