Application and validation of pesticide leaching models*: *Based on a paper presented at the symposium "Pesticide Movement through Soil", organised by the Physicochemical and Biophysical Panel of the Pesticides Group and by the Water and Environment Group of the Society of Chemical Industry on 27 March 1990.

Two lysimeter studies with the pesticides cloethocarb and bentazone were used to validate a modified version of the computer model SESOIL (Seasonal Soil Compartment Model), developed by Bonazountas and Wagner and to transfer the results of the lysimeter study to another climate scenario. For cloethocarb, an experimental insecticide without marked mobility in the soil, as indicated by the lysimeter study, the simulations were in excellent agreement with the lysimeter study. Calculations for bentazone revealed higher leaching than found in the lysimeter study. This discrepancy was resolved by a more careful and realistic inclusion of sorption in the lysimeter soil into the simulation model