PEDOHYDROLOGICAL CYCLES DEVELOPMENT IN THE SPRUCE ECOSYSTEM UNDER THE CURRENT CLIMATIC CONDITIONS OF SLOVAKIA

The paper analyzes the balance of soil water in the spruce stand mountain conditions in the Upper Orava region, Slovakia. The long-term research (1991-2014) shows that the predominant moisture interval in the vegetation period (V-X) is semi-uvidic soil interval (MCC -PDA) with a good or sufficient supply of usable water. In the growing period, (VI-VIII) there is a marked differentiation of the soil water supply in the whole physiological profile (0-100 cm). In the summer months (VII-VIII) soil moisture varies between MCC and wilting point (WP) hydrolimites, while in dry periods that are accompanied by higher temperatures and precipitation deficiency, the available water supply in the surface and middle layers (0-40 cm) may fall to low or lower inadequate supply. Ongoing climatic conditions during the study, with a gradual reduction of precipitation (81.3% of average) and increase of air temperature (+ 1.3 degrees C), pose the danger associated with the development of dry periods to the spruce. The lack of water affects the surface and middle layers of soil (0-40 cm) mainly in extremely dry and longer drought periods, the shortage of available water also occurs in deeper horizons for a short time. Under such conditions the spruce is threatened with drought, and its response is physiological weakness, reduced evapotranspiration, increased fall of assimilation organs, reduced increment, degradation of physical and hydrological properties of soil, and reduction of transport of mineral and organic substances.