Bioenergy efficiency of growing paulownia in the Right Bank Forest Steppe of Ukraine
Authors: Karpuk L. M. , Titarenko V. A. 
Published: December 2024

Purpose. To determine the effect of the application of fertilizer, cryoprotectant and foliar fertilizer on the formation of biofuel and the efficiency of growing paulownia.
Methods. The research was carried out in 2021–2023 at the experimental plot of the Bila Tserkva National Agrarian University located in the forest plantations in the Right Bank Forest Steppe of Ukraine (Kyiv region). Design of the experiment: factor A – fertilization: 1) without fertilizers, 2) application of organic fertilizer Vermykompost before planting (400 kg/ha); factor B – application of cryoprotectant: 1) without cryoprotectant, 2) cryoprotectant Mars-EL (0.5 l/ha) applied at the beginning of leaf growth; factor B – foliar application of fertilizers: 1) no treatment, 2) Quantum-AmiNoFrost (1.5 l/ha), 3) SmartGrow Recovery (2.0 l/ha).
Results. In the first year of the paulownia cultivation, the estimated biofuel yield was 2.07 t/ha, and the energy output from it was 30.8 GJ/ha. In the second year of cultivation, the energy yield and output were 8.84 t/ha and 131.6 GJ/ha, respectively, which is quite small from the point of view of efficient use of such biomass. In the third year, the average yield of biofuel was 18.4 t/ha, and the energy output was 273.4 GJ/ha, while the application of organic fertilizer ensured increase of these parameters, on the average, by 2.64 t/ha and 38.9 GJ/ha, and application of cryoprotectant by 0.81 t/ha and 11.5 GJ/ha, respectively. In the experiment, the highest energy productivity was obtained annually in the treatment with combination of all three factors, i.e. Vermykompost fertilizer, Mars-EL cryoprotectant and foliar fertilizer Quantum-AminoFrost or SmartGrow Recovery. In particular, in the third year of paulownia cultivation, the yield of biofuel was 20.2 t/ha, and the energy output was 299.6–301.3 GJ/ha.
Conclusions. The average indicator of the gross profit obtained for the cultivation and processing of the harvested paulownia for biofuel was 211.0 thousand UAH/ha, and the lowest was in the control treatment of the experiment – 189.8 thousand UAH/ha. The highest gross profit – 232.8 thousand UAH/ha, as well as the lowest costs for planting material – 102.9–103.1 thousand UAH/ha, were recorded under complex application of all studied factors of the experiment. After all, under such conditions, the highest survival rate of plants was observed, that is, it was necessary to plant much less new seedlings to form a highly productive plantation. The maximum of additional effect of the studied factors contributed to the fact that the cost of plantation care amounted to 11.0–11.9 thousand UAH/ha, while in the control control it was only 4.7 thousand UAH/ha. Despite this, under the influence of the elements of agricultural technology, the total costs were the lowest in the experiment – 112.7–114.8 thousand UAH/ha, while in the control treatment they reached 122.6 thousand UAH/ha. Therefore, ensuring high viability of expensive planting material is a fairly effective measure to reduce the cost of industrial paulownia cultivation. The complex application of the studied agricultural measures, namely the introduction of Vermykompost during the main fertilization followed by the treatment of plants during the growing season with cryoprotectant Mars-EL and fertilizers Quantum-AmiNoFrost or SmartGrow Recovery, provided an increase in the net profit by 48.6–51.5 thousand UAH/ha, reduction of the production costs by 1.68–1.79 thousand UAH/ha, which ultimately ensured a 46.3–49.2% higher level of profitability.