The objective of this study was to determine the effect of vermicompost application on microbial biomass carbon (MBC), dehydrogenase activity (DHA), and the functional diversity of microbial communities (BIOLOG assay using EcoPlatesTM
) in the cultivation of maize. The greenhouse experiment included variants: control (no fertilizer), CAN (mineral fertilizer calcium ammonium nitrate 60 kg N ha-1
), V20+CAN (vermicompost 20 t ha-1
+mineral fertilizer 30 kg N ha-1
), V40 (vermicompost 40 t ha-1
) and V80 (vermicompost 80 t ha-1
). Soil samples were analyzed at the start and end of the experiment (after 74 days). More pronounced influence of fertilization on biological parameters was found at the end than at the start of the experiment. MBC was statistically significantly higher in variants V40 (14.8%) and V80 (32.4%) than in the control. The application of CAN had a significantly negative effect, but the combination of V20+CAN positively influenced dehydrogenase activity. However, soil BIOLOG data indicated that the Shannon diversity index and evenness were significantly the lowest in the V20+CAN variant. The study suggests that vermicompost improves soil quality, and represents a suitable alternative to mineral fertilizers in the cultivation of maize.