降雨-径流条件下土壤溶质迁移过程模拟

通过雨滴的打击加速土壤表面溶质迁移至地表径流过程。通过设计3种水文条件即控制排水状态（-5 cm）、土壤水分饱和状态和土壤渗流状态（5 cm），采用人工模拟3种降雨强度（30、60和90 mm/h），及同时外加模拟相对于降雨量的0、2、4和10倍径流量，研究土壤溶质迁移到地表径流过程中扩散过程的规律。试验结果表明降雨强度、或地表径流总量、或地表水位线的增加，均加速土壤溶质的扩散过程。渗流作用下，对流-扩散作用存在着一种交互作用，能加速分子扩散过程。土壤溶质迁移过程同降雨强度、地表径流量和地下水位高低有着重要关系。

Movement of soil solute under simulated rainfall runoff

Raindrop impact can increase solute transport process from soil into surface runoff. A laboratory flow cell and experimental procedures to study chemical transport from soil to runoff as a diffusion process were developed. Different vertical hydraulic gradients were imposed by setting the flow cell to free drainage condition (-5 cm), saturation condition and artesian seepage conditions (5 cm) under 30, 60 and 90 mm/h simulated rainfall and 2, 4 and 10 times simulated flow rate to rainfall. The experimental data clearly demonstrated that all of rainfall intensity, total flow rate, and water table can accelerate diffusion process. There is an interaction between diffusion and convection to increase chemical loss from soil into runoff under artesian seepage conditions. Chemical transport has a significant relationship to rainfall intensity, surface runoff flow rate and groundwater table.