Summary:

The aim of the study was to compare the deadlines of irrigation established on basis of various atmospheric parameters and indicators and an initial verification of their practical usefulness. The study compares four methods for determining the deadlines of irrigation, using the results of a simple meteorological
measurements. Calculations were made for a full season of irrigation, covering the period from 11 May to 15 September. Simulations were conducted for two growing seasons: dry of 2008, and of 2010 wet but with a very uneven distribution of precipitation. Meteorological data from standard measurement conducted in UTP Research Station, located in Mochełek near Bydgoszcz were used. It was found that the indices of water consumption , that have been calculated on the basis of various meteorological parameters differed largely, both in terms of seasonal averages and also extremes, but were characterized by a significant correlation. An irrigation the most saving the water have proved to be controlled by the method of balance by Drupka, and secondly by the method on the basis of precipitation measurements. Most deadlines of irrigation, both in dry and wet season, were established under the balance method using the ratio of water consumption calculated by Hargreaves method. Setting of time irrigating plants by balancing revenues and expenditures of the water on the basis of indicators of Drupka and by only measuring the precipitation, it is recommended for the practice due to the saving water in those methods and use only the simplest standard or automatic meteorological me-asurements.