The article highlights the importance of resource-saving nutrition of spring barley plants based on the use of biopreparations for foliar fertilizing and their impact on the main indicators of grain quality of the two studied varieties grown in the zone of arid southern Steppe of Ukraine. It was established that the use of modern biopreparations for the nutrition of spring barley, significantly affected the implementation of the biological potential of the crop, contributed to the growth of the crop and improved the main quality indicators of both spring barley varieties. It was determined that growing crops in the arid southern steppe of Ukraine, it was increased not only the level of grain yield, and in a certain way and its quality it influenced by the optimization of the supply change, including increases the mass of 1000 grains, nature of grain protein content and its conditional harvesting per unit area. These indicators depended on weather conditions and primarily on the amount of precipitation that fell before sowing and during the vegetation period. Most of the protein in the spring barley grain was accumulated in 2018, and the least of it was in 2016. In the context of varieties the significant difference in the protein content was not defined. The amount of it in both varieties increased depending on the optimization of nutrition and, on average, for three years it was increased from 10.8 % in the control to 11.3-11.6% in variants with fertilizing in Stalker variety and from 10.7 to 11.3-11.6% in Vakula variety. The conditional protein harvesting on average during the years of research increased respectively from 0.26 to 0.38 t/ha and from 0.26 to 0.39 t/ha, respectively. Our studies proved that the optimization of the nutrition of spring barley plants through the use of modern growth-regulating preparations was quite important, which was already manifested in recent years and would be enhanced in the future, including on other crops. After all, due to insufficient amounts of organic, mineral and micronutrients and changes in climatic conditions, the importance of nutrition in increasing crop yields and significantly improving the main indicators of the quality of grown products is clearly manifested

Keywords: spring barley, varieties, plant-growth regulators, grain quality, content and conditional protein harvesting