1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau; Northwest A&F University; Yangling Shaanxi P. R. China
2. State Key Laboratory of Loess and Quaternary Geology; Institute of Earth Environment; Chinese Academy of Sciences; Xi'an P. R. China
3. School of Agriculture; Ningxia University; Yinchuan P. R. China
4. Institute of Environmental Sciences; University of the Bosphorus; Istanbul Turkey