Abstract: Spatial variation of soil water content in soil profiles 0-8 m deep as affected by landform and vegetation was studied in the Longtan catchement of Dingxi in Gansu Province.Results show that topographic factors,such as position,inclination and exposure of a slope have signifluences on content of shallow soil water.However,spatial variation of deep soil water is more affected by growth conditions of the vegetation thereupon.The vegetations different in growth condition differ in consumption of soil water,thus the better the vegetation grows,the lower the content of deep soil water is.Slope gradient has significant influences on both shallow and deep soil waters.Soil water content is obviously higher in gentle slopes than in steep in the entire 0-8 m soil profile.Management measures such as soil and water conservation and tillage activities can effectively enhance iniltration of rain water,thus in creasing soil water storage in deep soil layers,and therefore be extrapolated as effective approaches to improvement of soil water regime in this region.

Key words: loess hilly and gully region, vegetation restoration, soil water, spatial variation