典型黄土坡面天然草地产流产沙规律试验

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

通过野外模拟降雨试验，研究黄土区天然草坡的产流、产沙规律。试验设2个地类（草地和裸地）、3个降雨强度水平和3个坡度水平。结果表明：坡面初始产流时间与降雨强度呈负相关关系，与裸地相比，草地在降雨强度较大时（〉2.0 mm/min）加快坡面产流，在中（1.0-2.0 mm/min）、小等级降雨强度（〈1.0 mm/min）下则延缓产流；降雨强度较大时，裸地大坡度的产流强度随时间呈对数函数形式增长，中小等级降雨强度下的增长方式不符合这一规律；与中、小等级降雨强度不同，裸地在降雨强度较大时的产流产沙过程不一致；与裸地相比，草地的产流过程更为复杂，并不符合产流强度随时间呈对数函数形式增长的一般规律，草地产沙过程线与产流过程线的相对吻合程度受降雨强度的影响不明显。

The paper studied the runoff generation and sediment yield regulations of the natural slope-greenland 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 resuhs 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.