Spatial variation of soil nutrients of Tamarix ramosissima nebkhas and interdune areas in a desert-oasis ecotone Research on the morphological interactions between Tamarix ramosissima thickets and Nebkhas under different sand supply conditions:a case study in Cele oasis-desert ecotone Varying characteristics of soil seed banks during the succession process of Nitraria Tangutorum vegetation in an arid desert area Characteristics and spatial heterogeneity of Tamarix ramosissima Nebkhas at Desert-Oasis Ecotone Spatially heterogeneous characteristics of surface soil particles around nebkhas in the Gobi Desert