Effect of fertilisers on yield, water consumption and energy capacity of grain sorghum (<i>Sorghum bicolor</i> L.)

This study aimed to determine how fertiliser rates affect biological yield, water use, and energy capacity of grain sorghum. Field experiment was conducted at the Uladovo-Lyulynetsk Research and Selection Station (49° 35ˈ N, 28° 24ˈ E) in 2017–2021. Trial was arranged using a randomized experimental design in four replications with a seeding plot area of 62 m2, a harvesting area of 50 m2. The investigated factors were: control, without fertiliser, winter wheat straw at the rate of 4 t ha-1 as a background, mineral fertilisers at rates of N60Р60К60, N90Р90К90, N120Р120К120 and the estimated rate of N105Р35К60. Grain sorghum produced high yields of biomass on black soils against the background of natural fertility with a yield of grain – 5.96 t ha-1, stems – 30.3 t ha-1. Application straw and mineral fertilisers ensured efficient moisture consumptions by plants. Estimated fertilisers rate N105P35K60 against the background of 4 t ha-1 of straw provided similar productivity of sorghum with the maximal rate of N120P120K120 and can be recommended for fertilising as more cost-effective. This fertilisation increased grain yield - by 35 %, bio-ethanol output - by 41 %, solid biofuel - by 17 %, total energy output - by 23 %.