General upwind difference method for soil solute transport equations

The General Difference Method(GDM) was used to solve the soil solute transport equations, Upwind Schemes was used for the convection term. This method was verified with the water and salt balance and numerical experiments. The results were compared with the calculated results done by HYDRUS software (Galerkin Finite Element Method). From the results of numerical calculation and the validation of water and salt balance, this method is of high-accuracy. It is obvious that the amount of calculation can be decreased and the calculation procedure can be simplified by GDM. Especially the upwind scheme can effectively avoid the numerical dispersion and oscillation even under the condition of dramatic changes of salt contents and without dense nodes.