中文摘要：

利用2005年5月在桂西北喀斯特汁地10m×10m地块范围内的网格（2m×2m）采样数据，川地统计学方法分析了两种土地利用类型（耕地和牧草地）0—80cm土壤水分的垂直变异结构及其分布格局。结果表明，耕地和牧草地土壤水分呈现弱变异特征，两者的垂直变异趋势大致随土层加深先减小后增大，其中牧草地土壤水分的变异程度相对较大；耕地和牧草地土壤水分在垂直层面均具有良好的半方差结构和较强的空间相关性，均可用球状模型拟合，变程分别是66．0cm和49．1cm。垂直变异还具有明显的各向异性，均用指数模型拟合；土壤水分的空间相关性及变程与土壤容重具有一定关系。研究显示，洼地退耕还草后土壤总体上朝着有利于水分保蓄和植被恢复的方向转变。

英文摘要：

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 semivariance 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.