Spatio-temporal differentiation in the intensity of organic matter biological destruction in urban soils under the impact of motor vehicles

The aim of the study was the assessment of the intensity of organic matter transformation in urban soils impacted by auto transport. Thorough seasonal field studies were carried out in 2023–2024 in the southwestern part of Moscow (Russian Federation). The chemical properties of soils, as well as their biological activity, were studied. For assessing organic matter biological destruction two indicators were used, cellulolytic activity and biological oxygen consumption. The pH value of roadside soils was 7.8 ± 0.6 units, electrical conductivity was 185 ± 98 μS/cm, and the organic carbon content was 4.8 ± 2.1%, which corresponds to literary data on urban soils in Moscow. It has been revealed that the biological activity of soils of roadside lawns and median strips is characterized by significant dispersion of values, from 38 to 87%, depending on the season. The highest rates of cellulolytic activity in roadside soils were determined in the summer-autumn and spring observation periods, 11.9 ± 7.6 and 12.0 ± 3.0 mg of readily organic matter mg/(g day), respectively. During the cold season it was several times less, 4.1 ± 3.1 mg/(g day). In spring the biological activity of urbo-soody-podzolic soils (Retisols Prototechnic) in central parts of large urban greenery areas was 6 times lower than in roadside soils. In other seasons, no reliable dependences were found between the studied indicators and the intensity of traffic. The leading factors determining the intensity of organic matter biological destruction in urban soils under the impact of auto transport are specific soil formation in constructozems (Technosols), urban microclimate, as well as diversity in geochemistry of roadside soils due to applying chemicals in roads maintenance work.