1. State Key Laboratory of Hydraulics and Mountain River Engineering; Sichuan University; Chengdu China
2. Department of Drainage and Irrigation Engineering; Sichuan University; Chengdu China
3. Department of Agronomy; Kansas State University; Manhattan KS USA
4. USDA-ARS Rangeland Resources and Systems Research Unit; Fort Collins CO USA
5. Department of Agronomy and Horticulture; University of Nebraska-Lincoln; Lincoln NE USA