Numerical sim ulation of transport and transform ation of insecticide 1-(2-chlorobenzoyl)-3-(4-chlorophenyl) urea in unsaturated soil

A numerical simulation model of pesticide transport and transformation in unsaturated soil is presented in this paper．The model was developed under basic principles of movement of water and solute in soil under transient condition and overall consideration water flow：pesticide convection，diffusion, dispersion，sorption and degradation．The model was tested for the persistence and leaching of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea(CCU)using data from soil columns under laboratory conditions．The results of the test indicate that the modeling approach is simple and effective in describing movement and transformation of pesticides in soils．