Engineered Soil Microbes Could Boost Africa’s Food Security Sustainably

In western Kenya, smallholder farmers grow maize on small plots of land, often battling poor soils, high input costs and unpredictable weather. Now, researchers from the Massachusetts Institute of Technology and Field to Future say a new type of fertilizer could help transform those fields. Tavneet Suri from MIT Sloan School of Management, Robert D. van der Hilst from MIT's Department of Earth and Planetary Sciences, and Petar Madjarac of Field to Future have tested a genetically engineered microbial fertilizer that may increase yields while cutting pollution.

Their study comes at a critical time. Africa's population is rising quickly, yet crop yields remain low compared to other parts of the world. Maize alone provides more than 30 percent of caloric intake across the continent. At the same time, climate change is making farming harder. Higher temperatures, irregular rains, floods and droughts are putting pressure on already fragile food systems.

Why Traditional Fertilizer Is a Problem

For decades, farmers around the world have relied on synthetic nitrogen fertilizers to increase crop production. These fertilizers are produced through an energy-intensive industrial process that converts nitrogen gas into ammonia. While this method helped boost global food supplies in the twentieth century, it also consumes large amounts of fossil fuels and generates significant greenhouse gas emissions.

In Africa, synthetic fertilizer is often too expensive. Most of it is imported, and transportation costs push prices much higher than in countries like the United States. Many small farmers simply cannot afford enough fertilizer to significantly improve their yields. As a result, fertilizer use per hectare in Africa remains far below global averages, and cereal yields lag far behind other regions.

There is also an environmental cost. Excess fertilizer releases nitrous oxide, a powerful greenhouse gas, and can pollute rivers and lakes. Finding a way to increase food production without increasing emissions has become an urgent goal.

The Science Behind Microbial Fertilizer

The product tested in Kenya, called PROVEN40, works differently. Instead of supplying nitrogen made in factories, it uses genetically modified microbes. These microbes live on plant roots and capture nitrogen from the air, delivering it directly to the plant throughout the growing season. The maize crop itself is not genetically modified. Only the microbes are engineered to improve nitrogen fixation.

To test the product, researchers carried out a randomized controlled trial in Siaya and Vihiga counties in western Kenya. They selected 509 farmers across 50 villages. About half were randomly chosen to use the microbial fertilizer on a quarter acre of maize, roughly one-fifth of their maize land. The rest continued farming as usual. Farmers received training and support, and researchers collected soil samples and detailed survey data before and after harvest.

What the Farmers Experienced

The results were encouraging. On plots treated with the microbial fertilizer, maize yields increased by between 15 and 27 percent compared to untreated plots. In some cases, after adjusting for outliers, the increase reached 26 percent. If the entire farm had been treated, researchers estimate total yield gains could have reached 20 to 45 percent.

However, soil quality mattered. Farms with moderate nutrient levels saw the largest benefits, with some plots experiencing yield increases of up to 110 percent. On very poor soils with extremely low nitrogen and phosphorus levels, the product showed little or no impact. This suggests that microbial fertilizer works best when soils are not severely degraded.

The study also found that overall synthetic fertilizer use did not increase at the household level. Farmers used more household labor, likely because bigger harvests required more work. Importantly, the higher yields came without additional chemical fertilizer use.

Lower Costs and Lower Emissions

The economic comparison is striking. To achieve the same yield gains using traditional synthetic fertilizers would require large amounts of imported fertilizer, costing around 160 dollars per farmer. Yet the extra maize produced would be worth only about 81 dollars, making it unprofitable.

The microbial product, by contrast, is estimated to cost about 43 dollars per quarter acre under local packaging conditions. That makes it potentially profitable, especially on better soils.

The environmental difference is even larger. Producing and applying enough synthetic fertilizer to match the yield gains would generate roughly 205 kilograms of carbon dioxide equivalent emissions per farmer. The microbial alternative would generate about 13 kilograms, mostly from local transportation. That is about sixteen times lower.

Farmers showed interest in the product, although some remained cautious. Overall, the findings suggest that microbial fertilizers could help Africa increase food production more cleanly and affordably. While not a solution for severely degraded soils, the technology offers a promising step toward feeding a growing population without worsening climate change.