A research study has been performed in a natural soil of Senegal to follow the development of four provenances of Acacia mangium inoculated with an ectomycorrhizal fungus Pisolithus sp. (strain COI024) and/or a Bradyrhizobium sp. isolate (Aus 13c), to evaluate the impact of these symbioses on the microbial biomass and on the indigenous rhizobial and fungal symbiotic microflora and to determine the impact of these controlled inoculations on the structure of nematode communities. The results showed that the dual inoculation significantly improved plant growth for all provenances. When the plants were transferred into 20 l pots filled with a nonsterilized soil, the positive effect on the plant growth of the dual inoculation disappeared and no significant difference was recorded between the plants inoculated with the fungus alone and those inoculated with both Bradyrhizobium and the ectomycorrhizal fungus. However, the microbial biomass, the nitrogen contents, the number of nodules per plant and the structure of the nematode communities were significantly influenced by the A. mangium provenances and the microbial treatments. The impact of controlled mycorrhization of different A. mangium provenances on soil biofunctioning is discussed in terms of plant growth, microbial and nematode biodiversity.