Optimizing maize productivity in the Sahel region through the incorporation of exotic shrub species and reduced mineral fertilization

Abstract Smallholder farming systems in the Sahel face severe vegetation loss and declining soil fertility, which threatens food security and livelihoods. While native shrubs and trees have traditionally been used as mulch, some exotic species have recently gained attention due to their faster decomposition rates and potential to increase crop productivity. Therefore, identifying optimal combinations of mulch species and fertilizer inputs is essential for developing low-cost, sustainable soil fertility strategies suited to Sahelian conditions. A two-year field study (2023–2025) at the Farako Agricultural Research Station in Mali compared the decomposition rates and effects on maize productivity of two exotic species ( Gliricidia sepium , Leucaena leucocephala ) and three local species ( Parkia biglobosa , Vitellaria paradoxa , Guiera senegalensis ). Decomposition was modeled using an exponential regression to estimate 50% and 100% decomposition. Maize grain yield and dry matter responses were assessed under pruning applications with or without mineral fertilizer. The results showed that Leucaena leucocephala and Gliricidia sepium significantly improved maize productivity, achieving yields comparable to or greater than those with full mineral fertilization applied alone or with half the recommended fertilizer rate. In contrast, Parkia biglobosa and Vitellaria paradoxa reduced maize yields compared to the control. These findings demonstrate the strong potential of Leucaena leucocephala and Gliricidia sepium to enhance productivity while reducing fertilizer dependence. Future research should investigate the long-term impacts of these species on soil restoration and evaluate the potential of slower-decomposing local species such as Guiera senegalensis and Piliostigma reticulatum across diverse agroecological zones in partnership with smallholder farmers.