Energy productivity of grain sorghum depending on the elements of cultivation technology in the Right-Bank Forest-Steppe of Ukraine

Abstract

In Ukraine, grain sorghum is an important grain crop used in bioethanol and solid fuel production. It stands out signifcantly from other grain crops by its economically valuable features, drought resistance, high productivity and universality of use. Grain sorghum is grown for use in the food industry (the main processed products are sorghum starch, glucosefructose syrups, alcohol, etc.), in fodder production and, more recently, in the energy industry. Therefore, the research of the elements of the cultivation technology, namely the sowing time and the depth of planting of grain sorghum seeds, is expedient and perspective. The article highlights the research results of the influence of the sowing time and the depth of planting seeds on the energy productivity of sorghum crops of the grain varieties ‘Dniprovskyi 39’ and ‘Vinets’ in the Right-Bank ForestSteppe of Ukraine. The purpose of the research is to establish the optimal sowing time and the depth of planting of grain sorghum seeds and to substantiate their influence on the crop energy productivity in condition of the Right-Bank Forest-Steppe of Ukraine. The research was conducted during 2016–2020 at the Bilotserkivska Research Station of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Sciences of Ukraine. It was found that the highest crop yield was obtained by sowing grain sorghum seeds in the 1st decade of May at a planting depth of 4–6 cm. At the same time, the grain yield of the ‘Dniprovskyi 39’ variety was 7.1–7.4 t/ha, of the ‘Vinets’ variety – 6.3–6.7 t/ha; the yield of biomass of the ‘Dniprovskyi 39’ variety was 40.2–44.4 t/ha, of the ‘Vinets’ variety – 37.3–39.5 t/ha. The highest bioethanol yield was obtained by sowing grain sorghum seeds in the 1st decade of May at a depth of planting of seeds of 4–6 cm. Cultivation of the ‘Dniprovskyi 39’ variety allowed to obtain 2.37–2.47 t/ha of bioethanol, the ‘Vinets’ variety – 2.08–2,21 t/ha. The yield of solid biofuel in this variant of the experiment was also the largest and amounted to 9.29–10.26 t/ha for the ‘Dniprovskyi 39’ variety and 8.62–9.12 t/ha for the ‘Vinets’ variety. The total energy yield from the obtained biofuel of the ‘Dniprovskyi 39’ variety was 210.66–228.98 GJ/ha, of the ‘Vinets’ variety – 192.37–203.95 GJ/ha. Key words: grain sorghum, varieties, sowing time, seeding depth, energy productivity.