Application of soil modifiers is a widely used practice in agriculture to improve soil quality in support of good agricultural practices. This paper presents an assessment of the effect of zeolite modifiers combined with four soils of Polish and Slovakian origin on their hydrophysical properties. Under laboratory conditions, the characterization of the applied soil additives was carried out along with particle soil analysis. In addition, the prepared soil mixtures were examined using contact angle and saturated hydraulic conductivity. The results suggest that the increase in hydrophobicity occurred mainly after the application of fly ash, and the values for Polish Silty clay soil and Slovak soils: Sandy soil, Silt loam soil, and Silty clay soil compared to the control changed from 73.02° to 96.22°; 8.67° to 24.88°; 29.23° to 33.94° and 19.9° to 26.16° respectively. The increase in hydrophobicity could be explained by the higher CaO content of the high-carbon fly ash compared to the other materials. The parameters of saturated hydraulic conductivity were reduced after the application of all zeolite materials in the case of Polish Silty clay and Slovak Sandy soils. By filling the space between the soil particles, the porous soil additives decreased the hydraulic conductivity. In Slovak soils such as Silty loam soil and Silty clay soil, the opposite effect was observed. The soil additives increased the number and size of pores, which resulted in faster filtration of water and thus an increase in the saturated hydraulic conductivity value.

Leaf area index (LAI) is an important vegetation leaf structure parameter in forest and agricultural ecosystems. In the paper, we deal with the estimation of leaf area index (LAI) and woody area index (WAI) values in a decline climax spruce forest. The research is conducted on the Červenec research plot at an altitude of 1,420 m a.s.l. in the Western Tatra Mountains in the Jalovecký Creek catchment. We carried out the initial measurements during June, August and October 2023. We estimated the values of the LAI and WAI in the mature living and dead spruce stands using hemispherical photography and HemiView software. LAI and WAI values weren´t corrected with clumping index. The average values in the living and dead forest stands were 4.7 and 3.0, respectively. In addition to the estimation of the spruce canopy layer LAI, we measured the LAI values of the understorey vegetation in the living, dead stand and in an open area using the SunScan instrument and the SunData software. The highest LAI values of the understorey in the living stand (1.9), in the dead stand (5.3) and in an open area (2.9) were obtained in August, when the vegetation was fully leafy. On the other hand, the lowest LAI values in the understorey were reached in the living stand (1.2) and in an open area (1.8) in October, when the vegetation was already without leaves.