1. College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, China;
2. Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing, China;
3. USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, USA;
4. Environmental Sciences Program & Department of Biological Sciences, Southern Illinois University, Edwardsville, IL, USA;
5. Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, China