Introduction. Today, alternative natural resources are increasingly used as the main industrial raw material used not only for the production of biofuels and various types of energy, but also other products. Bioenergy crops of miscanthus and switchgrass, which are characterized by long-term high yields, in contrast to, for example, agricultural waste, can be a promising way to attract new sources of high quality cellulose and for the production of bioplastics. The latest scientific research of miscanthus confirms the hypothesis of Ukrainian scientists of the 1980s and scientists from other countries that the raw material of this cellulose-containing crop is fully positioned as a material for the production of cellulose and bioplastics, and for biotechnological production of soluble carbohydrates and biofuels. Conclusion. It is proved that bioenergy crops of miscanthus and switchgrass can be a promising way to attract new sources of high quality cellulose for bioplastics production.

Growing and utilizing bioenergy crops as feeding substrates in biogas plants may aid the development of the biogas sector in Ukraine. Therefore, research was done on potential methane yields from 22 high-yield varieties of 7 different crops grown in Ukraine for their biogas production suitability. Annual crops (maize, soybean, sweet sorghum and sorghum hybrids) and perennials (miscanthus, paulownia and switchgrass) harvested at three different harvesting times (H1, H2 and H3) related to specific stages of phenological development were investigated. The perennial crops studied were from different vegetation years. The samples were analysed in Ukraine on their dry matter- and volatile solids contents, dry matter yield (DMY) and crop nitrogen (N) uptake. The 55 °C -dried samples were delivered to Germany for their analysis with the Hohenheim Biogas Yield Test (HBT) on their specific methane yield (SMY). Based on DMY and SMY, the areal methane yields (AMY) were calculated. The highest SMY and AMY were found for maize, sweet sorghum and miscanthus. The highest average SMY of 0.35 ± 0.03 m3CH4 kgVS−1 was found for maize samples harvested at H2. Miscanthus “Giganteus” from the 8th vegetation year harvested at H1 has shown the highest AMY of 7404.50 ± 199.00 m3CH4 ha−1.

In Ukraine, 6.5 million hectares of agricultural land characterized by heavy clay soil could be available for sustainable bioenergy crop cultivation because they are considered marginal for food crop cultivation. This study investigated the biomass dry matter yield (DMY) of willow (Salix triandra L. and Salix viminalis L.) and Miscanthus (Miscanthus × giganteus Greef et Deuter) at two experimental sites with heavy clay in Ukraine. To promote plant rooting and adaptation in the first year of cultivation under low-input conditions, tillage, moisture-retaining agents, foliar fertilization, planting density and row spacing were varied. Willow obtained notable DMY on hard clay soils (clay >50%). The variety 'Tora' revealed the best DMY performance, indicated by the highest increment (4.1-4.6 m) in the first year of the second cycle. The highest biomass DMY (28.8 Mg ha −1 ) was obtained at a planting density of 15 000 plants ha −1 and a row spacing of 0.75 × 1.50 m. However, neither willow nor Miscanthus allow for a feasible biomass production at clay contents above 64%, because the young roots are damaged and deprived of nutrients as the soil dries out. For Miscanthus, plowing provided better soil loosening and easier sprouting of rhizomes compared with mini-till. The application of moisture-retaining agent Aquasorb (200 kg ha −1 ) supported Miscanthus plants with moisture in the first year of vegetation, but it did not maintain soil moisture in the long term. Therefore, growing willow and Miscanthus on soils with clay contents above 64% is not feasible because the soil texture and tendency to crack significantly reduce the DMY.