The aim of the paper was the comparison of sour cherry-tree water requirements in the regions of Bydgoszcz and Wrocław in 1976-2015. The sour cherry-tree water requirements were determined for each year on the basis of air temperature in the period April - August for light soils, medium soils and heavy soils. The sour cherry-tree water requirements in the period April - August in the region of Wrocław were higher than those in the Bydgoszcz region. The sour cherry-tree water requirements in the Bydgoszcz region amounted 253 mm on the heavy soils, 316 mm on the medium soils and 379 mm on the light soils. The sour cherry-tree water requirements in the Wrocław region amounted 261 mm, 326 mm and 391 mm, respectively. From among five months, July was characterized by the highest water requirements. The water requirements in July in the Bydgoszcz region amounted 65 mm on the heavy soils, 82 mm on the medium soils and 98 mm on the light soils. The water requirements in July in the Wrocław region were higher and amounted 67 mm, 84 mm and 101 mm, respectively. In the vegetation period (IV-VIII), the significant tendency to increase the water requirements of sour ...
