[Terrapreta] Interesting article on char

[Michael Bailes]

An interesting article on carbon which seems somehow to have something to
say about the grass/forest/co2 debate.
http://abc.net.au/science/features/soilcarbon/

How soil loses carbon

Professor Alex McBratney from the University of Sydney has been studying
soil carbon decline in the Namoi Valley, north western NSW.

The soils in this area have taken a beating, due largely to intensive cotton
farming over the past 30 years. Once pastureland, the conversion to cotton
crops has seen soil carbon levels decline from 1.5 to 0.8 per cent, he says.
How does this happen? In healthy soils, carbon exists as long, sticky
string-like molecules.

These strings twist around individual soil particles and literally bind them
together. Soil micro-organisms tend not to bother consuming these large,
unpalatable molecules, preferring fresh or rotted plant matter – the stems,
roots and other plant parts which over time become incorporated into the
soil.

But if the soil loses this plant content (because the stubble is burnt or
removed), the soil microorganisms have no choice but to make a meal of the
carbon molecules. Once the carbon is gone, the structure of the soil breaks
down making it difficult to retain water and nutrients.
[image: Trees effect carbon levels in surrounding soil]
Trees versus crops. Carbon levels in forest soils are usually much higher
than those under agriculture. *Pic: Brian Murphy* [image: phases of the Moon
explained]

-- 
Michael the Archangel

"You can fix all the world's problems in a garden. . . .
Most people don't know that"
FROM
http://www.blog.thesietch.org/wp-content/permaculture.swf
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