The heterogeneity of urban soils in the light of their properties

Despite 30 years of work on the issue of urban soils, there are still differences in opinions on the real significance of soil diversity for the functionality of urban areas. This also reflects a significant difference in the perception of the environment itself by representatives of natural sciences and engineering. The research was carried out in the town and administrative commune of Zielona Gra-a medium-sized town located in the western part of Poland (51A degrees 56'07aEuro(3) N, 15A degrees 30'13aEuro(3) E). This paper is a synthesis of more than a decade of research on soils covering the Zielona Gra urban area. A total of 562 samples were analysed from 105 soil profiles (to a depth of 150 cm) and 32 additional surface samples. Soils were classified according to the WRB 2007. Laboratory tests were conducted using standard procedures for soil investigation. As a result of the research, several soil groups were identified in a relatively small area-Podzols, Brunic Arenosols, Luvisols, Albeluvisols, Gleysols, Phaeozems as well as large areas covered by Hortic Anthrosols, Technic Regosols, Technic Arenosols, Mollic Technosols, Urbic Technosols and Ekranic Technosols. It was found that the transformation of soil under different land use forms was diversified, which was especially connected with soil profile decapitation, building rubble admixture, admixture of wastes, soil covering and compacting. As a consequence of this, different soil properties were noted, especially calcium carbonate content, pH, EC and concentrations of Cu, Pb and Zn. Urban soils are frequently characterized by a strong horizontal and vertical heterogeneity. The differentiation of the soil sites is significantly related to the site age, human impact intensity and the form of land use. Not all properties of soils within urban areas are spatially strongly diversified when areas with a similar construction and use are taken into account. pH values and particle size distribution are unified over large areas of the city.