[Terrapreta] Charcoal mix continued

[Sean K. Barry]

Michael,

Christoph Steiner mentioned, on reading the comment about 30% density of charcoal in Terra Preta soil that he thought that number was high (maybe even quite high).  I have never actually measured charcoal content in any soil, let alone Amazon Terra Preta soil.  He has.  I think we should take heed of his first hand experience with the actual Terra Preta soil in the actual places where it was discovered.  By his reference, I would consider it a given that charcoal is not nearly as dense as 30% in any known Terra Preta soils.  I do think Christoph would agree that the charcoal found in some examples of Terra Preta soil exists in quite deep layers (up to 5 feet?) and that it probably was laid down in those areas slowly over quite a long period of time.

I do not believe, either, that density of charcoal alone is a defining issue as to what makes Terra Preta soil a much better plant growing medium than surrounding soils.  I think, rather, that Terra Preta soil is an ecology of soil, a habitat in the soil, that promotes improved health of soil microorganisms.  The improved soil microbiological activity then improves the soil habitat for plants which grow above the soil and root into it.

The significant improvement of food crops grown in Terra Preta soils versus surrounding oxisol native soils in the Amazon rainforest, may also be related to the substantial defiicit that those native soils present for food crops.  Even a normal bloom in a desert would be measured as outstanding one by anyone familiar with what can and does normally grow in a desert.

SKB
  ----- Original Message ----- 
  From: Michael N Trevor<mailto:mtrevor at ntamar.net> 
  To: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Wednesday, April 18, 2007 9:38 PM
  Subject: Re: [Terrapreta] Charcoal mix continued


  Dear Sean

  Thanks for the addition feed back and information. So in human terms charcoal addition is partially permanent, being long term
  and persistent. I like your comment, its presence being like a catalyst in as what ever it does it seems to remain..
  If it has built up to 30% in some places over thousands of years then the actually beneficial amount needed in short term
  must actually be pretty small. If my reasoning is not wrong and we get 30 % for 3000 years, then doses like 10 and 20 percent
  should be pretty high up on the scale since even amounts like.03 percent per year might have accumulative effects over time.

  Regards,

  Michael

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