THE EFFECT OF UREA AND UREA WITH UREASE INHIBITOR ON THE CONTENT OF MACRONUTRIENTS IN TUBERS AND TOPS OF POTATOES (SOLANUM TUBEROSUM L.)

MUSILOVA, L., LOSAK, T., HLUSEK, J., VITĚZOVA, M., JŮZL, M., ELZNER, P., FILIPCIK, R., JŮZL, M., BENNEWITZ, E.: The eff ect of urea and urea with urease inhibitor on the content of macronutrients in tubers and tops of potatoes (Solanum tuberosum L.). Acta univ. agric. et silvic. Mendel. Brun., 2012, LX, No. 5, pp. 167–172 In two-year small-plot fi eld experiments in Žabcice u Brna we explored the eff ect of nitrogen fertilisation with urea and urea with urease inhibitor (Urea + UI) on the content of macronutrients (N, P, K, Ca, Mg) in tubers and tops of potatoes of the variety Karin. The experiment involved 7 treatments. Nitrogen rates in treatments 1–7 were the following: 1) 90 kg N/ha – Urea; 2) 72 kg N/ha – Urea; 3) 54 kg N/ha – Urea; 4) 90 kg N/ha – Urea + UI; 5) 72 kg N/ha – Urea + UI; 6) 54 kg N/ha – Urea + UI; 7) unfertilised control. Each treatment was repeated 4 times. Both fertilisers (Urea, Urea + UI) were refl ected irregularly in the contents of N, P, K, Ca, Mg in the potato biomass and were based on the weather of the year, rate of fertiliser and analysed plant organ (tuber, top). In both years the contents of N, K, Ca and Mg were higher in the tops. The P content was balanced both in the tops and tubers. Some changes in the chemical composition were observed particularly in the case of nitrogen. In 2010 the nitrogen content was higher in tubers (1.44–1.65% N)