ECOLOGICAL ANALYSIS OF SOWN GRASSLANDS IN LOWLAND REGIONS OF SLOVAKIA

During the years 1971 to 1991 we analyzed temperature and moisture sup ply of sown grasslands depending on altitude in lowlands of Slovakia. As an integral index of temperature conditions of grasslands, the sum of temperatures during observed period (the 1st April to the 31st Octo ber) was applied. Moisture conditions were evaluated on the basis of c alculated hydrothermic coefficient K-3 according to Kurpelova (1983). The results obtained were tested according to the individual districts and altitudes (Tab. I). The graphical scheme of the grasslands temper ature and moisture supply in lowlands of Slovakia are stated in Pig. 1 . Temperature supplied to grasslands (2 898 to 3 443 degrees C) during grazing period does not appear to be a limiting factor of the phytoma ss production. The values of irrigation coefficient (K-3) fluctuate fr om 0.77 to 1.77 in evaluated stands. The driest region is western Slov akia. On the course of the years 1991 to 1995, we registered 151 tropi cal days and 407 summer days (Tab. II). Balance between intake and exp enditure of moisture was at the value K-3 of 1.2 (Fig. 1). The stands up to 250 m of altitude have permanent moisture deficiency. The stands above 251 m do not have permanent moisture supply and in dependence o n moisture balance of the year they have relatively good conditions fo r sown grasslands growing and their utilization by animal grazing.