Spatial Distribution Of Soil Moisture In Southern Slope Of Qilian Mountains

Water,as one of the most important components of soil, is the basic element on which terrestrial plantsrely for existence. Analysis on the spatial distribution characteristics of soil moisture can provide theoretical basis for regional ecological function zoning. The southern slope of Qilian Mountains is located in the northeast of the Qinghai-Tibet plateau.In terms of the soil moisture in Qilian Mountain area, there are few studies on soil moisture on the southern slope of Qilian Mountain within Qinghai province. With the southern slope of Qilian Mountains as the research object, this paper has conducted field sampling and indoor laboratory analysis, by using softwares like GS+ and ArcGIS10.0 as well as geostatistics and multiple linear regression analysis, studied the spatial distribution of soil moisture on the southern slope of the Qilian Mountains.Results are as follows:(1) Woodland, shrub and grassland are the three different types of land use on the southern slope of Qilian mountain, their soil water content decreases as the soil layer deepens while soil bulk density increases when soil layer deepens.theirsoil porosity decreases as the soil layer deepens. In the five depth from 0 to 50 cm, the soil moisture content is: Woodland>shrub>grassland; soil bulk density is: grassland>shrub> Woodland; soil porosity is: Woodland>shrub>grassland. According to the descriptive statistics analysis, oil water content, bulk density, porosity were medium variant, they were in line with the normal distribution used single-sample K-S test(2) Based on geostatistics, we have learned that average soil moisture content within the range of depth from 0 to 50 cm all the determination coefficients of optimal semivariance function fitting model exceed 0.75, which is higher than that of average soil moisture content within the range of depth from 0 to 50 cm. The soil moisture content of five different depth and the average soil moisture content within the range of depth from 0 to 50 cm have shown a feature of “low at both sides and high in the middle” in the direction southeast- northwest of the mountain. The water content of soil from 0 to 10cm、10 to 20cm、20 to 30 cm enjoy good spatial continuity, however, the spatial continuity of water content of soil from 30 to 40 cm are worse, displaying an uneven distribution in plaque shape.Average interpolation results in each layer is not ideal,it is not the real reaction of soil moisture spatial distribution.(3) Based on multiple linear regression analysis, we have learned that average soil moisture content within the range of depth from 0 to 50cm’s coefficients of optimal semivariance function fitting model is 0.68. Soil moisture content decreases from Southeast to Northwest.Soil moisture’s maximum value is 0.67 g/gin the south slope region of Qilian Mountains, soil moisture content in a larger area is mainly distributed in the North and the Southeast which is located in Midwest of Qilian and Menyuan county. For the spatial distribution’s interpolation method of soil moisture in southern slope of QilianMountains, multivariate linear regression method based on DEM is more appropriate than the laws of statistics.