Our research shows that corn crops in conditions of unstable moisture of the Right Bank part of the Forest-Steppe of Ukraine had a transpiration coefficient that varied from 254 to 325 m3/t.
Determination of laboratory germination of seeds of the studied maize hybrids testified to their high sowing qualities and only insignificant differences were observed. Thus, on average over the years of research, the laboratory germination of the hybrid DN BEER was 93.6 %, in the hybrid corn DN ORLIK 94.2 %, and in the hybrid DN SARMAT, respectively, 93.9 %.
During the transition of maize from vegetative to generative growth, we recorded features in the duration of phenophases. Thus, the appearance of panicles in hybrids DN ORLYK and DN SARMAT at crop densities of 75 thousand units/ha on average over the years of research was delayed by one day compared to other variants of densities. It is obvious that the thickened crops somewhat slowed down the generative growth of plants, although we cannot note this as a negative feature.
It was studied that in the early stages of the growing season corn plants had a rather insignificant height. Thus, it was found that at the time of full germination, the average experiment was 5.0 cm. The differences in plant height between different variants of the experiment were mostly within the error of the experiment. But the plants of hybrids DN ORLYK and DN SARMAT were systematically larger in comparison with the average values.
In the hybrid DN PIVYHA the maximum parameters of the leaf area at a plant density of 75 thousand pieces/ha amounted to 31.16 thousand m2, and the best option was to use a mineral fertilizer system - 32.53 thousand m2. Similarly, in the hybrid DN ORLYK the average area of leaves for plant densities was 30.50 thousand m2, and for mineral fertilizers - 31.84 thousand m2. In contrast to earlier and less tall hybrids in medium-ripe DN SARMAT, the maximum parameters of leaf area were observed for plant densities of 65 thousand units/ha - 28.46 thousand m2, although for densities of 75 thousand units/ha formed not much less leaves - 28.16 thousand m2. Similarly, the maximum values of leaf area were obtained using a mineral fertilizer system.
It is established that the regularities of slow growth of maize plants in the interphase period are full shoots - the formation of 7 leaves is reflected in the data of net productivity, and on average according to the experiment accumulated 1.43 g m2 per day of dry matter. And in the interphase period of 7 leaves - 15 leaves, respectively, significantly increased the net productivity of photosynthesis to the level of 15.94 g m2 per day of dry matter.
It was found that the vegetative part of corn plants accumulated 29.1 kg/ha of phosphorus, but in grain it was much more - 58.4 kg/ha.
The maximum values of grain yield from cobs were provided by plow-mineral and organic systems of corn fertilizer at pre-harvest density of hybrids of 65 thousand units/ha.
The best yield indicators in the studied early-ripening hybrid DN PIVYHA and middle-early DN ORLYK were obtained at pre-harvest plant density of 75 thousand units/ha, but for medium-ripe hybrid of maize DN SARMAT with FAO 380, the parameters of pre-harvesting were optimal in 65 thousand units. /Ha.
It was investigated that the highest level of yield in the experiment was obtained for growing medium-ripe hybrid of maize DN SARMAT with FAO 380 at pre-harvest density of 65 thousand units / ha and the use of combined organo-mineral fertilizer system (N120P60K20 + 3.5 t Organic compost) - 12.36 t/ha.
The application of a mineral fertilizer system contributed to a slight increase in the protein content of corn grain. But the maximum starch content was obtained at the pre-harvest density of plants 55 thousand pieces / ha and fertilizer with organic fertilizer Organic compost, 7 t/ha, respectively 73.40% (DN PIVYHA), 74.20% (DN ORLYK) and 73, 05% (DN SARMAT).
It was found that the maximum level of profit in the experiment - 56921 UAH / ha obtained for growing a hybrid DN SARMAT on the application of combined organo-mineral fertilizer (N120P60K20 + 3.5 t Organic compost) for plants of density at the time of harvest 65 thousand units/ha.
It was investigated that the application of complete mineral fertilizer of corn is quite energy-intensive, so the best in terms of energy balance were options for the introduction of organic fertilizer systems. The best coefficient of energy efficiency in the experiment was found for the cultivation of maize hybrid DN SARMAT for fertilizer Organic compost, 7 t/ha and plant density at the time of harvest 65 thousand pieces/ha - 5.37.
Key words: hybrids, organo-mineral fertilizer system, water consumption, photosynthetic productivity, yield, bioenergy productivity.
