In the karst depression areas of Northwest Guangxi Zhuang Autonomous Region

grid sampling method(2 m×2 m) was adopted in the square area(10 m×10 m) and soil moisture content in 0—80 cm soil profiles at a 10 cm interval with two landuse types was measured in May

2005.The vertical variability construction and distribution pattern were analyzed by the geo-statistics method.Results showed that cropland and grassland had weak variability.Their vertical variability decreased and then increased along with increased soil depth but grassland had greater spatial variability.Both cropland and grassland had good semi-variance structure and strong spatial correlation and could be well expressed by spherical model.The ranges of the two landuse types were 66 and 49.1 cm

respectively.They both had obvious anisotropy in vertical soil layers and could be fit with exponential model.It was also found that the spatial variability of soil moisture in vertical depth had a close relationship with soil physical properties under both landuse types.Conclusions from the research help to maintain soil moisture and promote vegetation restoration in the depression areas after the grain-for-green project.