Oku, E. et al. 2021. Soil fertility status of soils of Sudano-Sahelian and Humid Forest Zones of West Africa and some soil management strategies for smallholder farms. EQA - International Journal of Environmental Quality. 46, (Jan. 2021), 25–36. DOI:https://doi.org/10.6092/issn.2281-4485/12745.