1. State Key Laboratory of Grassland Agro‐ecosystems, Department of Pastoral Agriculture Science and Technology Lanzhou University Lanzhou China
2. Present addresses: Department of Animal Science and Technology Anhui Agricultural University Hefei 230036 China
3. College of Grassland Agriculture Northwest A & F University Yangling China
4. Soil and Land Systems Group School of Earth and Environmental Sciences, The University of Adelaide Roseworthy Australia
5. Department of Agronomy and Plant Genetics University of Minnesota St. Paul MN USA