A total of 4 dye infiltration experiments, using iodine-starch staining method and Brilliant Blue dye staining method, were conducted in loam and sand with various initial and boundary conditions. The measured soil water content and solute concentration distributions resulted from preferential flow were simulated and predicted using active region model (ARM) and mobile-immobile region model (MIM), and were evaluated and compared using the relative root mean square error (RRMSE) analysis. Furthermore, sensitivity analysis was conducted to study the impacts of ARM parameter (γ) on the predictions using ARM with various infiltration conditions. The model evaluation and comparison revealed that, ARM produced more accurate infiltration depth, and soil water content and solute concentration distributions predictions; the ARM captured the macroscopic behavior of preferential flow and transport. Sensitivity analysis revealed that, the predicted infiltration depth using ARM was more sensitive to ARM parameter (γ) when the ARM parameter (γ) was higher; while the predicted infiltration depth using ARM was less sensitive to the ARM parameter (γ) under higher infiltration amount and higher initial soil water content conditions.%在壤土和砂土条件下分别采用碘-淀粉染色示踪方法和亮蓝染色示踪方法各开展了2个染色示踪试验,分别采用活动流场模型和二域模型模拟计算了各试验入渗后染色区内的土壤含水率和溶质浓度分布,通过相对均方根误差分析评价了两个模型模拟预测优先流发展的有效性;此外,通过敏感性分析研究了不同入渗条件(土壤质地、入渗水量和土壤初始含水率)下活动流场模型模拟预测结果(入渗深度)对活动流场模型分形特征参数变化的敏感度.模型检验分析结果显示活动流场模型对土壤水入渗深度、入渗后染色区内土壤含水率和溶质浓度分布的预测精度要明显高于二域模型的模拟预测精度;活动流场模型较好的捕捉到了优先流运动整体的非均匀特征.敏感性分析结果显示,当降雨入渗水量和土壤初始含水率相同时,入渗深度对活动流场模型分形特征参数(γ)的敏感度随着γ的增大而增大;相同活动流场模型分形特征参数(γ)值条件下(即流动非均匀程度相同),入渗深度对活动流场模型分形特征参数(γ)的敏感度随着入渗水量的增大和土壤初始含水率的升高而减小.
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