APPLICATION OF PESTFADE TO SIMULATE SALT MOVEMENT IN SOILS

Abstract

This paper describes the application of a new solute transport model called PESTFADE (PESTicide Fate And Dynamics in the Environment) for simulating salt accumulation and leaching in soils. PESTFADE is a one-dimensional, transient, numerical model which can simulate water and solute transport in unsaturated, homogeneous soil systems. Also, the model considers the effects of dispersion, adsorption and macropore flow on solute movement. The numerical solution was verified with an analytical solution for a simplified case, and the model was validated using data from a soil column study involving irrigation with different amounts of total dissolved salts. Results from both the verification/validation runs indicate that PESTFADE can simulate salt movement in soils with good accuracy. Since the model can be run for different salinity, irrigation water management and drainage scenarios, it can provide information on appropriate water table management systems which can minimize salinity problems in arid and semi-arid regions.