[Terrapreta] The Science of Terra Preta Formation

[Sean K. Barry]

Hi Greg, Jim, Lou, et al.,

If the clays in the TP formations found in the Amazon are chemically different or weakly impart any biochemical activity, then the chemical basis for the inclusion into the soil seems doubtful.  I think the mechanical properties of the pottery shards in the soil may have more impact.

We've mentioned hardness, better drainage, the ability of fired pottery to hold water longer and to provide air pockets in water-logged soil, etc.
These things could be beneficial, if you are trying to deal with heavy rain all of the time or even with drought.  If shards of pottery prevent charcoal and nutrients from washing away from soil, then these combined amendments (charcoal and fired pottery shards) could help form TP like properties in the soil wear other areas lost the nutrients to outflow from rainfall.

Could the combination of pottery shards and charcoal be only required in tropical high rain areas?  Will aggregate size, friability, and SOM content in soil from temperate areas hold charcoal and nutrients better anyway?  Not like the heavily rained upon and accelerated decay state of organic matter in tropical soils?

Regards,

SKB
  ----- Original Message ----- 
  From: Jim Joyner<mailto:jimstoy at dtccom.net> 
  To: Terra Preta<mailto:terrapreta at bioenergylists.org> 
  Sent: Sunday, April 06, 2008 7:10 PM
  Subject: Re: [Terrapreta] The Science of Terra Preta Formation


  Greg.

  Greg and April wrote: 
    Does not the reports from Glaser et al. (1998 and 2003) and Brodowski et al. (2005) have any merit?    They specifically state that " formation of condensed aromatic structures depends on the manufacture of charcoal ". 

    In which case you can increase the exchange potential, by the addition of char with these compounds, and not just due to different particle size.
  All I know is that when char alone has been added to soil the CEC does not increase. Richard has a set of soil tests that strongly indicate, if not prove, this. Soon I will have a similar set that will probably show the same thing.

  I think you might be confusing CEC with the saturation base. The CEC is the collective ability of the soil to hold nutrient. The saturation base is where the nutrient is actually held (the soup, the electrically charged interstices among soil particles -- inert mineral for the most part). Changing the contents of the saturation base does not change the CEC but it does change the soil nutrient make up..

     Do you have any documentation that show's / suggests that fired clay can not change the soil cation exchange potential, in any way? 

  No. But you are making the claim that it does. The burden of proof is on you. Show us that fired clay has some special quality influencing CEC or even the saturation base. 

    One major company disagrees with you - even to the point that they are marketing a product, in the form of fired clay intended to raise the CEC of aquarium gravel.
  The CEC of aquarium gravel . . . ? I'm not sure how that is relevant but it's a free country, companies can market snake oil if they like. Do they present proof? Do they indicate how this might be applicable to soil? Do the have "soil" tests?   
    What if the fired clay is inclined to act as a receptor for different ions, than the local unfired clay?    Even if in minute quantities, it could be enough to ensure that long term collection of key trace minerals makes a given piece of land more productive than another piece of land 50-100 yards away.
  "What if" indicates a rather large universe of possibilities. Got any theories?  
    I have never stated in any way, that I thought that the shards did more than assist in the beginning of the formation of TP. 

  Sorry, I may have read that into what you were saying.  

    I think the char is catalytic in nature, increasing the potential of the local soil.   

  I think we just don't know what it does at molecular level. It may ultimately indicate re-thinking the way we think about soil structure. Like you, I could guess, but beyond getting some char and putting in the soil I can't do or know much else.

    Further, I think that the shards, do not really contribute to the current soil ( TP ), but, were instrumental in getting it established - wither this was accidental or on purpose, I don't know - perhaps it was accidental at first, but later on?    Who knows.    Just how it did it's job, is very much open for debate.
  Amen

  Jim

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