This experiment was conducted at the Lviv National University of Nature Management (LNUP – Dublyany) in 2020-2021, in the Pasmovo Pobuzhye area of the Western Forest-Steppe of Ukraine, on soil that was dark-gray, podzolic light loam, low in humus (Greyic Luvic Phaeozem). The study aimed to determine the activity of nitrapyrin in the form of N-Lock™ in soil after applying different doses and forms of nitrogen fertilizers to a winter barley field. The agrochemical properties of the soil were determined according to classical indicators. The soil reaction in the 0-20 cm horizon was slightly acidic, with pHKCl of 6.10-6.11. The content of easily hydrolyzable N in the 0-20 cm horizon was 65-70 mg kg-1 of soil, decreasing down to the depth 40 cm to 50-53 mg kg-1. The content of nitrate anion changed from 20-28 mg kg-1 in the 0-20 cm layer to 16-18 mg kg-1 in the 20-40 cm layer. Fertilization of winter barley N37 in the phase of the onset of spring vegetative growth with the introduction of N23P60K60 in the autumn for pre-sowing cultivation without the use of nitrapyrin was less effective. The use of the urease inhibitor in the early vegetative growth phase rather than at the phase of resumed vegetative growth alongside the same doses of mineral fertilizer contributed to the harvest of 7.1 and 7.4 Mg ha-1 grain in 2020 and 2021, respectively. In general, the yield of winter barley correlated with the dose of nitrogen fertilization in 2020 (r ± = 0.76) and in 2021 (r ± = 0.81), while the concentration of nitrates in the arable layer correlated with the dose of fertilizer in 2020 (r ± = 0.88). The calculation of the payback of fertilizers showed that the application of N23P60K60 (NH4)2HPO4 + NH4NO3 + KCl + N37 (NH4NO3) + nitrapyrin (N-Lock™) in the phase of spring vegetative growth is the most economically viable option of providing nitrogen nutrition to winter barley in the market situation of 2021.

28.1.2023