Autor:innen:
Lena Philipp | Helmholtz Center for Environmental Research – UFZ Halle, Germany/ Leipzig University, Germany | Germany
Evgenia Blagodatskaya | Helmholtz Center for Environmental Research – UFZ Halle, Germany
Martin Schädler | Helmholtz Centre for Environmental Research, Halle, Germany/German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Germany
Marie Sünnemann | German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Germany/ Leipzig University
Thomas Reitz | Helmholtz Centre for Environmental Research, Halle, Germany/German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Germany
In agroecosystems, soil bacteria and fungi are crucial for ecosystem functioning through major contribution to decomposition of organic matter, element cycling and nutrient provisioning for plant growth. However, land use intensification and climate change pose increasing threats to soil biodiversity and thus to ecosystem functioning.
Here we investigated the single and interacting effects of land use and climate change on soil functioning using the Global Change Experimental Facility (GCEF) in Bad Lauchstädt. In this field experiment, two croplands (conventional and organic farming), and three grasslands (intensive meadow, extensive meadow and extensive pasture) are exposed to ambient as well as to predicted future climatic conditions. We collected soil samples from three depth layers of all treatments in May 2022 and determined abiotic soil properties (pH and C, N, P, K content). Microbial community structure in the different soils was analyzed through amplicon sequencing (16S, ITS). Further, the microbial activity was assessed by respiration and the activities of enzymes involved in different element cycles.
We observed strong differences in enzymatic activities among land use treatments in the uppermost soil layer with the lowest activity in the organic farming soil. However, this pattern was inverted in the deeper soil layers. While we observed a significant decrease of enzymatic activity with increasing soil depth in all other land use types, the activity indices of the organic farming soil remained on a higher level, by what the organic farming soil showed the highest activity along all land use types in the two deeper soil layers. These observations were mirrored by the microbial biomass and basal respiration. Moreover, the observed activity pattern along the treatments were strongly linked to changes in the structural composition of fungal and bacterial communities. Surprisingly, and although some soil properties as well as the community composition were significantly affected by climate change, we could not find a significant effect of the climate treatment on microbial activity indices.
With this work we contribute to elucidate the global change impacts on soil functioning. As part of a joint project (GLIMPSE), we will link our results to other ecosystem compartments (plant community, soil-root-interface) in a systemic soil model that will simulate different global change scenarios.