GRK 1086 The Role of Biodiversity for Biogeochemical Cycles and Biotic Interactions in Temperate Deciduous Forests

Project description B5

Scientific advisors
Prof. Dr. H. Flessa

Project
Effects of nutrient cycling through litter of different broadleaved deciduous tree species on soil biochemical properties and the dynamics of carbon and nitrogen in soil

This project is focussed on the role of tree litter composition for nutrient availability in soils, neutralisation of soil acidity and the transformation processes of carbon (C) and nitrogen (N). The effects of different broadleaved tree species and species mixtures (e.g. Fagus sylvatica, Fraxinus excelsior, Tilia cordata and T. platyphyllos) on litter decomposition, soil acidity, exchangeable nutrients and carbon and nitrogen stocks in soils are analyzed in a field study in the Hainich National Park. Soil samples from selected cluster areas (see cluster design) with different tree species and species mixtures but similar soil parent material (loess over limestone) are sampled to determine species related effects on soil properties.
In addition a laboratory incubation experiment with 13C and 15N labelled leaf and root litter of beech and ash will be carried out to determine the effects of litter quality and litter mixtures on mineralization, transformation and partitioning of litter derived C and N in soil.
Together with the subprojects A1 (Jasmin Weiße), A4 (Verena Eißfeller) and B6 (Andrea Scheibe) we will analyse the partitioning of litter C and N within the microbial and mesofauna food web.
A in-situ 13C labelling experiment with young trees will be conducted together with the other subprojects to determine the fate of root-derived carbon in soil.

Methods


  • Determination of nutrient stocks and chemical and physical soil properties (analyses of soil texture, bulk density, concentrations and stocks of carbon, nitrogen and exchangeable cations, soil pH, soil acidity, composition of the litter layer)
  • Production of 13C and 15N labelled trees (beech and ash) in a greenhouse using 13C enriched CO2 and 15N labelled nutrient solution. Incubation of labelled and unlabelled leaf and root litter in different combinations. Analyses of CO2 production, δ13C of CO2, production and isotopic composition of DOC and DON, net-N mineralization, microbial biomass C and N and its isotopic composition, 13C and 15N in physically isolated soil fractions.