Historical and present slope evolution in hilly farmland (on the example of the Myjava Hill Land, Slovakia)

Abstract

The overwhelming majority of the Myjava Hill Land, namely its eastern and central part, is specific with the relatively short-term human interference into the original natural landscape. The mentioned territory was settled in two stages between the early 14th and late 18th centuries. It is possible to distinguish two different types of slope evolution in this area in the past after the transformation of former woodland into farmland. The first type was characteristic by the leading role of linear water erosion, occurring in time of colder and wetter fluctuations in the course of the Little Ice Age, when disastrous gully erosion resulted in the formation of a dense network of gullies. The second type was typical for the combined acting of areal water erosion and tillage erosion. It was linked temporally with the periods between and after climatic fluctuations and spatially with the slope portions not suffered by gullying. The operation of these processes, lasting centuries, resulted in the lowering of the surface of slopes and ridges with different nature in case of slope portions cultivated along contours and gradients. The slope evolution was totally changed due to the collectivization in agriculture. Its results are the total smoothing of slopes and marked acceleration of their lowering. Conclusions of this study are still more valid for the hilly environments in Slovakia with much longer duration of agricultural interference.