摘要
本文采用改进型Picard迭代差分法求解土壤水分运动的混合型Richards方程，避免了采用Picard迭代法求解h型Richards方程所出现的质量平衡误差问题。同时，采用迎风二次型插值差分法求解土壤盐分运移的对流扩散方程，避免了采用一般差分格式时所出现的数值弥散问题。最后，将上述动力学模型对塔里木盆地绿洲农田，在灌溉入渗条件下的土壤水盐运动过程进行了数值模拟，模拟结果与测量值吻合较好．
To study the law of water-salt movement in soil has both theoretical and practical significances, especially for improving saline soil and controlling secondary salinization or alkalinization of farmland. The area of saline or alkaline wasteland is about 20 million hm'and that of farmland is about 6. 7 million hm2 including a part of secondary salinized land in China. Therefore, one of the urgent matters is to improve saline soil and control secondary salinization of farmland for rapid development of agriculture in China, especia1ly in north west China.In this paper, the modified Picard iteration method is applied to solve the mixed form of Richards equation for water movement in soil. The mass balance error in this algorithm is far less than that in traditional procedure in which the Picard iteration method is applied to soIve the capillary pressure in based form of Richards equation. Furthermore, the quadratic upstream interpolation difference method is used to solve the convection-diffu sion equation for salt movement in soil, it can avoid the munerical dispersion. Finally, this mechanical model is used to simulate water-salt movement in soil of oasis cropland in Tarim Basin under condition of permeance. The numerical results are in a good agreement with the experimental data. The model can provide scientific basis for improving saline soil.
出处
《干旱区地理》
CSCD
北大核心
1998年第1期10-17,共8页
Arid Land Geography
基金
国家自然科学基金!49471005
