Test of different varieties of sweet sorghum in Polissia for needs of bioenergetics

Abstract

Goal. To assess different varieties and hybrids of sweet sorghum of domestic selection to establish their adaptability in the zone of Polissia, to study empirical features of recovery of biogas and optimization of cultivation technology for the needs of «green» energy. Methods. The ontogenetic characteristics and productivity of different varieties of sweet sorghum of domestic selection were studied at the experimental field of the Institute of agriculture of Polissia of NAAS in two-factor (factor A — cultivar; factor B — fertilizer system) short-term field experiment in 2017–2018. Results. According to the peculiarities of plants’ development of sweet sorghum in terms of area of Polissia they selected hybrids that differ in the intensity of the growth of the vegetative mass, regardless of vegetation conditions (dynamics of the daily growth made 1.08–3.44 cm/day). They studied the fluorescence intensity in the leaves of sweet sorghum depending on year and fertilizer system, which in dry conditions was 400–960 cond. units, and if sufficient moisture was increased by 2.1–2.6 times. In the zone of Polissia varieties and hybrids of sweet sorghum have secured biomass at the level of 38–118 t/ha (in conversion to dry substance — 4.7–30.5 ts/ha). Different length of vegetation period allows creating a dynamic conveyor of receipt of the biomass of sweet sorghum to fill methane tanki for 34–64 days. They determined the sugar content in plants of sugar sorghum (4.48–14.99%), dynamics of its accumulation in plants (maximum on the 21st day from the start of flowering), content (10.33–10.79 MJ/kg) and energy output (23,8–205.9 GJ/ha), which was transformed into biomethane (2233–4952 m3/ha). The use during two active phases of development of plants of sweet sorghum of foliar treatment with preparation Greinaktiv-S improved the growth processes of plants on 26%, the rate of photosynthesis — on 48.7, the yield — on 2–57%, the sugar content — on 0.56–3.76%. Conclusions. It is established that in the conditions of Polissia it is possible to successfully grow different varieties of sweet sorghum for the needs of «green» energy. Vegetative mass of plants including crop yields (38–118 t/ha) provides a specific yield of biomethane per hectare on the level of 571–4952 m3/ha depending on variety, hybrid, and fertilizer system.