Biofuels

Land use change from woody biomass to herbaceous species for bioenergy in marginal lands has an impact on soil organic carbon, which challenges the positive effect of fossil-C substitution. Scientists Nocentini and Monti showed that land use change from poplar to ten years of switchgrass and giant reed increased substantially and differently soil organic carbon stocks. These increases contributed significantly to life-cycle carbon savings of both perennial grass crops when biomass was used to produce advanced ethanol to supplant fossil fuels.

Tobacco is an industrial crop traditionally used for manufacturing cigarettes but due to European subsidies restriction, an alternative use should be found. Tobacco could be used as an oilseed crop with an oil yield ranging from 30 to 40% of seed dry weight. Grisan et al. review the performance of tobacco cultivar Solaris in Italy. Seed production was evaluated to be 1.1 – 1.8 t/ha, with an oil yield up to 0.59 t/ha. In North Est Italy two seed harvests determined a total seed yield of 4.5 t/ha, from which 1.48 t of oil/ha could be obtained.

Second generation biofuels from non-edible biomass, such as bioethanol from cereal straw, are more sustainable than first generation biofuels such as bioethanol from maize seeds. Sustainability could be further enhanced by cultivating both cereals and legumes, such as pea, because legumes are enriched in nitrogen that fertilises later the cereals. Nitrogen-rich cereal straw should facilitate yeast fermentation to produce bioethanol because yeast needs nitrogen to grow. Agronomists Pellicano et al. tested wheat, barley, triticale and oat grown in intercrop with pea. They found indeed that pea improves the N content of the straw mixture.

The global energy demand is predicted to grow more than 50% by 2025, inducing possible adverse effects on climate due to increasing atmospheric CO2, a greenhouse gas, from fossil fuel burning. This issue can be solved by replacing fossil fuels by renewable fuels such as trees. The use of trees such as poplar, eucalyptus, salix, paulownia (photo), and black locust has many advantages such as allowing multiple harvests, revitalizing local economies, promoting energy self-sufficiency, and reducing environmental problems. Scientists Durán et al. show the benefits of short-rotation tree plantations for the bioenergy sector.

In New Zealand 70% of the country’s electricity generation is already renewable. Plant biomass can be used for multiple forms of bioenergy, and there is a very large potential supply, depending on which global assessment is most accurate in terms of land area that could be available for biomass production. The most suitable plant species must be identified before the potential biomass production in a particular region can be quantified. This in turn depends on the degree of climatic adaptation by those species. A review article by Kerckhoffs and Renquist identified the most suitable crop species and assessed their production potential for use within the climatic range present in New Zealand.