Résumé
In the context of the revitalization of the Great Green Wall (GGW), the potential of combining agroforestry with Soil and Water Conservation techniques (SWC) can accelerate the rehabilitation and resilience of Sahelian agrosystems. Indeed, if woody cover improves water and soil conservation, SWC practice enables tree regeneration. Thus, the research questions raised by the JEAI-PRESAF project are: how can the innovations of Farmer Managed Natural Regeneration (FMNR) and soil and water conservation (SWC) fit into an agroforestry space? what is the level of sustainability of these types of associations? This intensification practice can only be sustainable and up-scaling if the bottleneck limiting its adoption is known. Compared to the unique practice of FMNR or SWC, and through their augmentative effects, the rehabilitation of agrosystems is accelerated and the capacity of the ecosystem to provide goods and services is increased. Our approach is based on a diagnosis of past and present socio-economic, agronomic and environmental contexts and performance through the study of two variants of agroforestry space associated with SWC in Niger. In order to provide pathways for adjusting and optimizing agroforestry practices associated with SWC, we are investigating two sites in Niger: 1) a multi-species park resulting from FMNR combined with zaï in Maradi region, and 2) a Piliostigma reticulatum park combined with half-moons in Tahoua region. In order to perpetuate the actions of this project, we aim to set up a scientific observatory "Societies-Environments" as a tool to support land management with the purpose of predicting the long-term innovations impact on the matter cycle (e.g., carbon, water, and nutrients) in order to evaluate the impacts on biodiversity, plant production, and carbon sequestration capacity; and finally, determine the Spatio-temporal, socioeconomic and biophysical criteria for scaling up.