1. Institute
of Geography, University of Bern, Hallerstrasse 12, CH-3012 Bern, Switzerland
2. Institute
of Agricultural Sciences, ETH Zurich, Eschikon 33, CH-8315 Lindau, Switzerland
3. Swiss
Soil Monitoring Network (NABO), Agroscope, Reckenholzstrasse 191, CH-8046 Zürich, Switzerland
4. Department of Earth Science & Engineering, Imperial College London, SW7 2AZ London, U.K.
5. Institute
of Geography and Geoecology, Karlsruhe Institute of Technology (KIT), Reinhard-Baumeister-Platz 1, 76131 Karlsruhe, Germany