The article highlights the peculiarities of growing winter barley crops in the southern steppe zone of Ukraine and its importance in the grain balance of the state. The influence of biological characteristics of the crop and changes in climatic conditions on the productivity of winter barley in different weather factors of growing years is substantiated. The results of research conducted during 2016-2019 yrs on Southern chernozem in the Educational, Scientific and Practical Center of MNAU with four varieties of winter barley are presented. The research was devoted to improving the nutrition of crops based on the principles of resource conservation by using modern biopreparations in the main periods of vegetation of winter barley plants for foliar treatments of crops of varieties taken for study. Studies determined the influence of various types of biopreparations and the period of top dressing on the growth and development of winter barley plants, the formation of productivity in the context of varieties, technology elements and years of cultivation, which differed in climatic conditions. The positive impact of the use of biopreparations on the growth processes of plants and the yield of winter barley grain was established, the most productive varieties, the best biopreparations and the timing of foliar top dressing were determined. Adaptation of elements of winter barley cultivation technology to specific conditions is extremely relevant for the current state of management, since it allows not only to fully meet the needs of plants, but also to obtain the maximum possible productivity with minimal energy and material resources while preserving the environment. The agricultural technique of growing crops in the experiment was generally accepted and it met the recommendations for the southern steppe zone of Ukraine, except for the factors taken for study. The soil of the experimental plots is Southern chernozem, which has an average supply of mobile nutrients, the humus content in the soil layer of 0-30 CM was 2.9 - 3.2%, phosphorus content was -6.8-7.2. the experiment scheme included the following options: Factor A-Grade: 1. Dostoiny; 2. Valkyrie; 3. Oscar; 4. Jason; Factor B – foliar top dressing: 1. control (water treatment); 2. Azotophyte; 3.Mycofrend; 4. Melanoriz; 5. organic balance. Studies with the latter were conducted during 2018 yr and 2019 yr. The rate of use of drugs was 200 g/ha, and the working solution was 200 l/ha. Foliar top dressing of winter barley was carried out once during the spring tillering phase and twice during the growing season, in addition to tillering, also at the beginning of stooling. The sown area was 72m2, the accounting area was 30 m2, the repetition of the experiment was four times. The predecessor of winter barley was peas. The positive impact of foliar top dressing with modern growth-regulating preparations of winter barley plants on the growth processes of the crop and the level of grain yield was determined. Thus, the treatment of crops during the spring tillering phase led to an increase in the height of plants and an increase in their aboveground biomass. To an even greater extent, these indicators increased from double top dressing, namely, in addition to the tillering phase, also during the period of stooling phase of plants. The maximum amount of raw aboveground biomass was accumulated by plants during the earing phase. If 3310 g/m2 was formed during the treatment of crops with water (in the control), and on average, this indicator increased up to 4044 g/m2 or by 22.5% during double treatment for all the studied preparations and varieties. In the subsequent growing season of winter barley, the accumulation of biomass, on the contrary, significantly decreased due to the loss of moisture by plants during the grain ripening period, although the difference between the treated crops and the control remained. Optimization of plant nutrition of the studied varieties of winter barley had a positive effect on the grain yield levels. Productivity differed significantly in terms of varietal characteristics of winter barley, growth-regulating preparations, the number of foliar top dressing carried out by them, and the conditions of the growing year. The highest grain yield of the studied varieties of winter barley was formed by carrying out of two top-dressings during the spring tillering phase and the stooling phase. Obtaining the maximum yield levels it was provided by the preparation Organic-Balance on Valkyrie varieties of 5.63 t/ha, and on Oscar varieties it was 5.60 t/ha of grain in the option of double processing on average for two years of cultivation. The biopreparation Azotophit, which in comparison with the Organic Balance provided slightly lower yield levels, and for the decent variety-even higher than the Organic Balance, it was also determined to be effective in its ability to provide stable grain yield increases of the studied varieties of winter barley. Mycofrend and Melanoriz preparations were less effective in influencing on the yield of winter barley. According to the obtained research results, it is advisable for farms to recommend using Valkyrie and Oscar varieties when growing winter barley in the Southern steppe zone of Ukraine, and to optimize their nutrition, use foliar top dressing with Organic-Balance or Azotophit biopreparations twice during the growing season – during spring tillering and stooling.
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