ADSORPTION AND DESORPTION OF BENSULFURON-METHYL ON ITALIAN PADDY FIELD SOILS

A study on bensulfuron-methyl adsorption and desorption processes has been carried out in three different Italian paddy field soils (silt-lo am, sandy-loam and loamy-sandy). The kinetic study has shown that equi librium was reached in the early stages (twenty minutes) of contact be tween soil and herbicide. The results of the experiments on adsorption fit Freundlich's equation. K-oc values have shown that bensulfuron-me thyl adsorption mainly regards the clay mineral fraction. The desorpti on of the pesticide from sandy-loam and loamy-sand soil has resulted t o be about 50% when soil washing is carried out with a water volume 7. 5 times greater than soil mass, while the amount released from silt-lo am soil is 21%. (C) 1998 Elsevier Science Ltd. All rights reserved.