Dry matter and ash content in leaves and stems of bioenergy crops

Abstract

Purpose. Determine the content of dry mass and ash in the leaves and stems of bioenergy crops (miscanthus, switchgrass, willow).
 Methods. Samples were taken at the end of the growing season (October). The dry matter content was determined by thermogravimetric method, ash content by burning in a muffle furnace.
 Results. The dry matter content of the leaves varied depending on the year of research and crop. Thus, on average over the years of research, this figure was highest in switchgrass and willow, 65.8–66.0% with an ash content of 4.3–4.5%. The content of dry mass in miscanthus leaves was 9–10% lower compared to other energy crops. The ash content was at the level of 2.8% or 1.5–1.6 times. Physico-chemical parameters of the leaves of energy crops have changed since one year of the study. In miscanthus leaves it varied from 59.9 to 60.2%, switchgrass from 54.5 to 76.9%, and willow from 60.7 to 72.2%. The ash content varied in a smaller range of all energy crops. In the stems of miscanthus, the dry matter content was in the range from 57.5% to 58.9%, in switchgrass it was the largest, from 54.9 to 65.3%, and in the stems of willow from 51.3 to 57.1% over the years of research. The stems of all energy crops had a lower ash content compared to the leaves. Thus, this indicator in miscanthus leaves was at the level of 1.5–1.6%, switchgrass 1.3–2.2%, willow 2.0–2.5% (1.5–3.0 times).
 Conclusions. The content of dry mass and ash in the leaves and stems varies depending on the type of energy crop. The highest content of dry mass is formed in the leaves of switchgrass (54.5–76.9%) and willow 60.7–72.2%. The ash content is 4.1–4.9% and 4.0–4.5%, respectively. The content of dry mass in miscanthus stems is 57.5–58.9%, switchgrass 54.9–65.3%, willow 51.3–57.1%. The content of ash in the stems of miscanthus is 1.5–1.6%, switchgrass 1.3–2.2, willow 2.0–2.5% or 1.5–3.0 times.