非饱和土中溶质地表径流迁移模型及解析模拟

针对非饱和农田在降雨引起肥料溶质地表径流迁移流失的实际问题,建立了二层结构溶质地表径流迁移模型,根据溶质质量守恒定律和水量平衡原理,求得模型的解析解,并采用室内非饱和土壤实验验证解析模型的合理性。通过敏感性分析,探讨了模型参数和土壤物理参数对溶质地表径流迁移流失过程的影响。研究结果表明:非饱和土的吸附性增大将增强土壤溶质迁移流失到地表径流水的能力;土壤干容重增大将减少土壤溶质的地表径流迁移;土壤的初始体积含水率越高,土壤溶质的地表径流运移作用越强。

Model for chemicals transfer to surface runoff in unsaturated soil and its analytical modeling

There exists ponding water during rainfall or irrigation inducing runoff into the unsaturated soil of farmland,and the soil chemical is lost into the surface runoff.A two-layer system model is established to describe the chemical transfer to surface runoff.An analytical solution for the model is obtained based on the chemical conservation laws and water balance equations,and the unsaturated soil experiment shows that this two-layer analytical model is reliable and reasonable.The effects of various soil properties on the chemical transfer to surface runoff are discussed by sensitive analysis of some parameters of the unsaturated soil in the model and experiments.It is found that higher adsorptivity of unsaturated soil will reinforce the ability of the soil chemical transfer to surface runoff,but the soil with greater bulk density decreases and higher initial volumetric water content of soil increases the soil chemical transfer to surface runoff.