[Terrapreta] Interesting article

[folke Günther]

I haven't received the pdf yet, but since there as been quite a discussion,I
will go through the background. When I have got the pdf, I will go through
it and give some more details.
The basic is this: 

1.	Burying charcoal in the soil always sequesters carbon (carbon
dioxide) from the atmosphere

*	This is true disregarding the route this charcoal may have taken to
the soil. I.e. even if the 'footprint' of this special  charcoal is larger
than its actual content of coal (say that it is flown around the world),
burying the charcoal mean that this certain amount is eliminated fro the
atmosphere. 
*	 I.e. If you burn it, it will return to the atmosphere, If you bury
it, it will stay in the soil for thousands of years

2.	Charcoal increase soil metabolism. 

*	This may not come as a surprise to any of the members of this
list.The reasons for that, and its effects, have been discussed, and easily
observed, for a long time.

3.	If you mix litter and charcoal, the litter will decompose faster
than if it is not mixed with charcoal.

*	This was confirmed by the study. A large part (25% i the first two
years) of the litter was metabolised by the microorganisms. I do not know if
a simultaneous increase of the plants living in, on or near the bags was
observed. One could expect  that.

4.	In bags with only litter, some metabolism would be observed,
although smaller than in the litter mixed with charcoal.

*	This is perfectly normal. 

5.	Thus, the presence of charcoal increase the rate of litter
decomposition.

*	Why am I not surprised?
*	Jumping to the conclusion, however, that the presence of charcoal in
the soil would be offset by the increased metabolism of litter, is wrong.
After a century or two, all the litter would be expected to be metabolised,
charcoal or not.

6.	Therefore, the sequestration effect of charcoal is not counteracted
by increased soil metabolism, since the SOM (Soil Organic Matter) is
ephemeral in comparison to the charcoal, and will decompose anyhow. However,
the in increased metabolism is reflected in a change in litter decomposition
rate. 

It would be very interesting to have the real figures, since that might
allow a calculation of the metabolism increase. A friend observed a
surprisingly high increase in the decomposition of a small compost heap when
charcoal was added



2008/5/2 folke Günther <folkeg at gmail.com>:

In the latest number of Sciene, (2 May), David Wardle, Marie-Charlotte
Nilsson och Olle Zackrisson delivers an article: "Fire-Derived Charcoal
Causes Loss of Forest Humus", where they claim that charcoal particles
remaining after fire increase the microbial activity so they break down
humic particles at a rate that counteracts the carbon sequestration effect
of the carbon.
I haven't read the article myself, but I am interested in he content. I
asked David Warle for a pdf.

FG

-- 
----------------------------------------
Folke Günther
Kollegievägen 19
224 73 Lund
Sweden
Phone: +46 (0)46 141429
Cell: +46 (0)709 710306
URL: http://www.holon.se/folke
BLOG: http://folkegunther.blogspot.com/ 




-- 
----------------------------------------
Folke Günther
Kollegievägen 19
224 73 Lund
Sweden
Phone: +46 (0)46 141429
Cell: +46 (0)709 710306
URL: http://www.holon.se/folke
BLOG: http://folkegunther.blogspot.com/ 

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