Features of the growth of domestic varieties of Salix viminalis in the energy plantations on peat bog soils of Kyiv Polissia

Abstract

Purpose. To define the peculiarities of the growth of two domestic varieties of the Salix viminalis L.: 'Ternopilska' and 'Zbruch' on the peat bog soils of Kyiv Polissia of Ukraine.

Methods. Studies were conducted during 2017–2019 in the floodplain of the Teterev River in the Ivankivsky district of the Kyiv region on peat bog soil with a peat layer of 30 cm. Cuttings 25 cm long were planted in twin rows with a row distance of 0.75 m between twins and 1.50 m between twin rows. In a row cuttings were placed every 0.89; 0.59 and 0.45 m, which corresponds to densities of 10, 15 and 20 thousand cuttings per 1 ha. The area of the accounting site was 38 m² with 3 times repetition of options; the placement of the sites is randomized. The survival rate of cuttings and the safety of willow plants was expressed as a percentage of the preserved plants to the number of planted cuttings; the height of the bushes was determined by a measured bar to within 1 cm, and the mass was determined by weighing on an electronic balance to within 5 g. The obtained data were processed on a computer using the Microsoft Excel package.

Results. It was found that the survival rate of cuttings of 'Ternopilska' variety according to the density options was from 48.6 to 54.8% after the first year, and for 'Zbruch' variety from 72.8 to 86.6%. After the second year it decreased to 41.8–52.2% and 42.0–65.5%, and remained unchanged in the third year. After the end of the third year of vegetation, the average heights of 'Ternopilska' variety was from 144.6±4.69 to 178.7±4.94 cm and for 'Zbruch' variety - from 180.2±5.03 to 248.6±6.79 cm depending on planting density. In all variants of the experiment, height increment increased each year. The maximum growth rates in height (104.2 cm) were in plants of 'Zbruch' variety with a density of 20 thousand units / ha in the third year of vegetation, while being planted on loamy and sandy soils, the maximum growth of its plants in height was in the second year. In all variants of plant density, plantations of 'Zbruch' variety had a much higher dry mass productivity. At the same time, in the plantations of both varieties, the biomass yields increased with an increase in the number of plants per 1 ha and reached a maximum (9.84 t/ha in 'Zbruch' variety and 3.29 t/ha – in 'Ternopilska' variety) at 20 thousand plants per 1 ha.

Conclusions. Of the two varieties of Salix viminalis studied on peat bog soils of Kyiv Polissya, 'Zbruch' variety is more suitable for creating energy plantations, which is characterized by a higher survival rate of cuttings, more intensive growth and higher biomass productivity (up to 9.84 t/ha).