Assessment of soil fertility in arctic cities using the soil-ecological index

The fertility of urban soils in the Arctic is limited by harsh climatic conditions and high anthropogenic pressure. In addition to the typical impacts of residential use, recreation, and transportation common in any urbanized areas, the ecosystems of Russian Arctic cities are subject to the technogenic influence of heavy industry hubs, which often serve as the foundation for these cities. Under such conditions, the soil cover of the largest cities in the Russian Arctic — Murmansk, Vorkuta, and Norilsk — has formed. An analysis of the physical and chemical properties of urban soils, an assessment of their fertility, and the limiting factors are necessary for the creation and maintenance of urban green infrastructure, which is one of the key factors in the ecological comfort of city life. This study evaluates the acidity, organic matter and total nitrogen content, availability of mobile forms of phosphorus and potassium in the topsoil of these cities and provides an integrated assessment of their fertility based on the soil-ecological index (SEI) by I.I. Karmanov, adapted within the study for application to northern soils and territories. It is shown that, based on the combination of indicators, the soils of the studied sites form the sequence Murmansk > Vorkuta > Norilsk, from the most fertile to the least fertile. The influence of anthropogenic factors on soil properties is noted, which can be both positive (a decrease in average soil acidity across all sites) and negative (toxic concentrations of mobile phosphorus in the soils of Murmansk). Based on the obtained SEI values, it is concluded that the soils of the studied sites have relatively high overall fertility, comparable to that of soils in the middle and southern taiga.