Soil Degradation in East Africa: A Growing Crisis
A 2025 soil assessment released by the Heinrich Boll Foundation, a German think‑tank known for rigorous environmental research, found that more than 40 percent of East Africa’s soils are degraded. The report estimates that this degradation translates to an annual loss of over US $65 billion in agricultural productivity across the region.
The study attributes the decline to a combination of factors, chief among them the overuse of synthetic fertilisers, shifting climate patterns, and intensive farming practices that strip organic matter from the soil.
The Role of Chemical Fertilisers and Rising Costs
Synthetic fertilisers have long been promoted as a quick fix for low yields, but they often create a vicious cycle. As Robert Mwangi, a farmer in Nakuru County, explains, “the more you use it, the more the productivity of the soil goes down, because it creates an acidic environment which is not good for the microbes that are responsible for maintaining and improving soil fertility.”
In 2026, fertiliser prices spiked further after the outbreak of conflict in the Middle East, which disrupted global supply chains. This price shock has pushed many smallholders to seek cheaper, locally sourced alternatives.
Kenyan Farmers Turn to Vermicompost
In Kenya’s central highlands, where 32 percent of cropland is classified as strongly acidic (Heinrich Boll Foundation, 2025), farmers like George Muturi Kamau have adopted vermicomposting as a practical solution.
Muturi’s system consists of about 70 wooden beds, each teeming with at least 5,000 redworms (Eisenia fetida). The beds are layered with food scraps, crop residues, and cow dung, which the worms break down over roughly six weeks into a dark, nutrient‑rich material known as vermicompost.
- Improves soil structure and water retention.
- Increases organic matter content, helping to neutralise acidity.
- Boosts crop yields even during dry spells, according to Muturi’s field observations.
While acknowledging that large‑scale adoption would require substantial volumes, Muturi notes measurable improvements on his vegetable plots and has begun selling the compost to neighbouring farmers.
Black Soldier Fly Larvae: Turning Waste into Feed and Fertiliser
About 200 km north of Nairobi, Robert Mwangi has pioneered a complementary approach using the larvae of the black soldier fly (Hermetia illucens). He collects organic waste from Nakuru’s main market, feeds it to the larvae, and harvests two valuable outputs:
- Frass – the larval excrement, used as an organic fertiliser.
- Dried larvae – a high‑protein feed supplement for poultry and fish.
Mwangi reports that the frass not only supplies essential nutrients but also helps restore microbial activity in soils that have been acidified by prolonged chemical fertiliser use.
Expert Perspective on Organic Alternatives
Harun Warui, an agro‑ecologist with the Kenya Agricultural and Livestock Research Organization (KALRO), emphasizes that synthetic fertilisers address only a narrow slice of plant nutrition. “Vermicompost and insect‑based frass support the soil’s broader biology,” he says. “Benefits become apparent over time as microbial diversity rebounds, leading to more resilient agro‑ecosystems.”
Warui adds that while transitioning away from chemical inputs will take years, farmer testimonials and field trials increasingly show that dependence on synthetic fertilisers is not a sustainable long‑term strategy.
Path Forward: Scaling Organic Solutions in East Africa
The experiences of Muturi, Mwangi, and the growing body of peer‑reviewed research suggest a clear roadmap:
- Invest in decentralised composting units – simple, low‑cost structures that can be replicated across smallholder farms.
- Facilitate access to training – extension services should disseminate best practices for vermicomposting and insect‑based waste conversion.
- Create market incentives – premium prices for organically produced crops can offset the initial labour and material costs.
- Leverage policy support – governments can subsidise organic inputs or provide tax breaks for waste‑to‑resource enterprises.
By integrating these strategies, East Africa can begin to reverse soil degradation, reduce reliance on costly synthetic fertilisers, and meet rising consumer demand for organic food—all while turning urban and agricultural waste into valuable farm resources.
