入渗水量和试验尺度对土壤水非均匀流动的影响

Effects of Infiltration Amount and Experimental Scale on Heterogeneous Soil Water Flow

[目的]研究入渗水量和试验尺度对土壤水非均匀流动(最大入渗深度和平均入渗深度、土壤水流运动非均匀程度和土壤优先流尺寸的影响)的影响,为农业灌溉施肥的高效利用、地下水环境保护以及流域水文过程预测等方面提供理论支撑。[方法]采用亮蓝染色示踪方法在砂土条件下开展了9组18个(每组2个重复)不同入渗水量(分别为1.25,2.5和5.0cm)和试验尺度(分别为0.25m×0.25m,0.5m×0.5m和1.0m×1.0m)的入渗试验。[结果](1)相同试验尺度条件下,土壤水最大入渗深度和平均入渗深度均随着入渗水量的增大而增大;土壤水流运动非均匀程度随入渗水量的增大而先增大后减小。(2)相同入渗水量条件下,当入渗水量较小时,土壤水最大入渗深度和土壤水流运动非均匀程度随着试验尺度的增大而增大;当入渗水量很大时,试验尺度的变化对最大入渗深度和土壤水流运动非均匀程度的影响不明显。(3)入渗水量的增加和试验尺度的增大都将使得优先流通道尺寸增大。[结论]入渗水量和试验尺度对土壤优先流运动有重要影响。

[Objective]To study the effects of infiltration amount and experimental scale on heterogeneous soil water flow（including both the maximum infiltration depth and the average infiltration depth,preferential flow heterogeneity and the size of preferential flow path）,in order to provide theoretical support for efficient use of agricultural irrigation-fertilization,protection of groundwater environment and prediction of hydrological process etc.[Methods]18infiltration experiments,using the comassie brilliant blue staining as the dye tracer,were conducted in sand soil with various infiltration amounts（i.e.1.25,2.5and 5.0cm）and experimental scales（i.e.0.25m×0.25 m,0.5m×0.5mand 1.0m×1.0m）.[Results]（1）Both the maximum infiltration depth and the average infiltration depth increase with the increasing of infiltration amount under the same experimental scale,and the preferential flow heterogeneity increases firstly and then decreases with the increasing of the infiltration amount under the same experimental scale;（2）While under the same infiltration amount condition,the maximum infiltration depth and the preferential flow heterogeneity increase with the experimental scale when the infiltration amount is relatively small but the maximum infiltration depth and the preferential flow heterogeneity keep almost unchanged when the infiltration amount is considerably high;（3）Furthermore,the increasing of infiltration amount and experimental scale both make the preferential flow path expanded.[Conclusion]The infiltration amount and experimental scale have obvious impacts on the heterogeneous soil water flow.