Reversing declining soil fertility and productivity under smallholder farming is a must if Africa is to be food secure and it can be done.
About USD 42 billion in income and 5 million hectares of productive land are lost annually due to land degradation. Also the equivalent of about 4 billion worth of fertilizer is lost annually due to loss of nutrients removed with crops under conditions where little or no fertilizers is used.
A practical and sustainable approach to reverse this situation is one that integrates the use of organic and inorganic fertilizers, it is not an either or solution. Organic fertilizer is needed to improve the organic matter content of soil, improve its physical and biological properties, increase its water retention properties and retain nutrients applied for plants use. They can also add some nutrients but this is only possible when applied in large that are often uneconomical. Their integration with inorganic fertilizers, at recommended amounts, can meet provide the nutrients that are not available in adequate amounts from the organics sources. This requires an increase in fertilizer use by smallholder farmers which currently stands at 8-10 kg per hectare, a rate that is only 4-5% of most developed countries. The high cost of fertilizers in Africa ranges between USD 800 to 1200 in most rural areas a cost that makes it impossible for smallholder farmer to access thus it needs to be addressed. This is, indeed, what the Alliance for a Green revolution in Africa (AGRA) through its Africa-wide program on soil health is working towards.
One of the most promising technologies is fertilizer "microdosing", which has been pioneered by the International Centre for Research in the Semi-Arid Tropics (ICRISAT) in West Africa and its national partners.
This practice involves applying small quantities of fertilizer – usually a full bottle top – either at planting or at the base of young plants two to three weeks after they emerge. For good results, the fertilizer must be applied together with farm yard manure in the same hole. About 360,000 small-scale farmers in the three countries – Burkina Faso, Mali and Niger are being supported with this technology. And the results are remarkable – yields of sorghum and millet (their staple food crops) have increased by 3-4 times, up from the typical under 0.5 tons per hectare.
With the increased yields this technology can, indeed enhance household and national food security if scaled up.
Farmers are also supported to intercrop or rotate the cereals with grain legumes, especially cowpeas that does well in these Sahelian countries.
Like many other grain legumes, cowpeas can add to the soil significant amount of nitrogen (100 to 200 kg per hectare) from the atmosphere. This can be used to either supplement or reduce the amount of fertilizer nitrogen used. They also provide valuable grain that can be sold for income or eaten as nutritious food. The crop residues are used as livestock feed and in the process generate manure that is used to improve soil fertility.
The governments in the 3 countries have embraced the technology which seeks to restore soil health and its productivity and are now planning to scale it up to benefit millions of farmers. Other countries following suite include Tanzania where thousands of farmers are being helped to scale up maize-pigeon pea production systems because of its multiple benefits, including soil fertility improvement, food security and income enhancement.
These examples, indeed, demonstrate that Africa can and must address its soil health crisis if the continent is to reverse its food security and economic development. Improved soil health also increases the resilience of the crops to drought and water scarcity that is becoming a common phenomenon in this era of climate change. As the current drought in the maize belt of the USA unfolds, and as its impacts is felt around the world in terms of higher food prices and limited supplies, the need for Africa to step up – first to feed itself and then help feed others – becomes ever more clear. And it starts with fixing the soils.
Dr. Bashir Jama, Director, Soil Health Program and Director, Accra Office.