关键词: 绿洲棉田, 水盐运动, 预估校正法, 迎风二次型插值, 数值模拟

Abstract: The Prediction-Correction method is applied to solve the h type of Richards equation for water movement in soil. Satisfactory precision is gotten while the iteration steps are constrained by this method. Furthermore, the quadratic upstream interpolation difference method is adopted to solve the convection-diffusion equation for soil salt movement. It can avoid the problem of numerical dispersion and presents steeper apex of soil salt profile. Finally, this mathematical model is also utilized to simulate water-salt movement and the process of upwards accumulation of soil salt in cotton field of arid land under the condition of evaporation. The numerical results turn out in good agreement with the experimental data, thus the mathematical model may provide seientific basis for predicting salinization of soil. The water-salt movement in cropland with canopy and evaporation influence may be calculated by the present model, and the variation with depth of salt can also be obtained.

Key words: oasis cropland, water-salt movement, Prediction-Correction method, quadratic upstream interpolation, numerical simulation