Economic and environmental sustainability of Sida and other biomass crops on Italian farms

Two perennial exotic grasses, Virginia Mallow (or Sida -Sida hermaphrodita (L.) Rusby) and Cup plant (Silphium perfoliatum L.), were tested in the frame of SidaTim project (FACCE-SURPLUS) in two sites in Italy, in continental North West and in Mediterranean areas. In this work, we reported the results of the possible utilization of the two species to feed an automated boiler system (200 kW) mixed with poplar chip. The economic analysis emphasizes the sustainability of chip-fed system for the production of thermal energy. The lignocellulosic chips represents the main cost, while other costs correspond to the electric energy for pumping water in the pipe and for other minor auxiliary equipment of the boiler. We have also assesses sustainability of these two crops/species investigating the productivity and water use efficiency (WUE, intrinsic and agronomic ones) in comparison to common energy crops (poplars Short Rotation Coppice and maize and sorghum for biogas). Additionally, the environmental impact was assessed comparing the competiveness of Sida in comparison to endemic vegetation (crops, forage species and seeds bank) in controlled experiments. During the establishment year, Sida showed a lower WUE in comparison to maize, although preliminary data of the second growing season estimate much better WUE. Sida competiveness depends of crop/forage species, requiring an implementation of this issue with field experiments.