The calendar dates and the duration of the interphase periods varied significantly under the influence of the peculiarities of the weather conditions during the growing season. In the DKC 3730 hybrid at a stand density of 50 thousand/ha, this indicator was equal, on average for this factor, to 217 cm, and at other densities (60-80 thousand/ha) it increased by 2,7-6,2%. The introduction of nitrogen-phosphorus fertilizers significantly (by 4.1-13.9%) increased plant height.
The highest yield of raw aboveground mass at the level of 85 t/ha provides sowing of hybrid DKC 4795. The maximum values of the index, both in the years of researches and on average, for three years, were obtained for the formation of plant stand density at the level of 80 thousand/ha, which amounted to 73, 83, 107 and 88 t/ha, respectively. The maximum area of leaf surface was formed by plants of hybrid DKC 4795 45.3 thousand m2/ha for plant densities of 80 thousand units / ha and fertilizer background N120P120. For all hybrids under study, this indicator was the maximum for the use of standing density of 80 thousand/ha against the background of fertilizer application at the dose of N120P120. The highest value of pure photosynthesis productivity was determined in DKC 4795 hybrid for plant densities of 70 thousand/ha and fertilizers N120P120. The highest photosynthetic potential was in the DKC 3730 hybrid - 3.15 million m2 × days/ha; DKC 4964 - 2.96; DKC 4795 - 3.05 million m2 × days/ha. The highest water consumption (4683 m3/ha) was observed in the hybrid DKC 4795, while in the hybrids DKC 4964 and DKC 4795 this indicator decreased by 2.3-12.0%.
Grain moisture was the lowest in the DKC 3730 hybrid, with a slight (1.3-3.9 percentage points) increase in the DKC 4964 and DKC 4795 hybrids -3.4 percentage points. The maximum level of grain yield - 14.5 t/ha was obtained for the cultivation of DKC 4795 hybrid. The highest productivity of this hybrid is formed by the plant densities of 80 thousand/ha, and the hybrids DKC 4964 and DKC 4795 - at densities of 70 thousand/ha. The introduction of mineral fertilizers provided an increase in grain yield, an average of 1.8–4.7 t/ha, compared to the control. The maximum average grain yield of the crop - 16 t/ha was obtained by fertilizing at a dose of N120P120. According to the results of the analysis of variance, it was determined that the factor C (fertilizer) had the greatest influence on the formation of grain productivity of hybrids of culture, its share was 56%. The effect of factors A and B was much smaller, accounting for 5 and 22% respectively.
Corn grain quality indicators varied to a great extent under the influence of the studied factors. Among the studied hybrids in the grain of the DKC 4795 hybrid, the highest protein content was recorded - 8.9%; maximum starch content - 71.6%, was established in DKC 3730 hybrid. Most fat - 4.8% was contained in the DKC 3730 and DKC 4964 hybrids grain affected the quality of corn grain. Developed elements of corn grain technology have a significant impact on economic performance. Thus, the lowest cost level (1.93-1.98 thousand UAH/t) was recorded in the hybrid DKC 3730 for plant densities of 80 thousand/ha and for the hybrid DKC 4795 - for the density of 70 thousand/ha. Contingent net income exceeded UAH 40 thousand/ha for hybrids: DKC 3730 - for plant densities of 80 thousand/ha; DKC 4964 - for densities of 70 thousand/ha; DKC 4795 - for densities of 70-80 thousand/ha.
Production is recommended in the conditions of insufficient humidity of the Southern Steppe of Ukraine for yield of high-quality corn grain more than 17 t/ha for growing it on irrigation. In order to obtain maximum grain yield and purity it is necessary to sow hybrids: DKC 3730 - for plant densities of 80 thousand/ha; DKC 4964 - 70 thousand; DKC 4795 - 70-80 thousand/ha. The introduction of the developed elements of the technology of cultivation of hybrid DKC 4795 - at a plant stand density of 70 thousand/ha and fertilizer at a dose of N90P90 provides maximum conditional net profit at the level of 46 thousand UAH/ha, profitability level of 143% at low cost of production.
Key words: corn, hybrid, stocking density, fertilizer, productivity, water consumption, yield, grain quality, economic efficiency, energy evaluation.
