Effect of the forecast climate change on the peach tree water requirements in the Bydgoszcz region

The aim of the present research has been an attempt at evaluating the water requirements of peach trees over 2016-2050 in the Bydgoszcz region drawing on the forecast changes in temperature. The paper draws on the forecasting of mean monthly temperature for the Bydgoszcz region in 2011-2050 according to the climate change scenario for Poland SRES: A1B (Bąk, Łabędzki 2014). The water requirements of the peach tree have been determined based on the indispensable precipitation determined by Kemmer and Schulz. The water requirements were calculated for the period January through December and May through September for each year in the 35-year period (2016-2050). The reference period was made up by a 35-year period immediately preceding it (1981-2015). In 2016-2050 in the Bydgoszcz region, in the light of the forecast scenarios of changes in temperature, one should expect an increase in water requirements of the peach tree. Determined according to the Kemmer and Schulz method, the required optimal annual (January-December) precipitation will increase for peach from 486 mm to 612 mm (by 126 mm, which accounts for 26%). The optimal precipitation time variation trend equations show that in the reference period (1981-2015), calculated based on the Kemmer and Schulz number, the optimal annual precipitation was increasing in the peach tree in each pentad by 4.4-4.8 mm. In the forecast period (2016-2050) the water requirements of the peach tree will be increasing in each pentad in a greater range - from 6.4 to 7.2 mm. In the summer period (May-September) determined by Kemmer and Schulz, expressing water requirements, the total precipitation optimal for the peach tree in 2016-2050 will increase by 63 mm.