Summary:

The study estimated the needs of emergency irrigation in malting barley and illustrated their high temporal variability. The original test method, based on the results of many years of field experiments was used. Experiments were carried out in the area of particular deficit in the water (region of Bydgoszcz) on two soil types: very light with a drained subsoil and light with a dense subsoil. A total of
17 annual experiments were carried out, in three multi-year cycles, involving
13 growing seasons.
There was a significant correlation between grain yield at a non-irrigated plots, and increases in grain yield under the influence of irrigation and the amount of precipitation during the period of increased water needs of barley, including the months May and June. Based on the analysis of these relationships and the total rainfall in May and June in the years 1971-2010, it was found that the great barley irrigation needs, requiring the use of at least 5 doses of irrigation (in total at least 100-120 mm of water) are found in the region of Bydgoszcz on the very light soil in 30% and on the light soil in 12.5% of the years. The use of irrigation in these years leads to a significant increase in grain yield of barley, of at least 2.50 t.ha-1. In the current economic conditions, the value of even such high-production effects of sprinkler irrigation does not provide a cost-effectiveness of this treatment. An argument for the desirability of the introduction of irrigation for growing malting barley technology can be a beneficial change of grain quality. The experiments showed that irrigation resulted in not only the growth and stability of grain yield, but also contributed to the gathering of raw material that meets the criteria of suitability for brewing, regardless of the existing shortages of precipitation in the growing season.