Every year, the world loses billions of tonnes of topsoil to overgrazing, deforestation, pollution and other threats.
That, say experts, is a worrying trend. Soil supports the vast majority of the food humanity eats. It is one of the most important warehouses of planet-warming carbon. And, according to a recent study in the journal Nature, it is home to nearly 60 per cent of all species.
Soil is a hot topic as countries gather in Riyadh, Saudi Arabia for the 16th Conference of the Parties (COP16) to the UN Convention to Combat Desertification (UNCCD). Negotiators are slated to discuss commitments that nations have made to stem the loss of soil and achieve land degradation neutrality by 2030.
“Soil degradation impacts food security, water systems, biodiversity and climate resilience,” said Bruno Pozzi, Deputy Director of the Ecosystems Division at the United Nations Environment Programme (UNEP). “By addressing the root causes of soil degradation, we can restore soil health and create a more sustainable future for hundreds of millions of people.”
On World Soil Day, celebrated annually on 5 December, here are five key reasons for the decline in soil health and potential solutions.
1. Drought
Over one-third of the world’s population lives in water-scarce regions, according to the UNCCD’s Global Land Outlook report. As land degrades, soil loses its ability to retain water, leading to vegetation loss and creating a vicious cycle of drought and erosion. This issue, exacerbated by climate change, is particularly severe in Sub-Saharan Africa, contributing to food insecurity and famine.
Through water management practices, such as drip irrigation and rainwater harvesting, and ecosystem restoration, communities can improve soil moisture and reduce the impact of drought.
2. Land degradation
Human activity has altered more than 70 per cent of the Earth’s land, causing widespread degradation of forests, peatlands, and grasslands to name a few ecosystems. This diminishes soil fertility, reduces crop yields and threatens food security.
Extreme weather events, such as heavy rains followed by drought, accelerate degradation, while deforestation and overgrazing reduce soil quality by compacting it and depleting essential nutrients.
To combat this, practices like adding compost and organic materials to soil, improving irrigation techniques and using mulching to maintain moisture are essential. Restoring soil health through conservation agriculture also helps prevent further land degradation.
3. Industrial farming
While industrial farming produces large volumes of food, it significantly harms soil health. The use of heavy machinery, tilling, monocropping, and excessive pesticide and fertilizer use degrades soil quality, pollutes water sources and contributes to biodiversity loss. Industrial agriculture also accounts for about 22 per cent of global greenhouse gas emissions.
Sustainable practices, such as zero-tillage, the reintroduction of animals into cropping systems, crop diversification and the incorporation of organic matter, can help preserve soil integrity and kick-start dormant soil biology. Shifting to no-till farming, using cover crops and integrating trees and shrubs with crops can improve soil structure, prevent erosion and enhance fertility.
For example, many countries in Africa are adopting the “forest garden” model which incorporates trees and shrubs into agricultural systems with the goal of building soil fertility and boosting the yields of smallholder farmers.
4. Chemicals and pollution
Soil pollution, often invisible, harms plant, animal and human health. Industrial processes, mining, poor waste management and unsustainable farming practices introduce chemicals, like synthetic fertilizers, pesticides, and heavy metals, into the soil.
Excessive fertilizer use disrupts nutrient balance, while pesticides harm beneficial soil organisms, like earthworms and fungi. Heavy metals, like lead and mercury, accumulate in the soil, interfering with microbial activity and plant nutrient uptake.
Reducing pollution, minimizing chemical use and promoting organic farming can restore soil’s vitality.
5. Diet and nutrition
The world’s current diet and nutritional choices significantly affect soil health through the agricultural practices used to produce food. Diets reliant on staple crops, like wheat, corn and rice, often promote intensive monoculture farming. This practice depletes soil nutrients, reduces organic matter, and leads to compaction and erosion.
Similarly, diets high in animal products, particularly beef, increase land use for grazing and feed crops. Overgrazing by livestock exacerbates soil compaction and erosion. Transitioning to diverse, plant-based diets can lessen the demand for intensive farming. By aligning dietary habits with sustainable agricultural practices, countries can enhance soil health and ensure long-term food security.
About the UN Decade on Ecosystem Restoration
The United Nations General Assembly has declared the years 2021 through 2030 the UN Decade on Ecosystem Restoration. Led by the UN Environment Programme and the Food and Agriculture Organization of the UN, together with the support of partners, it is designed to prevent, halt, and reverse the loss and degradation of ecosystems worldwide. It aims at reviving billions of hectares, covering terrestrial as well as aquatic ecosystems. A global call to action, the UN Decade draws together political support, scientific research, and financial muscle to massively scale up restoration.
