1. Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
2. State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Beijing 100081, China
3. South Subtropical Crop Research Institute, China Academy of Tropical Agricultural Sciences, Zhanjiang 524091, China
4. Agricultural Production and Resource Economics, Technical University of Munich, 85354 Freising, Germany
5. College of Economics and Management, China Agricultural University, Beijing 100083, China