A pedological investigation of soil erosion severity on undulating land in Lithuania

Abstract

It is essential that we can rapidly characterize soil erosion severity. This paper describes a field methodology to classify soil erosion severity on Dystric Albeluvisols in Lithuania. The goal was to assess cumulative soil loss due to the combined action of accelerated and natural soil erosion. Evaluation of soil erosion severity helps us understand which segments of the landscape are susceptible to erosion and therefore require soil conservation. Factors considered in evaluating soil erosion severity included the existing genetic soil horizons remaining after soil erosion processes, the estimated thickness of lost soil, and slope inclination. The estimated depth of soil loss due to the combined action of natural (geological) and accelerated soil erosion was 0.1–0.8 m on the undulating hilly topography of the Zemaiciai Uplands of Western Lithuania. Erosion rates increased with slope steepness. Soil erosion changed soil physical and chemical properties. Therefore, natural soil fertility, as indicated by spring barley yields, decreased 22, 40 and 62% on slopes of 2–5° (3.5–8.3%), 5-10° (8.3–17.7%) and 10–15° (17.7–26.3%), respectively, compared with flat land. Crop yield was strongly negatively correlated (R2 = 0.79, P < 0.001, n = 138) with erosion severity. Due to pedological translocation, non-eroded Dystric Albeluvisols had relatively little clay and silt in eluvial (E) soil horizons, with their relative accumulation in illuvial (Bt) horizons . Thus, severely eroded soils had argillaceous top soils, due to exhumation of Bt horizons. The suggested classification system enables rapid assessment of past soil erosion severity and may have broader applicability in areas of Podzolic soils. Key words: Dystric Albeluvisols, soil erosion severity, slope steepness, soil properties, pedology