EN
The aim of the works is to evaluate the effect of habitat factors frequency of moving the grassland on mineral soil, supplied with ground water, on the use of water during the period of grass vegetation. The consumption of water by grassland was expressed by the level of evapotranspiration acc. to lysimetric ET measurements in the years 1973-1993 on the objects of the Experimental Plant of Land Reclamation and Grasslands in Falenty. The studies demonstrated the highly statistically significant effect of all the factors which determined the level of the crop on ET variability. The level of water use by grass community was principally affected by the method of management. Pasture management (moving the cover 6 times) causes the decrease of water use by meadow cover during the vegetation period by 30% and the decrease of hay yield by 40% in comparison to 3-times moving management. Under the conditions of the conducted studies a deficit in air humidity has a highly significant effect on ET variability of grasses in relation to the analysed climate conditions. Then, ET variability was modified by precipitations and air temperature. The studies on the objects with permanent mirror of the ground water showed the statistically significant differentiation of ET level of grass community in the particular outgrowths and the years of the studies, depending on the depth of this mirror.