Productivity of giant miscanthus plantations depending on the applied elements of cultivation technology in the conditions of the Forest Steppe of Ukraine

Abstract

Purpose. To improve the technology of caring for giant miscanthus plantations, starting from the second year of the crop vegetation, and to establish the peculiarities of the formation of biomass yield with the use of different types of fertilizers. Methods. The research was carried out in the years 2020–2021 in the conditions of the Bila Tserkva Experimental and Breeding Station of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Agrarian Sciences located in the zone of unstable moisture of the Right Bank Forest Steppe of Ukraine. The design of the experiment involved the application of mineral fertilisers (ammonium nitrate N24 kg/ha a. i., ammonium nitrate + ammonium sulfate N24 + S6 kg/ha a. i.) in row in the spring, foliar application of humates (Vermisol, 8.0 l/ha, Humifield VR-18, 0.4 l/ha), and complex fertiliser with amino acids (Quantum Aminomax, 0.5 l/ha). Mineral fertilizers were applied locally in row before the emergence of miscanthus seedlings. Split foliar application of humates and amino acids was carried out in the five-leaf stage and two weeks later. Results. Productivity of miscanthus plants differed significantly over growing seasons, while the main regularities of the influence of the investigated elements of plantation care technology on the productivity formation were maintained. In the second year of vegetation (2020), each plant formed from 18 to 37 shoots and in the third year from 37 to 50 shoots. Four-year-old plants had 28–50 shoots each. The yield of raw biomass at the end of the growing season in 2020 varied from 14.5 to 43.5 t/ha. Compared to 2020, in 2021 the biomass yield increased 1.5–2 times – up to 31.0–74.6 t/ha. According to the experiment, the average yield of biomass for the fourth year of the growing was 17% lower compared to the respective indicators of 2021 and varied according to the experiment treatments from 25.3 to 67.1 t/ha. The yield of dry matter varied from 9.78 to 28.30 t/ha in 2020, from 17.50 to 37.85 t/ha in 2021, and from 12.11 to 32.46 t/ha in 2022. The estimated energy output from miscanthus biomass, depending on the influence of the experimental factors, was 174.8–509.6 GJ/ha in 2020, 315.5–683.2 GJ/ha in 2021, and in 2022 – 219.0–587.3 GJ/ha. Conclusions. The minimum values of all studied productivity indicators of miscanthus were obtained in the control treatment of the experiment. Application of ammonium nitrate (N24) and ammonium nitrate with ammonium sulfate (N24 + S6) in spring contributed to a significant increase in the number of shoots per plant, as well as biomass yield and estimated energy yield per hectare. Similarly, significant increase in all indicators of productivity was ensured by foliar application of humates (Humifield BP-18, 0.4 l/ha and Vermisol, 8,0 l/ha). In general, over the years of research, the maximum indicators of the number of shoots per plant, the yield of biomass and the estimated energy output from biomass were obtained under the combined application of mineral fertilisers [ammonium nitrate + ammonium sulfate (N24 + S6)] with two-time foliar application of humates (Vermisol, 8.0 l/ha or Humifield VR-18, 0.4 l/ha) and complex fertiliser Quantum Aminomax, 0.5 l/ha.