Nitrogenous substances in potato (Solanum tuberosum L.) tubers produced under organic and conventional crop management

The contribution presents data on crude protein and protein, free amino acid and nitrate contents in potato tubers produced under different crop management – conventional and organic. Field trials were carried out with five potato cultivars on two sites of different altitude in 2005. Mean content of crude protein was significantly higher in tubers from organic crop management than in tubers from conventional system (10.92 and 9.76 % in dry matter, respectively). Similar result was observed in protein content (5.44 and 5.09 % in dry matter, respectively). Cultivar was the factor having the highest direct effect on crude protein as well as protein contents. Tubers from conventional crop management showed an increased tendency to accumulate nitrates.