Microbial biomass carbon in the profiles of forest soils of the southern taiga zone

In the mineral horizons of the soils under different southern taiga forests (oak, archangel spruce, and aspen in the Kaluzhskie Zaseki Reserve of Kaluga region and the green moss spruce and spruce-broadleaved forests of the Zvenigorod Biological Station of Moscow State University in Moscow region), the carbon content in the microbial biomass (C-mic), the rate of the basal respiration (BR), and the specific microbial respiration (qCO(2)= BR/C-mic) were determined. The C-mic content was measured using the method of substrate-induced respiration (SIR). In the upper humus horizons of the soils, the C-mic content amounted to 762-2545 A mu g/g and the BR ranged from 1.59 to 7.55 A mu g CO2-C/g per h. The values of these parameters essentially decreased down the soil profiles. The portion of C-mic in the organic carbon of the humus horizons of the forest soils was 4.4 to 13.2%. The qCO(2)values increased with the depth in the soils of the Biological Station and did not change in the soils of the Reserve. The pool of C-mic and C-org and the microbial production of CO2 (BR) within the forest soil profiles are presented.