Comparison of computer model predictions with unsaturated zone field data for aldicarb and aldoxycarb

Abstract

Abstract The ability of the Pesticide Root Zone Model (PRZM) to simulate the movement of aldicarb or aldoxycarb residues was evaluated using the soil properties and amounts of rainfall and irrigation measured in 34 unsaturated zone field study plots. Maximum leaching depth values obtained from the PRZM simulations agreed relatively well with those observed in the field experiments. Where irrigation water was applied in spatially nonuniform patterns to a field (as in furrow or flood irrigation), simulations show that the placement of the pesticide in relation to irrigation water must also be considered. The comparisons presented in this paper show that PRZM (if supplied with the proper degradation rates and appropriate soil, weather and agricultural parameters) can be used to assess movement of pesticides in agricultural environments. When used in conjunction with multiple year rainfall records, this model can be used to develop probability distributions of pesticide movement in the unsaturated zone. PRZM can also be linked to a ground water solute transport model to provide predictions of pesticide concentrations and transport in ground water. These techniques are useful in performing risk assessments and in developing potential management practices when needed.