Adsorption and desorption of herbicide imazosulfuron in soils

Adsorption and desorption of imazosulfuron in soils were investigated using the compound labeled 14C at pyrimidine ring. Batch soil adsorption study of imazosulfuron was conducted using five kinds of soils in Japan, and the adsorption equilibrium time was found to be 2hr. Freundlich adsorption coefficients of imazosulfuron showed range from 0.96 to 5.27. Desorption constants of imazosulfuron in two kinds of soils were determined 0, 7, 30 and 60 days after treatment, and were 0.98 and 15.7 on day 0, and increased with time up to 35.8 and 37.0 on day 60. From these findings, it was suggested that imazosulfuron was found to be hardly desorbed from the soils with time.