When Benson Wanjala started farming in his village in western Kenya two and a half decades ago, his 10-hectare farm produced a bountiful harvest of 200 bags of maize. Now he produces just 30. He says his once fertile soil has become a nearly lifeless field from which he can no longer earn a living.
Like many other farmers, he acidifying fertilizers in Kenya and other African countries in recent years. He said he started using the fertilizers to increase his yield and it worked – until it stopped. Kenya’s government In 2008, the government introduced a fertilizer subsidy for the first time to facilitate small farmers’ access to chemical fertilizers.
About 63 percent of Kenya’s arable land is now acidic, according to the Ministry of Agriculture, which has seen a decline in the production of staple crops such as maize, as well as key exports horticulture and tea. Maize production fell by 4 percent to 44 million tonnes in 2022, according to the Food and Agriculture Organization of the United Nations (FAO), but did not specify the reasons.
The agriculture ministry did not respond to questions, particularly after the fake fertilizer scandal in April. The fertilizer turned out to be pit soil in misleadingly labelled bags distributed to farmers through a national subsidy program. President William Ruto said about 7,000 farmers had bought the fake fertilizer and would be compensated with the real product.
Soil health problems are growing as the African continent struggles to feed itself. Africa has 65% of the world’s remaining uncultivated arable land, but spends about $60 billion annually importing food, according to the African Development Bank. This spending is expected to rise to $110 billion by 2025 due to increased demand and changing consumption habits.
In May, Kenya hosted an Africa-wide summit on soil health to discuss declining production, climate change and other issues that have heightened concerns about food security. Agriculture is a key part of Kenya’s economy, generating more than a quarter of GDP.
At the summit, Stephen Muchiri, executive director of the Eastern Africa Farmers Federation, called for a return to traditional farming practices to restore lifeless soils, including growing diverse crops and minimizing soil disturbance.
“Inorganic fertilizers were never intended to be the basis for growing crops,” he said, later adding: “Because of commercial agriculture, our soils today are barren, acidic, poor in biomass resources and devoid of life!”
He said farmers should rotate crops in their fields and obtain compost from livestock such as goats: “There has to be some kind of transition and adaptation to make our soils fertile again.”
According to experts, soil acidification leads to soil erosion because it reduces the availability of plants and vital nutrients, making the soil more vulnerable to structural deterioration and erosion.
The programme coordinator of the Alliance for Food Sovereignty in Africa, Bridget Mugambe, advised a gradual phase-out of the use of chemical fertilizers.
“Soil health can no longer be achieved with quick fixes such as chemical fertilizers. In fact, chemical fertilizers have severely damaged our soils in Africa. We need to look at our soils more holistically,” she said.
At the African Union Summit on Soil Health, which had already recommended the use of chemical fertilizers to its members in 2006, a ten-year plan was adopted that calls for increased investment in local production of both organic and chemical fertilizers and a tripling of their use to increase production.
During the summit, AU Agriculture Commissioner Josefa Leonel Correia Sacko claimed that the continent loses “over $4 billion worth of soil nutrients every year.”
Due to low local production, Kenya is heavily dependent on imported fertilizers. The main supplier is the European Union, followed by Saudi Arabia and Russia.
John Macharia, Kenya manager of the Alliance for a Green Revolution in Africa, said the recent fertilizer scandal in Kenya should not discourage farmers.
“It remains imperative that we work with the government to ensure that our stores are supplied with the right fertilizers,” Macharia said. He recommended both chemical and organic fertilizers as long as they address the specific problem of the soil, and said farmers could take guidance from soil analysis.
Deteriorating soil quality poses a problem for food security throughout Africa.
In Zimbabwe, once the region’s breadbasket, about 70 percent of soils are acidic, according to the government. In the past, the government used chemical fertilizers to strengthen soils, but the misuse led to a decline in organic matter.
“Before the introduction of mineral fertilizers, our ancestors knew that adding organic fertilizer would make the soil more fertile and crops grow better,” says Wonder Ngezimana, associate professor of plant science at Marondera University of Agricultural Sciences and Technology in Zimbabwe. “This is a traditional norm in Zimbabwe and elsewhere in Africa, where people look for any kind of organic material to add to the soil.”
These include animal manure, grass, leaves and twigs, crop residues, ash and compost. But many farmers in Zimbabwe no longer have livestock due to the recent drought, says Ngezimana: “Farmers are struggling to maintain the health of their soil because they cannot produce enough organic material.”
AGRA recommends that farmers check the acidity of their soil and apply lime to balance out excessive acidity.
But farmers say both options are limited and expensive. Soil tests are available from state agriculture departments, public universities and private organizations for between $20 and $40.
Farmer Wanjala said he could not even raise enough money for livestock and fertilizer, and barely enough for seeds.
“I can’t afford any more expenses,” he said.