Вплив густоти і внесення мінеральних добрив на ріст і продуктивність плантацій енергетичної верби в умовах Прикарпаття

Abstract

Purpose. Study of the influence of agrotechnical measures applied during the establishment of willow plantations on their growth, development, the productivity of energy biomass and calorific value of the feedstock. Methods. Field, laboratory, analytical, statistical. Results. It was found that during the first year of vegetation, the average height of willow plants was 156–180 cm. The maximum values were recorded in the variant with a maximum growing space (plant density of 12,000 pts/ha) and application of N80P300K300. During the second year, the intensity of energy willow growth increased significantly. The highest values of the height of shoots (385.0 cm and 421.0 cm) were recorded in the variant with a plant density of 12,000 pts/ha. The average diameter of the central shoot ranged from 27 to 31 mm. The introduction of mineral fertilizers (N80P300K300) contributed to an increase in the diameter of shoots by 14.8% and in the height by 9.3%. Studies conducted in 2018 showed that during the third growing season, the intensity of energy willow growth under the conditions of this stud substantially decreased. Conclusions. In sod-podzol medium-loamy soils of Carpathian region, in the first years of cultivation, the increase in the growing space and the introduction of mineral fertilizers positively affect the intensity of growth of the energy willow plantations. When applying mineral fertilizer at the minimum plant density (12,000 pts/ha), the largest sizes of two-year shoots were recorded as follows: the average height of 421.0 cm and the average diameter of 31 mm. The highest yield of two-year energy willow biomass (28.1 t/ha of green mass and 15.9 t/ha of dry biomass) was obtained at a maximum density of planting (18,000 pts/ha) and mineral fertilization. In the variant with a plant density of 15,000 pts/ha, the yield was less by 6.4%, and at plant density of 12,000 pts/ha by 18.1%. The introduction of mineral fertilizers provides an increase in yield by 6.5–12.3%, while the maximum positive effect of fertilizers was observed in plantations of the lowest density. The maximum yield of solid biofuel (17.5 t/ha) and energy (279.8 GJ/ha) from a two-year willow plantation was obtained in the variant with the highest yield of biomass (with a planting density of 18,000 pts/ha and mineral fertilizers). The energy yield in this variant was 18.7% more compared to the variant with 12,000 pts/ha and 6.7% more than in the variant with a plant density of 15,000 pts/ha.