Experts Warn Farmers Against Overuse of Synthetic Fertilizers

In Summary

• Experts caution Kenyan farmers against heavy use of synthetic fertilizers, citing soil degradation.
• Soil expert Dennis Murithi warns of risks to long-term food security.
• Over 70% of farmers rely on chemical inputs, says Ministry of Agriculture.
• Studies link prolonged use to declining fertility, soil acidity, and reduced yields.
• Farmers encouraged to adopt organic alternatives and conduct regular soil testing.
• Government and partners rolling out training and subsidies for sustainable practices.

Kenyan farmers have been urged to rethink their dependence on synthetic fertilizers, with experts warning that decades of heavy use are depleting soil fertility and threatening the country’s food security.

Speaking during a farmers’ forum in Nairobi on August 21, 2025, soil health expert Dennis Murithi, CEO of Pure Plant Organics, said while chemical fertilizers deliver quick results, they gradually weaken the soil.

“Synthetic fertilizers provide immediate boosts, but over time they strip the soil of vital nutrients. If this continues, we risk undermining both soil health and future food production,” Murithi said.

According to the Ministry of Agriculture, more than 70% of Kenyan farmers depend on synthetic fertilizers such as DAP and NPK, particularly for maize, tea, and horticultural crops. Research, however, paints a worrying picture. A study done in 2024 by the Kenya Agricultural and Livestock Research Organization (KALRO) reported a 20% decline in soil organic matter in major farming zones like Uasin Gishu and Nyeri over the past 20 years.

Farmers on the ground are already feeling the impact. Mary Wambui from Kiambu said her maize yields dropped after years of using chemicals. “Soil testing showed my land was too acidic. When I switched to compost and crop rotation, things began improving,” she explained. In Eldoret, maize farmer John Kamau highlighted another challenge: affordability. “Fertilizer prices keep climbing. We need cheaper organic options and practical training,” he said.

Beyond farms, experts warn that chemical overuse is also polluting rivers and lakes, worsening environmental and health risks. Murithi and other specialists are advocating for organic solutions such as manure, cover crops, and biofertilizers, which can restore soil balance while protecting ecosystems.

Government agencies are stepping up efforts to encourage sustainable farming under the Bottom-Up Economic Transformation Agenda. The Ministry of Agriculture, working with KALRO and the Organic Agriculture Centre of Kenya, has already trained more than 5,000 farmers in Nakuru, Kirinyaga, and Bungoma on integrated soil fertility management.

Dr. Esther Kimani, a soil scientist at KALRO, said soil testing is a simple but critical first step.

“Blanket fertilizer use is both wasteful and damaging. Every farmer needs to know exactly what their soil requires before applying anything,” she stressed.

To support this, KALRO has deployed mobile soil testing labs in 10 counties, charging KSh 500 per test. Meanwhile, the National Soil Health Campaign launched in 2023 aims to train 50,000 farmers by 2027 and expand the distribution of organic alternatives. In 2024 alone, 10,000 tonnes of biofertilizers were distributed through government subsidies.

Stakeholders argue that stronger incentives are needed to make organic farming more attractive. “Organic produce can fetch up to 30% more in premium markets. If policies support farmers to go organic, it will benefit both incomes and soil health,” said Jane Kinyua of the Kenya Organic Agriculture Network.

With soil degradation on the rise, experts agree that a shift toward sustainable practices is no longer optional. The challenge now, they say, is scaling up training, support, and awareness so that more farmers can secure long-term productivity without sacrificing the health of their land.