Macroand microelements have an effect on the process of photosynthesis and transpiration. Foliar fertilizers increase the content of elements in leaves and affect the course of gas exchange. This work have presented the results of the study aimed to estimate the effect of soil (NPK 280 and 420 kg·ha^-1 ) and foliar (Basfoliar^® 12-4-6, ADOB^® Mn, Solubor^® DF) fertilizer application on the intensity of gas exchange in potato plants of semi-early to late cultivars. In the research hypothesis it was assumed that macroand microelements contained in foliar fertilizers will affect the intensity of process of photosynthesis and transpiration in the field conditions, which in consequence may affect the yield and quality of potato tubers. Measurements of photosynthesis and transpiration were made using the portable gas analyser LI-COR 6400 (DMP AG SA LTD). Readings for gas exchange parameters were performed at several days’ intervals. The obtained high photosynthesis rate, reaching even up to 35.59 µmol CO2·m^-2·s^-1 in 2010, indicated a good general state of plants. The late cultivar Ślęza has shown the highest photosynthesis rate – 18.45 µmol CO2·m^-2·s^-1. No effect of differentiated rates of soil fertilizers on photosynthesis intensity was observed. In the experiment, potato ultivars and the applied rate of soil NPK fertilization of 280 kg·ha^-1 significantly differentiated transpiration intensity. For the semi-late cultivar, the lower rate of soil fertilization resulted in a higher intensity of the process of transpiration. Transpiration proceeded more dynamically after a period of heavy rainfalls. No effect of microelements contained in foliar fertilizers on processes of gas exchange has been indicated.

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