关键词: 土壤微生物, 土壤酶, 营养元素, 枯枝落叶, 自肥能力

Abstract: Soil moisture is a major factor driving the formation and evolution of vegetation patterns. The exploration of spatial heterogeneity of soil moisture in salt marsh wetland in arid area is helpful for revealing the environmental adaptation of wetland plants and the interaction mechanism between soil moisture and wetland plants. In this study, the variogram models of soil moisture content (0-90 cm) and vegetation coverage were established according to the vegetation cover conditions (high, medium, and low) of three Calamagrostis pseudophragmitesdominated population patches in the wetland of Cao Lake, Jiayuguan City, using the geostatistical method. The spatial distributions of soil moisture and vegetation coverage were mapped with the Kriging interpolation method, and the spatial autocorrelation properties of soil moisture and vegetation coverage in the wetland were determined by the Moran’s I coefficients. Finally, the spatial heterogeneity of soil moisture and vegetation cover in wetland and their interaction relationships was analyzed. Results showed that soil water contents in different sites of the Cao Lake wetland were in order of lakeside>dry lake>flat land between dunes, and salt content was in order of dry lake>lakeside>flat land between dunes. On the patch scale, soil moisture and vegetation cover were in line with the normal distribution model. The spatial structure of soil water content in each layer and vegetation cover of C. pseudophragmites in the three sites all had an obvious patch-like distribution and exhibited high degrees of spatial heterogeneity. The spatial distribution of soil moisture contents and vegetation coverage in all three plots had positive correlations and agglomeration characteristics. The spatial agglomeration intensity of soil moisture content for the 60-90 cm soil layer was larger than those of 0-30 and 30-60 cm soil layers, and the spatial clustering characteristics of vegetation cover was more obvious in the lakeside plot. Therefore, C. pseudophragmites maximized the use of soil water resources, and thus improved its adaptability to drought habitats, which, to a certain extent, affected the spatial distribution of soil moisture on small scale.