Biological activity of urban soils of park tree plantations with different levels of recreational load

The research was conducted in the parks of the city of Dnipro, within two functional zones of urban territories in steppe conditions, allocated in accordance with the zoning of urban areas. For the studied test plots, taking into account the recreation coefficient, minimal, moderate, and strong levels of recreational load were allocated. Applied methods for determining the biological activity of the soil, statistical methods of data processing (descriptive statistics, the method of multiple comparisons of means according to the Tukey criterion) were used. The cellulose-destructive activity of the soil was determined by the rate of cellulose mineralization, by weight loss (in percent). Proteolytic activity was calculated by the percentage of decomposition of the gelatin coating on glass. In the study of natural associations of microorganisms in soil, the method (modified by Kholodny) was used. According to the results of the research, it was found that on average the cellulolytic activity of soils in parks in the city varied from 10.23±8.41% (Tunelna Balka tract) to 26.48±0.98% (Khmelnytskyi park), which indicates a different degree of enrichment of soils with the enzyme cellulase. The highest cellulolytic activity was recorded in Khmelnytskyi park. In the soil on the territory of the Tunelna Balka tract, the cellulolytic activity indicator turned out to be the lowest. The proteolytic activity of soils in the territory of the city parks studied varied from 44.32±4.33% (Botanical Garden of the O. Honchar DNU) to 64.62±1.15% (Kozak Glory Park – Kyrylivka), which indicates a different degree of enrichment of soils with the enzyme protease. It was found that in the soils of the landscape and recreational urban area (Forest Park of Druzhba, Park of Cossack Glory – Kyrylivka) and in the residential area and the urban center of the urban area (Khmelnytsky Park) with an increase in the level of recreation, cellulolytic activity increases; for the proteolytic activity of edaphotic soils of the landscape and recreational urban area (Forest Park of Druzhba, Park of Cossack Glory – Kyrylivka) the opposite trend was observed – with an increase in the level of recreation, proteolytic activity decreases.