Growing of highly productive perennial plants becomes the guarantee of opportunity of stable provision with raw materials for the production of solid biofuels in modern conditions. The purpose of the research was to increase yielding capacity of Miscanthus biomass at the expense of the nutritional background and foliar top dressing. Four-year observations of the condition of Miscanthus plantations were performed at Station in the Forest-steppe zone of Ukraine during 2016-2019. Over the years of observations, a noticeable effect of background nutrition in combination with foliar feeding, plant growth regulators and growth stimulants and their one-time and double treatments has been revealed. The highest result was obtained in 2016 with an excessive amount of moisture during the growing season-392 mm. In the first variant of factor A with the one-time treatment by means of preparation Quantum Gold the leaf surface was 46.7 thousand m 2 /ha; on the nutritional background N 30 P 30 K 30 with one-time treatment by means of preparation Vympel-K-45.6 thousand m 2 /ha; with increase of the dose of mineral fertilizers on the nutritional background twice (N 60 P 60 K 60) at one-time treatment with the preparation Vympel-K the leaf surface was 45 thousand m 2 /ha. The lowest results were obtained in 2017, when 183 mm of precipitation was registered during the entire growing season. In the first variant of the same factor A at one-time treatment with the preparation Quantum Gold the leaf surface was 3.8 thousand m 2 /ha, in the second variant, when treated with the preparation Vympel-K, its leaf surface was 7.4 thousand m 2 /ha, in the third variant (control)-11.4 thousand m 2 /ha. In the control variants of factor B, the leaf surface area with the application of mineral fertilizers (second and third variants of factor A) increased. In consideration of the data obtained, it can be argued that the application of mineral fertilizers had the positive effect on plant growth and development, even with a critically minimal amount of precipitations. The application of the preparation Quantum Gold significantly affects the growth and development of the aboveground part of the Miscanthus gigantic. The application of the preparation Vympel-K stimulates the development of the root system and increases the yielding capacity of the investigated crop.

Miscanthus giant is a tall perennial herbaceous plant with a well-developed root system, which is used for biofuel production. The aim of the study was to establish the effect of gi-ant miscanthus in the first year of growing season on the state of soil organic matter, removal and balance of nutrients and biological productivity of crops for fertilization. A four-year survey of the condition of miscanthus plantations was conducted at ‘Veselo Podilska’ research and breeding station during 2016‒2019 in the forest-steppe zone of Ukraine. Indicators of biomass productivity of giant miscanthus and the state of fertility of the grant for fertilizer application in the area of the left-bank of the Forest-Steppe of Ukraine for the production of solid biofuels are characterized. In the first year of the growing season, giant miscanthus produces more organic matter in the root system than in its terrestrial biomass ‒ 2.5 and 1.6 tons of dry matter/ha, respectively. It was found that foliar fertilization with microfertilizers significantly increased the yield of terrestrial biomass of giant miscanthus in the background of mineral fertilizers. The highest biological yield of ground mass of giant miscanthus was achieved with the introduction of N60P60K60 and two foliar fertilization with microfertilizer Vympel-K, 0.5 l/ha: yield of terrestrial biomass ‒ 3.1 tons of dry matter/ha with the advantage of control without fertilizers ‒ 1.5 tons/ha. In the first year of cultivation miscanthus giant uses a small amount of nutrients from the soil: nitrogen ‒ 20.4‒33.8 kg/ha, phosphorus ‒ 3‒5.3 kg/ha, potassium ‒ 6.1‒12.4 kg/ha . The application of N30P30K30 ferti-lizers was sufficient to form a balanced and expanded balance of nutrients in the soil. The appli-cation of mineral fertilizers did not affect the dynamics of organic matter in typical chernozem. Growing giant miscanthus in the first year of the growing season ensured the stability of the or-ganic matter content in the soil at the level of 4.04‒4.11%. At the same time, the content of mobile phosphorus at the end of the growing season decreased by 17‒18 mg/kg, potassium ‒ by 13‒43 mg/kg of soil. Reducing the content of mobile forms of phosphorus and potassium in the soil at the end of the growing season leads to efficient use of plant nutrients, chemical transformation of phosphorus into insoluble compounds and non-exchange adsorption of potassium ions by the soil complex in the biocenosis of miscanthus.