[Terrapreta] Interesting article on char

[Sean K. Barry]

Thank you, Michael.

"Carbon levels in forest soils are usually much higher than those under agriculture."  One more for the "not so counter-intuitive"!

SKB
  ----- Original Message ----- 
  From: Michael Bailes<mailto:michaelangelica at gmail.com> 
  To: terrapreta<mailto:terrapreta at bioenergylists.org> 
  Sent: Sunday, September 23, 2007 2:57 AM
  Subject: [Terrapreta] Interesting article on char


  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/ <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.


  Trees versus crops. Carbon levels in forest soils are usually much higher than those under agriculture. Pic: Brian Murphy 

  -- 
  Michael the Archangel 

  "You can fix all the world's problems in a garden. . . . 
  Most people don't know that"
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