Through the simulated rainfall experiment

the effects of slope and antecedent soil water content on the process of rainfall runoff and sediment on bare land and alfalfa land of coarse texture soil were investigated. The experiment treatment included three slopes（5°

15° and 25°）and three antecedent soil water content（low

middle and high）. The results showed that the processes of runoff on bare land and alfalfa land were at first increased and then leveled-off under different slopes and antecedent soil water content

and the effects of slopes on runoff volume were marginal. Sediment losses were greatly increased with the increasing slopes

which were increased firstly and then tended to be stable

and also greater changes occurred in bare land. Both of the runoff volume and the mean infiltration were significantly affected by antecedent soil water content. Under the same slope gradient

when antecedent soil water content increased from low to middle

and from low to high

the runoff volume of bare land increased 38.2%—52.8%

and 39.7%—42.8%

respectively

while the runoff volume of alfalfa land increased 27.3%—77.8% and 45.5%—91.1%

respectively. Slopes had significant influences on sediment losses and sediment concentration. Under the same antecedent soil water content

when slope increased from 5° to 15°

and from 15° to 25°

the sediment losses of bare land increased 96.3%—268.7%

and 6.9%—40.3%

respectively

whereas the corresponding values of alfalfa land increased 81.1%—384.2%

and 61.7%—169.9%

respectively. The results showed runoff volume and sediment losses of alfalfa land were significantly lower than bare land at same slope and antecedent soil water content. The findings indicate that antecedent soil water content and slope of coarse texture soil play important roles on the process and amount of soil erosion. The vegetation not only reduces runoff by canopy interception

but also decreases antecedent soil water content through consuming soil moisture.