1. State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, Qinghai 810016, China
2. College of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai 810016, China
3. Tongren County Forestry Technology Extension Station, Huangnan, Qinghai 811300, China
4. Forestry and Grassland Bureau of Qinghai Province, Xining, Qinghai 810000, China
5. Agricultural Technology Extension Station of Qinghai Province, Xining, Qinghai 810000, China