Spatial Distribution of Microbial Biomass and Its Respiratory Activity in Soils of Different Land Uses in the Moscow Region and Metropolitan Moscow

Across eleven administrative districts of the Moscow region and the Moscow metropolitan area, 559 survey sites were studied from 2001 to 2020. These sites were grouped by land use types (forest, meadow and fallow land, arable land, and urban soil) and the main soil groups: Albic Podzols, Folic Retisols, Greyzemic Phaeozems, and Luvic Chernozems. At all survey sites, the dominant vegetation and geographic coordinates were recorded, and soil samples were collected from the upper 10 cm of the humus-accumulative layer. Forest soils were represented by 204 sites, meadows and fallow lands by 120, arable land by 43, soils of small towns (8 in total) by 108 sites, and those of the Moscow metropolitan area, by 84. In towns and cities, survey sites were selected in recreational, residential, and industrial land uses. The soil samples were analyzed for organic carbon (Corg), microbial biomass carbon (Cmic), basal (microbial) respiration (BR), and pH. The Cmic/Corg and BR/Corg ratios were calculated. It has been shown that the microbial parameters of soils for different land uses in small towns did not differ significantly, but in the megalopolis they did. In forest soils, the Cmic, BR, Cmic/Corg, and BR/Corg values were the highest and amounted, on average, to 589 μg C/g, 1.07 μg C–CO2/(g h), 1.99%, and 36.0 μg C–CO2/(g Corg h), respectively; in meadows they were lower, and in arable lands and in small towns they were the lowest (on average, 249 and 328 μg Cmic/g, 0.41 and 0.60 μg C–CO2/(g h), 1.14 and 0.82%, 18.3 and 15.1 μg C–CO2/(g Corg h), respectively). The spatial distribution of microbial indicators of soils in the region is visualized using the spatial interpolation method, separately for natural (forest, meadow, and fallow lands) and anthropogenically transformed (arable land, small towns) ecosystems.