[Stoves] [biochar] Pine char gasification

[Ronal W. Larson]

Lists, 

    1.  This (up now to #18) thread started late last month (only on the biochar list) with Tom Miles relaying a story from Crispin on Purdue researchers making a fuel from char.  I think one could write a novel about this tortuous path.  I decided to respond because of Crispin’s “blah, blah, blah” insert below.

    2.  For those who wonder if there is a different version of the human side of the terra preta story, I suggest a short version by Dr.  Johannes Lehmann  (Biochar’s principal spokesperson, and who also did a thesis on this topic in Brazil.
     http://www.css.cornell.edu/faculty/lehmann/research/terra%20preta/terrapretamain.html
and a longer one (because it was highlighted in the short version and is free) by same author at
     http://www.css.cornell.edu/faculty/lehmann/publ/PlantSoil%20249,%20343-357,%202003%20Lehmann.pdf

   Anyone have something more up to date?

    3.  I find the interesting number for terra preta is not gm C/kg soil, but rather tonnes C/ha -because of the depth where C is found in anthrosols  (a term that Crispin presumably denies is valid - at least as far as the terra preta part of Brazil is concerned.)

Ron


On Jan 2, 2014, at 2:46 PM, Crispin Pemberton-Pigott <crispinpigott at gmail.com> wrote:

> Dear Kevin
> 
> I was not sure where this message went so I am reporting it.
> 
> Regards
> Crispin
> 
> +++
> 
>> # KC: This seems to be "The Unspoken Elephant in the Room." Just how
>> did the Terrapretians actually make Terra Preta??? Did they actually
>> make it on purpose, OR did it just happen, when they disposed of
>> wastes, either ``jungle wastes`` or ``domestic wastes``? What is the
>> difference between making "Terra Preta" and the Milpa Agriculture, as
>> practised in Belize?
> 
> A member of this list is Cecil Cook, the stove anthropologist. He doesn't say much on this list but he reads it.
> 
> When he was at Harvard doing his PhD research (meaning, in Motto 
> Grosso, Brazil for 4 years) he encountered Terra Preta and he has the 
> following observation which is important for all the duffers 
> like me discussing it.
> 
> The original peoples of Brazil definitely farmed on terra preta soils. These soils appear in patches. There is nothing like 'big farm lands stretching to the horizon' when it comes to terra preta. What he observed is that the terra preta occurs on those places where they practised slash and burn agriculture on land chosen because it was already the most productive. Doh!
> 
> In short, the reason the land is so productive is that it was already 
> the most productive before the slashing and burning started tens of 
> thousands of years ago. To attribute, in its entirely, the 
> productivity of the soils to char alone is quite incorrect.
> There is a combination at work of slash and burn (which provides 
> minerals and soil conditioner – char) on land that is already the best 
> in the area for what might be a multitude of reasons, but drainage and 
> good watering would be two.
> 
> Cecil points out that in a rain forest the fertilising resource is above the ground.
> 
> I have read that ‘on the edge of the farmed TP area the soil is much 
> worse’ blah-blah-blah but all they are documenting is the fact that 
> the First Nations people picked the good agriculture spots and worked 
> those. That can’t be too surprising.
> 
> The accumulation over millennia of additional char is accidental, not 
> crafted, and it is not the source of the ‘fertility’. Char is not a 
> fertiliser. Minerals from the ash are.  After a few short years the fertility drops and they let it go back to forest for a few years to accumulate 'inputs' for the next go-round. I have heard of cycle times of from 3 to 7 years.
> 
> Yes all sorts of amazing things can happen within char, or not,  
> depending on whether the char created is toxic or benign or   
> beneficial. As you know it is easy to generate dioxins by burning  
> chlorine containing biomass, and all sorts of other things. Nature  
> is not as simple as our understanding of it.
> 
> Neither is Terra Preta. Where the land was good, they farmed it.  
> Where it was not, they left it alone as not worth the effort. It is  
> still true. We should be both cautious and not surprised.
> 
> Regards
> Crispin
> 
> 
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