Fire induced water repellency in the forest soil covered with different types of forest floor biomass

The intensity and severity of a wildfire can influence the persistence of soil water repellency (SWR) in the affected area. The effects of fire on the SWR of forest soils depend on the type of forest vegetation, the quantity of the organic component of the forest soil, the characteristics of the organic matter, the soil type, and its properties. Three study sites were located in the Borská nížina lowland (southwestern Slovakia). The first site IL1 represents a 100-years-old stand of Scots pine ( Pinus sylvestris ), the second site IL2 is a 30-years-old stand of Scots pine ( Pinus sylvestris ), and the third site LL is a deciduous stand with a predominance of alder ( Alnus glutinosa ). The article aimed to determine the influence of forest floor biomass (FFB) in IL1, IL2 and LL on SWR induced by different heating temperatures. WDPT test was measured on the surface of burned mineral soil samples without FFB, and two series of measurements were carried out in samples covered with FFB. First were carried on the surface of burned FFB and second, under burned FFB on the exposed mineral soil. Our first hypothesis was that heating temperatures would induce higher SWR persistence on soil covered with forest floor biomass compared to bare soil; the second hypothesis was that different forest floor biomass would induce different post-fire SWR persistence. The differences between the samples covered with FFB and samples without FFB in mean values of SWR induced by different temperatures were not statistically significant for either research site. On the other hand, the highest individual SWR values were measured at or below the forest floor biomass in both deciduous and coniferous forests. The second hypothesis was not confirmed. We found similar fire-induced SWR in the different types of forest floor biomass and the soil under forest floor biomass.