Nitrogen is a key factor which shapes the fertility and fecundity of soils. Liming and mineral fertilization significantly modify transformations of nitrogen compounds in soil. The aim of our experiment was to evaluate the influence of liming and ammonium sulphate or calcium nitrate fertilization on the content of total nitrogen and its mineral forms in soil. The study was based on chemical analysis of the soil material obtained from a twoyear pot experiment. The design of the experiment comprised 9 treatments in 4 replications on acidic soil and an analogous number of trials on limed soil. The experimental factors were: liming (acidic soil, limed soil), fertilization with ammonium or nitrate nitrogen at two levels (N1, N2) as well as fertilization with phosphorus at two levels (P1, P2). Liming was applied only once, before setting the experiment. The mineral fertilizers were applied every year before plant sowing in the form of fertilizers: ammonium sulphate, calcium nitrate and triple granulated superphosphate. The test plant was spring barley, which was harvested at its full ripeness. The results indicated that the biggest influence on the N-NH4 content was produced by liming and fertilization with nitrogen. The application of calcium carbonate as well as calcium nitrate led to a decrease in the ammonium nitrogen content in soil. The content of nitrate nitrogen was higher in objects fertilized with calcium nitrate than in those fertilized with ammonium sulphate. Liming and nitrogen fertilization had the largest effect on the formation of mineral nitrogen content in soil. Liming contributed to decreased mineral nitrogen amounts in soil. A reverse situation was observed after increasing the rates of fertilization. The application of calcium carbonate and nitrate form of nitrogen contributed to a decrease in the total nitrogen content in soil. This fact can be explained by increased yield of spring barley in the objects limed and fertilized with calcium nitrate compared with the barley yield in the non-limed and ammonium sulphate fertilized trials.