NUMERICAL SIMULATION OF THE TRANSPORT OF PHOSPHATE IN UNSATURATED SOIL DURING INFILTRATON
入渗条件下土壤中磷离子迁移的数值模拟

A two-dimensional finite element model was developed to describe the non-steady transport of interacting solute through unsatruated soil during infiltration under non-uniform soil,complex boundary conditions. A simulation program for solute transport through unsaturated soil was complied and validated with horizontal soil column experiment. The results suggested that P moves very slowly because it is adsorbed by the soil, even though the concentration is ashigh as 500 ppm, most of the P remains in the top soil horizon of 20 cm for four days. Therefore, P as a fertilizer will not lost by seepage and the water pollution by P is mainly come from top soil erosion.