[Terrapreta] Low Temp Chars

[AJH]

On Thu, 10 May 2007 00:09:27 -0500, Sean K. Barry wrote:

>I do not think microorganisms will digest or oxidize pure carbon. 

Nor I and that was never part of the question. The question related to
how the non fixed carbon part of the charcoal survived. As a poster
had suggested the tars and oils associated with the char were utilised
by microbes I wanted to know whether the carbon part of these still
stayed in the soil and could be claimed to be sequestered.

One answer so far was that as a higher soil zoomass was a feature of
terra preta soils that the carbon in these microbes could be
considered sequestered.

<snip>

>
>Other evidence, perhaps more compelling, about the resilience of carbon in soil (in the form of charcoal) is the carbon dating of the charcoal in the Terra Preta. 

Yes we know the age at which the plant matter ceased absorbing CO2
from the atmosphere and can safely assume it was charred soon after.

Presumably we can also test the composition of this char if we can
find a big enough piece. The fact that we can see cell structure may
give us a clue about pyrolysis temperature but we have reason to
believe this was relatively low, sub 500C, and we would expect this to
give us fixed carbon of <80% of the biochar. 

So are results that show how the non fixed carbon, non ash, portion of
the char survives over time?

AJH