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研究论文

NUMERICAL SIMULATION OF THE TRANSPORT OF PHOSPHATE IN UNSATURATED SOIL DURING INFILTRATON

摘要：针对土壤非均质,边界条件复杂、土壤水分动态变化而且溶质与土壤存在吸持反应的情况,建立了土壤二维对流-弥散溶质迁移的有限元模型,编写了计算机模拟程序,作为模型的初步应用,对4种不同性质的土壤,KH₂PO₄溶液一维水平入渗条件下的迁移进行了数值模拟。结果表明,模拟结果能够很好地与室内土柱实验结果吻合,该模型可以用于研究伴有吸持情况下土壤溶质的迁移规律。另外模拟与实验结果均表明,对于象磷这种与土壤强吸附反应的离子,由于进入土壤中的大部分P离子被土壤吸附,因而往深层土壤迁移很慢,当溶液浓度高达500ppm时,绝大部分溶质入渗4天左右,还集中于地表20cm以上,因而作为施肥可不必考虑渗漏损失问题,而磷对水环境的污染主要来自于耕层土壤的流失,由于下渗对于地下水的污染是次要的。

Abstract：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.