Dissipation kinetics of glyphosate in tea and tea-field under northwestern mid-hill conditions of India

Abstract

A study was conducted to determine the dissipation of glyphosate applied at three dose levels in tea crop in mid hill conditions of northwest Himalaya, India in two consecutive seasons. More than 65% of the initial residues in the soil were found to have dissipated within 30 days following application to the tea irrespective of the dose. Glyphosate persisted in the soil for up to 30, 45 and 60 days at application doses of 0.5, 1.0 and 2.0 kg/ha, respectively. Glyphosate residues in the tea leaves were detected for up to 15 days with all three treatments. Half lives of glyphosate ranged from 5.80 to 19.10 days in the soil of the tea fields and 5.82 to 7.91 days in the tea leaves at the three doses. Glyphosate concentrations in the tea leaves were found to be below the maximum residue limit (1 mg/kg).