Rozwój śródpolnego wąwozu drogowego w świetle badań pedologicznych i pomiarów GPS

Abstract

The article presents the development of a small, midfield form of road, which cuts the side of a loessic valley. The contemporary shape of the surface was determined by GPS measurements (Leica System 500), set together in ArcView and ArcGIS. Changing of its position was determined by a field analysis of the construction of 50 profiles of the Luvisols with varying degrees of erosion or aggradation. Calculation and visualization were performed in the ‘Surfer’ program. The results are interpreted in the context of changes in the agrarian structure since the end of the 19th century. It was found that the development of erosional forms is associated with an intensive use, since the late 1930s, of the road traced at the end of 19th century. Significant rate of its cutting is also the result of earlier soil erosion, due to its agricultural use since the late Middle Ages. Until achieving the depth of about 1 m, the form was the shape of a trough, because the road also served as a zone of turning round during the cultivation of the adjacent transversal-slope fields. In the 1970s, after a change in cultivation mode, erosion took the form of a box-like section. The average annual rate of cutting into the deepest section increased from 2.5 to 4 cm and the depth - to 1.8 m. These conclusions confirm the profile of deposits on the extended cone at the gully mouth at the valley bottom. Their lower series, with thickness of 1.7 m and a massive structure, are products of soil erosion accumulated for several hundred years. The laminated top series with thickness of 0.8 m is distinguished by CaCO3 content growing towards the surface. Its accumulation at a rate of 1.2 cm per year is the result of a deeper cutting of the road on the slope.