African agriculture faces a triple challenge: producing enough to feed a growing population with increasing consumption of animal-based products, while reducing the use of synthetic inputs (chemical fertilizers, pesticides, etc.) and preserving natural ecosystems.

In this context, agroecology—which relies on natural processes rather than industrial inputs to maintain soil fertility—emerges as an alternative to conventional agriculture. The latter, which drove increases in agricultural yields during the “Green Revolution” of the 20th century, is now widely considered unsustainable due to its impacts on ecosystems and public health.

However, to fertilize soils, the ecological transition requires sourcing nitrogen, a key nutrient for crops, beyond cultivated land. In agroecology, nitrogen comes from natural sources such as legume crops, animal manure, and compost, which themselves require space. As a result, this can have significant implications for land use: meeting agricultural needs while adhering to agroecological principles may lead to an expansion of agricultural and grazing land, encroaching on natural areas (particularly forests, grasslands, and savannas). Issues of soil fertility and land use are therefore closely intertwined with those of biodiversity conservation.

The TAASF2050 research project aims to assess the relevance and feasibility of an agroecological agricultural model in Africa: can agroecological scenarios meet food demand? Do they make African countries more or less dependent on imports? What scope do they offer for reducing the use of synthetic fertilizers while preserving natural ecosystems?

By taking into account various factors (changes in dietary patterns, agricultural yields, and nitrogen fertilizer use), the project seeks to evaluate the implications of an agroecological transition for food sovereignty in African countries and for the preservation of natural ecosystems. More specifically, it aims to determine how far such a model can be scaled without exceeding the limits of land and ecosystems, while improving Africa’s food self-sufficiency. To this end, the project models land use and nitrogen fertilization in Africa up to 2050.

The findings will be valuable for AFD, for which agriculture and biodiversity are key priority sectors. They will also contribute to discussions with African governments on the opportunities and constraints associated with an agroecological transition in their respective national contexts.

The project relies on the GLOBAGRI simulation model developed by CIRAD. Changes in population dietary patterns, agricultural yields, and nitrogen fertilizer use are the model’s main input variables. The preservation of natural capital is treated as a fundamental constraint (the protection of tree-covered areas, the elimination of inputs derived from fossil resources and agricultural pollution, and the maintenance of soil fertility), within a strong sustainability framework.

The project led to the development of GlobAgri Africa 2050, an open-access interactive modelling tool that allows users to explore, country by country, four agricultural scenarios for Africa by 2050. It enables users to test different assumptions regarding dietary patterns and environmental constraints for each of the 45 African countries.

Initial simulations confirm the strong tension between, on the one hand, maintaining agricultural land within limits compatible with the preservation of forest cover and natural grasslands and savannas areas, and, on the other hand, limiting import dependence to a reasonable level for all African countries.

The current results, which correspond to scenarios for changes in dietary patterns (towards protein-richer diets, or toward healthier diets, or those that limit the expansion of agricultural land), can be further enriched with scenarios that AFD's partners may wish to test.

Finally, a more detailed analysis of the availability of organic fertilizing resources is expected, within the next year, to provide an assessment of the risks, at both local and national levels, of failing to ensure sufficient agricultural production to guarantee food security for populations.

• Benoit Faivre-Dupaigre ; Researcher at AFD
• Patrice Dumas ; Researcher at CIRAD, UMR CIRED 
• Rémi Prudhomme ; Researcher at CIRAD, UMR CIRED 
• David Berre ; Researcher at CIRAD, UMR AIDA