Optimization of nitrogen top dressing of the winter wheat at growing on the bare fallow

The influence of nitrogen top dressing on the yielding capacity and grain quality of modern varieties of soft winter wheat in the Northern Steppe were discovered. The field trial was placed on the bare fallow. The rate of application of mineral fertilizers under presowing cultivation was N30P60K30. Three varieties of winter wheat was sown: Kokhanka (SI The Institute of Grain Crops), Pylypivka and Misiia Odeska (Selection and Genetic Institute). The sowing time of the winter wheat is September 20, the sowing rate is 5 million germinable seeds per 1 ha. The following nitrogenous fertilizers were used for the top dressings: ammonium nitrate and carbamide. Ammonium nitrate was applied at the end of the spring tillering stage by means of a seeder locally (30 and 60 kg/ha of active substance) end carbamide (30 kg/ha of active substance) and a tank mixture of carbamide (30 kg/ha of active substance) and fungicide Falcon (600 ml/ha) – in the earing phase foliar. It is established that top dressing of the winter wheat crops at the end of the tillering stage locally with ammonium nitrate contributed to an increase in yield of varieties by 0,34–0,64 t/ha, moreover the maximum yield gains were for the application of fertilizers in the rate of 60 kg/ha of nitrogen. A significant increase in yielding capacity was provided by the treatment of crops in the earing stage with the tank mixture of carbamide and fungicide. Nitrogen top dressings, as a rule, had a positive effect on both the physical indicators of the winter wheat grain (grain weight per hectoliter and vitreousness) and biochemical indicators (protein content, gluten content, sedimentation rate). It is found, that the varieties Kokhanka and Pylypivka in all variants of the experiment formed the grain weight per hectoliter over 800 g/l. In these varieties the content of protein and gluten were higher. In the strong grain quality varieties Misiia Odeska and Pylypivka in comparison with the variety Kokhanka (valuable) were noted higher values of sedimentation. According to the set of indicators, food grain of the second class was obtained in Kokhanka variety in the variant where the tank mixture of carbamide with fungicide was used for crop treatment, and in Pylypivka variety – for top dressings of crops at the end of tillering stage locally (N30–60) or N30 foliar. Keywords: winter wheat, variety, bare fallow, nitrogen fertilization, yielding capacity, protein, gluten.