Re terra preta thread.
This was part of the the last post.
An especially interesting article in nature on carbon sequestration.
Quote:
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Originally Posted by erich
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Good article.
This was especially interesting re global warming
Quote:
According to Glaser's research, a hectare of metre-deep terra preta can contain 250 tonnes of carbon, as opposed to 100 tonnes in unimproved soils from similar parent material.
The extra carbon is not just in the char — it's also in the organic carbon and enhanced bacterial biomass that the char sustains.
That difference of 150 tonnes is greater than the amount of carbon in a hectare's worth of plants. That means turning unimproved soil into terra preta can store away more carbon than growing a tropical forest from scratch on the same piece of land, before you even start to make use of its enhanced fertility.
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and
further on
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The remarkable thing about this process is that, even after the fuel has been burned, more carbon dioxide is removed from the atmosphere than is put back. Traditional biofuels claim to be 'carbon neutral', because the carbon dioxide assimilated by the growing biomass makes up for the carbon dioxide given off by the burning of the fuel. But as Lehmann points out, systems such as Day's go one step further: "They are the only way to make a fuel that is actually carbon negative".
. . .
Then he discovered that his employees were reaping the culinary benefits of the enormous turnips that had sprung up on the piles of char lying around at the plant. Combining this char with ammonium bicarbonate, made using steam-recovered hydrogen, creates a soil additive that is now one of his process's selling points; the ammonium bicarbonate is a nitrogen-based fertilizer.
. . .
Brown thinks a 250-hectare farm on a char-and-ammonium-nitrate system can sequester 1,900 tonnes of carbon a year.
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