[Terrapreta] Black soil

[Philip Small]

On Tue, Jun 3, 2008 at 11:37 AM, Philip Small <psmall2008 at landprofile.com>
wrote:

> I do not have the reference at hand, but I have read that some soil
> scientists are persuaded that...


"read" is perhaps too strong a characterization.  Here is is my
source<https://www.soils.org/discussions/index.php?BBID=19&topic=1.msg3#msg3>:


Barry Bewley
Re: Welcome
Reply #2 on: December 07, 2007, 09:08:55 AM

Quote from: Edward Small on November 08, 2007, 12:30:12 PM

In the eyes of the public, unraveling the mystery of Terra Preta is the
> single hottest topic in soil science.  As a profession, we soil scientists
> owe it to the public to inform ourselves in this area.
>

This is the first I have heard of terra preta. Very interesting!

A question... How does the formation of the Terra preta soils differ from
the formation of the Midwest prairie soils? Obviously much of the Midwest
soils have been influenced by glaciers (terra preta were not), but *the dark
color comes mainly from indigenous activity (e.g., burning of the prairie)*.
I'm assuming the terra preta is similar??

Barry passed along a PDF
source<http://iledi.org/ppa/docs/00/00/00/00/09/02/20061002190618_ISWSCR2003-02.pdf>that
supports his statement:

...While humus (especially in organomineral form) helps give soils a black
> color (Duchaufour, 1978), the literature shows correlation between forest
> and grassland soil color to BC — the blacker the soil the higher its BC
> content (Schmidt and Noack, 2000)...
>

I haven't read Schmidt and Noack, 2000. Black carbon in soils and sediments:
Analysis, distribution, implications, and current challenges. Global
Biogeochemical Cycles
14:777-793<http://www.agu.org/pubs/crossref/2000/1999GB001208.shtml>.
but at only $9 to d/l, tempting.

The source for the "10-30% of org-C is char-C" statement is Skjemstad, J.O.,
D.C. Reicosky, A.R. Wilts, and J.A. McGowan. 2002.
Charcoal carbon in U.S. agricultural soils. Soil Sci. Soc. Am. J.
66:1249–1255 <http://soil.scijournals.org/cgi/reprint/66/4/1249>

(Tom: I am adding Skjemstad into the
bibliography<http://terrapreta.bioenergylists.org/biblio>)
-philip
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