Identifying the origin of soil water repellency at regional level using multiple soil characteristics: The white Carpathians and Myjavska Pahorkatina Upland case study

Abstract

This paper evaluates the relationship between water repellency and multiple characteristics of topsoil samples belonging to seven Reference Soil Groups, taken from the area of the White Carpathians and the Myjavska pahorkatina Upland. In order to quantify water repellency, the Water Drop Penetration Time test and the Molarity of an Ethanol Droplet test were performed on 210 soil samples. The water repellency data were confronted with a number of categorical and numerical soil variables. It was observed that the particular land-use type and the nature of soil parent material, both are related towards detected water repellency of soil samples. All samples taken from the agricultural (tilled) and grassland soils were wettable. On the contrary, all samples which exhibited water repellency, belonged to the group of forest soils, although, not all forest soils were water repellent. Samples which showed considerable repellency were soils developed either on consolidated sedimentary rocks (sandstones, limestone-dolomitic rocks, flysch) or unconsolidated sediments of aeolic or polygenetic origin. On the other hand, the great majority of soils developed on recent alluvial deposits were clearly wettable. Correlation and regression analyses showed that susceptibility of forest topsoil to exhibit water repellency generally increases with increasing sand and organic carbon contents, and with a simultaneous decrease of soil pH value. An interesting observation came out regarding CaCO3 and water repellency relation. Although certain soils with higher CaCO3 exhibited water repellency (Rendzic Leptosols and Cambisols), all soils that developed on loose sediments and contained CaCO3 were wettable.