Degradation Dynamics of Halosulfuron-methyl in Two Textured Soils.

A laboratory experiment was conducted to study the degradation dynamics of halosulfuron-methyl residues in sandy loam and clay loam soil. The herbicide formulation was applied at 0.034 and 0.068 mg kg equivalent to field application dose of 67.5 and 135 g a.i. ha as single and double dose respectively. Soil samples were collected on 0 (1 h), 1, 3, 7, 10, 15, 30 and 45 days after treatments. Extraction was done using modified QuEChERS method. Residues were estimated by UPLC coupled with quadrupole Dalton mass detector. Average recoveries ranged from 85.5% to 94.5% for both soils at different fortification levels of 0.005 to 0.1 mg kg with limit of detection (LOD) and limit of quantification (LOQ) as 0.001 and 0.005 mg kg, respectively. Dissipation followed first order kinetics with half-life of 8.4 to 10.7 days in both soil at two doses. The residues reached below LOQ of 0.005 mg kg after 45 days of herbicide application.