Tropical forests are hotspots of modern-day land-use change and are, at the same time, among the largest terrestrial carbon reservoirs. In particular, the African continent will be facing huge environmental and societal challenges, with a projected population growth of 400 % by the end of this century. Despite their importance, tropical soils and ecosystems, particularly in Africa, are among the least studied in the world. Our lack of knowledge on the consequences of land-use change in the region on plant–soil interactions also limits our ability to predict future trajectories of tropical ecosystem services to mitigate climate change. Established observatories in the Congo Basin focus on questions related to biodiversity preservation and C storage in the biosphere, largely ignoring soils. In this SOIL Special Issue, we highlight the research that is done in tropical Africa on plant–soil interactions, biogeochemistry, and soil ecology.