London — Around 1.7 million smallholder farmers in 13 African countries have adopted practices to improve the health of the soil in their fields, boosting poor crop yields and incomes, the organisation that trained them said on Friday.
A report from the Nairobi-based Alliance for a Green Revolution in Africa (AGRA) said its soil health programme has led to the rejuvenation of more than 1.6 million hectares (3.95 million acres) of degraded land in the past five years.
Farmers participating in the initiative in Tanzania, Malawi and Ghana are doubling and even tripling yields of maize, pigeon pea and soybean, and every dollar invested in those countries has returned between $5 and $17 for farmers, it added.
Improving soils is a big challenge in Africa because in many areas soils are naturally low in key nutrients and highly acidic. Farmers are struggling with a problem called "nutrient mining," where crops extract nutrients such as phosphorous and nitrogen from the soil at a faster rate than they are returned, largely due to low fertiliser use.
Soil health issues are costing African farmers $4 billion a year in lost crop productivity, roughly equivalent to the gross domestic product of Malawi, the report said.
"Unhealthy soils...could kill Africa's hopes for a prosperous, food-secure future," warned AGRA, which is a regional partnership working to improve smallholder farming in Africa.
For example, farmers in many parts of the world regularly harvest up to five tonnes of maize per hectare (around 2.5 acres), but African farmers typically harvest just one tonne.
Leaders of African Union countries noted in a July declaration on ending hunger in Africa by 2025 that despite "the tremendous potential" of Africa to improve its agriculture, productivity on the continent remains on average the lowest among developing regions.
Unsustainable farming practices, like not rotating crops or applying fertilisers, have contributed to the situation, together with ongoing soil erosion, the report said.
The AGRA programme promotes a method known as "integrated soil fertility management". It includes mixing organic matter such as crop residues and manure into the soil, applying small doses of mineral fertilisers, and planting legume crops like cowpea, soybean and pigeon pea that naturally fix nitrogen in the soil.
Amos Chipokosa, a Malawian in his mid 20s, is one farmer who has benefited. According to the report, he and his wife followed advice on how to take care of their soils and used manure and other inputs to get the most out of an improved soybean variety. With the extra money they earned, they started a small store, expanded the crops they were growing, purchased pigs and goats, and built a four-room house for their family.
"We've shown that it's possible to work on a very large scale to help smallholder farmers adopt sustainable and profitable approaches to crop production, with the proof there for all to see in the form of significantly larger yields," Bashir Jama, director of AGRA's soil health programme, said in a statement.
A key part of the AGRA initiative is to boost the availability of high-quality fertilisers, and enable farmers to apply it in appropriate quantities. African farmers use on average only about 10kg of nutrients per hectare, compared with a global average of more than 130kg, due to low supplies and high prices, the report said.
To help rectify that situation, AGRA is helping rural agricultural supply dealers stock more fertilisers, and is working with researchers in Burkina Faso to develop a new machine that applies fertiliser in efficient "micro-doses", adding just a few pellets for each seed.
AGRA has also invested in the African Fertiliser Agribusiness Partnership (AFAP) which aims to develop new fertiliser production, storage and retail operations, to expand supplies and lower the prices farmers pay by at least 15 percent.