Alxa Left Banner in the west of the Inner Mongolia Autonomous Region, China, is a typical arid desert area in the middle temperate zone between the northern border of China and the eastern Alxa Plateau. Due to overgrazing and human activities, soil degradation (or desertification) in the area is becoming increasingly severe due to loss of soil organic matter (SOM). Low SOM content impacts soil quality directly in this arid desert area. Understanding the spatial variation and distribution pattern of SOM cont...