Dynamic of soil organic matter und element fluxes

DFG FOR 562 TP 4: (2005-2008)

From 04/2005 to 10/2008

Principal Investigator: Werner Borken, Egbert Matzner
Staff: Kerstin Schulze, Uwe Hell, Bruno Glaser, Andrea Schmitt
Grant: FOR 562 Dynamics of soil processes under extreme meteorological boundary conditions

The frequency of prolonged summer droughts with subsequent heavy rainfall or intensive soil frost and thaw events are likely to increase globally in the next decades IPCC (2001). These extreme events may rapidly increase the microbial availability of soil organic matter, which can trigger changes within the ecosystems as well as changes of adjacent systems in the long run. The objectives of this project are the identification and quantification of available carbon, nitrogen and metal cation pools in the soil matrix and soil solution of a spruce forest and a fen. Field experiments and laboratory experiments with undisturbed soil columns will be performed to evaluate the effect of intensity and frequency of dry-wet and frost-thaw cycles on carbon, nitrogen and element turnover and fluxes. Origin, stability and age of dissolved and particulate organic matter will be determined by analysis of plant and microbial biomarker, stable isotopes and radiocarbon. The effect of the experimental manipulations on structural properties of dissolved organic matter will be assessed by fluorescence, UV und ¹³C-NMR spectroscopy.