变雨强对黄土坡地水土养分流失机制研究

Study on the Mechanism of Soil,Water and Nutrient Loss on Loess Slope Under Variable Rainfall Intensity

通过人工降雨装置模拟了一次降雨事件中3种雨强变化(100,130,160mm/h)对黄土坡地径流、泥沙及养分含量变化的影响。结果表明:(1)降雨过程中,雨强的变化是影响地表产流的重要因素,雨强由大到小降低的产流量明显高于雨强由小到大渐增的产流量;(2)径流产沙过程中,雨强由小到大渐增的降雨产流携沙量最多,对坡面土壤侵蚀最严重;(3)变雨强对养分流失影响与径流相似,雨强由大到小降低的降雨养分流失累计量高于另外2种降雨,表明初期雨强较大的降雨对于坡地养分流失最严重。

Based on an artificial simulated rainfall experiment on loess slope, the 3 different rainfall intensities （100, 130, 160 mm/h） changing in a rainfall event was set up to study the effect of variable rainfall intensity on soil, water and nutrient loss on loess slope. The main results were showed as follows： （1） Rainfall intensity was the important factor influencing the surface runoff. The runoff amount was much larger under the variable rainfall intensity changing from large to small than that under the rain{all intensity changing from small to large; （2） In the sediment-yielding process, under the variable rainfall intensity changing from small to large, the runoff and sediment yield were the highest, showing the most serious soil erosion on slope; （3） The variable rainfall intensity had the similar effect on nutrient loss compared to that on runoff, and the nutrient loss was much larger under the variable rainfall intensity changing from large to small than those under the rainfall intensity changing from small to large, which showed that the rainfall with larger rainfall intensity at initial stage had more serious effect on nutrient loss.