Nitrogen is a macronutrient that increases crop yields the most, but its high doses and low uptake by plant may have a negative impact on the environment. The aim of the study was to evaluate the dynamics of nitrogen uptake and utilisation from the mineral fertiliser and from the soil by spring triticale (Triticosecale Wittm. ex A. Camus) calculated by the isotopic dilution method. The first experimental factor was the application of the total nitrogen dose of 120 kg N·ha-1 as follows: a whole dose 120 kg N·ha-1 pre-sowing, 60 kg pre-sowing and 60 kg at 35 BBCH, 40 kg pre-sowing and 40 kg at 22 BBCH and 40 kg at 51 BBCH. The second factor was the growing stage of triticale, according to BBCH: 22, 34, 51, 65, 75 and 92. Nitrogen was applied in the form of (NH4)2SO4 with excess of isotope 15N of 5%. Following the application of a single nitrogen dose, spring triticale took up 65.05 kg N·ha-1 from the fertiliser, and the utilisation coefficient of N amounted to 54.3%. The split application of the total amount of fertiliser divided into two and three doses increased the amount of nitrogen taken up from the fertiliser by 7.31 and 14.90 kg N·ha-1, respectively, and the value of the coefficient of its utilisation rose by 6.0 and 12.4%, respectively. The amount of this element taken up from the soil reserves was not dependent on the test variants of nitrogen fertilisation. A significant increase of the uptake and utilisation of nitrogen from the fertiliser by triticale was obtained from BBCH stage 22 to stage 65. From BBCH stage 65 to stage 92, no significant increase in the amount of nitrogen taken up from these sources or in the value of the coefficient of utilisation was noted.  

24.1.2019