Wu Gao-Lin1 2  Wang Dong1 2  Liu Yu1 2  Ding Lu-Ming3  Liu Zhen-Heng4  Wu  GL (reprint author)  Northwest A&F Univ  Inst Soil & Water Conservat  State Key Lab Soil Eros & Dryland Farming Loess P  Yangling 710020  Shaanxi  Peoples R China