INFLUENCE OF FORECROPS AND SUPPLEMENTARY FERTILIZATION OF WINTER WHEAT AT DIFFERENT PERIODS OF ITS VEGETATION ON YIELD FORMATION AND GRAIN QUALITY

Research on the study of effectiveness of nitrogen fertilization on productivity and quality of winter wheat grain was conducted in the conditions of the Volga region in 2017-2021. A two-factor experiment was set on leached heavy loamy black soil (humus - 6.5% by Tyurin; pH of the salt extract - 6.3-6.5; P2O5 - 185-216; K2O - 80-85 mg per 1 kg of soil) according to the following scheme: I - forecrop (factor A): complete and sown fallow; II. fertilization with ammonium nitrate (factor B): 1. control (N0); 2. autumn (N34); 3 with a seeder (N34); 4. early spring (N34); 5 early spring (N34) + at the shooting stage (N34); 6 early spring (N34) + at the shooting stage (N34) + N15at the heading phase. Lack of moisture at the start of the experiments did not allow to obtain friendly seedlings (complete fallow - 75.9-78.3%, sown - 71.7-75.2%). Frequent temperature fluctuations at the beginning of the vegetation season and lack of precipitation during the period of grain filling had a negative impact on survivability of plants by the harvesting time (complete fallow - 44.9-50.3%, sown - 29.2-34.2%). The highest grain yield (4.48 t/ha) was formed when winter wheat was sown on complete fallow in combination with fertilizer application (N34+N34+N15), which exceeded the control by 1.11 t/ha (34.9%). High content of protein (13.7%) and gluten (31.8%) provided the variant with early spring fertilization in a scattered way at a dose of N34. An increase offertilization frequency led to a decrease of protein (13.3%) and gluten (30.4%). Cultivation of winter wheat on sown fallow reduced yield by 1.19 t/ha (36.2%) and quality parametres (protein 12.2%, gluten 26.9%) of the grain. The highest net operating profit (25,883 rubles/ha) and high profitability (136.8%) of the grain were obtained when sown on complete fallow in combination with fractional fertilization at different stages of plant development. The cost of 1 ton of grain was 4220 rubles.