YUAN Jian-ping, JIANG Ding-sheng, GAN Shu

(1.Institute of Soil and Water Conservation, Chinese Academy of Science and Mini stry of Water Resources, Yangling, Shaanxi 712100, China;
2.Department of Resources and Environment,Beiji ng Normal University,Beijing 100875, China;
3.Zhejiang University, Hangzhou, Zhejiang 3100 29, China)

Abstract: Results of simulating Experiment on Normal Integral Model of different forest and grass coverage degrees, show that forest and grass measures of small w atershed are effective in reducing runoff and sediments. They can attain initiall y the lowest value of 60 percent and the best value of 78 percent in conserving soil and water by taking forest and grass measures for small watershed managemen t, giving the critical value of 65 percent of runoff and infiltration ratio for small watershed.

Keywords: coverage degree; small watershed; model experiment; forest and grass meas ure