Original paper

Water erosion on agricultural foothill slopes (Carpathian Foothills, Poland)

Święchowicz, Jolanta

Abstract

The paper shows results of soil erosion research undertaken in November 2006 on 7 experimental plots located in agricultural Dworski Stream catchment (Carpathian Foothills, Poland) for two hydrological years (2007 and 2008). All the plots were 2 m wide. Four of them were 22.1 m long while the remaining three were 11.1, 5.5 and 2.8 m in length. All the plots were closed with 2 m Gerlach troughs. Eroded material was collected in tanks placed by every plot, while runoff was registered by means of limnigraphs. The inclination of the plots was 8 degrees. Studies were carried on silty pseudogley soil (Stagnic Luvisols). The main aim of the article is to determine the amount of soil loss in relation to rainfall erosivity and type of crops. In 2007 the rainfall erosivity factor (EI30) was 1628.9 MJ·mm·ha−1·h−1 and turned out to be almost two times as much as it was for 2008 (667 MJ·mm·ha−1·h−1). In the summer half-year of 2007 hydrological year there were 13 slope wash events whereas in 2008 there were none. Runoff varied considerably in the summer half-year. Maximum values of runoff coefficient amounted to 39.2 % for the potato, 34.2 % for the fallow land, 16.3 % for the winter wheat and 12.0 % for the grassland. In the summer half-year of 2007 slopewash values amounted to 27.0 kg.ha−1 for winter wheat, 42.0 kg.ha−1 for grassland, 43,396 kg.ha−1 for potato and 47,340 kg.ha−1 for fallow. During 93 % (2007) and 100 % (2008) of days in a summer half-year, the slopes were stable, because rainfalls did not occur or were too small to initiate overland flow and slope wash. Rainfalls of the maximum 30-minut intensity above 15 mm.hr−1 always resulted in overland flow and slope wash but their morphological effectiveness (the total amount of the transported soil) depended on land use. In the hydrological year 2007, the highest soil erosion during the single rains took place on root crop field and bare fallow.

Keywords

rainfall erosivityrainfall intensitysoil erosion by watercarpathian foothillspoland