吸附作用与不动水体对土壤溶质运移影响的模拟研究

STUDY ON INFLUENCES OF SOIL ADSORPTION AND IMMOBILE WATER ON SOLUTE TRANSPORT IN SOIL BY NUMERICAL SIMULATION

本文通过等温静态吸附与动态吸附实验建立了土壤吸附模型，用饱和水动力弥散实验建立了土壤不动水体模型，并给出了土壤吸附作用与不动水体影响下的饱和－非饱和溶质（盐）运移数学模型的特征－有限元数值计算格式，采用特征－有限元法对蒸发与入渗实验条件下溶质运移进行了数值模拟。并对土壤吸附及不动水体对表土积盐作了四种处理，进行了模拟比较，结果表明，土壤吸附作用与不动水体对溶质运移影响较大，它在土壤水盐运动的定量研究中不应忽视。

The soil adsorption model and immobile water model were established through experiments of isotherm static adsorption and dynamic adsorption, and hydrodynamic dispersion in saturated soil respectively. The numerical model of the characteristic method combined with finite element scheme (CMFE) was proposed to solve the mathematical model of solute transfer through saturated-unsaturated soil under the influence of soil adsorption and immobile water conditions. The solute transport were simulated by the CMFE method under evaporation and infiltration experiment conditions. A comparison among the mathematical models considering the following four cases respectively: (i) neglected influence of soil adsorption and immobile water, (ii) soil adsorption only, (iii) immobile water only, and (iv) both influences of soil adsorption and immobile water was done systematically. It was shown that the influences of soil adsorption and immobile water on solute transport were very large and could not be neglected in the soil water-salt control and monitoring, in the research of salinized soil, and in the accurate and quantitative research.