Energy efficiency of using different rates of mineral fertilizers and plant growth regulators in corn growing in the conditions of the Left-Bank Forest-Steppe of Ukraine

In world practice, along with the assessment of the economic efficiency of input elements in cultivation technologies, energy assessment is becoming increasingly widespread. This is due, on the one hand, to the global problem of reducing fossil energy resources, and on the other, to the need to save them due to their price increase. In Ukraine's agricultural sector the need for energy assessment arose when the country experienced monetary inflation in the late 1980s-early 1990s, which led to the search for energy-saving technologies for growing crops. The essence of energy assessment is to establish the ratio of the gross energy of the crop to the amount of total energy spent on its cultivation, which is embodied in the energy coefficient. The article presents the results of the calculation of energy efficiency indicators of the elements of the technology for growing corn hybrids for grain according to the factors of experiments in the conditions of the Left Bank Forest-Steppe. According to the data provided for determining the energy efficiency of mineral fertilizer rates and plant growth regulator «Vitazym» for treating corn crops, the highest yield level (11.11 t/ha), energy output accumulated by the crop (195536 MJ/ha), and energy efficiency coefficient (5.78) were obtained when growing the «Alekksandra» hybrid on the background of the calculated rate of mineral fertilizers and treating crops with the «Vitazym» plant growth regulator at the 17th microstage on the BBCH scale with a drug consumption rate of 1.0 l/ha. The energy efficiency calculations made it possible to establish effective options for seed and crop treatment depending on the growth regulator type. When treating only seeds, a slight advantage was noted for the «Vuksal» growth regulator. In particular, the yield increased by 0.59 t/ha for the «Dniprovsky 257 SV» hybrid; 0.74 t/ha for «Aleksandra»; 0.70 t/ha for «Okksizhen», which is 0.03; 0.11 and 0.10 t/ha more, respectively, compared to seed treatment with «Vitazym». The highest energy efficiency was obtained when carrying out complex treatment of seeds and crops with the Vitazym growth regulator at the 17th microstage of the VVSN for the Aleksandra hybrid. In particular, with a yield of 11.92 t/ha, the energy output with the crop was 209792 MJ/ha, and the energy efficiency coefficient was 5.90. This is promising from the standpoint of energy saving and appropriate for practical implementation in production on chernozems typical of the Left-Bank Forest-Steppe of Ukraine. Key words: corn, hybrid, mineral fertilizers, growth regulators, microstages of VVSN, yield, energy costs, energy accumulated by the crop, energy efficiency coefficient.