1. Dep. of Soil Management; Ghent Univ.; Coupure Links 653 9000 Gent Belgium
2. Institute for Land Use (Univ. of Rostock); Justus von Liebig, Weg 6 18059 Rostock Germany
3. Dep. of Geology and Soil Science; Ghent Univ.; Krijgslaan 281 9000 Gent Belgium