Yield of winter barley with different systems of mineral fertilizer and use of urease inhibitor

Abstract

The use of urease inhibitors with nitrogen fertilizers is gaining relevance. There was a need to substantiate the expediency of combining these technology elements when growing winter barley. We conducted field experiments at the Lviv National Environmental University in the Banded Forest of the Western Forest Steppe conditions in 2020–2022. Our research goal is to describe the interaction of mineral fertilizers with the N-LokTM brand inhibitor, which restrains the formation of nitrates but improves the agrochemical parameters of the soil. This had a positive effect on the yield of winter barley. The soil is a dark gray forest gilded light loam with low humus. We used traditional methods of field research and standardized methods of laboratory analyses. The nitrogen fertilization system N97(NH4NO3) during vegetation restoration + N-LokTM (before sowing or during vegetation restoration) on the background of N23P60K60 ensured the initial content of easily hydrolyzable nitrogen in the arable layer of 132–136 mg/kg of soil. Applying N97(NH4NO3) + N-LokTM to winter barley during the restoration of vegetation on the background of N23P60K60 under plowing provided the highest yield in the experiment of 7.69 t/ha on average for 2020–2022. The average grain increase relative to the N97(NH4NO3) control (vegetation restoration) on the N23P60K60 background was 1.08 t/ha. On the other hand, applying N97(NH4NO3) during the restoration of vegetation + N-LokTM in autumn before sowing on the same background contributed to a more significant yield increase – by 1.26 t/ha only in 2021. The absence of a phosphorus-potassium background in the winter barley fertilization system reduced the crop yield by 0.11–0.44 t/ha. The significant importance of mineral fertilizers for obtaining high grain harvests, especially in less good years, is proven by the established high correlation coefficients of the parameters of available compounds of nitrogen, phosphorus, and potassium at the start of the growing season with the harvest in 2020–2021. The regression 3D model of winter barley grain yield under the influence of the synergistic effect of nitrogen fertilization rates and the resulting enrichment of the soil with easily hydrolyzable nitrogen illustrates the importance of fertilizers for increasing the fertility of the dark-gray podzolized light loam soil in Pasmovy Pobuzhzhia of the Western Forest Steppe.