岩溶高原地区小流域土壤厚度的空间变异特征

土壤厚度是制约石漠化地区生态修复的重要因子。在贵州省金沙县乌箐河小流域，通过实地调查土壤厚度，结合地统计学和经典统计学方法，研究岩溶高原地区小流域中3种典型土地利用类型下土壤厚度的空间变异及其分布格局。结果表明：研究区土壤厚度总体呈中等强度空间变异，个别样地属强度变异，具有良好的半方差结构，其变异趋势大致为随着坡位的降低而逐渐减小，而土壤厚度随坡位的降低逐渐变厚。坡耕地土壤厚度空间相关性相对较好，存在一定的连续性；荒山和意大利杨树林地土壤厚度的空间变异程度均较大，斑块状分布明显。除个别样地可以用高斯模型和球状模型拟合外，其余样地均可用指数模型拟合，且拟合效果较好（R^2≈0．8）。研究结果加深了对岩溶高原地区土壤厚度的认识，为石漠化综合治理工程的合理布局和土地资源的有效开发利用提供重要依据。

Spatial variability of soil thickness in a small watershed of Karst plateau

Soil thickness is one of the most important factors restricting the ecological restoration in the region of Karst plateau. A case study was conducted in Wujinghe small watershed in Guizhou Province, China. The aim of this study was to characterize the spatial variability regulation and distribution pattern in soil thickness in Karst plateau. The soil thickness of three typical landuse types was measured in October, 2010 and analyzed by using traditional statistics and geostatistics methods. The results show that the degree of spatial variability in soil thickness in this study area was overall moderate, but strong in a few plots. All three landuse types had good semi-variance structure, and the spatial variability decreased with the decrease in slope position. The soil thickness was increased with the decrease in slope position. Relatively good spatial correlation and continuity of soil thickness exist between different sloping farmland. On the contrary, the degree of spatial variability in soil thickness was larger in both the barren hilly and Populus euramevicana plantation, and its spatial pattern came out as fragmentized distributions. Soil thickness can be well expressed by exponential model（R^2 ≈0.8）in almost all plots, but fitted with spherical model and Gaussian model in a few plots. The research findings can provide deepen understanding of soil thickness, which will provide the foundation for Karst rocky desertification control project and rational utilization of land resources in Karst plateau region.