The thesis is devoted to the introduction of promising foreign energy willow varieties and improvement of cultivation technology for willow plantations in Western Polissia.
Of the 8 studied varieties of willow, the highest index of rooting of cuttings had ‘Tora’: with manual planting – 95.1%, and at mechanized – 89.4%. The varieties ‘Tordis’, ‘Tora’ and ‘Inger’ had the highest average growth of three-year plants (respectively 2.97, 2.79 and 2.76 m). Their shoots also had the largest diameters – respectively: 30.9 mm, 30.1 mm and 28.1 mm. There is an inverse relationship between the density of plantations and the average diameter of their shoots.
The yield of three years dry biomass of willow was highest in the varieties ‘Inger’, ‘Tora’ and ‘Tordis’ (respectively, 30.27, 28.12 and 24.76 t/ha). At the same time, the highest yield was at the average plant density (16.4 thousand pcs./ha) in the ‘Inger’ variety, and the highest yield of varieties ‘Tora’ and ‘Tordis’ was at a minimum landing density of 12, 9 thousand pcs./ha).
Fertilization of 4-year plantations of varieties ‘Tora’, ‘Tordis’ and ‘Inger’ by ammonium nitrate (N35, N70, N105 and N140) positively influenced on the biometric indices of three-year shoots and the productivity of biomass. On ‘Tora’ variety control plot yild was 39.82 t/ha, on ‘Inger’ – 21.58 t/ha and on ‘Tordis’ – 26.94 t/ha. At fertilizing in a soil N35, N70, N105 and N140, the productivity of ‘Tora’ variety plantations increased by 6.91, 6.15, 4.10 and 1.59 t/ha respectively; ‘Inger’ variety plantations increased by 5.94, 6.65, 3.32 and 1.24 t/ha, while the ‘Tordis’ variety – by 4.57, 4.11, 2.45 and 1.39 t/ha.
The higher productivity of the ‘Tora’ variety, compared with the varieties ‘Inger’ and ‘Tordis’, is provided by a greater area of the leaf surface (from 32.8 to 40.1 thousand m2 per hectare), with a higher productivity of pure photosynthesis (from 5.28 g/m2/day – at the control, up to 6.80 g/m2/day – for maximum fertilizer doses) and a longer period of vegetation.
In three-year biomass, the willow contains 1.1–1.5% nitrogen, 1.65–1.90% phosphorus, 1.9–2.4% potassium, and 1.1–4.1% ash content. At the same time, all these indicators are increasing with the increase of the norm of mineral fertilizers. The 200 kg/ha ammonium nitrate (N70) norm is optimal.
The calorific value of biomass is from 17.9 to 18.4 MJ/kg, decreasing with increasing fertilizer dose, which is associated with an increase in the content of ash. The ‘Tora’ variety three-year biomass had greatest energy – from 729 to 1056 GJ/ha, depending on the norm of fertilization.
To provide a lucrative level of growth of willow biomass, financial support of at least 60% of the cost of plantation creation is required.
Keywords: bioenergy, willow, energy biomass, varieties, introduction, planting density, nitrogen fertilizer application, growth intensity, yield, the content of macroelements, ash content, the calorific value of biomass.
