INFLUENCE OF SEED SOWING RATES AND FERTILIZATION SYSTEM OPTIMIZATION ON FORMATION OF MAIZE HYBRID PRODUCTIVITY IN FOREST-STEPH CONDITIONS

The fertilizer system is one of the most expensive elements of crop production technology, including corn. In today's difficult conditions, there is an acute shortage and rising prices for various types of energy resources, including mineral fertilizers. The variability of climatic and weather conditions and the high cost of mineral fertilizers leads to the search for alternative approaches to optimize existing and develop new technological methods of cultivation. This article evaluates and identifies the main aspects of optimizing the corn fertilization system through the use of modern biofertilizer Grandfix in combination with mineral fertilizers in full and with a reduction in their rate by 30%. The urgency and production necessity of such technological solutions and the search for optimal options for maximizing the yield potential of modern maize hybrids are determined given the importance of this crop for the formation of Ukraine's export potential. The efficiency of application of soil biofertilizer Graunfix produced by BTU-Center, which is recommended for pre-sowing cultivation, in combination with full and reduced rate of mineral fertilizers at different rates of seed sowing. It was established that with the application of soil biofertilizer Groundfix at the rate of 6 l / ha, the increase in yield was, respectively, 5.4-7.1%, or 0.82-0.97 t / ha. The maximum yield in the experiment was 18.31 t / ha and was recorded in the hybrid P8834 on the variant with a seeding rate of 75 thousand / ha. In addition, it should be noted that in the options with a decrease in the rate of mineral fertilizers by 30% N80P40K40 (70%) + Graunfix 6 l / ha received a fairly high yield of 15.07-16.53 t / ha in the hybrid P8834, 14.02 -14.96 t / ha in P9074 and 12.46-13.56 in P9241, which has a high positive effect from an economic point of view.