The Relationship Between Soil Moisture and Topographic-Vegetation Factors in Mobile Dune in Gurbantunggut Desert
[Objective]The aims of this study are to determine the distribution pattern of soil water in desert dunes,to clarify the relationship between soil water and various terrain and vegetation factors,so as to provide scientific and reasonable suggestions for the protection and reconstruction of vegetation in desert areas.[Methods]There were four different micro-landforms,including windward slope,leeward slope,hill top and bottom.The soil moisture was divided into surface(0-40 cm),middle(40-200 cm)and deep(200-300 cm)layers.The distribution characteristics of soil water on different micro-landforms and depths in Gurbantunggut Desert were studied on the small scale.Generalized linear model,generalized additive model and random forest were used to study the relationship between soil moisture and topographic-vegetation factors.[Results](1)The soil moisture on the windward slope and the bottom of the hill was higher than that on the lee slope and the top of the hill at different depths.There were significant differences of surface soil moisture between the lee slope(including the top and bottom of the hill)and the windward slope.(2)The effect of topographic factors on soil moisture was greater than that of vegetation factors.The main factors affecting surface soil water were slope and slope direction.The main factors affecting middle and deep soil water was shrub cover.(3)The fitting effect of the random forest was significantly higher than that of the generalized linear model and generalized additive model.[Conclusion]As for soil moisture on different micro-landforms,topographic factors have a greater impact on mobile dunes in Gurbantunggut Desert than vegetation factors.Slope and slope direction have the important influence on surface soil moisture.Shrub cover has a major effect on middle and deep soil moisture.