Biomass and bioenergy production of Arundo donax L., Pennisetum purpureum schum. and Pennisetum purpureum Schumack. × Pennisetum glaucum L. in short rotation cropping system in Costa Rica

Nowadays different alternatives of short-rotation crops have been planted as renewable energy production around the world. The objective of this research was to evaluate biomass and energy production of the first rotation (6 months) of Arundo donax, Pennisetum purpureum and Pennisetum purpureum×Pennisetum glaucum propagated by plant and rhizomes in short-rotation crops condition in humid tropical conditions in Costa Rica. These crops were established with spacing of 1 m×1 m when was established by plant and 1 m×6 m when was established by rhizomes, in plots of 50 m². At six months, within these areas, total height, number of sprouts, biomass production and its respective energy produced were evaluated. The results obtained showed that P. purpureum propagated by plant had the lowest ash percentage (13.33%), A. donax the lowest moisture content (52.28%) and P. purpureum×P. glaucum presented the highest calorific value (20218 kJ/kg). P. purpureum showed the best yields in biomass production (24.45 ton/ha and 22.52 ton/ha) propagated by rhizome and by plant respectively and therefore these two short-rotation crops were the highest energy produced (470 GJ/ha) after six months.