Vertical and horizontal variation of carbon pools and fluxes in soil profile of wet southern taiga in European Russia

Vertical and horizontal distributions of soil organic carbon, potential microbial activity and basic soil properties were studied in a boreal mixed forest (Central Forest Reserve, TVER region) to elucidate whether the soil CO2-efflux is related to basic soil properties that affect the C pool and activity. Soil cores (0–100 cm depth) were taken from two transects every 50 meters (44 points) immediately after completion of soil CO2-efflux measurements. Soil was separated into layers and moisture, bulk density, root density and bacterial counts were determined within one day after soil was taken. Microbial respiration, biomass, CN contents and pH were measured within few months. The variability in the soil CO2-efflux and microbial activity was mainly explained by soil bulk density. Results further indicate that laboratory measurements of microbial respiration can represent heterotrophic soil respiration of a distinctive ecosystem in natural conditions, if microbial respiration is measured after the effect of soil handling disappears.