Affiliation: | aMinistry of Agriculture Key Laboratory of Plant Nutrition and Nutrient Cycling, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 12 Southern Street of Zhongguancun, Beijing 100081, China;bThe Key Lab of Resource Environment and GIS, College of Resource Environment and 26 Tourism, Capital Normal University, 105 North Road of Xisanhuan, Beijing 100037, China |