PEARL model for pesticide behaviour and emissions in soil-plant systems : description of the processes in FOCUS PEARL v 1.1.1

Abstract

The use of pesticides in agriculture presents risks to the environment, which are increasingly evaluated by using computation models. The new PEARL model simulates the behaviour of pesticides in soil-plant systems and their emissions to the environment. The pesticide model is used in combination with the hydrological model SWAP. Various agricultural situations and ways of applying the pesticides can be simulated. The model accounts for different sorption mechanisms, in equilibrium and non-equilibriumdomains of the soil. Pesticide transport in the liquid and gas phases is described by the convection-dispersion-diffusion type equation, which is supplemented with sink terms. Comprehensive reaction schemes are processed in matrix form. The rate in first-order transformation kinetics is dependent on temperature, soil moisture content and depth in the soil. Besides computing persistence and distribution of the pesticidal compounds in soil, the model computes volatilization into the air, lateral drainage to water courses and leaching to groundwater