Natural aspects of a new approach to erosion of loess soils in Poland

Up-to-date studies on erosion, including erosion on loessial soils, are based on the division of an actual topographic surface into three zones assumed a 'priori': top area, eroded slope area and foot-hill area as depositional area. As the main research method for the field survey the soil-levelling cross-section has been used most frequently. Although this method allowed us to introduce erosion protection measures in the form of antierosion fields, however, these measures did not work properly in practice because of two reasons: 1) insufficient recognition of the soil cover variability on the basis of soil-levelling cross-sections for establishing the agroecological zones, and 2) basing the analysis of erosion effects mainly on the course of chemical properties. A new approach, described in this paper, evaluates the soils in the eroded loessial region also on the basis of their physical properties. A point valorization scale was developed basing on eight physical and two chemical features of the eroded soils. Computed synthetic valorization indices allow us to classify the uneroded, totally eroded or deluvial soils into the category of good soils, while those being slightly, moderately or severely eroded are classified as medium quality soils.