[Terrapreta] Methane and pottery

[Robert Klein]

I posted this on my Blog.  Go there for my ongoing
discussion on Terra Preta

http://globalwarming-arclein.blogspot.com

In the end concerns over methane production are
irrelevant. We have doubled production in the last
century and it is all gone. The reason is ultimately
very simple. It migrates to the upper atmosphere and
is consumed. This is something that is not an option
for CO2.

Does the sharp increase in methane reaching the
troposphere have any effect whatsoever? The quick
answer is nothing that is obvious. It is a little like
measuring the effect of the Mississippi on the
Atlantic. The practical answer as always is to make as
much as you desire and see were it takes you. My guess
is nowhere.

That means that methane production concerns regarding
all forms of biowaste combustion are misplaced. My
real concern would be for well intentioned government
regulation been actively imposed forcing a larger
industrial price for the use of the method.

The second issue that has attracted comment is the
association of pottery shards in the terra preta
soils. I naturally postulated that this was partly to
do with the disposal of kitchen waste in the corn
stover stack kilns as we described in earlier postings
in July. I also realized that a large bowl would have
to be used to transport hot coals to the top of the
stack and perhaps dumped into a prepared chimney.

These bowls are as primitive as you can get and very
prone to heat breakage, so the presence of pottery is
no surprise. My discomfort came from the fact that
they would have normally taken broken pottery away
with them for disposal elsewhere. So why not?

The answer came to me this morning. It is natural to
take the bowl of coals to the top of the stack and to
dump them there in the center and to let the coals
slowly burn out a chimney. The problem is that you
have to cover these coals with dirt to prevent flame
out. The best way to do that is to upend the bowl on
top of the coals and to throw dirt on top of that.
Otherwise, the coals will end up been smothered by the
dirt. The bowl would then migrate slowly to the bottom
of the stack. In the process the high heat would cause
this low quality pottery to breakup into very small
pieces not worth recovering or causing any difficulty
for cultivation.

Actually a pretty nifty solution to the problem of
controlling the ignition coal mass. While this was
progressing, the farmer would stand by to throw dirt
on any emerging openings in the stack to prevent a
flare up.


       
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