Soil moisture and vegetation growth

as well as the balance of accumulated soil moisture over eleven years

were analyzed for runoff regulation and control projects on level terrace with slope and the terrace as contrast in Anding District

Dingxi City.Results indicated that the level terrace with slope was preserved perfectly

where annual average runoff and sediment yields in runoff generating area(25 m2)were 0.3 m3 and 3.96 kg

respectively.Runoff and sediment were totally retained by impounding area

which effectively controlled soil and water loss

increased water resources

and relieved the water shortage for tree and grass water demands.Soil water content in the 2 m layer varied inversely with vegetation growth.In the terrace as contrast

soil water content was highest

but the reduction of crop yield by drought reached the maximum.In the level terrace with slope

soil water content was lower and alfalfa yield was reduced greater in runoff generating area.In impounding area

however

soil water content was the lowest

while the growth of platycladus orientalis was strong.Annual average evapotranspiration for the level terrace with slope(forests and grass mixed by belts) was 428.6 and 2.2 mm higher than that for the terrace as contrast.