The present project is developed to analyze microbial litter decomposition in order to define parameters influencing decomposition rate and to identify the microbial populations and their activity.
Decomposition of plant litter is addressed through a combined effort of microbiologists, soil scientists and chemists. It is the aim to analyze the organic matter decomposition via population dynamics, changes in biomass and C and N pools and through humus fractionation, and also to identify indicator populations of functions to be used for assessing changes in land use.
The function and structure of microbial communities on litter and in soil is analyzed as a function of litter quality and quantity and under influence of soil physical and chemical factors with emphasis on water content and temperature. The plan for the project includes two agricultural soil types - silty and sandy - and a climate gradient from Denmark, through Bavaria and Austria to southern Italy. As organic substrate all participants will use a special maize litter enriched with 15N.
The actual decomposition experiments will be conducted as laboratory experiments as well as field testing. The controlled laboratory experiments with and without mixing of maize litter into the soil allow easy sampling including emission of CO2 and N2O. The field experiments will be less frequently sampled but will be helpful in understanding the decomposition processes on a larger scale.
The analytical work consists of fungal and bacterial isolation, identification and biomass determination, directly and by SIR-methods. Fumigation will be used for biomass determination and for extraction of C and N pools. Isotopic analysis will be used for determination of C and N pools and turn over and humus fractionation used for identifying the dynamics of decomposition.
Funding SchemeCSC - Cost-sharing contracts