广西典型岩溶区土壤水分含量空间自相关分析

以广西壮族自治区马山县为研究区，在野外调查、室内实验测试获取182个土壤水分含量数据的基础上，采用半方差函数和Moran’s I统计量对研究区域土壤水分含量的空间自相关关系、空间相关尺度和空间分布规律进行了研究。结果表明:(1)研究区域土壤水含量平均值为16.97%，受结构性因素和随机因素共同作用，土壤水分含量具有中等强度的空间异质性；(2)研究区域土壤水分含量Moran’s I指数为0.423，表明研究区内土壤水分含量存在空间自相关性，在0~21 km和31~34 km范围内土壤水分含量自相关性为正，在21.7~31 km和34~45 km范围内自相关性为负；(3)Lisa聚类图表明，土壤水分含量空间聚集区和空间孤立区相伴存在，其中“高—高”空间聚集主要分布在马山县东北部，“低—低”聚集区主要分布在东南部。“低—低”聚集区和“高—低”孤立区土壤水分含量缺乏风险大。 

Spatial autocorrelation analysis of soil water content in a karst region of Guangxi Province

Mashan county, located in the middle Guangxi Zhuang Autonomous Region, southwestern China, was selected as the study area. Based on the plentiful information from field surveys, soil sampling and laboratory analysis, we were studied the spatial autocorrelation coefficients, correlation distances and spatial patterns of soil water content in topsoil (0–20 cm) using semi-variances and Moran’ s Istatistics. The results show that the mean value of soil water content is 16.97%. Soil water content shows a moderate spatial autocorrelation within the distance of 78.8 km, which is affected by the constitutive and random factors. (2) Moran index of soil water content in the study area is 0.43, suggesting that the soil water content possesses spatial autocorrelation. In the ranges of 0-21.7 km and 31-34 km, the values of Moran′s Iof soil water content are greater than 0, implying positive spatial autocorrelation; while in the ranges of 21.7-31 km and 34-45 km, the values are negative, indicating negative spatial autocorrelation. Lisa cluster maps show that there are spatial aggregation areas and spatial isolated areas of the soil water content. The “high-high” spatial aggregation areas cluster in the northeast of Mashan county and “low-low” spatial aggregation clustered in the southeast. There are bigger risk of short of soil water content in the “low-low” spatial aggregation and “high-low” spatial isolated areas.