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GCB Bioenergy

Cover image for Vol. 9 Issue 7

Edited By: Steve Long

Impact Factor: 4.655

ISI Journal Citation Reports © Ranking: 2016: 2/83 (Agronomy); 15/92 (Energy & Fuels)

Online ISSN: 1757-1707

Associated Title(s): Global Change Biology

GHG emissions from perennial and annual biofuel crops

GHG emissions from perennial and annual biofuel crops

Biofuels release fewer greenhouse gasses than fossil fuels and thus reduce climate change. In order to maximize the benefits of bioenergy, it is important to understand how different crop types contribute to greenhouse gas (GHG) emissions.

Drewer and coauthors studied the emissions of three greenhouse gasses- nitrous oxide, methane, and carbon dioxide - of four different crops. Two of the biofuel crop species, Miscanthus and willow, are perennial and grow back year after year. The other two species, oil seed rape and wheat, are annual crops that must be planted every year. These four crops were grown on adjacent fields in NE England and emissions were measured monthly

The authors found that nitrous oxide emissions from the annual crops were 5 times larger than the perennial bioenergy crops. This is primarily because the annual and perennial crops require different agricultural management. Annual crops require regular fertilizer application and soil is tilled annually prior to planting. In contrast, perennial crops utilize nutrients more efficiently and therefore do not require fertilization. The authors speculate that if the perennial crops were fertilized nitrous oxide emissions would increase substantially and the GHG savings in comparison with annual crops would be even smaller. On the other hand, methane and carbon dioxide emissions from annual crops were not significantly different from emissions from perennial crops.

Drewer, J., Finch, J. W., Lloyd, C. R., Baggs, E. M. and Skiba, U. (2011), How do soil emissions of N2O, CH4 and CO2 from perennial bioenergy crops differ from arable annual crops? GCB Bioenergy. doi: 10.1111/j.1757-1707.2011.01136.x Read this paper.

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