Introduction
Every year on December 5, the world celebrates World Soil Day (WSD) — a global event established by the Food and Agriculture Organization (FAO) of the United Nations to promote awareness about the importance of healthy soils. The theme for World Soil Day 2025 is “Healthy Soils for Healthy Cities,” emphasizing the critical role of soils not only in agriculture but also in creating sustainable, climate-resilient, and livable urban spaces. Soil is more than just dirt beneath our feet; it is a living ecosystem that sustains food production, filters water, supports biodiversity, and regulates the planet’s climate (Lal, 2020). Without healthy soils, there can be no sustainable future.
Why Soil Health Matters
Soil provides essential ecosystem services that are fundamental to life — it supports food production, regulates water, stores carbon, and nurtures biodiversity. A single gram of healthy soil can contain billions of microorganisms that decompose organic matter and recycle nutrients (FAO, 2015). These microorganisms maintain soil fertility, influence carbon dynamics, and sustain the productivity of ecosystems.
However, the world’s soils are under severe threat. According to the FAO (2020), over one-third of global soils are degraded, primarily due to erosion, nutrient depletion, compaction, salinization, and pollution. Degraded soils lose their ability to store carbon and water, contributing to desertification and climate instability (Smith et al., 2023). Healthy soils, by contrast, can store significant amounts of atmospheric carbon dioxide, thus acting as a natural climate regulator (Paustian et al., 2016).
The message of World Soil Day 2025 is clear: healthy soils are the foundation for a healthy planet, healthy food, and healthy people.
The 2025 Theme: Healthy Soils for Healthy Cities
Urban Soil and the Modern Challenge
By 2050, nearly 70% of the global population is expected to live in cities (UN, 2024). Urbanization brings development but often comes at a cost to soil health. Construction, paving, and industrial activities cause soil sealing, where natural surfaces are covered by asphalt and concrete. This process prevents water infiltration, reduces biological activity, and increases the risk of flooding and heat accumulation in cities (FAO, 2025).
Healthy urban soils, on the other hand, act as natural infrastructure. They regulate water by absorbing rainfall, filter pollutants, and support vegetation that cools the city environment. Green roofs, community gardens, and urban farms can help restore soil organic matter and biodiversity within city boundaries (Blanco-Canqui & Ruis, 2018). Thus, the 2025 theme “Healthy Soils for Healthy Cities” calls on communities and policymakers to integrate soil restoration into urban planning to build more resilient cities.
The Role of Soil in Sustainable Development
Healthy soils directly contribute to several United Nations Sustainable Development Goals (SDGs), including Zero Hunger (SDG 2), Sustainable Cities and Communities (SDG 11), and Climate Action (SDG 13). Soils are not only the foundation of agricultural productivity but also a key factor in water regulation, waste recycling, and carbon storage. Maintaining soil health ensures that these services continue to sustain life.
Soil degradation, however, has already affected more than 75% of agricultural land globally (FAO, 2020). Reversing this trend requires sustainable land management practices such as conservation tillage, cover cropping, organic amendments, and reduced soil disturbance (Lal, 2015). These practices enhance soil structure, prevent erosion, and improve resilience against climate extremes — lessons that can also be applied to urban landscapes.
Insights from Agricultural Research
While the 2025 theme focuses on urban soil management, much of what we know about soil restoration comes from agricultural research. My PhD research at The Ohio State University focuses on how long-term organic amendments and conservation practices influence soil physical and carbon dynamics under no-till management. The research, conducted in a 27-year field experiment in central Ohio, evaluates how compost, manure, and cover crops affect soil organic carbon (SOC), water retention, and structural stability under continuous corn production.
The findings demonstrate that compost and manure significantly enhance soil structure and water retention compared with untreated plots. These organic materials increase SOC, promote aggregate formation, and reduce bulk density — leading to healthier, more resilient soils. Similar principles can be applied in urban areas, where composting organic waste and planting vegetation can restore degraded soils and improve ecosystem functioning (Lal, 2021).
Healthy soil management is not limited to farmland; it is a universal strategy for sustainability in all environments.
Soil Health and Climate Resilience
Healthy soils are one of the most effective natural tools for climate change mitigation. Globally, soils store more carbon than the atmosphere and vegetation combined (Smith et al., 2023). By improving soil management, we can significantly increase this storage capacity. Practices that build soil organic matter — such as composting, mulching, and cover cropping — reduce greenhouse gas emissions and strengthen resilience to droughts and floods (Lal, 2020).
Urban soils can also contribute to climate adaptation by improving infiltration and reducing surface runoff. For instance, vegetated urban areas lower surface temperatures through evapotranspiration, while organic-rich soils retain water during heavy rainfall events. Restoring soil carbon not only supports plant growth but also enhances the overall livability of cities.
Urban Soil Restoration Strategies
Restoring urban soils requires both ecological and policy-based actions. Cities can adopt green infrastructure designs such as permeable pavements, rain gardens, and bioswales, which allow water to infiltrate into the soil rather than flow away as polluted runoff. Compost derived from household organic waste can be applied to parks and urban farms to restore soil fertility and biological life (FAO, 2025).
Soil testing and monitoring programs are essential to detect contamination and nutrient imbalances in urban soils. Replacing synthetic fertilizers with compost and encouraging native vegetation planting can help restore natural cycles. Policymakers and city planners should prioritize soil protection during construction and promote green zones that preserve topsoil and biodiversity.
Incorporating soil into urban planning is not merely an environmental concern but a public health and resilience strategy.
The Human and Social Value of Soil
Beyond its ecological importance, soil has a profound cultural and social significance. Access to green and fertile land improves mental well-being, fosters community engagement, and strengthens food security. Urban gardening, composting, and tree planting reconnect people with nature and cultivate a sense of stewardship.
In educational institutions, teaching soil science fosters environmental awareness among students. Public campaigns like World Soil Day encourage citizens to take simple actions — reducing waste, supporting composting, or planting trees — that collectively protect our most vital natural resource.
Soil and Food Security
Healthy soils are the cornerstone of food security. Nutrient-rich soils produce crops with better yield and nutritional quality (Lal, 2015). Practices that maintain soil organic matter, such as composting, crop rotation, and biochar use, ensure long-term fertility without heavy reliance on chemical fertilizers.
Urban agriculture initiatives, including rooftop gardens and raised beds, depend on fertile soil to produce food locally. Restored soils not only feed people but also strengthen community resilience, reduce food transport emissions, and close the organic waste loop.
A Global Call to Action
World Soil Day 2025 is not just a day of celebration but a call for global action. Governments, scientists, farmers, and citizens all share the responsibility of protecting soil. Sustainable practices like conservation agriculture, organic waste recycling, and urban greening are key solutions. Every action — from composting at home to implementing soil restoration policies — contributes to a healthier planet.
Healthy soils are our natural defense against hunger, climate instability, and biodiversity loss. Investing in soil health is investing in the future of humanity.
Conclusion
The 2025 theme, “Healthy Soils for Healthy Cities,” underscores the universal truth that life begins and depends on soil. Whether in farmlands or urban centers, healthy soils are essential for food security, environmental resilience, and human well-being. My research and that of many other soil scientists affirm that soil can recover when managed with care. Organic amendments, compost, and biochar offer practical solutions to restore fertility and sequester carbon in both rural and urban soils. On this World Soil Day 2025, let us recognize soil as the living foundation of our planet and take collective action to protect it — for healthy soils create healthy cities, and healthy cities sustain healthy lives.
References
- Blanco-Canqui, H., & Ruis, S. J. (2018). No-tillage and soil physical environment. Geoderma, 326, 164–200. https://doi.org/10.1016/j.geoderma.2018.04.011
- Food and Agriculture Organization of the United Nations (FAO). (2015). Status of the world’s soil resources: Main report. FAO, Rome.
- Food and Agriculture Organization of the United Nations (FAO). (2025). World Soil Day 2025: Healthy soils for healthy cities. FAO Press Release.
- Lal, R. (2015). Restoring soil quality to mitigate soil degradation. Sustainability, 7(5), 5875–5895. https://doi.org/10.3390/su7055875
- Lal, R. (2020). Soil organic matter and water retention. Journal of Soil and Water Conservation, 75(2), 27A–32A. https://doi.org/10.2489/jswc.75.2.27A
- Paustian, K., Lehmann, J., Ogle, S., Reay, D., Robertson, G. P., & Smith, P. (2016). Climate-smart soils. Nature, 532(7597), 49–57. https://doi.org/10.1038/nature17174
- Smith, P., House, J. I., Bustamante, M., Sobocká, J., Harper, R., Pan, G., & Powlson, D. (2023). Managing soils for climate and food security. Nature Reviews Earth & Environment, 4(3), 210–222. https://doi.org/10.1038/s43017-022-00464-5
- United Nations (UN). (2024). World Urbanization Prospects 2024: Highlights. United Nations Department of Economic and Social Affairs, New York.