1. State Key Laboratory of Arid Agroecology, Lanzhou University, Lanzhou, 730000, P.R. China
2. Soil Science and Fertilizer Institute, Gansu Agriculture Academy, Lanzhou, 730070, P.R. China
3. Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, Saskatchewan, Canada, SK, S7N 5A8
4. Agriculture and Agri‐Food Canada, Research Station, Melfort, Saskatchewan, Canada, SK, S0E 1A0