This report by Frontiers in Ecology and the Environment describes a current indigenous soil management system in West Africa, in which targeted waste deposition transforms highly weathered, nutrient- and carbon-poor tropical soils into enduringly fertile, carbon-rich black soils, hereafter “African Dark Earths” (AfDE). AfDE provide a model for improving the fertility of highly degraded soils in an environmentally and socially appropriate way, in resource-poor and food-insecure regions of the world. The method is also “climate-smart”, as these soils sequester carbon and enhance the climate-change mitigation potential of carbon-poor tropical soils. »