Analysis on grey correlation degree of soil moisture content under different land use types in a wind-blown sand area.

In this paper,the grey correlation analysis is used to analyze the vertical and monthly dynamic change of soil moisture content under 4 land use types in a wind-blown sand area in Yanchi County,Ningxia Hui Autonomous Region of China.The results show that the vertical change of soil moisture content under different land use types are quite different,the similarity of soil moisture content in the middle layer(30～70 cm in depth) and the deeper layer(70～100 cm) is high,with an order of Caragana korshinskii land natural grassland Glycyrrhiza sp.land Medicago sativa land.The grey correlation degree of soil moisture content between the top layer(0～30 cm in depth) and the deeper layer(70～100 cm) was the lowest,and the difference of soil moisture content is the highest.In Glycyrrhiza sp.land,the grey correlation degree of soil moisture content and similarity of soil moisture content change are higher during the period from August to October,however it is quite different in July;in Caragana korshinskii land,the grey correlation degree is the lowest in September,and it increases gradually in other months;however,it fluctuates strongly in the change trend of high-low-high-low in Medicago sativa land and natural grassland.The method of grey correlation analysis can be used to ideally identify the similarity or dissimilarity of soil moisture content change under different land use types.