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UAN is a popular nitrogen fertilizer, broadly used in world agriculture. Research concerning the effects of this fertilizer is just as common. Contrarily, studies on the combined application of UAN with P, Mg or S are lacking. This fact has stimulated our study, undertaken in order to evaluate the effects of maize grown for grain and fertilized with UAN enriched with the macronutrients (P, Mg and S) on the crop’s yields and nitrogen metabolism. The following nitrogen fertilizers were applied: UAN 32%N, UAN + S—26% N + 3% S, UAN + P (Medium)—26% N and 11% P2O5, UAN + P (Starter)—21% N and 18% P2O5, UAN + Mg—20% N + 4% Mg. Based on the results of chemical analyses and yields of maize, the following indicators of nitrogen use efficiency (NUE) were calculated: agricultural efficiency (AE), physiological efficiency (PE), internal N utilization efficiency (IE), reciprocal internal N utilization efficiency (RIE), grain share in N accumulation (HIN), recovery of N from mineral fertilizers (RN) and partial nitrogen balance (PNB). The highest grain yields were harvested after the application of UAN + S/UAN + Mg, and after the pre-sowing and top-dressing application of UAN or UAN + P (Medium). Values of all calculated nitrogen use efficiency indicators were more strongly dependent on the weather conditions, which determined volumes of maize yields in a given year, than on the applied fertilization.

The aim of this research has been to analyse the effect of a cultivation system on the content of minerals in carrot roots. Roots of two carrot cultivars (Koral and Bolero) grown in organic plantations and plantations maintained according to integrated agriculture guidelines were chosen for the study. The thermal and moisture conditions differentiated the content of macro-and microelements more than the cultivation system or genotype specific traits of the cultivars did. In general, a significantly higher content of the analysed minerals was observed in the first year of the experiment. Carrot grown in the integrated system contained higher amounts of N and Mg as well as Cu, Zn and Mn, while organic carrot roots had more P, Fe and Pb. The late cv. Koral contained significantly more P as well as Mg and Cu, Zn and Pb, while the cultivar Bolero was richer in N. With respect to the other elements, no differences were determined between the cultivars. After storage, the content of N in roots of both cultivars decreased, while the levels of the other macronutrients was higher. Larger changes in the content of N, Na, Mg and Ca were detected in roots of the carrot from organic plantations, while P and K differed more in carrot roots from the integrated system.

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