World Soil Day, celebrated on 5 December, serves as an annual reminder of the urgent need to protect one of the planet’s most essential yet quietest resources. Established by the FAO/UN, this date highlights the vulnerability of soils to erosion, desertification, biodiversity loss, contamination and climate change, reinforcing the idea that soil is a living, finite and irreplaceable system. At CESAM, this occasion carries particular significance, reflecting the continuous and multidisciplinary contribution of its research clusters to understanding, monitoring, conserving and restoring soils. To mark the date, CESAM is hosting a scientific and educational event dedicated to soil health, featuring recent research findings, outreach initiatives and an exhibition that underscores soil as a crucial resource for life on Earth.
Within CESAM’s research activities, several projects illustrate how science can support more balanced agricultural and forestry practices, develop circular bioeconomy solutions, assess environmental risks and propose strategies to rehabilitate degraded soils. Among these, the BioValChar project stands out, having explored the valorisation of residual forest biomass into biochar applied to soils, assessing its effects on microbial activity, carbon cycling and physicochemical soil properties. Results show that moderate doses of biochar substantially increase water retention (up to 334%) and sequestered carbon (up to 143%), while excessive applications may disrupt soil microbiota and intensify soil respiration (up to 783%). These findings demonstrate that circular solutions are only sustainable when applied with scientific rigour and clear safety thresholds.
Aligned with climate mitigation and sustainable soil management, the TRUESOIL project has been investigating the relationship between agricultural practices, carbon dynamics and greenhouse gas emissions in different soil types across climatic gradients. In biodiverse pastures enriched with biochar, a clear reduction in CO₂ and N₂O emissions was observed, together with increased carbon sequestration at depth and no rise in methane emissions, demonstrating that agricultural productivity can be compatible with effective carbon sequestration strategies.
Complementing these efforts, the SOILSPONGE project aims to strengthen the soil’s capacity to store water—its “sponge function”—through soil engineering with biochar. Experimental studies show significant increases in infiltration and soil moisture, along with strong reductions in erosion, paving the way for the application of these solutions in Mediterranean landscapes affected by drought and extreme weather events, where desertification is an escalating threat.
In the interior of the Iberian Peninsula, the Soil@INT project is developing an innovative soil health monitoring system that combines field measurements, high-resolution imagery and machine learning methods. This approach enables early detection of degradation signals, the establishment of reference conditions and the support of strategic land management decisions, strengthening the ecological and socioeconomic resilience of vulnerable regions.
The connection between science and society—another core axis of CESAM—was strongly visible in the “Painting with Soil” activity carried out within the European projects CURIOSOIL and TERRASAFE (curiosoil.eu; terrasafe.eu), funded by the EU Soil Mission. Using natural soil pigments, primary school students created artworks illustrating the contrast between healthy soils and soils at risk of desertification. This hands-on experience showed that creative and sensory approaches enhance soil literacy among younger generations, fostering emotional connection to nature and encouraging responsible behaviours. The artworks will be displayed at tomorrow’s commemorative event, symbolising the intersection of science, education and community.
From 2026 onwards, CESAM will further strengthen this research line through the LIFT project, dedicated to exploring the potential of white-rot fungi as a natural solution for restoring soils degraded by salinisation or contamination. Preliminary results indicate that these fungi promote plant growth under high salinity and stabilise soils affected by mining residues, reducing toxic elements and enhancing biological activity. This work highlights the potential of fungi-based technologies to restore soil health and support more resilient agri-food systems.
In parallel, CESAM’s research also evaluates the risks associated with persistent agricultural contaminants, such as triazole fungicides, whose presence in the environment can affect key soil organisms. Recent studies show that cyproconazole (CPZ), even at environmentally realistic concentrations, alters multiple neurophysiological, metabolic and antioxidant biomarkers in Eisenia fetida, a key organism in soil structuring. These results reveal that commonly used agricultural compounds may compromise vital ecosystem services, emphasising the need for careful, evidence-based management practices.
Altogether, these projects demonstrate that soil is a living infrastructure essential to ecological stability, human well-being and the economy. Protecting this resource requires an understanding of its limits, the restoration of compromised functions and the establishment of sustainable practices that safeguard biodiversity, food security and climate resilience. On this World Soil Day, CESAM reaffirms its commitment to generating robust, socially relevant scientific knowledge that contributes to the regeneration and sustainable use of this irreplaceable resource.
Amadeu Soares, Director of CESAM, notes that “Marking World Soil Day is above all an acknowledgment of the vital importance of this discreet resource, essential to environmental balance and human activities. At CESAM, we work to generate rigorous knowledge that supports soil conservation, monitoring and restoration. Science provides the foundations necessary for responsible decision-making and for a management approach that respects the limits of this irreplaceable resource.”
