Influence of the Fertilization Method on the Silphium perfoliatum Biomass Composition and Methane Fermentation Efficiency

Abstract

Biogas production is one of the solutions for replacing fossil fuels, which promotes the widespread use of green energy. The aim of this study was to determine the potential of Silphium perfoliatum as an energy crop for biogas production, as well as the effect of different fertilization doses (0, 85 and 170 kg N ha−1) on the production potential (NL CH4 kg−1 VS) of Silphium perfoliatum. The study investigated the use of different feedstocks, such as raw and ensiled Silphium perfoliatum biomass. The methane production ranged between 193.59 and 243.61 NL CH4 kg−1 VS. The highest biogas production potential was achieved with the biomasses which were cultivated with the highest fertilization dose (170 kg N ha−1), both for raw and ensiled crop biomasses, although the difference from the other fertilization doses was not significant. The feedstock (biomass and silage) and digestate parameters were investigated as well. The use of Silphium perfoliatum for biogas production seems very promising since its methane production potential was found to be similar to that of the most common energy crop, such as maize, indicating that Silphium perfoliatum can compete in the future with maize.

Evaluation of the Intra- and Interspecific Development of Different Accessions of Silphium perfoliatum L. and Silphium integrifolium Michx.

“…Green Silphium biomass is mainly harvested for energy use in biogas plants [55,65]. Plants used for fiber production for the packaging industry also have the same maturity period as those for energy use, since a cascade use is possible here [66].…”

“…To maximize methane yield, a harvest in summer at the end of flowering in BBCH 6 6 is envisaged. Dry matter should then range from 20% to 25% [55,65]. If Silphium is to be harvested together with maize (Zea mais L.), a late-maturing accession, such as SPS, would be suitable here.…”