[Terrapreta] Black soil

[Philip Small]

I do not have the reference at hand, but I have read that some soil
scientists are persuaded that, to a significant degree, the black appearance
of prairie soils is due to charcoal, and that 10 - 30% of the organic-C in
these soils is in the form of charcoal. My thought is that it was probably a
lower percent before tillage increased the rate at which org-C evolves to
CO2, (pre-Columbian was 5-15% of the org-C maybe?) since char would be more
persistent.

On Tue, Jun 3, 2008 at 10:56 AM, Kevin Chisholm <kchisholm at ca.inter.net>
wrote:

> Dear Rich
>
> Richard Haard wrote:
> > Not all black soil soil is Terra Preta
> > <http://www.flickr.com/photos/rchaard/2548787688/>
>
> Very interesting point! What are your thoughts on the difference between
> "Black Soil" and "Terra Preta"?
>
> When is a "dark earth" simply "Black Soil", and when is it Terra Preta?
>
> Kevin
>
>
>
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-- 
Philip Small, RPSS
Land Profile, Inc. * PO Box 2175 * Spokane, WA 99210
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