The influence of fertilization with various nitrogen forms on cation composition of spring barley cultivated on acid and limed soil was determined in two-year pot experiment. The factors of the study were: liming, fertilization with two nitrogen forms at two levels and fertilization with phosphorus at two levels. The test plant was harvested at its full ripeness. The obtained results indicated that liming of very acid soil contributed to significant increase of calcium, magnesium and sodium ions in spring barley as well as to decrease of potassium ions content. Plants fertilized with calcium nitrate had higher concentrations of calcium, magnesium and sodium than plants fertilized with ammonium sulphate. A different situation was observed in the case of potassium content. The applications of differentiated rates of nitrogen and phosphorus did not cause as significant changes in the content of these elements as liming and fertilization with various nitrogen forms. Liming as well as use of calcium nitrate positively influenced the cation composition of spring barley and contributed to improvement of its fodder value.