Sorption-desorption of flucarbazone and propoxycarbazone and their benzenesulfonamide and triazolinone metabolites in two soils

• Published in: Pest management science 2006-07, Vol.62 (7), p.598-602
• Main Authors: Koskinen, W.C, Calderón, M.J, Rice, P.J, Cornejo, J
• Format: Article
• Language: English
• Subjects: aged residues; amides; benzene; benzenesulfonamide; Benzenesulfonamides; Benzoates - chemistry; binding capacity; Biological and medical sciences; clay loam soils; desorption; flucarbazone; Fundamental and applied biological sciences. Psychology; Herbicides; hysteresis; metabolites; Parasitic plants. Weeds; Pesticides - chemistry; Physical properties; Phytopathology. Animal pests. Plant and forest protection; propoxycarbazone; sandy soils; Soil - analysis; soil chemical properties; soil chemistry; soil physical properties; soil transport processes; Soils; Sorption; Sulfonamides - chemistry; sulfonylaminocarbonyltriazolinone; Time Factors; triazole herbicides; Triazoles - chemistry; triazolinone; Weeds
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.1196

Sorption-desorption interactions of pesticides with soil determine the availability of pesticides in soil for transport, plant uptake and microbial degradation. These interactions are affected by the physical and chemical properties of the pesticide and soil and, for some pesticides, their residence time in the soil. While sorption-desorption of many herbicides has been characterised, very little work in this area has been done on herbicide metabolites. The objective of this study was to characterise sorption-desorption of two sulfonylaminocarbonyltriazolinone herbicides, flucarbazone and propoxycarbazone, and their benzenesulfonamide and triazolinone metabolites in two soils with different physical and chemical properties. K(f) values for all four chemicals were greater in clay loam soil, which had higher organic carbon and clay contents than loamy sand. K(f-oc) ranged from 29 to 119 for the herbicides and from 42 to 84 for the metabolites. Desorption was hysteretic in every case. Lower desorption in the more sorptive system might indicate that hysteresis can be attributed to irreversible binding of the molecules to soil surfaces. These data show the importance of characterisation of both sorption and desorption of herbicide residues in soil, particularly in the case of prediction of herbicide residue transport. In this case, potential transport of sulfonylaminocarbonyltriazolinone herbicide metabolites would be overpredicted if parent chemical soil sorption values were used to predict transport.