[1] Univ Bonn, Inst Crop Sci & Resource Conservat Soil Sci & Soi, D-53115 Bonn, Germany
[2] Univ Dortmund, Inst Environm Res INFU, D-44221 Dortmund, Germany
[3] Forschungszentrum Julich, Inst Chem & Dynam Geosphere 4, D-52425 Julich, Germany
[4] Swiss Fed Inst Aquat Sci & Technol, CH-8600 Dubendorf, Switzerland
[5] Tech Univ Berlin, Inst Ecol, Dept Soil Sci, D-10587 Berlin, Germany