Long-Term Dynamics of Carbon Emission in Artificial Soils under Urban Lawns in the Steppe Zone Conditions

The carbon emission by artificial soil structures (constructozems) of different compositions under conditions of urban landscapes of the steppe zone is considered. The study has been conducted at the experimental facilities for studying soil constructions organized in 2020 at the Botanical Garden with Southern Federal University using lawn grasses as a vegetation cover. The background is a plot of Haplic Chernozem in the Azov Steppe area with restored steppe vegetation at the final stage of ecological succession. Long-term monitoring shows the dependence of carbon emission on hydrothermal conditions, namely, the highest emission is observed at the soil moisture content of 20–30% and the temperature of 25–35°C in the root layer. The genesis of materials composing the remediated humus (RAT) horizon determines the main differences in emission dynamics. The intensity of carbon emission by the constructozems with peat as the main component is considerably higher in the first year, reaching 25 g С/(m2 day) with an interquartile range of 5.9–13.7 g С/(m2 day) as compared with the background soils, reaching 17.5 g С/(m2 day) with an interquartile range of 4.7–12.0 g С/(m2 day), and the constructozems with dark humus horizon, reaching 15 g С/(m2 day) with an interquartile range of 2.5–7.6 g С/(m2 day).