Characteristics of nitrogen and phosphorus loss from rainfall runoff in farmland in the Huaibei Plain
(1. School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China; 2. Rural Water Conservancy Institute, Anhui and Huaihe River Institute of Hydraulic Research, Hefei 230088, China; 3. Key Laboratory of Water Science and Intelligent Water Conservancy, Anhui and Huaihe River Institute of Hydraulic Research, Bengbu 233704, China)