The environmental conditions in the tropical forests of Africa are different from other tropics with respect to soil type and vegetation. The most widely distributed soils in Africa are Oxisols, which have low nutrient availability. This contrasts with Southeast Asia, where Ultisols (strongly acidic) are dominant. In terms of vegetation, the proportion of woody legume biomass is much greater in Africa than in Southeast Asia. These soil and plant properties characterize uniqueness of the ecological processes, especially N cycles, in Africa. In this talk, first, I will compare distinct N fluxes between contrasting soil types (Ultisols and Oxisols) under tropical forests in Cameroon. Soil pH appeared to affect N transformation processes and plant strategy of N uptake. Second, we compared soil P dynamics, which is closely coupled with N dynamics, based on phosphatase activities of plant roots and soils, which have essential roles for P cycling in highly-weathered soils. A new picture of plant-soil N and P dynamics of African tropical forests will be useful to discuss the uniqueness and similarity compared to the other tropical regions.