Summary:

This paper attempts to evaluate rainfall in the context of expected climate changes for the purpose of irrigating plants. For a chosen meteorological station in Central Poland total precipitation was being simulated for conditions current and expected, according to GISS Scenario (GISS Scenario as typical for Poland assumes doubling the CO2 concentration as expected for years 2050-2060). Two 300-year daily rainfall series were compared to analyse periods for crucial
irrigating starting in May and ending in September. For the simulated data prob-ability density function of total rainfall were estimated in examined periods and subsequently used for tail area approximation.
The results present a slight increase in the average sums of rainfall (up to
5 per cent) in considered periods, as well as much greater height variance (as much as 20 per cent). In the context of irrigation, this means a greater risk of drought and a need for providing water requirements for plants in critical periods.
The results suggest a need to use a comprehensive model taking en bloc meteorological variables into account.