photo: Ricky via flickr
A new study coming out of Duke University asserts that if reducing greenhouse gases is the goal, then leaving land unfarmed and set aside in conservation reserves would be better than expanding the planting of corn and making ethanol from it:The authors point out in Ecological Applications that,
Converting set-asides to corn ethanol production is an inefficient and expensive greenhouse gas mitigation policy that should not be encouraged until ethanol production technologies improve.
Depending on prior land use, our analysis shows that carbon releases from the soil after planting corn for ethanol may in some cases completely offset carbon gains attributed to biofuel generation for at least 50 years.
Cellulosic Ethanol Can Increase Soil Carbon Levels
However, cellulosic ethanol fares much, much better,
By analyzing 142 different soil studies, the researchers found that conventional corn farming can remove 30 to 50 percent of the carbon stored in the soil. In contrast, cellulosic ethanol production entails mowing plants as they grow -- often on land that is already in conservation reserve. That, their analysis found, can ultimately increase soil carbon levels between 30 to 50 percent instead of reducing them.
It's worth pointing out that not all cellulosic ethanol production involves 'mowing' as this paper's authors assert. Many potential sources for cellulosic ethanol exist, and most (from what I've seen) involve processing waste products (agricultural waste, woody construction waste, commercial waste...).
via: Science Codex
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