Adsorption-Desorption of Isoproturon on Eight Soils of Hyderabad, Andhra Pradesh

Adsorption-desorption was studied by batch equilibrium technique at 37 ± 1°C at five different initial concentrations of isoproturon. Adsorption isotherms conformed to Freundlich equation (A = KC1/n). Desorption isotherms showed considerable hysteresis which was more prominent when desorption was carried out at higher concentrations of adsorbed isoproturon. Desorption isotherms from lowest level of adsorbed isoproturon concentration were close to adsorption isotherms. The cumulative desorption after five desorption steps was significantly different for all the initial concentrations of adsorbed herbicide and for all the soilS. Desorption isotherms conformed to Freundlich's equation and the Freundlich's constants ‘K’ and ‘n’ increased with increasing initial concentration of adsorbed herbicide thus confirming the irreversible nature of the adsorption of isoproturon on these soils.