A crisis beneath our feet

What is the state of soil worldwide?

Anneke Trux: Every second, healthy soil the size of four soccer pitches is lost worldwide - that's a total of 100 million hectares per year. Experts call this “soil degradation”. The commitment of current and future generations is more important than ever to halt and reverse this trend and meet global commitments to restore one billion hectares of degraded land by 2030. This is crucial to feed a growing world population. At the same time, a third of the world's land is already severely degraded. This directly affects 3.2 billion people, especially smallholder farmers in rural areas, often the poorest of the poor.And what does our agriculture and land use have to do with it?

Trux: Agriculture and land use can be the cause of poor soil health, but they also offer numerous solutions. Unsustainable monocultures and soil management, overgrazing and deforestation put soils under considerable stress. They are also under increasing pressure from climate change. Loss of humus and nutrients from soils is a critical problem. This is exacerbated by flooding or wind in dry regions with little vegetation, which in turn reduces the water storage capacity of the soil. This increases the risk of soil erosion, the loss of fertile soil. In Germany, land use is another decisive factor: a significant problem is that fertile soils are being converted into cultivated land at an ever faster rate, for example through the construction of roads, residential buildings or industrial plants. Pressure on producer prices and sometimes contradictory regulations do not make it easy for farmers to invest in soil health.

How can degraded soils be revitalized?

Trux: Soil is the most species-rich habitat on earth. It consists of water, minerals, air and organic matter such as roots, humus and soil organisms. Nutrients, humus and diverse soil organisms are in short supply in degraded soil. One square meter of healthy soil contains more living organisms than there are people in the world. In order for them to survive or return to life, the soil first needs nutrients - for example from compost or green waste. In the project, we combine several methods: We plant ground-covering plants, regularly rotate the types of plants grown and use worm compost to make the soil fertile. Sparing but targeted use of mineral fertilizers can help to compensate for any remaining nutrient deficiencies. Soil protection should be part of agricultural training. Laws and financial incentives can also help to make soil restoration worthwhile.

How can we better protect soils from climate change in the future?

Trux: One best-practice example is the rehabilitation of degraded dry valleys in Ethiopia with so-called “river sills”. These are stone walls that lie in a cascade across the dry valleys and slow down the floods during the rainy season. Water seeps into the soil, fertile alluvial material is deposited and forms new arable land behind the stone walls. In this way, farmers can control the climate risk of extreme flooding and the groundwater is replenished. New green landscapes are being created that can provide food for up to 6,000 people in a dry valley. Since 2020, we have been measuring how much carbon is stored in the soil. In 2024 alone, we were able to save 725,000 tons of CO₂ - as much as 67,000 people in Europe emit each year. The costs of such measures are high, but the high potential yields make them economically viable after just three years.

One way to achieve environmentally and climate-friendly agriculture is agroecology - which is also a focus of your project. What exactly does that mean?

Trux: Agroecology is a holistic approach - from farm to fork, which also takes into account aspects of justice in the agricultural and food system. The market and politics are important instruments for controlling this. For German development cooperation projects, this means integrating approaches such as crop rotation, soil cover or organic inputs such as biochar or worm compost into the education and training of farmers, but also enabling the processing of urban waste into compost and the exchange of people who want to bring about a change towards sustainable agricultural and food systems. Together with our teams in the respective countries, we have created a cookbook with information on the plants that promote soil health. This is another small piece of the puzzle towards fairer and more regional food systems.

With your project, you are active in seven countries in Africa and Asia. What can we in Germany learn from countries in the global South?

Trux: In my observation, soil protection has moved to the top of the political agenda in many countries of the global South in recent years. Agriculture is an important economic sector that provides income and employment for a large part of the population. The issue is taken more seriously than it is here in Germany. We often still find it difficult to recognize soil protection as a political issue. But it is an issue that concerns all of us in terms of global food security. We can learn from our partner countries in this respect.

Our soils are also affected by droughts and other extreme weather conditions. What would you advise the amateur gardeners among our readers to do to better protect and preserve our soils?

Trux: One piece of advice: remove the term “green waste” from your vocabulary and your Saturday activities. Tree cuttings, hedge cuttings, lawn cuttings and organic kitchen scraps in the garden are not waste, but raw material for valuable compost or mulch. So save yourself a trip to the green waste yard. Share a shredder with neighbors. Make sure that the soil in your garden is not bare and tidy, but is covered by plants all year round. Create a raised bed. Enjoy earthworms and insects. Don't plant water-hungry exotic plants, but choose plants that attract insects and survive prolonged drought without the need for regular watering. Enjoy a bit of wilderness in your garden.