EN
In the tubers of 5 potato cultivars (Darga, Irga, Jagoda, Fala, Lawina) cultivated in 1993 at the Agricultural University Experimental Station at Mydlniki near Cracow the contents of dry matter, nitrates and nitrites as affected by phosphorus fertilization rate, were determined. The content of nitrates was on average 199 mg/kg and of nitrites 1.83 mg/kg. The calculated values differed with respect to cultivar and phosphorus fertilization rate. Statistically significant differences were found between phosphorus fertilization rate and the contents of nitrates i nitrites in the tubers of cultivars Irga and Jagoda.