How can soil fertility be managed to boost food sovereignty in Africa?

Food insecurity remains a major issue in Africa, the continent where it has increased the most in recent years. Experiencing significant demographic growth, Africa needs to produce more to ensure its food sovereignty, without doing so at the expense of its environment. Improving soil fertility is therefore fundamental to guaranteeing sustainable agricultural production capable of meeting this fast-growing demand for food.

With this in mind, the first part of the conference dealt with the theme of "Global issues and soil fertility", through two presentations ("Food security in Africa remains an important issue" and "Soil fertility is the pillar of agricultural production"). The second part dealt with "Fertilizer use and agroecology: how compatible?", with a presentation by Gatien Falconnier, a researcher at CIRAD's Aïda unit, based in Harare (Zimbabwe), entitled "Using mineral fertilizers to complement agroecological practices to boost agricultural production in Africa".

Gatien illustrated that increasing soil fertility does not call for a single response, but a combination of means that include agroecology and chemical fertilisers. "Four studies carried out in various sub-Saharan African countries have estimated that the maize yield needed to improve food security is around 6 tonnes per hectare. But farmers' current yields are around 2 tonnes per hectare. The main reason for this is a lack of nutrients", he points out.

So how can we provide sufficient nutrients to achieve this security? "Among the agroecological solutions, fertiliser trees and crotalaria are very effective, but farmers are not interested in them, because they have no nutritional or commercial value and block part of the plot. They prefer seed legume crops and manure, but these do not provide enough nutrients. To supplement this, the use of chemical fertilisers is unavoidable".

However, "progress needs to be made with regard to their production, which accounts for 3.5% of greenhouse gas emissions. In addition, it is essential to use the right fertiliser, in the right quantity, in the right place, at the right time, in combination with agro-ecology, in particular legume crops and forest cover, which greatly increase the efficiency of chemical fertilisers" stresses the researcher. "On the other hand, farmers must receive aid and incentives. They cannot be the only ones to bear the cost of agro-ecology, in terms of land, labour and cash flow, even though it is beneficial for the environment and society", he added.