Study on Rainfall Runoff-Sediment Yield Under Modeling Rain Condition in the Loess Plateau

The issue of erosion and sediment yield caused by rainfall and water runoff is the world's largest environmental problems.Research on processes of rainfall,runoff and sediment yield can serve as development of process-based mode of soil erosion,soil and water conservation,and ecology construction on loess region.The rule of erosion sediment and runoff infiltration and dependency relation were studied under different surface using field simulated rainfall trails.The results show that:the greatest runoff is the original habitat,is 28.4 L/min,forest grass land is the minimum,fluctuated with 4.1~7.6 L/min when the rainfall intensity is 90 mm/h,when the rainfall intensity is 120 mm/h,the original habitat 36.05 L/min and the forest grass land is fluctuated with 6.85～10.88 L/min.The barren land is the greatest and the forest grass land is the smallest with sediment yield,the barren land fluctuated with 45.77~252.94 g and 52.76~162.48 g under the two different rainfall intensity,the forest grass land fluctuated with 2.82~6.99 g and 7.33~40.24 g.The forest grass land is the greatest and the original habitat is the smallest with the infiltration rate,the forest grass land is 1.18 mm/min and the barren land is 0.09 mm/min when the rainfall intensity is lower and the forest grass land is 1.42 mm/min,the barren land is 0.12 mm/min when the rainfall is higher.When sediment yield and runoff large that the infiltration rate is small,they have perfectly correlativity,which show that the regulation mechanism with vegetation cover have the water and soil conversation function,they can increase the infiltration rate and reduced the runoff and sediment yield.The research are significantly understanding the process of watershed runoff and sediment yield and can provide reliable experimental support for related model research and to provide important scientific evidence and ecological construction for the soil and water conservation in the future.