Substantiation of the application rates of mineral fertilezers at the cultivation of winter wheat in the conditions of the Western Ciscaucasia

The influence of rates of mineral fertilizers on the yield and grain quality of soft winter wheat on leached chernozem in the conditions of the Western Ciscaucasia is considered. The effect of foliar fertilization with a polycomponent fertilizer Aqualis of a type 18 : 18 : 18 + 3MgO + ME on winter wheat crops in the fourth rotation of grain-grass-rowed crop rotation was studied. An agrochemical analysis of leached chernozem was carried out according to the vegetation phases of soft winter wheat: spring tillering, budding and flowering. According to the research results, the average yield of winter wheat in the control variant was 5.08 t/ha, at the application of a single rate of a complete mineral fertilizer (N40P30K20), the yield was 6.0 t/ha. The increase to the control amounted to 0.92 t/ha (18.1%). The application of double (N80P60K40) and triple rates of the mineral fertilizer (N120P90K60) increased the yield to 6.75 and 6.85 t/ha, respectively. The increase relative to the control is 1.67 t/ha (32.9%) and 1.77 t/ha (34.8%), respectively. The protein content in grains in the control variant was 10.9%, the protein yield was 553.72 kg/ha. The application of single (N40P30K20), double (N80P60K40), and triple rates (N120P90K60) of the complete mineral fertilizer increased the protein content in grains and amounted up to 11.6, 12.2, and 12.2%, protein yield - 696.0, 823.5, and 835.7 kg/ha, respectively. The gluten content in the control was 20.1%; the maximum gluten content was found in the variant when applied the water-soluble polycomponent fertilizer Aqualis at the application of a triple rate of the complete mineral fertilizer (N120P90K60) - 23.8%, which is 3.7% more than in the control variant. Foliar fertilizing with water-soluble polycomponent fertilizer Aqualis at the application of single (N40P30K20), double N80P60K40), and triple (N120P90K60) rates of the complete mineral fertilizer provided a significant increase in winter wheat yield, which amounted to 1.60, 2.67, and 2.82 t/ha. This is higher than the control by 31.5, 52.6, and 55.5%. The protein content in grains and protein yield when applying Aqualis at the application of the complete mineral fertilizer ranged from 12.4-12.8% and 976.5-1011.2 kg/ha, respectively.