Institute of Soil Science,Chinese Academy of Sciences,P.O.Box 821,Nanjing,210008,P.R.China Fax:86-25-3353590,E-mail:bzhang@issas.ac.cn;
Geographical Institute,Ruhr-University Bochum,D-44780 Bochum,F.R.Germany Fax:49-234-32-14469,E-mail:zepp@geographie.ruhr-uni.de;
Water Resources Bureau,Jiangshu,Province;