Katelevskyi V. Improvement of cultivation practices in growing miscanthus (Miscanthus giganteus) for biofuel in the Forest-Steppe of Ukraine.

The thesis is devoted to the improvement of selected agronomic practices in the cultivation of miscanthus. We investigated new practices of the cultivation technology that involve the use of mineral fertilisers in doses of N30P30K30 and N60P60K60, pre-planting soaking rhizomes combined with foliar application of growth-promoting product Vympel-K and growth-regulating product Quantum Gold. The miscanthus variety for the study was ‘Osinnii Zoretsvit’ (Miscanthus x gigantheus) (originator − Institute of Bioenergy Crops and Sugar Beet). Application of new cultivation practice − soaking of planting material in the solutions of growth-promoting and regulating agents (Vympel-K and Quantum Gold) − showed that the treatment with growth-promoting product Vympel-K ensured better plant survival, an average of 66.8% for four years. Meanwhile growth-regulating product Quantum Gold caused stress in plants, which was especially noticeable in dry years. The highest plant height on average over four years (140 cm) was recorded against the background of N60P60K60 together with the double foliar dressing. The most intensive shoot formation occurred in the late summer − early autumn period (August − September). The largest number of leaves (15) was recorded against the background N30P30K30 combined with double foliar dressing with a solution of Quantum Gold. In the aspect of dry aboveground mass yield, the largest increment (1.1 t/ha) was observed for soaking rhizomes in Vympel-K solution and double foliar dressing with the same product. The highest yield of underground biomass (3.5 t/ha) was observed in the treatment with soaking rhizomes in Quantum Gold followed by two foliar dressing (Vympel-K and Quantum Gold). The largest accumulation of nitrogen in miscanthus plants was observed in the leaves (1.3% in dry biomass). Phosphorus content was even in all parts of the plant (0.2%). Potassium content was the highest in the dry biomass of the underground part (1.3 %). In terms of energy yield, the most attractive treatments were (i) a combination of mineral fertiliser backgrounds (N30P30K30 and N60P60K60) and double spraying with Vympel-K (54 MJ/ha); (ii) pre-planting soaking rhizomes and two foliar dressing with Vympel-K (59 MJ/ha). Key words: bioenergy; miscanthus; biomass; growth-regulating agents; foliar dressing; energy yield; economic efficiency.