College of Resources and Environment,China Agricultural University/Key Laboratory of Arable Land Conservation(North China),Minstry of Agriculture/Key Laboratory of Agricultural Land Quality Monitoring,Ministry of Land and Resources,Beijing 100193,P.R.China;
School of Earth and Environment,Anhui University of Science and Technology,Huainan 232001,P.R.China;
College of Resources and Environment,China Agricultural University/Key Laboratory of Arable Land Conservation(North China),Minstry of Agriculture/Key Laboratory of Agricultural Land Quality Monitoring,Ministry of Land and Resources,Beijing 100193,P.R.China;
College of Resources and Environment,China Agricultural University/Key Laboratory of Arable Land Conservation(North China),Minstry of Agriculture/Key Laboratory of Agricultural Land Quality Monitoring,Ministry of Land and Resources,Beijing 100193,P.R.China;
College of Resources and Environment,China Agricultural University/Key Laboratory of Arable Land Conservation(North China),Minstry of Agriculture/Key Laboratory of Agricultural Land Quality Monitoring,Ministry of Land and Resources,Beijing 100193,P.R.China;
Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,P.R.China;