Occurrence of dry periods in oak stands and their effects on soil water supply

Abstract

The presented paper deals with the impact of long lasting dry periods on the water regime in oak forest stands growing in lowlands. Cycles of low or insufficient available water supply reflect changes to soil moisture conditions that may cause physiological weakening of the trees. The research was carried out on the research plots in Čifáre, during years 1984-2007. Soil samples were taken from the depth of 0-20 and 0-100 cm. Soil water dynamics was observed especially in the extremely dry years 2000 and 2003. The results have confirmed the soil desiccation beginning in autumn. Dry periods in the growing season are characterized by an semiarid and arid soil moisture interval in the upper 20 cm soil layer. Here, also the hardly accessible or even inaccessible for plants water was observed. Across the whole physiological soil profile, the semiarid interval with soil moisture content ranging between the point of diminished availability (PDA) and the wilting point (WP) was dominant.