1 Universität Koblenz-Landau, Institute for Environmental Sciences, Working Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau, Germany. Electronic address: schaumann@uni-landau.de.
2 Technische Universität München, Institute of Hydrochemistry, Munich, Germany.. Electronic address: tbaumann@tum.de.
3 Albert-Ludwigs-Universität Freiburg, Institute of Forest Sciences, Chair of Soil Ecology, 79085 Freiburg i.Br., Germany. Electronic address: friederike.lang@bodenkunde.uni-freiburg.de.
4 Universität Koblenz-Landau, Institute for Environmental Sciences, Working Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau, Germany. Electronic address: metreveli@uni-landau.de.
5 Helmholtz Centre for Environmental Research - UFZ, Department Soil Physics, Theodor-Lieser-Strasse 4, D-06120 Halle, Germany; Martin-Luther-University Halle-Wittenberg, Institute of Soil Science and Plant Nutrition, Von-Seckendorff-Platz 3, 06120 Halle/Saale, Germany. Electronic address: hans-joerg.vogel@ufz.de.