Fungal to bacterial biomass ratio in the forests soil profile

The carbon content in microbial biomass (C_mic-MB) was determined in various horizons of the soil profile (sod-podzo, gray, podzol, and rzhavozem) of various forests (oak, spruce archangel, spruce moss, aspen, spruce broadleaf) in the southern taiga of European Russia (Moscow and Kaluga regions) by the substrate-induced respiration (SIR) and direct microscopy (DM) methods. The fungi-to-bacteria ratio was measured by the selective inhibition technique and DM. A quantitative differentiation of the fungal mycelium was suggested. The C_mic-DM / C_mic-SIR in various horizons of the soil profile was about 98%. The fungal contribution to MB was 52–74% and 92–99% according to the SIR and DM methods, respectively. The microbial parameters were associated with the CO₂ and N₂O production by the soils. The contradictory data about the fungal portion in the MB of soils of various ecosystems were discussed.