Sulla (Hedysarum coronarium L.) leaves and stems as a potential biofuel feedstock

Sulla (Hedysarum coronarium L. syn., Sulla coronaria [L.] Medik.) is a short-lived perennial legume native to the Mediterranean basin, where it is extensively grown as a 2-year forage crop playing a key role in cereal-based systems of semi-arid regions thanks to its versatility, (e.g., used for grazing, hay and silage production, and grazing associated with hay production), good-quality forage, and environmental benefits. To date, sulla has not been considered as a bioenergy crop. This research aimed to evaluate the potential of sulla biomass as a biofuel feedstock; in addition, due to the possibility to separate the leaves from the stems as suggested for alfalfa, the biomass composition was analyzed separately for the leaf and stem fractions. The experiment was conducted in a typical semi-arid Mediterranean area of inner Sicily, Italy, during the two years of the crop cycle. The preliminary results of the research show that the biomass of sulla could be suitable for obtaining two very different co-products: leaves can be used in livestock nutrition thanks to their high protein content and nutritive value, whereas stems that are very rich in water-soluble carbohydrates and lignocellulose materials, less palatable for animals and with a lower nutritive value than leaves can represent a source of fermentable carbohydrates usable in the biofuel industry.