The paper presents the results of soil research in the Prinevskaya lowland within the boundaries of St. Petersburg. The study of the direction and rate of change in the properties of fallow lands, aimed at understanding the process of post-agrogenic transformation of soils, as well as the development of a monitoring system for changes in the parameters and properties of fallow soils will contribute to the optimization of the soil-ecological state of soils excluded from agricultural turnover in St. Petersburg and the Leningrad region.