Persistence of Metsulfuron-methyl in Soil

Field and pot culture experiments were conducted in 1991–92 and 1992–93 at CCS Haryana Agricultural University, Hisar to study the effect of moisture, sunlight, soil pH, microbes and temperature on the persistence of metsulfuron-methyl in soil. The residual toxicity of metsulfuron after 120 days of its application on onion was more at low soil moisture than at high moisture level. Solar light did not play any role in altering the persistence of this herbicide. Half-life of metsulfuron at 15, 25 and 35°C was found to be 147, IOg and 70 days. respectively. Alier 120 days incubation at 25°C the loss of metsulfuron was 53% in unsterilized soil as compared to 39% in the sterilized soil and the half-life was 70 and 167 days, respectively. The degradation rate of metsulfuron was faster in acidic silty loam Solan soil as compared to high pH Hisar soil.