Urban soils of one of the new Moscow districts as sources of methane and carbon dioxide to the atmosphere

Abstract

The regularities of methane and carbon dioxide emission from soils and the factors that determine them were investigated in the settlement of Kommunarka (New Moscow) on the building sites of 1938-2014 years and in the recreational zone. It has been shown that the intensity of the formation and oxidation of methane and, as a consequence, the content of this gas in soils and emissions into the atmosphere depend on the time of creation of Urbic Technosols (Folinovic) and the age of other urban soils. In the summer period, the emission of methane from the soils of the residential zone was absent according to median values ​​or did not exceed 0.01 mg CH4·m-2·h-1. Methane was absorbed from the atmosphere. However, local CH4 emission from some soils was observed. During the period with sufficient moisture, maximum emission from the youngest Urbic Technosols (Folinovic) reached 5.25 mg CH4·m-2·h-1 and decreased by an order of magnitude from soils near houses built in 2001 and older. During the dry period, the local emission from young Urbic Technosols (Folinovic) was only 0.03 mg CH4·m-2·h-1 and decreased by three times near houses built in 1938. The most dangerous source of methane to the atmosphere was waterlogged urban soils containing household waste. The maximum CH4 emission from them was 57.15 mg CH4·m-2·h-1. The content of carbon dioxide in the technogenic horizons of Urbic Technosols (Folinovic) and Urbic Technosol (Someriumbric) decreased with an increase in the building age. The emission of carbon dioxide, to a lesser extent than methane, depended on the time of soil formation. Nevertheless, under conditions of sufficient humidification, the maximum CO2 emission were from young Urbic Technosols (Folinovic) (up to 3606 mg CO2 ·m-2·h-1). Under conditions of insufficient moisture, maximum CO2 emission were from the soils of older microdistricts (up to 664 mg CO2 ·m-2·h-1) and from Folic Gleyic Fluvisol (up to 1901 mg CO2 ·m-2·h-1).