松华坝水源区等高反坡阶对坡耕地雨季土壤水分空间分布的影响

Impacts of Contour Reverse-slope on Spatial Distribution of Soil Moisture in Sloping Farmland During Rain Season in Water Source Area of Songhuaba Reservoir

[目的]分析昆明市松华坝水源区等高反坡阶对雨季坡耕地的土壤水分分布的影响,为该区域内等高反坡阶的改造提供理论依据。[方法]在水源保护区迤者小流域内坡耕地布设等高反坡阶,对不同位置坡面和阶面及其不同土层深度不同时期的土壤水分含量进行了观测。[结果]在长期大量降雨停止后2d,上阶、下阶土壤水分含量一直保持在较稳定水平,随时间变化的变幅较小,上阶降低2.71%,而坡面在降雨结束后迅速变化,上坡降低9.04%,中坡降低10.41%。[结论]等高反坡阶具有较强拦蓄地表径流,保墒保水的功能,且其对土壤水分具有缓释、再分配作用,主要作用对象为深度20—40cm土层。

[Objective]The objective of this study is to analyze the impacts of contour reverse-slope on the spatial distribution of soil moisture in sloping farmland during rain season serious in order to provide theoretical basis for the improvement of the contour reverse-slope in water source area of Songhuaba reservoir in Kunming City.[Methods]We set up contour reverse-slope in the sloping farmland in Yizhe valley,and observed the soil moisture content at different soil depth in different positions of slope during different periods.[Results]Soil moisture content in contour reverse-slope maintained at stable level after 2rainy days.At the upper reverse-slope,it reduced by 2.71%.In contrast,soil moisture changed greatly in different positions of slope.Soil moisture at upslope reduced by 9.04%,while at the middle slope,reduced by 10.41%.[Conclusion]Contour reverse-slope can retain soil surface runoff and moisture,and influence the distribution of soil moister in 20—40cm depths of soil layer.