Microbial Activity of Technosols Based on Peat-Sand Mixtures in Different Climatic Zones

The microbiological parameters of technosols based on peat-sand mixtures, made in cities of different bioclimatic zones: Apatity (subarctic), Moscow (temperate humid), Rostov-on-Don (temperate dry), were determined for the first time. Such properties as microbial biomass, activity and specific respirationMicrobial specific respiration of technosols were evaluated by the technics of substrate-induced and basal respiration, as well as the physiological profile and functional diversity of soil microbial communities by the MicroResp technic. Fungal biomass was assessed using light luminescence microscopy. In technosols from different climatic zones, microbial biomass carbon and microbial activity (basal respiration) values were found to be lower compared to natural (background) reference soils. Fourteen months after the beginning of the experiment, the microbial biomass in Moscow and Rostov-on-Don decreased by around 1.5 and 2 times, respectively, compared to background soils, whereas in Apatity, on the opposite, it increased. Microbial respiration in the conditions of the north increased by 1.2 times, while in temperate climate it decreased by 1.2 (Moscow) and 3.4 times (Rostov-on-Don). The specific respirationMicrobial specific respiration (microbial metabolic quotient) qCO2 was found to be sufficiently high (3.5–4.5 CO2-C µg-1 Cmic h−1) for the first two years of the study for all experimental stations. Alterations in the microbial community physiological profile of technosols in different bioclimatic zones were discovered, most noticeably demonstrated in Moscow. In terms of fungal biomass, the technosols of Rostov-on-Don are closest to the background soil, while in Moscow it is lower by 2 times and almost 3.5 times in Apatity. After 14 months in the technosols, created in temperate humid and temperate dry conditions, tended to change the functional diversity of microbial communities towards natural reference. Under northern conditions, the physiological profile of the microbial community changed insignificantly. Alterations in the microbiological characteristics of technosols in various bioclimatic conditions revealed over a period of 14 months demonstrate a significant impact of the climatic factor on the formation of stable soil systems.