Application of de-icing salt affects the chemical properties of the soil, and consequently the growth and physiology of the plants in the road-side areas. Effects of de-icing salt applied for road maintenance was studied in the area of Pokljuka (Triglav National Park), where a reference site without the impact and two sites exposed to intensive use of de-icing salt were selected. Plant growth rate and selected physiological parameters were measured on Norway spruce (Picea abies). The following parameters were measured in the years 2009 and 2010: photochemical efficiency of photosystem II (PS II), water potential, transpiration, the content of chlorophyll a and b and the cations (Na+, K+, Ca2+ and Mg2+) in the needles. In these sites, soil and snow samples were taken for further analyses, where the chemical parameters, namely, the electrical conductivity, and the cation exchange capacity (Ca2+, Mg2+, K+, Na+) were measured. Analyses showed significantly higher levels of Na+ in the snow and in the soil in the spring samples. Statistically significant differences between salted and unsalted sites were calculated in case of plant water potential, as well as in the biomass of shoots. In the site V1s, where the soil is shallower, most of physiological parameters showed statistically significant differences in comparison with the reference site (V6ns). Most probably, due to less favourable growth conditions and lower water capacity of those soils, the effects of de-icing salt are more pronounced. In the year 2013, after the winter, when the highest amount of salt was applied, the growth of plants was significantly lower at both salted sites, in comparison with the unsalted, reference site.
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