[Terrapreta] Pottery Shards and Terra Preta

[code suidae]

On Dec 10, 2007 3:09 PM, Robert Klein <arclein at yahoo.com> wrote:
> I have every reason to suspect that the terra preta biochar was manufactured
> by the building of tightly packed corn stover stacks with earthen walls created
> by the brick like root balls.  [...]
>
> In order to start and maintain the burn it is necessary to carry a charge of
> coals onto the top of the stack and to tip in into the center and then cover
> same.  The only way available would be to use a sun dried clay platter

Possible, but it seems a bit of a leap to suggest that a clay dish is
'the only way available'.

> This easily explains the buildup of 'pottery ' in the soils.

Again, possible, but I think 'easily explains' is a leap. I wouldn't
expect such a platter to fire particularly well, being near the
outside of a relatively cool-burning pile.

Also it seems that one ill-fired platter per char pile would not
explain the quantity of shards found.

Could you describe how large you think the platter would have been,
how well it would have fired, and approximately how much char you
expect would have been produced per platter (I suspect corn would
reduce quite a lot, so perhaps a relatively large amout of clay would
be left from a largish platter)?

Also, I'm curious whether the composition and firing characteristics
of recovered shards has been closely examined. If so it should be
reasonable to compare that to the ceramic material that comes from a
platter used in the manner suggested.

Have you performed field tests of this method yet? If not, what do you
think the minimum size for such a trial would be?

Dave K
-- 
"Our ignorance is not so vast as our failure to use what we know." -
M. King Hubbert