State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau;
Institute of Soil and Water Conservation;
Chinese Academy of Sciences and Ministry of Water Resource;
Yangling 712100;
P.R.China;
Graduate School of Chinese Academy of Sciences;
Beijing 100039;
P.R.China;
Northwest A & F University;
Yangling 712100;
P.R.China;
Institute of Geographical Sciences and Natural Resources Research;
Chinese Academy of Sciences;
Beijing 100101;
P.R.China;