1. Shanxi Province Key Laboratory of Soil Environment and Nutrient Resources, Institute of Eco-Environment and Industrial Technology, Shanxi Agricultural University, Taiyuan 030031, China
2. College of Natural Resources and Environment, Northwest A&F University, Xianyang 712100, China
3. Institute of Plant Nutrition, Resources and Environment, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
4. Key Laboratory of Cultivated Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affaris, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
5. National Field Observation and Research Station of Farmland Ecosystem in Qiyang, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Qiyang 426182, China