1. State Key Laboratory of Desert and Oasis EcologyXinjiang Institute of Ecology and Geography, Chinese Academy of Sciences Urumqi 830011 PR China
2. Key Laboratory of Soil and Water Conservation and Ecological Restoration in Jiangsu Province, Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu ProvinceNanjing Forestry University Nanjing 210037 PR China
3. National Engineering Laboratory for Improving Quality of Arable LandInstitute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences Beijing 100081 PR China