Periods of ammonium nitrate application during the cultivation of soft winter wheat variety Krasa Dona in the southern part of the Rostov region

Abstract
The studies were carried out in the southern part of the Rostov region in 2017-2019 on typical carbonate chernozem. Studied was the efficiency of periods of ammonium nitrate application (N30, N30+30 ) in autumn when the vegetation season is finished, in spring in the thawed soil, and during the tillering phaseon the yield and quality of winter wheat grain of Krasa Dona variety by different seed sowing rates (500, 600, 700 pcs/m2). Soft winter wheat variety Krasa Donacultivated after sunflower has shown a good reaction to double nitrogen top-dressing in autumn and in spring (N30 in autumn when the autumn growing season is finished + N30 in spring on thawed soil). In this variant there has been formed the largest yield of 6.09-6.18 t/ha. The productivity excess over the control variant (without nitrogen top-dressings) was 2.38-2.63 t/ha, depending on the seeding rate, which significantly exceeded the level of LSD05 in the experiment (LSD05 = 0.24 t/ha). In addition, in this variant with the seeding rate of 500 pcs/m2 the maximum economic efficiency was obtained. The profitability was 121.3 %, and the contingent net income was 34,268 rub/ha. The application of nitrogen fertilizing provided an increase in the mass of 1000 grains to 42.6-43.0 g (39.8-40.2 g in the control) and increased the gluten content in the grain to 20.5-21.8 % (18.6-18.8 % in the control).