Soil erodibility factor (K) in soils under varying stages of truncation

Abstract

Soil erosion is the most widespread problem in soil management. It leads to changes in the properties of soil horizons, which in turn can also affect the pace of slope processes. This may be signifi cant problem in young morainic areas where truncation of clay-illuvial soils (Luvisols, Retisols) transforms both the organic carbon content and texture of arable horizons. Changes in soil susceptibility to erosion can be measured using the soil erodibility factor (K) widely used in erosional models. The aim of the submitted study is a calculation of the erodibility factor (K) for soils represented different stages of truncation in a hummocky landscape of Northern Poland. Erodibility factor was calculated using the formula of the Erosion Productivity Impact Calculator (EPIC) model. For assessment of the factor, soil profi les were divided into four groups, varying degrees of soil truncation: completely eroded, strongly eroded, slightly eroded and non-eroded arable soils, noneroded forest soils. In the course of the performed study, it was noted that the soil erodibility K factor values were between 0.0172-0.0352 t·ha·h·ha-1·MJ-1·mm-1 and depended on the stage of soil truncation. Properties of surface horizons of completely eroded soils accelerate erosion about 6% compared to strongly eroded and 12% to slightly eroded soils and even 48% as against non-eroded forest Luvisols/Retisols. The main factors affecting erodibility growth in truncated profi les was a revealed decrease in both - ccarbon content and sand fraction in humus horizons. Susceptibility to erosion was also increased by exposure of Bt or C(k) horizons richer in clay fraction.