The structure of the yield of spring durum wheat varieties when applying leaf fertilizing according to various precursors

Changes in the indicators of the yield structure have been established when using leaf fertilizing in the cultivation of spring durum wheat varieties according to various precursors in the forest-steppe zone. Field experiments were conducted in Omsk State Agrarian University on meadow-chernozem medium-sized medium-humus heavy loamy soil in 2022-2023. Varieties of spring durum wheat Omsk emerald and Rusticano. The content of N-NO3 in the soil is high (15.1-19.2 mg/kg) for steam and low (5.4-8.0 mg/kg) for spring wheat, mobile P2O5 is increased (148-165 mg/kg) and K2O (328-345 mg/kg) is very high, mobile Cu (0.06-0.07 mg/kg) and Zn (0.50-0.53 mg/kg) is low. Fertilizers were used in the following doses: N30 (D.V. in the form of carbamide), micro fertilizers (ph.m. in the form of sulfates) Cu0.5, Zn0.1, Cu0.5Zn0.1, and N30Cu0.5Zn0.1; Microvit standard (complex macro- and micro-fertilizer, 0.8 l/ha); growth regulator Biostim grain (1 l/ha). In the arable horizon, a high content of nitrate nitrogen before sowing provided a higher yield of varieties (without fertilizing, the Omsk emerald variety 2.69 and Rusticano 2.98 t/ha) than for spring wheat by steam (2.05 and 2.19 t/ha, respectively). The use of all non-root top dressing significantly affected the grain yield of varieties: Omsk Emerald has an increase in steam of 0.12-0.96 t/ha, for spring wheat after steam - 0.23-1.00 t/ha; Rusticano, respectively, 0.18-0.86 t/ha and 0.10-1.14 t/ha. The maximum yield was obtained from N30Cu0.5Zn0.1 on both backgrounds of the predecessor in both varieties. Nitrogen fertilizing, both separately and in combination with trace elements, is more effective when there is a lack of nitrate nitrogen in the soil. The productive bushiness of the Omsk emerald variety against the background of an unpaired predecessor is significantly higher than in pairs; in wheat plants of the Rusticano variety, it is also higher in pairs, but to a lesser extent. In the Rusticano variety (on average, according to experience, 1.45), it is significantly less than in the Omsk emerald variety (1.89). The mass of 1000 grains of the Rusticano variety (on average 43.8) exceeds this indicator of the Omsk emerald variety (42.25). When using fertilizers and a growth regulator, it increased in all variants on both backgrounds of the precursor in the studied varieties.