[Terrapreta] Terra Preta & Pigs

[Frank Teuton]

Gentlemen,

Can we please be more specific as to the concerns about using charcoal on soils and crops? What are the circumstances under which charcoal may do harm to soils and crops? What methods should be used to produce charcoals from what source materials under what temperatures for specific effects? And, if the conditions and materials are indeed so very critical, how is it that a culture of people over a thousand years old was able to somehow able to create terra preta?

In my opinion general vague warnings are not 'very good feedback'...they are basically useless unless attached to specific concerns based on empirical findings.

As always, I have to wonder if those issuing such warnings are motivated by their own material interests, in for example patented technologies or the like.

I am ready to believe that charcoal production is likely best carried out in such a way that all possible by products are properly captured and utilized...less pollution into the environment, less waste, etc. Plus the controlled temps for producing the best qualities for specific purposes can probably be best assured under carefully controlled processes. Still, this cannot be how the original terra preta was made...and until the Eprida process or something like it comes online, the availability of agricultural charcoal is likely dependent on individuals doing something like what was done in antiquity to generate their own supplies. Also, in the third world the availability of industrially produced high quality agricultural carbon may take quite a long time to generate locally useful materials.

I would have thought a Terra preta list would have more information on the hands on process including advice for people intending to do it themselves...with appropriate do's and don'ts and whys and why nots. (aka concrete caveats).

For my part, I joined the list to keep up with current research, find methods I can use myself, and find sources of agricultural charcoal if possible.


  ----- Original Message ----- 
  From: Richard Haard 
  To: Douglas Clayton 
  Cc: terrapreta at bioenergylists.org 
  Sent: Saturday, February 24, 2007 1:08 AM
  Subject: Re: [Terrapreta] Terra Preta & Pigs


  Very good feedback - thanks all

  On Feb 22, 2007, at 8:20 PM, Douglas Clayton wrote:


    I spoke with Dr. Johannes Lehmann this morning and received the clear message from him that it was a mistake to go fooling around willy-nilly with charcoal at this time.  Not that it is dangerous but just that it is hard to learn anything definative. The science isn't there yet to know what we are doing.  This was a great disappointment to me but I understand where he is coming from.  


    Dr. Lehman indicated that the temperature at which the charcoal is produced is critical, the material being charred and the end use, the soil type and conditions and the crop being grown are variables about which we can not yet, say what is appropriate.  Not knowing the source material means something may work one time but not the next.  He indicated that it is definitely not a panacea and applying charcoal can, in some circumstances, do harm to soils and crops.


    Never the less, I plan to experiment a little bit in the garden this summer myself!


    How do we check the pH of the charcoal we purchase or produce?


    Douglas Clayton
    <snip>
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