Soil erosion led to the severe transformations of the soil cover of young morainic areas of northern Poland. Main alterations are connected with soil truncation on summits and in upper part of slopes, whereas at foot slopes and within depressions colluvial material is accumulated. Information and knowledge about the extent or intensity of erosion are mainly derived from sophisticated geospatial models or laborious field works. To reduce the effort associated with development of studies on erosion the use of easily available cartographic sources is required. The main aim of the paper is an elaboration of key to reinterpret information taken from soil-agricultural maps in the context of determining the degree of pedons truncation. The study is based on a comparison of the properties of soils representing various classes of erosional alterations with the data on existing maps. The correlation between descriptions recorded in the form of cartographic symbols with properties of pedons divided into several classes of vertical texturecontrast soil truncation and results from potential erosion maps was elaborated. The application of developed interpretative principles allows calculating the share of soil truncation classes within investigated area. The five test plots (each - 1 km2) were located along the north slopes of Noteć Middle Valley and Toruń Basin. The proposed interpretation of soil-agricultural maps reveals their significant value in studies on extent and degree of erosional alterations recorded in soil cover.