The object of research is the process of forming structural elements of productivity and quality of biomass of bioenergy crops depending on their biological characteristics and fertilization system. The aim of the research work was to establish the characteristics of growth, development, and productivity of bioenergy crops depending on fertilization in the agroecological conditions of climate change in the western region of Ukraine. During the research, general scientific methods were used: the method of hypotheses, analysis and synthesis, experimental modeling, as well as special methods: field – during the growing season, observation of plant growth and development, yield potential; laboratory – differentiation of seed sowing characteristics, composition of total sugars in plant stems, dry matter content of green mass; mathematical and statistical – correlation, dispersion, regression for the reliability of experimental data; computational and comparative – to determine the effectiveness of experimental factors in terms of economic and energy indicators. For the first time, under the conditions of climate change in the western region of Ukraine, the peculiarities of plant growth and development and the formation of the yield of giant miscanthus, switchgrass, sugar sorghum, and common corn when grown on sod-podzolic soil and using a fertilization system were studied. The technology for growing bioenergy crops has been improved by optimizing crop care elements, which has had a positive impact on the formation of high-quality biomass suitable for biofuel production. Further developments have been made in establishing the patterns of growth processes of bioenergy crops and the formation of their biometric indicators, as well as methodological approaches to determining the energy and economic assessment of the proposed agricultural measures. Based on the results of research for the Western region of Ukraine, optimal components of technology for growing various types of bioenergy crops are recommended for production. The results of research by domestic and foreign researchers on the basics of forming highly productive crops of perennial and annual bioenergy crops are analyzed. It was established that giant miscanthus reached full productivity in the 3rd–4th years of cultivation, forming 30–42 t/ha of green biomass depending on the fertilization option and weather conditions of the year. Combined fertilization options provided the highest yield increases (up to + 41% compared to the control), as well as minimal interannual fluctuations, indicating the crop's high adaptability to climate change. Switchgrass was characterized by a gradual increase in productivity and a stable response to the application of microfertilizers: yield increases were 14–17%, while combined options provided an increase of up to +34% compared to the control. Sugar sorghum provided the highest gross green mass yields (52–70 t/ha), but its increased moisture content and the significant influence of weather conditions led to a decrease in yield stability in 2024–2025. Microfertilizers provided a 24–25% increase, and the maximum effect was achieved when combined with mineral fertilizers (up to + 36% compared to the control). Common corn showed the highest increase in grain production under the influence of mineral fertilizers (up to + 54%) and a stable increase in the yield of by-products (by 6 – 9%). Combined fertilization options N90P90K90 + micronutrients provided the highest grain productivity (10.6–10.7 t/ha) and vegetative mass (17.7 t/ha). A comprehensive agronomic, economic, and energy analysis shows that giant miscanthus and common corn are the most suitable crops for bioenergy production and stable functioning of energy agrosystems, as they provide the highest yields, profitability, and energy efficiency. Switchgrass is technologically simple and cost-effective, while sweet sorghum requires changes in the product use model to transition to profitable production.
