1. School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
2. School of Geographical Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, China
3. Department of Civil Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia
4. Institute of Crop Science and Resource Conservation, University of Bonn, 53111 Bonn, Germany