Abstract:In order to accelerate the speed of restoration and reconstruction of vegetation in the plateau, moisture in the loess soil must be addressed. At first, the characteristics of aspect and slope gradient are analyzed for the farmland in Wuqi County of Northern Shaanxi. Then, four slope aspects(sunny slope, shady slope, semi-sunny slope, semi-shady slope)are selected, and four slope gradients(35°, 45°, 55° and 65°)are chosen for each slope aspect, finally, the water content in 0-100 cm depth soil is measured and a hierarchical cluster analysis is performed on the data. It is demonstrated that the land with above 35° slope gradient takes up about 39.00% of the total land. The shady slope is in 52.65%, and the sunny slope is 47.35%. The soil water content rises with increasing soil depth and gets saturated eventually. The water content varies significantly along the depth with increasing slope gradient. The slope gradient with shady aspect has the most significant correlation with soil water content. The slope aspect mainly affects overall moisture distribution condition in a slope, and has a less effect on soil moisture distribution along the soil depth. The influences of slope gradient, slope aspect and time span of slope on soil water content are mainly concentrated in 0-40 cm depth; beyond this depth, however, the influences are limited. The same conclusion is achieved after the hierarchical cluster method is applied. The methods used in this paper also can be applied to analyze soil water content in other regions, especially arid and semi-arid regions. The results of this study provide a reference for understanding characteristics of soil water content in steep slopes of Northern Shaanxi and a guide for vegetation restoration.
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