Metsulfuron-methyl residues in soil and wheat under North-Western midhill conditions of Himalaya

Abstract

A field experiment was laid out in a randomized block design consisting of metsulfuron-methyl (a herbicide) treatments at 2, 4, 8 g/ha along with control during two consecutive years to study metsulfuron-methyl degradation in soil and terminal residues in wheat straw and grain. Soil samples were collected at 0 (4 hr), 1, 3, 7, 10, 15, 30, 45, 60, 75 and 90 days after herbicide application for degradation studies. Wheat straw and grain were collected at the time of harvest for terminal residues study. The herbicide residues were quantified using high performance liquid chromatography (HPLC) equipped with UV-Vis detector using C-18 column. The degradation data generated in the present investigation during both the years indicated that higher dose of metsulfuron methyl i.e. 8 g/ha persisted in soil upto 45 days after herbicide application. The degradation was rapid and more than 90% of applied metsulfuron-methyl in soil dissipated within 15 days of application. The logarithmic plots of herbicide concentration at different doses versus time fitted first order kinetics decay curves during both years. At the time of harvest, the metsulfuron-methyl residues were non-detectable level in wheat straw and grain. Thus, the use of metsulfuron-methyl in wheat could be considered safe.