assessment of the water requirements of a mountain pasture sward in the Polish Western Carpathians

The water requirements of the pasture sward using the Penman-Monteith method (FAO- -56), which is seldom applied in Poland, was assessed. The reference crop evapotranspiration ET(o) from a hypothetical grass crop with an assumed crop height of 0.12 m, a fixed surface resistance of 70 s·m–1 and an albedo of 0.23, was used. These assumptions are similar under conditions of ruminant grazing. ET(o) was computed by using meteorological data from 43 weather stations. The crop evapotranspiration ET(c) is the product of ET(o), and single crop coefficient K(c). The differences between precipitation and ET(o) and ET(c) (climatic water balances) were determined for mountain pastures. The results were summarised form of a table and maps of isohyets and isolines elaborated by applying the Geographic Information System techniques (Arc View 9) with the data interpolated by the geostatic method (Kriging).