Results from studying urbanized territories highly depend on approaches and methods of interpreting data obtained in the course of investigations. A case study was made in the industrial city of Usolye-Sibirskoe (Irkutsk oblast, RF) to investigate and map the current ecological-and-biochemical status of soil cover affected by urbanization and technogenesis. T. V. Aristovskaya’s and M. V. Chugunova’s rapid method was used to reveal high indicators of the level of alkaline-acid conditions and biochemical activity of urban soils. The mapping enabled identification of the local features of the urban territory. A considerable part of it is occupied by soils with weak alkaline pH index (7.3–8.0). In absolute values, it is 6083.3 ha, or 77.2 %. The study determined a high and very high level of the soil biochemical activity. They occupy a large area of 6079.2 ha, i.e. 76 % of the city. A substantial increase in soil biochemical activity can lead to loss of a biogenous element, nitrogen, and this cannot be regarded as a positive phenomenon. Experimental data on the SBA – рН system for the residential zone of the city made it possible to determine a close correlation between them to be statistically significant.