From Proceedings to Actions: European Healthy Soils Conference 2023

From September 13 to 15, 2023, the first edition of the European Healthy Soils Conference took place at the FHNW School of Life Sciences in Muttenz, close to Basel, Switzerland. The conference program, focusing on soil fertility, was put together by experts from industry, academia, the Swiss Federal Office for the Environment, and the Food and Agricultural Organisation of the United Nations. The setting of this conference was unique as it brought together stakeholders from most if not all relevant areas engaged in the promotion of soil health: scientists, representatives from industry, the agricultural sector as well as the public and regulatory sector.

The contributions to this special issue of EJSS are meant to reflect the sprit, content, and topics discussed during this conference and gives tribute to the quality of science and interactions that took place. Healthy soils are in many ways the foundation of our economy, and our culture. They are not only a basis of our food production but also fulfil numerous other functions as they enable microbial, animal and plant biodiversity, purify and store water, and modulate increasingly alarming greenhouse gas emissions. Despite these well-known benefits, healthy soils are under pressure from intensive agriculture, sealing and pollution; from extreme environmental events; and from carbon loss. We therefore must develop means to sustain healthy soils, not only in Europe but across the world. What determines a healthy soil? How can we understand, monitor and maintain soil diversity? What is the underlying chemistry, biology and soil physical structure required to maintain sustainable crop cultivation and management? What are the main challenges to healthy soils? How is climate change challenging soil health, and how can healthy soils help mitigating climate change?

Over 30 international speakers, 40 poster presentations, and all participants addressed and discussed these topics and questions. The conference's opening lecture by Peter Wehrheim (European Commission, DG Research & Innovation, Food Systems and Bioeconomy) provided a European perspective and highlighted the importance of the conference topic. His talk "The EU mission—A Soil Deal for Europe" outlined how the mission will support the transition towards healthy soils by 2030 by putting in place an effective network of 100 living labs and lighthouses in rural and urban areas.

In the first session “Soil Diversity”, Peter Schad (TU Munich) and Sebastian Dötterl (ETH Zürich) presented the multiple environments on our planet which promote the formation of extremely diverse and fascinating soil types through physical and biological processes.

In the second session “Chemistry and Microbiology in Agronomical Soils for Sustainable Crop Cultivation”, Katie Field (University of Sheffield) discussed the effect of climate change on mycorrhizal fungi symbiosis function in crop fields and Elena Biagi (University of Bologna) likewise reported on how compost-based soil amendments impact soil biology and eventually crop quality. Franz Bender (Agroscope) illustrated soil's biological activity through the decomposition rate of buried cotton underpants in a Swiss nationwide study involving 1000 citizens. Mattias Rillig (Freie Universität Berlin) analysed how multiple environmental factors threaten soil health and biodiversity.

Giulia Gregori (Novamont) kicked off the third session “Today's Challenges to Soil Health”. In her lecture Soil regeneration and circular bioeconomy she emphasised not only the importance of healthy soils as a basis for a functioning and prospering circular economy, but also additional multi-stakeholder efforts required to move towards a sustainable European economy. In his talk, Niels Halberg (Aarhus University) followed-up on Peter Wehrheim's opening lecture and further detailed the The EU mission ‘A Soil Deal for Europe’ focusing on eight objectives including reducing desertification, soil sealing and soil pollution, conserving soil organic carbon, improving soil structure and biodiversity, preventing erosion and enhancing restoration. He highlighted the establishment of 100 Living Labs (LLs) and Lighthouses across all land uses: agricultural, forestry, natural, industrial and urban sites. The session concluded with a plenary lecture from Natalia Rodriguez Eugenio (FAO) discussing the global fertiliser crisis, looking at the challenge that reduced access to high quality fertilisers poses to food production, as well as the opportunities provided by more sustainable alternatives with reduced environmental impact.

The fourth session was dedicated to the topic “Soil and Climate Change: Interactions of Soil with Water and Atmosphere”. In his contribution, Axel Don (Thünen Institute of Climate-Smart Agriculture) discussed the opportunities and limitations of natural carbon sequestration in soils and their potential to partially mitigate the greenhouse gas emissions associated with modern agriculture.

In her closing plenary lecture, Serenella Sala (European Commission, Joint Research Centre, Land Resource and Supply Chain Assessments Unit) discussed the role of the EU Soil Observatory for collecting and analysing soil data to support soil management and precision agricultural practices to improve soil health across European countries.

In addition to those and other short talks and poster contributions, two workshops engaged participants during the conference: A pre-conference workshop dug into the topic “Upscaling regenerative agriculture” with input talks form Pascal Boivin (HEIPA), Bastian Sachet (Earthworm), Thomas Peyrachon (Nestle), Niall Curley (COPA Cogeca) and Luis Sanchez Alvarez (EU Commission), each presenting their organisation's programs towards scaling regenerative agriculture.

A second workshop addressed the question of soil health indicators: what are the biggest threats to healthy soils? And what indeed is a healthy soil and how to define the health of a soil? Collecting meaningful data across diverse soil environments is both a challenge, but also a prerequisite to recognise and understand trends in soil-health changes; some of the outcomes of this workshop are summarised in this special issue.

While the articles in this special issue cannot cover all the contributions and discussions that took place during this exciting first edition of the European Healthy Soils Conference Series, they do provide representative examples of the outstanding science reported at the conference, current activities taking place in Europe.

In the contribution Soil health—From practical issues to indicators: A workshop at the 1st European Healthy Soils Conference, Hitzfeld, Rodríguez Eugenio, and Wissemeier (2024) discuss the outcome of the their workshop; a majority of participants agreed that healthy soils are essential for ecosystem services, identifying soil erosion, loss of organic carbon, loss of biodiversity, and compaction as key threats, while emphasising the need for long-term monitoring and simplified methods for practical use by farmers and advisors.

In their article NETmicroplastic in agricultural soil and its impact on soil properties, Preininger, Hackl, and Stagl (2024) discuss the effort to consolidated various research findings, detection methods and political guideline in order to understand and reduce the increasing threat of microplastic in modern agriculture.

Nikolaos-Christos Vavlas and his team report in their contribution Remote sensing of cover crop legacies on main crop N-uptake dynamics (Vavlas et al. 2024) the benefits of remote sensing to explore how different cover crop monocultures and mixtures affect soil nitrogen availability and barley nitrogen uptake over time. They conclude that cover crop legacies significantly influenced barley's nitrogen uptake, biomass, and canopy nitrogen content, highlighting the potential of remote sensing to optimise nitrogen management and improve soil health.

The importance of soil monitoring is evident also in the contribution of Panagos et al. (2024). They summarise in their article How the EU Soil Observatory is providing solid science for healthy soils the functioning and the objectives of the EU Soil Observatory, which was established in 2021 in support of the European Green Deal.

In support of precision farming, advances in the measurements of concentrations of relevant soil components and nutrients is discussed in the communication of Metzger and Bragazza (2024) Prediction of nitrogen, active carbon, and organic carbon-to-clay ratio in agricultural soils by in-situ spectroscopy.

Of equal importance are the concentrations of pesticide residues in agriculturally utilised soils as they can have a profound impact on soil's habitat for beneficial organisms. Mathieu Renaud and his team discuss a Swiss effort to monitor plant protection products in soils in their contribution The ConSoil project: An integrated framework for monitoring plant protection product residues in agricultural soil (Renaud et al. 2024).

While monitoring health of today's soil is important, predictive tools are an important asset for scientists and regulators to suggest actions to promote soil's future health. In their article A nature-inclusive future with healthy soils? Mapping soil organic matter in 2050 in the Netherlands, Anatol Helfenstein et al. critically evaluate machine learning tools to predict future soil organic matter (Helfenstein et al. 2024).

In their spectrum and diversity, the contributions to this special issue of EJSS reflect the ambition of the conference to bring together stakeholders from soil sciences, the agricultural sector, and the public and European Commission's policymakers in a setting that allowed for intense and forward-looking discussion among the approximately 150 participants. Healthy soils are threatened by numerous factors, many of which we are only starting to understand. It is only by sharing policy strategy, economic and societal needs on one side, and fundamental science about the complexity and diversity of soil on the other side, that we can develop and implement ideas to secure healthy soils for future generations.

We are looking forward to the second edition of the conference, currently scheduled for Fall 2026.

December 2024.

Sebastian Wendeborn.

Conference Chair the European Healthy Soils Conference, first edition.

Guest Editor for this Special Issue of EJSS.

Sebastian Wendeborn: conceptualization (lead), writing – original draft (lead).