Browsing by Author "Tahvola, Essi"

Field bioenergy is a form of renewable energy, where plant biomass is used as feedstock in different energy production systems. Field based bioenergy will help to increase renewable energy utilization, which should be 20% of total energy consumption in year 2020 according to the EU regulations. Hemp (Cannabis sativa L.) and maize (Zea mays L.) are traditional crops with significant dry matter yield potential and they can be used as break crops in conventional crop rotations. The purpose of this study was to analyze the suitability of hemp and maize as feedstock crops in Finland, as well as the varietal differences based on feedstock quality and yield. Field experiment were conducted at the Viikki Experimental farm, University of Helsinki, Finland in 2007 and 2008. Studied traits were dry matter yield, nutrient uptake and feedstock chemical composition, ash, energy and soluble sugar content as well as C/N- and C/P-ratios. Experiments included three hemp cultivars, oilhemp Finola and fibrehemps Chamaeleon and USO 31 and five maize cultivars: Gavot, Campesino, Ronaldino, KXA7211 and KXA7251. Fertilizer rates were 60 N kg/ha for hemp and 120 N kg/ha for maize in 2007 and 210 N kg/ha in 2008. Chamaeleon produced the highest dry matter yield (18 000 DM kg/ha), and the difference to the next one, USO 31 was more than 20 %. Campesino, Gavot and KXA7251 produced the highest dry matter yield (15 500-18 000 DM kg/ha) of maize cultivars studied. Maize dry matter was rich in soluble sugars (177-215 mg/kg DM). Hemp and maize biomass was high in content of different elements and ash. The results indicated that hemp and maize can produce high dry matter yield. However the feedstock quality traits are not ideal for energy. High content of different elements in unprocessed dry matter interferes with the burning and imbalanced C/N- and C/P-ratio biogas production. Based on the results maize can be an excellent option as bioethanol feedstock due to high content of soluble sugars in the dry matter.