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 <[email protected]>
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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