1. Univ. of Hohenheim, Institute of Soil Science and Land Evaluation, Biogeophysics Section; D-70593 Stuttgart Germany
2. UFZ; Helmholtz Centre for Environmental, Research Dep. of Soil Physics; Theodor-Lieser-Strasse 4 D-06120 Halle/Saale Germany
3. China Agricultural Univ., College of Agricultural Resources and Environmental Sciences; Beijing 10009 P.R. China