DeepHorizon · DEploying Ecosystemic solutions to imProve soil Health and uncOveRing subsoil functIons in the critical ZONe

Life on Earth thrives on the foundation of healthy soils, including topsoil and subsoil. While extensive research has focused on the topsoil layer, the subsoils remain largely unexplored. By bringing together key experts and practitioners, DeepHorizon aims to unlock knowledge of the subsoil in critical zone in order to deploy ecosystemic solutions to improve subsoil functions for soil health. DeepHorizon goal is to develop tools that will enable practitioners, land managers and policy makers to access subsoil properties, subsoil functions, soil health indicators and financial decision support tools to promote sustainable subsoil management. Through a multi-actors approach from farmers to policy makers, DeepHorizon will (1) collect and use existing data on subsoils; (2) generate new knowledge through extensive subsoil sampling and experimental effort (40 core sites) to measure biological, physical and chemical properties of different subsoils with contrasted management, and different soil type (organic/mineral), land uses (forest, grassland, cropland and semi-natural areas) and climate ; (3) use innovative process-based models to quantify actual and potential subsoil functioning, and soil health indicators; and (4) involve practitioners and stakeholders in the project through living labs and partner networks to co-create, test and deploy innovative solutions to improve subsoil functions over 100 test sites across Europe. By creating its own community of end-users and key stakeholders, DeepHorizon will ultimately promote sustainable management practices, policy-incentives and guidelines at EU level for increasing carbon storage and ecosystem services in subsoils and disseminate and communicate materials to a better understanding of subsoil relevance to the general public. By improving knowledge and consideration of subsoils in general, DeepHorizon will enhance soil health and pave the way for a more sustainable and resilient environment in Europe.