古尔班通古特沙漠南缘干季土壤水分含量空间异质性

土壤水分含量是荒漠植被发育的主要制约因子。对古尔班通古特沙漠南缘个体、群落、丘间地0~100 cm干季土壤水分含量的空间异质性进行分析。结果表明：（1）同尺度下，土壤水分含量随土层深度增加呈显著升高趋势，且表层土壤水分含量的变异系数高于其他土层。（2）个体尺度，梭梭树干基部周围土壤水分含量在垂直和水平方向存在格局分异。垂直方向，土壤水分含量随土层深度增加呈升高趋势。水平方向，随距树干基部距离增加，坡顶土壤水分含量呈升高趋势，坡中和坡底土壤水分含量呈降低趋势，但没有显著差异。（3）梭梭群落尺度上土壤水分含量异质性较强，且呈斑块状分布。（4）地形是影响丘间地尺度土壤水分含量空间分异的主要因素，形成坡底土壤水分含量最高、坡中次之、坡顶最低的空间分布格局。

Multi-scale Spatial Heterogeneity of Soil Moisture in the South Gurbantunggut Desert during Dry Period

Soil moisture is one of the main limiting factors to vegetation development in arid and semi-arid area. During the dry season, spatial heterogeneity of soil moisture at the individual scale, community scale and dune-interdune lands scale was measured in the south Gurbantunggut Desert in 0-100 cm depth. Results showed that at the same scale, average soil moisture increased significantly with soil depth increasing from 0 to 100 cm. However, the coefficient variation (CV) of top soil was greater than other soil depths. At the vertical and horizontal directions, the patterns of spatial distribution of soil moisture around H. ammodendron base at individual scale were different. In the vertical directions, the soil moisture increased with the soil depths increasing; In the horizontal directions, with the outward from tree base increased, the soil moisture at crest increased,while the soil moisture decreased at midslope and interdune, and the difference was not significant. On H. ammodendron community scale, the spatial heterogeneity of soil moisture is strong, and represented a patch-shaped distribution. Terrain factor is the main factor which affect the spatial heterogeneity of soil moisture at the scale of dune-interdune lands, which lead the soil moisture was highest at the interdune, and lowest at the upper slope.