Chemical Composition and Biogas Formation potential of <i>Sida hermaphrodita</i> and <i>Silphium perfoliatum</i>

Abstract

Biogas production and use is one of the pillars of the EU strategy for fossil fuels replacement via renewable energies. In Poland, the most commonly used crop for biogas production is maize. There are many factors limiting the cultivation of this crop, which is why alternative plants are sought. The aim of the present paper was to assess the effect of establishing a plantation using seeds, seedlings, and various harvest dates on biogas production from Silphium perfoliatum L. (Silphium) and from two phenotypes of Sida hermaphrodita L. Rusby (Sida). Harvesting was conducted in the second (2017) and third year of crop growth (2018). These crops were harvested in June and at the beginning of October as a two-cut strategy. Additionally, Silphium was harvested in early autumn as a one-cut strategy. Specific biogas yield (SBY) and specific biomethane yield (SMY) were estimated using the modified Baserga method. The biogas yield per hectare (BY) was calculated. The crop species, method of establishing a plantation, as well as the date and the number of harvests had a significant effect on the content of the selected chemical components; however, significant differences in terms of SBY were not found for the two-cut strategy. In the case of Silphium, approximately 40% more BY was produced for the two-cut strategy compared to the one-cut strategy. The BY was found to be significantly affected by the biomass yield; markedly higher BY can be obtained from Silphium and the average amount obtained in one year was 8598 m3 ha−1 while 4759 m3 ha−1 was obtained from Sida.

Keywords

• renewable energy sources
• biomass chemical composition
• biogas yield
• <i>silphium perfoliatum</i> l.
• <i>sida hermaphrodita</i> l. rusby