[Terrapreta] charcoal mix & long lasing effects

[Hunt, Tony]

Hello

 

First of all, as my first post to this group I would like to say hello
to all here, I've been watching the list for a couple of weeks now and
it's certainly a lively discussion.  I'm attending the IAI conference in
a couple of weeks and look forward to hearing much more about this
subject and meeting some of you.

 

Regarding Christoph's posting below, this gels with what I've read
elsewhere about terra preta soils.  For example, an oft-quoted figure is
300 tonnes of C (as charcoal) per hectare.  Assuming approximately one
tonne of dry soil per square metre in the terra preta horizon (i.e. the
top layer of soil) then 300/10,000 = 0.03, or 3% on a weight/weight
basis.  An interesting question is thus whether all the benefits of
terra preta are realised at or below 3% char C w/w, or whether
increasing this ratio further provides additional benefit.  Presumably
the relationship would not be linear (I assume it would level off) so
where is the optimum on a cost-benefit basis?  

 

Regards

 

Tony Hunt

Group Environment Manager

Transfield Services

________________________________________________________________________
___________________

 

Date: Wed, 18 Apr 2007 08:43:37 +0200 (CEST)

From: "Christoph Steiner" <Christoph.Steiner at uni-bayreuth.de>

Subject: [Terrapreta] charcoal mix & long lasing effects

To: terrapreta at bioenergylists.org

Message-ID:

      <64695.83.215.117.89.1176878617.squirrel at mail.uni-bayreuth.de>

Content-Type: text/plain;charset=iso-8859-1

 

Hi,

30% charcoal in Terra Preta is definitely too high! The highest carbon
values we found were around 10% which means that the charcoal
concentration can not be higher. Dr. Bruno Glaser from the University of
Bayreuth measured black carbon contents and found black carbon
concentrations in the soil organic matter of up to 35%. Therefore
estimations of a maximum of 3% charcoal are realistic and is still a
huge amount of charcoal.

Terra Preta is still exceptional fertile, but the creation date back at
least 500 years.

 

Best,

Christoph

 

 


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