喀斯特地区典型洼地土壤水分的垂直变异性研究

In the karst depression areas at northwest Guangxi, grid sampling method was adopted (2m×2m) in a square area (10m×10m), and soil moisture content at 0~80㎝ soil depth by 10㎝ interval within two land use types was measured in may 2005. The vertical variability construction and distributing pattern were analyzed by the Geo-statistics method. The results showed that the corn land and the grassland possessed weak variability. Their vertical variability decreased and then increased along with soil layers but the grassland bad bigger spatial variability, The corn land and the grassland both had good semi-variance structure and strong spatial correlation, and they could be well expressed by spherical model. And their range were 66㎝ and 49.1㎝ respectively. They both had obvious anisotropy in vertical soil layers and could be fit with exponential model. The research also found that the spatial correlation and range of soil moisture have relationship with soil bulk density in this area. And it can help to maintain soil moisture and promote vegetation restoration in the depression areas after the “grain-for-green”.