Taking the decreasing water supplies into consideration, more attention should be paid to reasonable water management. However, in order to be able to minimise the water use and manage it reasonably, it seems necessary to investigate the plants water management and their reactions to water stress. Most of the previous studies concerning the effects of irrigation and fertilisation was conducted on apple orchards and there is little information in the literature about the influence of these factors on stone fruit trees.The study was conducted in 2011, 2013 and 2014 years in the Agricultural Experimental Station in Lipnik. The objective of the present study was to assess the impact of irrigation and mineral fertilization on photosynthetic activity, water use and yielding in cherry cv. ’Kelleris 16’. The first factor of the study was under-crown watering: 0 – controlled objects, with no irrigation, W – irrigated objects, with soil water potential below – 0.01 MPa. The secondary factor was nitrogen and potassium fertilization: 0 NK (control, no fertilization), 1 NK – 80 kg^.ha^-1 (40 + 40), 2 NK – 160 kg^.ha^-1 (80 + 80). The measurements of the leaves photosynthetic activity in each year were taken in the dynamic fashion, using a LCA-4 analyser (ADC Bioscentific LTD, Hoddeson, Great Britain). WUE increased under water shortage conditions and decreased when water was more available. The calculated water use efficiencies, both WUE and WUEI, were higher for the objects fertilized with 1NK dose. The application of the supplementary irrigation as well as NK fertilization significantly influenced the increase in cherry cv. ’Kelleris 16’ yielding. Moreover, it was found a significant positive correlation between yielding and intensity of assimilation, as well as between yielding and water use efficiency (WUE).

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