1. College of Land and Resources College of Resources and Environmental Sciences Hebei Key Laboratory of Farmland Eco‐Environment Hebei Agricultural Univ. Baoding 071001 China
2. State Key Laboratory of North China Crop Improvement and Regulation Baoding 071001 China
3. Shaanxi Key Laboratory of Earth Surface System and Environmental Capacity College of Urban and Environmental Science Northwest Univ. Xi'an 710127 China