The influence of nitrogen fertilizers on the productivity of energy biomass of willow

Abstract

Purpose. Determine the optimal rate of nitrogen fertilizers for fertilizing energy plantations of willow before the start of the second three-year cultivation cycle in the Central Forest-Steppe of Ukraine.
 Research methods. Field, analytical, statistical.
 Results and discussion. Appling of ammonium nitrate contributed to the active beginning of the growing season and the increase in the plant mass in hight. At the end of the first year of vegetation, the tallest plants were formed in variety ‘Tora’ using N70 – 4.67 m, which is more than in the control version (without fertilizer) by 0.71 m, or 16%. For N35, the average plant height was 4.32 m, which is 8% more than the control. The formation of more tall plants to restore more nitrogen was found in the variety’Ternopilska’. Hight of annual plant of this variety in control was 3.68 m, for application N35 – 4.08 m, and for dose N70 – 4.24 m. At the end of the second growing cycle, the average height of plants of the variety ‘Tora’ in control variant was 6.29 m. The highest plants with the distribution of ammonium nitrate in the maximum dose (N70) were 6.78 m, which is more than in control variant by 8%. For the application of N35, the height of plants of the plantation was 6.52 m and 5.79 m. In this case, the decrease in the share affects the height of plants up to 15.4%, and the share affects the varietal characteristics of growth up to 82.9%. Also nitrogen had a positive effect on biomass growth. The yield of dry biomass of three-year-old energy willow plantation in the other part of cyclic production under control (without fertilizers) was 65.3 t/ha (21.8 t/ ha/year) of dry biomass in ‘Tora’ variety, and 55.6 t/ha (18.5 t/ha/year) in ‘Ternopilska’ variety. In the variants with the use of ammonium nitrate in the dose of N35, the indicator increased due to the control in variety ’Tora’ by 2.8 t/ha and by 3.7 t/ha in the variety ’Ternopilska’. Increasing the nitrogen dose to N70 increases the yield of dry biomass in the varieties’Tora’ and ’Ternopilska’ by 8.8 t/ha and 9.3 t/ha, respectively, compared to the control.
 Conclusions. The application of ammonium nitrate and varietal characteristics have a significant impact on the yield of energy biomass of willow. Of the two studied varieties of willow on chernozem soil of the Central Forest-Steppe of Ukraine, the variety’Tora’ was noted for more intensive growth and higher productivity during the second three-year growing cycle. Plants of both varieties are characterized by higher yields for nitrogen application at a dose of 70 kg/ha a.i.