Uni-Bayreuth grafik-uni-bayreuth



Dynamics of soil processes under extreme meteorological boundary conditions

Given the climate scenarios, we expect in future an increasing frequency of extreme meteorological boundary conditions that result in a higher frequency of drying/rewetting and freezing/thawing of soils. The latter might be especially relevant in higher elevation sites. Such drastic changes of the meteorological boundary conditions to soils, which occur irregularly and with varying intensity are obviously influencing the turnover of C, N and S in soils to a larger extend than previously thought. Our knowledge about the mechanisms and relevance of such conditions for soil processes is very limited. One reason for that is the lack of field experiments.
The goal of the DFG Research Group is thus to investigate:
  • Which are the consequences of extreme meteorological boundary conditions for the element turnover and -output from soils as well as for microbial communities and roots?
  • What is the effect of different intensities of drying and frost?
  • What are the physical, biological and chemical mechanisms that cause the effects?
These questions can only be addressed by an interdisciplinary Research Group comprising soil scientists, hydrologists, microbiologists and plant ecologists. In a Norway Spruce forest (Podsol) and a fen (Histosol) we will experimentally initiate drying by roof construction and drainage, respectively, followed by controlled rewetting. Frost intensity of the forest soil will be enlarged by removal of the snow cover. In addition, laboratory experiments with soil columns will be conducted. The focus is on the emission of trace gases, the transport in solution and the related processes (C- and N-mineralization, nitrification, denitrification, DOC-release, methanogenesis, redoxreactions of S and Fe, formation of flow paths). Mechanisms will be investigated by identifying reactive soil fractions, by following root turnover and microbial community changes. Advanced methods, like component specific 13C, 15N, 18O analysis, determination of 14C age, biomarker and molecular analyses will be used. We expect that this research will substantially enhance our understanding of soil processes in general.
Through the joined field and laboratory experiments, coordinated sampling and data evaluation of results, the Research Group will gain a maximum of synergism, integration and innovation.

Coordination: Prof. Egbert Matzner , University of Bayreuth, Dept. of Soil Ecology mail

contact: Bayreuth Center of Ecology and Environmental Research - BayCEER Tel. (+49)(0)921 / 55 57 00, mail

last modified 2005-03-31