Comparative attributional LCA of annual and perennial ligno-cellulosic feedstocks production, under Mediterranean climate, for bio-refinery framework

Annual fiber sorghum (FS) and perennial giant reed (GR) cultivated in the Mediterranean area, appear of interest due to their high productivity under drought conditions and the potential use as lignocellulosic feedstock for biorefinery purpose. This study compares the environmental constraints related to FS and GR produced in an experimental farms (Campania region), by means of an attributional LCA approach, through an appropriate modelling of the perennial cultivation. For both crops, primary data were available for agricultural management while direct field emissions (DFE's) were computed, including the potential soil carbon storage (SCS). GR showed the lowest burdens for all impact categories analysed (for the most in the range of 40%–80% of FS values). More marked appeared the differences for Climate Change and Freshwater Eutrophication (respectively 80% and 81% lower for GR in comparison to FS). These results are due to the short-term SCS, experimentally detected for perennial GR crop (about 0.25 ton C ha−1yr−1, with a global warming offsetting potential of about 0.03 ton CO2/tonGR dry biomass), and to the annual application of triple superphosphate at the sowing fertilization for FS, differently from GR, where P fertilization was performed only at the phase of crop establishment and therefore properly spread along the overall crop lifetime. For both crops, after normalization, Terrestrial Acidification and Particulate Matter Formation were relevant impact categories, as a consequence of the NH3 DFE by volatilization after urea superficial spreading. Therefore, results suggest higher environmental benefits of perennial crop than annual crop. Integr Environ Assess Manag © 2014 SETAC