Growth and productivity of some foreign cultivars of energy willow in Volyn Opillia

Abstract

Purpose. To examine the feasibility of using certain foreign cultivars of willow for energy plantations under the conditions of the Volyn Opillia.

Methods. Field, laboratory, analytical, and statistical. The objects of research was energy plantations of four Swedish willow cultivars (‘Tora’, ‘Tordis’, ‘Inger’, and ‘Wilhelm’), three Polish varieties (‘1047’, ‘82’, and ‘1057’) and one Hungarian variety (‘Express’). The plantations were established in 2012/13 yrs on the old-arable lands in Volyn Opillya.

Results. Biological characteristics of the cultivars under study and planting density significantly affect the survivability of cuttings, their bushiness, a number of sprouts per hectare, plant height, the average diameter of sprouts and energy biomass productivity. After the first year of cultivation, the highest yield of dry mass was obtained in variants with the highest planting density (22500 plants/ha). During the second growing season, a significant increase in biomass yield was observed in all variants. It was especially intensive at a planting density of 16400 plants/ha. After the third year of vegetation, the highest yield of ‘Tora’, ‘Inger’ and ‘Tordis’ cultivars was reached at the density of 16400 cuttings per hectare.

Conclusions. Under the conditions of Volyn Opillya, the highest dry biomass productivity over the three-year harvest cycle of growing Swedish cultivars was as following: ‘Tora’ 25.72–28.12 t/ha, ‘Inger’ 26.71–30.27 t/ha, and ‘Tordis’ 21.58 to 27.56 t/ha. The conducted hierarchical cluster analysis of the studied cultivars for the survivability of cuttings, a set of biometric indicators and productivity showed that they are combined into 2 clusters. The first cluster includes cultivars of Swedish selection – ‘Tora’ and ‘Inger’, which have the highest rates for all the characteristics of growth and productivity. The second variety includes the remaining varieties, which are, to varying degrees, promising for cultivation in Volyn Opillia. This is especially true for the ‘Tordis’, ‘Wilhelm’ and ‘Express’ varieties located on the right side of the second cluster and are characterized by high performance. Energy plantations of willow should be established with an initial density of 12000–15000 plants per 1 hectare under the conditions of the Volyn Opillia.