Objective: The objective was to assess the growth and accumulation of biomass in seedlings of three forest species (Cedrela odorata, Tabebuia chrysantha and T. rosea), under bio-based and synthetic fertilization, as well as their effect on the rhizosphere.Design/methodology/approach: A completely randomized design with four replications was established and three treatments were evaluated for each forest species: T1, mycorrhizae based biofertilizer; T2, biofertilizer based on Azospirillum sp.; T3, synthetic slow release fertilizer, using from week one to four the commercial Starter® formula 10-15-5, applying 50 ppm/plant; while from week 10 to 12, 100 ppm/plant of Nitro® 30-0-0 were used, with their corresponding control. The growth variable was measured by height in a ten-day interval and the biomass accumulated at 12 weeks was estimated. Finally, rhizospheric soil samples were taken from each treatment, by species and free-living nitrogen fixing bacteria (FLNB) in Congo red agar. Results: The biofertilizer based on Azospirillum sp. improved plant growth and microbiological quality of the rhizospheric soil of Cedrela odorata and Tabebuia rosea; while with T. chrysantha, no statistical differences were found between the different types of fertilization. FLNB growth was favored by biofertilizers.Limitations on study/implications: The study lasted only three months, so it is suggested to analyze long-term variables, as well as their response in the field.Findings/conclusions: Biofertilization can be an alternative for the growth of commercial forest species such as Cedrela odorata and Tabebuia rosea.
