Experimental study on the law of runoff and sediment generation in the natural grassland of the typical loess slope

The paper studied the runoff generation and sediment yield regulations of the natural slope-green-land in loess zone by the simulated rainfall.There were two land types(grass land and bare land),three types of rainfall intensity and slope.The research results showed that: there was negative correlation between the original runoff generation time and the rainfall intensity.Compared with the bare land,the heavy rainfall intensity(2.0 mm/min) accelerated the runoff generation in the green land,while the mediate(1.0-2.0 mm/min) and light rainfall intensity(1.0 mm/min) made the runoff generation delayed.In the condition of heavy rainfall intensity,the strength of runoff generation increased with the time in the form of logarithmic function for the sharpen slope in the bare land,and this regulation was not suitable for mediate and light rainfall intensities.The processing of runoff and sediment generation in heavy rainfall intensity of bare land was inconsistent with mediate and light rainfall intensity.Compared with the bare land,the runoff generation process was more complex for green land,and the runoff generation intensity did not grow with the time in the form of logarithmic function.The effect of rainfall intensities on runoff and sediment hydrographs was no significant.