1. College of Agronomy and Key Laboratory of Crop Physi-ecology and Tillage Science in Northwestern Loess Plateau, Northwest A&F University, Yangling, Shaanxi, China
2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi, China
3. The UWA Institute of Agriculture, and School of Agriculture & Environment, The University of Western Australia, Perth, Australia