1. State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry
of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University; Lanzhou 730000, China
2. Grassland Technique Extension Station of Gansu Province, Lanzhou 730030, Gansu, China
3. State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education;
College of Pastoral Agriculture Science and Technology, Lanzhou University; Lanzhou 730000, China