[Terrapreta] Terrapreta Digest, Vol 15, Issue 14

[Sean K. Barry]

Hi Kevin,

Lately, I've been thinking that pottery shards in Terra Preta soils served mostly a mechanical purpose.  I think they were used to both drain the soil and prevent run off of nutrients.  The inclusion of pottery shards with charcoal in "Old Terra Preta" sites was either done as a soil amendment, to do something there with that soil, or maybe it was a coincidental, extraordinarily large pottery dump and they just repeated it (thinking it was part of the TP effect observed in that soil).

The scope of the projects (an area the size of France) suggests to me that it was really sort of an industrial soil remediation, involving large numbers of the population to manage the soils and the land.  There is evidence of elevated roads (which also you do not want to wash away) in Amazonia as well.  Fired pottery was likely some of the hardest, most water erosion resistant substances around.  Draining water or maintaining an elevated mound within an annual inundation would be easier in clay mud with lots of pottery shards around.  You might even be able to make a pile of them in a flowing river and build a bridge across that river.

Initial development of the idea that the mixture of wastes and charcoal made for better plant growth may have been inspired by observation of plant growth over old dump sites.  This seems plausible.  Maybe they just copied what they observed and pottery was incidental to the dump sites, so they put it in when they tried to build TP sites.  It seems that they then tried to repeat this TP phenomenon on a larger scale.  No TP site is naturally occurring?  All Terra Preta sites are synthetic?

I'm not sure the Amazon population then could have shit enough into enough chamber pots, and then broken them, in shatters, to make all the pottery shards found in all of the Terra Preta found in South America.  I suspect all of the broken fired pottery was used to hold all the soil from washing away.

Regards,

SKB


  ----- Original Message ----- 
  From: Kevin Chisholm<mailto:kchisholm at ca.inter.net> 
  To: Sean K. Barry<mailto:sean.barry at juno.com> 
  Cc: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> ; Greg and April<mailto:gregandapril at earthlink.net> 
  Sent: Monday, April 07, 2008 12:22 PM
  Subject: Re: [Terrapreta] Terrapreta Digest, Vol 15, Issue 14


  Dear Sean

  In your opinion, are pottery shards a necessary component in "Old Terra 
  Preta"?

  Kevin

  Sean K. Barry wrote:
  > Hi Greg,
  >  
  > I think that it is only where charcoal-in-soil was put.  If it 
  > spreads, why hasn't it in 4500 years?  How can we find individual 
  > sites now, closely spaced?
  >  
  > Regards,
  >  
  > SKB
  >
  >     ----- Original Message -----
  >     *From:* Greg and April <mailto:gregandapril at earthlink.net<mailto:gregandapril at earthlink.net>>
  >     *To:* terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org>
  >     <mailto:terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org>>
  >     *Sent:* Monday, April 07, 2008 11:22 AM
  >     *Subject:* Re: [Terrapreta] Terrapreta Digest, Vol 15, Issue 14
  >
  >     I think we do need to understand the origins of Terra Preta - at
  >     least in part to understand the mechanics of how it has
  >     become self sustaining, and wither or not the science behind it
  >     would be useful in other places.
  >      
  >     What clues can we find?    Other than pottery shards and the
  >     physical / structural makeup of the char,  there is not much else
  >     that I know of due to the nature of the area.
  >      
  >     You are correct, that studying the nature of the mined TP might
  >     give a few more clues.
  >      
  >      
  >     Why is it self sustaining?    Personally I think that it's a
  >     matter of achieving a given nutrient density and CEC level after
  >     which the density of the plant life is able to keep it going.   
  >      
  >     What I would like to know is it able to spread or is it just
  >     confined to the areas of human influence.
  >      
  >      
  >     Greg H.
  >      
  >



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