Led by FiBL Switzerland, SustainSahel promotes sustainable agriculture by combining agroforestry’s integrative approach with a strong participatory design.
Soil health is essential to secure our future because food production, and therefore our livelihoods, depend on it. The aim of SustainSahel is to introduce and promote practices that that can promote a positive synergy between crops, trees and livestock, leading to the enhancement of soil fertility and farmers’ revenues. As an international research project, it brings together 17 partners from 9 countries, representing the European and African continents. Led by Harun Cicek of FiBL Switzerland, the Research Institute of Organic Agriculture, the project has been funded under the EU Research Framework Programme Horizon since 2020.
Agroforestry aims at the development of sustainable systems that include a combination of trees, crops and/or livestock on the same area of land. Accordingly, SustainSahel integrates these elements – crops, shrubs and livestock – and seeks to promote their interaction for sustainable and resilient agriculture in the Sahel. According to Fernando Sousa, member of FiBL Switzerland and part of SustainSahel project, agroforestry has a twofold role: On the one hand, it contributes to the preservation and protection of ecosystem services and biodiversity. On the other hand, it is also related to the question of how people can farm sustainably and thus secure their food supplies in the long run. It is this double potential that brought Mr. Sousa, who has an academic background in conservation biology, to this field of research and specifically to FiBl.
SustainSahel includes seven different study areas in Senegal, Mali and Burkina Faso. As part of their work, researchers involved in the project investigated how the selection and density of shrubs and trees in the fields of farmers can have a positive effect on soil nutrition. Farmers in the Sahel often have trees and shrubs on their fields whose seeds can be eaten, such as the Néré (Parkia biglobosa), a legume tree with edible seeds that are fermented and eaten locally. A more famous example is the shea tree (Vitellaria paradoxa), from which farmers, usually women, produced shea butter used for the cosmetic industry all over the world. Therefore, farmers already integrate trees on their fields that are useful to them. However, this project seeks to better understand how the use of different tree and shrub species can be optimised to improve soil fertility while providing other services such as animal fodder. At the same time, it considers the priorities of farmers and local stakeholders, including crop yield and economic interests.
Part of the project’s strategy is to return enough organic matter to the soil to counteract the fast mineralisation caused by the high temperatures and soil mobilisation during farming activities. Trees and shrubs are functional for the valorisation of the soil because they lead to a higher abundance of biomass covering the soil, which then can better retain moisture after rainfall. They also provide the soil with additional nutrients.
Another part of the equation in the integrative approach is the livestock. Here, the planting of shrubs and trees that are particularly suitable as food for the animals can address the problem of feed shortage during the drought period. Livestock, in turn, are not only a central element of local agriculture – and important to farmers – but also play a positive role in the transformation of organic matter: they digest crop residues and convert plant biomass into organic matter that enriches the soil.
One important insight of the project concerns the ideal tree density. As several PhD students in Mali and Burkina Faso discovered during their research, a medium density of trees (between 10 and 15 trees per acre) positively influences crop yields compared to lower or higher densities. At the same time, the research also provided insights into the beneficial effects of combining different types of shrubs. Another important discovery concerns livestock health, as the project found that certain tree and shrub species’ leaves are particularly effective against nematodes in sheep. For example, feeding baobab leaves to an infected sheep can eliminate up to 70% of these parasites. This is a key finding for promoting sheep health. To make such results widely accessible, SustainSahel shares its findings through various methods, including information videos available online in multiple languages, as well as an extensive dissemination strategy that puts farmers at the centre of a participatory process.
In Fernando Sousa’s view, the “social dimension is the backbone of the project” as it is crucial for research that seeks to not only generate new data but a positive impact for farmers’ livelihoods. Therefore, farmers’ perspectives are essential, not only to determine which practices they would be willing to implement and how new and existing agricultural practices can be well integrated, but also to incorporate existing local knowledge. As part of the participatory design, the project has created so-called ‘innovation platforms’ for all project sides, which facilitate exchange with stakeholders. This includes not only farmers and agricultural product processors but extends to other stakeholders such as researchers, extension officers and local authorities. These platforms enable knowledge transfer in two directions: On the one hand, they allow researchers to find out what local stakeholders think about the results of the projects. This point is central, because by knowing farmers’ priorities and innovation adoption readiness the project is able to draft recommendations through a realistic lens. On the other hand, farmers can benefit from the exchange with the researchers.
To ensure long-term knowledge transfer, SustainSahel has organised several dissemination events per year to demonstrate the techniques developed. 30 to 40 farmers attend each of these events, which are held in all seven areas. As each farmer represents a village, a cascading effect of dissemination is set in motion, as they in turn can apply the technique and share the knowledge gained with their local communities.
Finally, as Mr Sousa emphasises, the training of talented young researchers is a key priority for SustainSahel. With thirteen PhD students and around two dozen MSc students in three countries, SustainSahel is actively contributing to capacity building and preparing researchers who may one day become professors. This new generation of transdisciplinary thinkers will bring to their future work a deep understanding of the complexity of agrosystems. They will also know how to work in an interdisciplinary environment – a crucial skill for research that aims at long-term positive impact.
As SustainSahel is coming to an end this year, there are two events to keep an eye on in the final months of the project: First, the project is bringing together nine large Africa-EU agroecology projects for a science-policy event on 6 May 2025 in Brussels to illustrate the compelling evidence on Agroecological Transition for Africa. Insights from nine EU-Africa projects will be shared at this event. Second, on 15 May, an agroforestry symposium will take place in Dakar, which also serves as a final meeting to present final recommendations for the farmers, extension officers, researchers and policymakers.
On the picture: Farmers and researchers discuss the impact of mulch with bush biomass on crop performance at the Katibougou research station, Koulikoro, Mali.