New technology moves farmers beyond fertilisers, via legumes

A four-year soil fertility project rolled out last year has raised the net returns for participating farmers in Western Kenya ten-fold in its first year through introducing state-of-the-art legume and rhizobial inoculant technologies.

Launched in Kenya and seven other African countries to triple the take-up of free atmospheric nitrogen through Biological Nitrogen Fixation, the project has delivered near-instant benefits through improved crop and livestock productivity, human nutrition, farm income, and soil health. It has also sparked a revolution in legume processing, specifically of soya, in Western Kenya.

The project’s total benefits at the end of the four years are projected to be at least $31.9m based on estimates of the increased productivity of the targeted grain legumes - which include soya-bean, common beans, cowpea, groundnut, chickpea, and pigeon pea - and through their contribution to the yield of subsequent maize crops.

However, in Western Kenya where around 20,000 smallholder farmers from more than 10 districts were targeted, smallholder farmers have already increased their net returns from soya-bean cultivation from four to 14 times. The initiative has also led to the creation of several Soya-bean Resource Centres in Western Province, with many farm families now easily accessing soya-milk, and farmers widely adopting soya-milk processing machines.

According to Agriculture experts, legume crops often fail to fix useful amounts of nitrogen in the soil in Africa because partner bacteria are not present, or because the soil lacks other nutrients, such as phosphorous.

But the new technology now allows farmers to introduce the bacteria as inoculants, together with the seed and small amounts of other nutrients. This simple package increases farmers’ yields while improving the soil’s fertility.

“Agricultural production in most parts of sub-Saharan Africa is dominated by smallholder farming systems, which are associated with low productivity. Although the inclusion of legumes has the potential to improve system productivity, often less than 5-10% of cultivated land is currently planted with field legumes.

Grain legumes are often included as minor intercrops in fields of cereals and other staple crops. This is because smallholder farmers operate under diverse socio-ecological constraints that limit the productivity of legumes and farmers ability to scale up the integration of legumes into their farming systems,” said Hon. Wycliffe Oparanya, Minister of State for Planning, National Development and Vision 2030 during the launch of the Biological Nitrogen Fixation project last year.

Despite an Africa Union resolution in 2006 when African leaders endorsed efforts to improve fertilizer access for small-scale farmers, by promoting locally-adapted fertilizer manufacturing and establishing financing mechanisms for fertilizer procurement, smallholders are still struggling to access the input.

Agro-experts have therefore become aggressive in pushing biological nitrogen fixation, which is sometimes free and is easy to learn, as the best route to follow for Africa. The process involves crop rotation, with the planting of legumes helping to fix nitrogen naturally.

According to researchers from Kenya Agricultural Research Institute, Kenya faces an enormous soil fertility problem, with research showing that in Western and Central provinces, 7.5 million hectares of land are highly acidic, a problem shared by large parts of Ethiopia, Rwanda, Uganda and Zambia. The high acidity is due to the leaching of nutrients by the abundant rains, continuous cultivation and misapplication of nitrogen fertilizers.

However, in Brazil and South Africa, agricultural scientists have manipulated the symbiotic relationship between the growth of legumes to ensure effective Biological Nitrogen Fixation by combining selected bacteria and legumes to obtain maximum crop production on land which is of low fertility and frequently unsuitable for the growth of non-legume crops.

In both countries, the rates of nitrogen fixation with soya-beans under field conditions have exceeded 300kg of nitrogen per hectare, paving the way for the launch of the new technologies across sub-Saharan Africa in an effort to move smallholders beyond fertilizers, and back to naturally fertile soil.

Written By Bob Koigi

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