Variability in macroelement content in the aboveground part of Helianthus tuberosus L. at different nitrogen fertilization levels

The contents of nitrogen (N), potassium, phosphorus, calcium, magnesium and sodium were estimated in tubers of Jerusalem artichoke Helianthus tuberosus coming from the field experiment conducted over 2010-2012. The experimental factors were the cultivars of Jerusalem artichoke cvs. Albik and Rubik and different nitrogen fertilization levels, against phosphorus and potassium fertilization and the full dose of manure. Determination of elements in the soil and the dry weight of the aerial parts are performed by standard methods. When using a fixed level of phosphorous-potassium fertilizer, the highest sodium content was obtained at a level of 50 kg N/ha, magnesium and sulphur at a dose of 100 kg of N, nitrogen - 150 kg N/ha, potassium and calcium - in the objects of fertilizer phosphorus-potassium, and phosphorus - in the building control without fertilization. Cv. Albik proved to be more abundant in mineral elements than cv. Rubik. The latter was characterized by a higher stability of characteristics.