基于土地利用和微地形的红壤丘岗区土壤水分时空变异性

    Spatial and temporal variability of soil moisture in hilly red soil region based on land use and microtopography

    • 摘要: 在红壤丘岗区冬春两季,以网格采样法测定了红壤丘岗区一块包含茶地、旱地和林地的缓坡的地表层和深层土壤含水率,采用经典统计结合地统计方法分析了其空间变异特征。结果表明:单一土地利用下,林地土壤含水率明显高于茶地和旱地,整体采样区土壤水分变异系数明显大于单一土地利用。同一季节表层和深层土壤水分具有类似的变异趋势;土壤水分在不同利用下存在截然不同的变异特征。通过半方差分析发现,茶地-旱地交界区土壤水分空间变异低于其他地方;另一方面,茶地-旱地土壤水分不具备空间相关性。另外,采样区表现出明显的各向异性且季节性变化明显,在冬季,土地利用和微地形共同影响水分变异特征;而在春季,土地利用是土壤水分变异的主导因素。除茶地-旱地交界区冬季水分不具有空间相关性外,土壤水分整体上具有良好的变异特征和空间连续性,因此可以利用地统计学在整体采样区进行水分空间变异的研究。

       

      Abstract: With the grid sampling method, the surface and subsurface soil moisture of hilly-sloppy lands was determinated in a subtropical soil region in winter and spring. The region includes tea land, upland and forest land. Spatial structures of the soil moisture were analyzed by geostatistics method and classical statistics method. The results showed that the soil moisture of forest land was more abundant than that of tea land and upland, the coefficient of variation of soil moisture in the entire research region was much higher than that of the single land use. The surface and subsurface soil moisture had similar trends of variation in the same season. According to autocorrelation analysis, soil moisture in the entire region had markedly different variation characteristics because of different land use types. Based on strange phenomena from seim-variogram functions,the spatial variation of soil moisture in forest-upland boundary was lower than that in the other places; on the other hand, the soil moisture in the area of tea -upland boundary had no spatial correlation at all. Sample variation was found to have an anisotropy character in the whole region. With respect to influence factors, such complex distribution of soil moisture was explained by different land use types and microtopographty in winter; however, land use was the dominant factor to the variation of soil moisture in spring. The soil moisture of the whole area except tea-upland boundary had good variable and spatial continuity. So it was advisable to apply geostatistics method to study the spatial variability of soil moisture in red hilly region.

       

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