The structure of the microbial community (the fungi-to-bacteria ratio) has been assessed by selective inhibition of the substrate-induced respiration (SIR) using streptomycin sulfate and cycloheximide antibiotics in the gray forest soil of eluvial, transite, transite-accumulative, and accumulative (meadow alluvial) parts of slope landscape on the right bank of the Oka River (near Pushchino, Moscow oblast) which represents an fallow, small-leaved wood, spruce forest, and meadow. The concentrations of bactericide and fungicide were selected experimentally for each landscape parts which provide the greatest SIR inhibition of the soil upon their individual application and in combination. Fungi were established to be predominant in the contribution to the total SIR which was found to be 82–97%. A dependence between the structure of the microbial community and the C/N ratio and pH of the soil was shown.