Bertram, H.-G., Becker-Heidmann, P. (1986): Depth distributions of natural carbon isotopes to study organic matter dynamics in Alfisols and Spodosols. – In: International Society of Soil Science (Hg.): Transactions, S. 241–242
From the global view it should be of interest to know carbon dynamics of the soils of the world, because soil organic carbon is the most important part of the global carbon cycle. Small changes within this compartment are able to influence the other parts of the system in an extended way, as for instance the atmospheric carbon dioxide content, and to interfere the global equilibrium. Our investigations concentrate on Alfisols and Spodosols, which are characterized by accumulation and transport effects of organic matter, and therefore are also important in the light of managing of problem soils.
Several Scandinavian Spodosols and German Alfisols have been sampled in 2cm thin layers for 13C- and 14C-analysis resulting in high resolution depth distributions. δ13C increases with depth in the upper horizons in both soil types, indicating isotope fractionation by organic matter decomposition. The depth distribution of carbon isotopes in the lower horizons is influenced by clay organic matter complexation and/or fixation, drainage and groundwater table. 14C-dates supply the derived hypothesis. A model computes the amount of C, which is lost from carbon input by respiration. An attempt is described to characterize the state of pedogenesis in these profiles.