1. School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093, China|
2. State Key Laboratory of Soil Sustainable Agriculture, Nanjing Institute of Soil Sciences, CAS, Nanjing 210008, China
National Natural Science Foundation of China, No.40771186; The Key Project of the State Key Laboratory of Soil Sustainable Agriculture, Nanjing Institute of Soil Sciences, Chinese Academy of Sciences, No.5022505