Previous project phases (2008 - 2017)
Dr. Marion Schrumpf
Dr. Ingo Schöning
Prof. Dr. Susan Trumbore
(MPI for Biogeochemistry, Jena)
Prof. Dr. Wolfgang W. Weisser
Land use and related above- and belowground productivity and biodiversity are assumed to modulate important soil processes and functions, such as organic carbon (OC) storage. With different work packages we will (1) evaluate to which extent soils carbon stores are affected by biotic and edaphic controls, (2) provide new insights into the key role played by roots for the storage of organic matter in soils, (3) determine the age of respired CO2 from mineral soil and use the combined information on soil carbon stocks, fluxes, and ages to model belowground carbon budgets.
Our project is embedded in the framework of the Biodiversity Exploratories research platform. The Biodiversity Exploratories provide the scientific infrastructure to study the impact of forest and grassland management on biodiversity and ecosystem functioning (Fischer et al. 2010). The study areas are located in North-, Central-, and South-Germany, in the Bioshere Reserves Schorfheide-Chorin and Schwäbische Alb, and in the Hainich National Park and its surroundings.
(1) We carried out a large scale soil carbon inventory at 3000 plots distributed over all Biodiversity Exploratories. Using geostatistics, digital terrain models, and soil maps the results of this carbon inventory will be extrapolated to determine the regional soil carbon budgets of the three Biodiversity Exploratories. With cross-calibrations the uncertainties of these budgets will be estimated. We will analyse how parent material, climate, land use management and related biodiversity affect soil carbon stores and develop strategies for a large scale soil carbon monitoring.
(2) In autumn 2011, we have established a large scale root litter decomposition study in each of the three Biodiversity-Eploratories using a standardized litterbag method for forest and grassland sites under different management, soil types and depths. We further intend to characterize the transfer of carbon and nitrogen from root litter into the soil by using stable isotopic labeling of living plants.
(3) Using an lab incubation approach and carbon models we will determine the carbon age in CO2 respired from soil samples. We assume that the age of the CO2 can be used as an early indicator for land use induced changes of soil carbon balances. For all samples, we will additionally determine abiotic variables such as soil pH, soil texture, cation exchange capacity (CEC), carbon and nitrogen content, and dithionite extractable Fe. In order to characterize microbial functions, enzyme activities (a-glucosidase, ß-glucosidase, phospatase, N-acetylglucosaminidase, a-cellulase, xylanase, peroxidase and phenol-oxidase) for forested sites will be analysed.
Joint soil sampling
In May 2011 we participated and co-organized a joint soil sampling of 10 soil groups at 300 plots of the Biodiversity-Exploratories. The Biodiversity Exploratories project follows an interdisciplinary approach and brings together botanists, zoologists, plant physiologists, microbiologists and soil scientists, all working at the same sites to achieve direct comparisons of their results. As soil fauna composition and activity often show a much higher spatial and temporal variability than the vegetation, a joint soil sampling was organized.