1. Key Laboratory of Arable Land Conservation in North China Ministry of Agriculture and Rural Affairs, College of Land Science and Technology, China Agricultural University Beijing China
2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources Yangling China
3. School of Forestry Northern Arizona University Flagstaff Arizona USA
4. Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwestern China, Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education Ningxia University Yinchuan China