1. State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences; Chinese Academy of Sciences; Beijing P.R. China
2. Center for Agricultural Water Research in China; China Agricultural University; Beijing P.R. China
3. Department of Geology and Geophysics; Texas A&M University; College Station Texas USA
4. Chinese-Israeli International Center for Research and Training in Agriculture; China Agricultural University; Beijing P.R. China