Using, as an example, the key plot established along meridian 78 in the north of Novosibirsk oblast, we identified and described ten circuses equal in size and 20 km in diameter. An analysis is made of the composition and characteristics of soil spectra (of the ranked lists of soil variants) for each circus having regard to changes in mean annual temperature and the location in the three subzones: northern forest-steppe, the subzone of hemiboreal forests, and southern taiga. A regional characteristic is given to the spatial structure of soil structure on the study territory of the West Siberian Plain. It is shown that the soil cover on the interface of the subtaiga–northern forest-steppe and subtaiga–southern taiga interface is characterized by a subzonal differentiation: the northern belt of northern forest-steppe is distinguished by the formation of meadow-chernozem solodic soils, meadow solonetzes and meadow saline soils with a general occurrence of peaty boggy low-level gley soils. The belt of West-Siberian small-leaved birch-aspen forests (subtaiga) differs from the northern belt of northern forest-steppe by the presence of grey forest gley soils, and by the absence of meadow-chernozem soils (both solonetzic and solodic) and meadow saline soils. They are unified by peaty boggy low-level gley soils with a maxima occurrence in the subtaiga subzone. The composition and characteristics of the soil spectrum in the southern belt of southern taiga are responsible for its considerable isolation from the other two subzones: occurrence of soddy gley soils, peaty raised boggy soils, and peaty raised boggy gley soils with the involvement of peaty boggy transitional soils. Subzonal soil series were identified by analyzing soil spectra. The circus method of investigating the composition and characteristics of soil cover coupled with identification of comparable territories and analysis of soil spectra, was used to obtain new information which cannot be acquired by some other technique, and to identify the unique regional features in the soil distribution in Novosibirsk oblast.Keywords: soil spectrum, soil variant, circus, northern forest-steppe, hemiboreal forests, southern taiga.