The function of the hyphosphere in carbon and nutrient partitioning between plants and microorganisms in grassland soils under different land-use intensities

Experiments 1 and 2: Carbon flow from plants to the hyphosphere and nutrient flow from the hyphosphere to the plants and back

The goals of these experiments are to understand (i) which fungi benefit most from plant-derived carbon in grassland ecosystems and which fungi are responsible for the ‘long-distance’ transport (>15 mm) of carbon, thereby providing resources for bacteria as secondary consumers (Fig. 2a), and (ii) which fungi are responsible for the transport ¹³C and ¹⁵N from the detritusphere through the hyphosphere to the rhizosphere (Fig. 2b). We will use a ¹³CO₂ pulse labelling approach to quantify the carbon flux of plant-fixed C into fungi and their associated bacteria, and a ¹³C and ¹⁵N labelling in the detritusphere compartment will allow us to measure long-term ¹³C and ¹⁵N incorporation in the microbial biomass as well as its transfer to the plant biomass.

Experiment 3: De-intensification of grassland sites – Direct versus indirect effects on soil microorganisms (multi-grassland land-use experiments)

De-intensification of land use may drive changes in microbial communities and in the soil functions they regulate. The newly established multi-grassland land-use experiments (Fig. 3) will make it possible to identify the direct and indirect mechanisms that may contribute to changes in microbial abundance and function.