中文摘要：

尽管连续混合器模型已经广泛应用于土壤中溶质迁移转化规律计算,但却仅限于饱和土壤条件。通过采用Kostiakov公式描述非稳定入渗过程,并结合活塞假设计算入渗过程中土壤水分的运动和分布规律,将连续混合器模型扩展应用于非饱和土壤的盐分淋洗过程计算,并求出了模型的解析解。分析发现,在一定的土壤质地、初始含水率剖面和初始含盐量剖面下,模型的计算结果会受到土层划分厚度的影响,而合理的土层厚度又与饱和导水率和溶质弥散系数之间存在量纲一的函数关系。当土层厚度选取合理时,连续混合器模型与HYDRUS-1D的计算结果十分接近,采用该模型模拟试验土壤盐分淋洗过程,显示了较好的计算精度。

英文摘要：

Though Series-Mixing-Cell-Model （SMCM） has been widely used in modeling solute transport and reac- tions, it＇ s mainly for saturated conditions. Therefore, SMCM was extended to simulate salt movement during leaching process of initial unsaturated soils, by employing Kostiakov equation and piston assumption to describe water movement during infiltration. An analytic solution of the extended model was derived and analysis showed that, for giv- en soil types, initial water and salt content profiles, simulation results would be influenced by layer thickness, and there was a quantitative relationship between optimized layer thickness, saturated hydraulic conductivity and solute dif- fusion coefficient. When layer thickness was chosen appropriately, results of this extended model were close to those of HYDRUS-1D. Further, the extended model was validated by experiment data, which showed that this model has advantages such as a small number of parameters which could be easily acquired and reasonably accurate modeling resuits.