THE DISTRIBUTION OF NITRATES IN THE POTATO PLANT IN DEPENDENCE ON NITROGEN APPLICATION RATES

Three-year trials were carried out to study three varieties of different length of the growing season for nitrate contents in tops, roots and tubers of a plant in the main growing stages. At the same time the proportion of nitrates in organs of a plant of the total amount of nitrates withdrawn by the whole plant was evaluated. It was found out that the above-mentioned values are dependent on main nutrients, especially on nitrogen, whereby an intensity of the influence of these factors depends, at the same time, on the variety and on the growing stage. The effect of nitrification inhibitor was not unambiguous, its positive effect in a decrease of nitrate contents was closely connected with the growing stage and with the variety whereby this was applied in the vegetative organs of a plant.