Soil multifunctionality: from biodiversity associations to understanding mechanisms

ended

Humanity places large demands on its cultivable soils for specific functions, e.g. food production, at the expense of the capacity of soils to provide multiple functions (carbon storage, biodiversity). However, currently multifunctionality is studied without considering the mechanistic linkages among individual soil functions. All soil functions depend on three key resources: energy, nutrients and water, producing critical trade-offs and synergies among functions. Furthermore, we lack a common measurement framework to assess soil multifunctionality. I propose to address these two challenges by 1) developing a soil multifunctionality assay that combines existing measurement techniques with latent variable models, and 2) causal modelling to test how different soil functions interlink across different soil types. I will sample grasslands across intensive-extensive land use gradients that are representative of NW European edaphic and management conditions as my study system. I will use latent variable models conditioned on multiple indicators per soil function, to develop a standardized testing procedure measuring five key soil functions (plant production, nutrient cycling, carbon and water storage, and habitat provision). Next, I will combine this standardized procedure with structural-causal modelling to test the role of resource division during plant-microbe-soil interactions in determining which functions predominate. My MSCA-project will elucidate the mechanisms underlying trade-offs and synergies among soil functions and reveal how differences among soils drive differences in soil multifunctionality.