The value of phosphorus-potassium fertilizers for the action of nitrogen and nitropyrin by the winter barley cultivation in Western Forest-Steppe

Abstract

Experiments were conducted at the Lviv National University of Nature Management in the area of Pasmove Pobuzhzhia of the Western Forest-Steppe nature-climatic zone from the fall of 2019 to 2021. The research aim – to find out the effect of phosphorus-potassium fertilizers at different rates of nitrogen application and the use of the urease inhibitor N-Lok^TM, which deters nitrates’ formation, on the agrochemical parameters of the soil and the yield of winter barley. The soil is a dark-gray forestal gleyed light-loamy with low humus content (Greyic Luvic Phaeozem). Traditional methods of field research and standardized methods of laboratory analyzes were used. On the phosphorus-potassium background P₆₀K₆₀, the application of various nitrogen fertilization systems of winter barley in dark-gray forestal gleyed light-loamy soil with low humus content before the beginning of spring vegetation, the 0–20 cm arable layer contained 35–45 mg/kg of soil more (depending on the year) mobile phosphates and 29–33 mg/kg more exchangeable potassium than without background.

Nitrogen fertilization systems N₉₇(NH₄NO₃) during vegetation restoration + N-Lok^TM (before sowing) or N₉₇(NH₄NO₃)+ N-Lok^TM during vegetation restoration on phosphorus-potassium backgrounds P₆₀K₆₀ and total N₁₂₀ ensured the initial content of easily hydrolyzable nitrogen in the arable layer 132–136 mg/kg of soil, depending on the conditions of the year.

Application under winter barley N₉₇(NH₄NO₃) + N-Lok^TM in 2020 during the restoration of vegetation on the background of N₂₃P₆₀K₆₀ under plowing provided an increase in grain yield by 0.94 t/ha, in 2021 – 1.09 t/ha. Instead, application of N₉₇(NH₄NO₃) during the restoration of vegetation + N-Lok^TM in the fall before sowing on the same background contributed to an increase in yield by 0.87 t/ha in 2020 and 1.26 t/ha in 2021 when harvested with N₂₃Р₆₀К₆₀ norms from the fall and N₃₇ during the restoration of vegetation 6.52 and 6.65 t/ha in 2021 and 2020, respectively.

The absence of a phosphorus-potassium background in the fertilization system of winter barley reduced the yield of the crop by 0.25–0.73 t/ha, depending on the nitrogen rates and weather conditions of the growing season. The grain yield in the absence of any fertilizers on the naturally fertile dark-gray forestal gleyed light-loamy with low humus content fluctuated in the range of 4.33–4.55 t/ha over the years of the study. But the absence of all types of fertilizers impoverished the arable layer by 12–15 mg/kg of soil in mobile phosphates, and by 13–15 mg/kg of soil in exchangeable potassium. With the application of only N₁₂₀, the amount of phosphates decreased by 7–9 mg/kg of soil, potassium – by 6–7 mg/kg of soil in different years of research. Therefore, the introduction of nitrogen fertilizers under winter barley without a phosphorus-potassium background depletes the soil of phosphates and potassium more than without fertilizers at all.