Wissenschaftliche Bearbeitung durch:
(MPI für Biogeochemie Jena)
Land use and related productivity and biodiversity are assumed to modulate important soil processes and functions such as soil organic carbon (OC) sequestration. With different work packages we
(1) study litter production in forests and grasslands,
(2) monitor basic soil properties affecting species diversity and soil functions,
(3) analyze links between organic matter mineralization and nutrient cycling in soils,
(4) study the formation and turnover of mineral associated soil organic matter.
Carbon and nutrient fluxes to soils are controlled by above- and belowground litter inputs. We determine the role of climate, soil fertility, forest management, and tree species composition for annual leaf litter production. The measurements of aboveground litter fall are complemented by analyses of root production at selected sites.
Repeated soil sampling campaigns are the fundament for the soil monitoring conducted in the Biodiversity Exploratories. We co-organize and participate in the 3rd soil sampling campaign at all 300 Experimental Plots. Soil properties such as bulk density, root biomass, soil acidity (pH?), and elemental contents (C, N and S) are determined for all sites. In addition, we measure microbial biomass and activities of extracellular enzymes involved in the carbon, nitrogen, phosphorus and sulphur cycle. By quantifying temporal changes in soil OC and radiocarbon (14C) content over time, we are able to identify how study region, land use, and management affect the active portion of OC in soils.
Land use and its intensity are major determinants of soil biodiversity and related soil organic matter decomposition. We explore how the production of extracellular enzyme activities and the mineralization rates of carbon and nutrients are related to grassland and forest management, site fertility and the composition of the decomposer community. As the mineralization in soils might be limited by energy or nutrients, the response of microorganisms (production of CO2 and extracellular enzymes) to the addition of easily available, 13C labeled, carbon sources and fertilization is evaluated (priming effects).
Large amounts of OC in soils are stabilized by interaction with minerals. The sorption of OC to new mineral surfaces under different land use and management intensities is studied by a novel method of ‘mineral bags’ in which well characterized mineral surfaces are placed in soils and then monitored for changes in OC over time. The persistence of mineral associated organic carbon is studied with 13C labeled soil organic matter.