REGULAR ARTICLE Initial differentiation of vertical soil organic matter distribution and composition under juvenile beech (Fagus sylvatica L.) trees Carsten W. Mueller & Nicolas Brüggemann & Karin Pritsch & Gunda Stoelken & Sebastian Gayler & J. Barbro Winkler & Ingrid Kögel-Knabner Received: 3 November 2008 / Accepted: 9 February 2009 / Published online: 28 February 2009 # Springer Science + Business Media B.V. 2009 Abstract In a lysimeter experiment with juvenile beech trees (Fagus sylvatica L.) we studied the development of depth gradients of soil organic matter (SOM) composition and distribution after soil distur- bance. The sampling scheme applied to the given soil layers (0–2 cm, 2–5 cm, 5–10 cm and 10–20 cm) was crucial to study the subtle reformation of SOM properties with depth in the artificially filled lysim- eters. Due to the combination of physical SOM fractionation with the application of 15 N-labelled beech litter and 13 C-CPMAS NMR spectroscopy we were able to obtain a detailed view on vertical differentiation of SOM properties. Four years after soil disturbance a significant decrease of the mass of particulate OM (POM) with depth could be found. A clear depth distribution was also shown for carbon (C) and nitrogen (N) within the SOM fractions related to bulk soil. The mineral fractions <63 μm clearly dom- inated C storage (between 47 to 60% of bulk soil C) and N storage (between 68 to 86% of bulk soil N). A drastic increase in aliphatic C structures concomitant to decreasing O/N-alkyl C was detected with depth, increasing from free POM to occluded POM. Only a slight depth gradient was observed for 13 C but a clear vertical incorporation of 15 N from the applied labelled beech litter was demonstrated probably resulting from faunal and fungal incorporation. We clearly demon- strated a significant reformation of a SOM depth profile within a very short time of soil evolution. One important finding of this study is that especially in soils Plant Soil (2009) 323:111–123 DOI 10.1007/s11104-009-9932-1 Responsible Editor: Philippe Hinsinger. C. W. Mueller (*) : I. Kögel-Knabner Lehrstuhl für Bodenkunde, Technische Universitaet Muenchen, D-85350 Freising, Germany e-mail: carsten.mueller@wzw.tum.de N. Brüggemann Forschungszentrum Karlsruhe, Institute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), D-82467 Garmisch-Partenkirchen, Germany K. Pritsch : S. Gayler Chair of Soil Ecology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany G. Stoelken Chair of Tree Physiology, Institute of Forest Botany and Tree Physiology, University of Freiburg, D-79110 Freiburg, Germany J. B. Winkler Department of Environmental Engineering, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany