Terra Preta According to Green Power Science
Yesterday I posted on Green Power Science's DIY Vertical Axis Wind Turbine video. But that's not all that Dan and Denise Rojas have been up to. In the video above they take on one of the buzz words of the sustainability movement - terra preta. As discussed in Tim's post on biochar last year - terra preta is a term used to describe the rich, dark soils of the Amazon basin that were enriched with charcoal, organic matter and other amendments. Of course the topic is not without controversy. First, we should probably note that open burning is not the best method for creating biochar (a term used to describe charcoal used as soil ammendment rather than fuel). Most biochar advocates promote gasification, with some folks even promoting microwave gasifiers for biochar production. That way the gases that are driven off during the charcoal making process are used to produce energy rather than floating off as pollution.
But the video above does show how years of adding composted biomass and charcoal can greatly improve the fertility of soil - giving some credence to claims that the addition of biochar can increase crop yields up to 17%. And then of course there are the carbon sequestration benefits of terra preta.
Let's not forget that the biochar movement is not without its critics. Some folks, like George Monbiot, think the terra preta/biochar meme is just another excuse for business as usual - a technical fix for our systemic problems. (He also thinks it's silly to call charcoal biochar.)
Whatever the truth of the debate, given Dan and Denise Rojas' scary looking extreme solar cooking techniques, I'd love to see them build a biochar gasifier rather than burning all that yard waste.
More on Terra Preta and Biochar
Biochar is No Climate Change Miracle Cure
Biochar Offers Answers for Healthy Soil and Carbon Sequestration
How to Make Biochar and Bio-oil: RE:Char Demonstrates (Video)
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