Project R-4574

Ectomycorrhizal fungi: fueling the belowground carbon cycle (Research)

Most trees in temperate and boreal forests live in symbiotic relationship with ectomycorrhizal (EcM) fungi. They receive up to 25% of fixed C from their host plant, similar to the plant investment in plant biomass, making the EcM pathway an equally important energy flow into the soil as plant litter. In relation to the soil carbon balance, the flow of plant energy into ectomycorrhizal fungi has traditionally been considered as a contribution to the soil carbon pool via the production of fungal biomass. On the other hand, there is growing evidence that this flux of easy metabolizable energy induces ('priming') the decomposition of more complex soil organic matter. Soils store a major part of total carbon present on earth. Small deviations in plant productivity (input) and soil respiration (output) can have major effects on the global carbon cycle. Evaluation of land management and environmental effects on the soil carbon balance is dependent on computer models, because direct measurements are difficult due to insensitivity of current analytical methods. But the models used, e.g. for EU legislations and policymaking, do not take into account EcM interactions with soil carbon. The objective of this project is to elucidate and quantify the positive and negative effects of EcM fungi on the soil carbon balance. A combined modeling/experimental approach will be used. Model simulations will be compared with measurements from locations with contrasting EcM and non-EcM vegetation.

01 October 2012 - 30 September 2015