Jan Rodzik

The effect of land use change on transformation of relief and modification of soils in undulating loess area of East poland.

The change of primary forest areas into arable land involves the transformation of relief and modification of soils. In this study, we hypothesized that relatively flat loess area was largely transformed after the change of land use due to erosion. The modifications in soil pedons and distribution of soil properties were studied after 185 years of arable land use. Structure of pedons and solum depth were measured in 128 and soil texture and soil organic carbon in 39 points. Results showed that soils of noneroded and eroded profiles occupied 14 and 50%, respectively, and depositional soils 36% of the area. As a consequence, the clay, silt, and SOC concentration varied greatly in the plowed layer and subsoil. The reconstructed profiles of eroded soils and depositional soils without the accumulation were used to develop the map of past relief. The average inclination of slopes decreased from 4.3 to 2.2°, and slopes >5° vanished in the present topography. Total erosion was 23.8 Mg ha−1 year−1. From that amount, 88% was deposited within the study area, and 12% was removed outside. The study confirmed the hypothesis of the significant effect of the land use change on relief and soils in loess areas.

Rozwój śródpolnego wąwozu drogowego w świetle badań pedologicznych i pomiarów GPS

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 to4 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.