Topical IssueSoils as a source and sink for CO2 – Mechanisms and regulation of organic matter stabilisation in soils (editors: I. Kögel-Knabner and E. Matzner). Synthesis of the DFG Priority Program SPP 1090 (German Research Foundation—“Deutsche Forschungsgemeinschaft”).
Stabilization mechanisms of organic matter in four temperate soils: Development and application of a conceptual model†
Article first published online: 31 JAN 2008
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Journal of Plant Nutrition and Soil Science
Volume 171, Issue 1, pages 111–124, February, 2008
How to Cite
von Lützow, M., Kögel-Knabner, I., Ludwig, B., Matzner, E., Flessa, H., Ekschmitt, K., Guggenberger, G., Marschner, B. and Kalbitz, K. (2008), Stabilization mechanisms of organic matter in four temperate soils: Development and application of a conceptual model. J. Plant Nutr. Soil Sci., 171: 111–124. doi: 10.1002/jpln.200700047
- Issue published online: 31 JAN 2008
- Article first published online: 31 JAN 2008
- Manuscript Accepted: 23 JUN 2007
- Deutsche Forschungsgemeinschaft (DFG)
- spatial inaccessibility;
- organo-mineral interactions;
- pool size;
- 14C age;
- density fractionation;
- HF demineralization;
- wet oxidation;
- active pool;
- intermediate pool;
- passive pool
Based on recent findings in the literature, we developed a process-oriented conceptual model that integrates all three process groups of organic matter (OM) stabilization in soils namely (1) selective preservation of recalcitrant compounds, (2) spatial inaccessibility to decomposer organisms, and (3) interactions of OM with minerals and metal ions. The model concept relates the diverse stabilization mechanisms to active, intermediate, and passive pools. The formation of the passive pool is regarded as hierarchical structured co-action of various processes that are active under specific pedogenetic conditions.
To evaluate the model, we used data of pool sizes and turnover times of soil OM fractions from horizons of two acid forest and two agricultural soils. Selective preservation of recalcitrant compounds is relevant in the active pool and particularly in soil horizons with high C contents. Biogenic aggregation preserves OM in the intermediate pool and is limited to topsoil horizons. Spatial inaccessibility due to the occlusion of OM in clay microstructures and due to the formation of hydrophobic surfaces stabilizes OM in the passive pool. If present, charcoal contributes to the passive pool mainly in topsoil horizons. The importance of organo-mineral interactions for OM stabilization in the passive pool is well-known and increases with soil depth. Hydrophobicity is particularly relevant in acid soils and in soils with considerable inputs of charcoal. We conclude that the stabilization potentials of soils are site- and horizon-specific. Furthermore, management affects key stabilization mechanisms. Tillage increases the importance of organo-mineral interactions for OM stabilization, and in Ap horizons with high microbial activity and C turnover, organo-mineral interactions can contribute to OM stabilization in the intermediate pool. The application of our model showed that we need a better understanding of processes causing spatial inaccessibility of OM to decomposers in the passive pool.