[Terrapreta] Charcoal costs

[Tom Miles]

Sean,

 

After making such a nice summary I find your last paragraph surprising,
especially from someone who drives a lot of discussion topics on this list.
The discussion on the list and the web site point to considerable technical
information about terra preta. For example, the Cornell (Cheng) poster on
CEC is linked on the site. We have a couple of Cornell researchers who have
stayed with the list. Janet Thies, who co-authored the Cheng (CEC) poster,
was on the list, unless we've driven her off. 

 

Internet discussion lists are proactive - they are what you make them. They
are a point of contact. You have to be willing to take the time to study the
sources and you have to be interested enough to do some research and
discussion off list. It's not going to be delivered to you predigested which
is what you seem to imply. 

 

Regards,

 

Tom 

http://terrapreta.bioenergylists.org 

 

 

 

From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Sean K. Barry
Sent: Sunday, December 09, 2007 10:29 AM
To: Kevin Chisholm; Jim Joyner
Cc: 'Nikolaus Foidl'; terrapreta at bioenergylists.org
Subject: Re: [Terrapreta] Charcoal costs

 

Hi Jim,

 

I have a book compiled by Dr. Johannes Lehmann, with contributed writings by
researchers for many years in the field of Terra Preta,

"Amazonian Dark Earths: Origin, Properties, Management".  It was a very
expensive book, like $229!  I have read some, but not all of it.  I have
also read many of the research papers that Dr. Lehmann and his associates
(Dr. Christov Steiner, et al.) from Cornell University.  Many of the papers
are available on the Cornell University site.

 

>From my reading of what their combined research has found, charcoal in soil
alone does not attribute the characteristics that make it a more fertile
soil (increased CEC, better water holding capacity, increased nutrient
holding capacity).  Rather, it is the interaction between charcoal in soil,
the soil microorganisms, and other organic matter, where the Terra Preta
effect is grown from.  Charcoal does provide structure to the soil and
because it is porous is has some ability to hold water in micro-reservoirs
in those pores.

 

As you suggest, charcoal is nearly chemically inert in the soil.  It can
oxidize when exposed to air, but only very slowly. The porous nature of the
charcoal (it's structure), however, once in the soil provides a haven (with
water) and a place to grow for soil microbes.  They have shown scanning
electron micrographs of "hyphae" grown by vesicular arbuscular mycorrhizal
(VAM) fungi permeating and growing through the pores of charcoal in soil.

 

The VAM fungi grows hyphae to serve plants in a symbiotic fashion.  These
are hollow tubes that the fungi attaches to the hairs of roots, which extend
penetration into the soil and deliver water soluble nutrients to the plants.
The fungi grows the hyphae in exchange for (the symbiosis relationship) and
using the energy from sugars provided by the roots of the above ground
plants.  The hyphae are covered with a sticky sheath, called "glomulin".
When the hyphae die, the glomulin is left in the soil.  The glomulin binds
up water soluble nutrients and forms "aggregates" in the soil.  This is the
mechanism that is believed to be responsible for the nutrient holding
capacity of TP soil.

 

In general, charcoal in the soil makes for a more hospitable environment for
soil microbes.  They bloom in greater numbers and are more active in soil
containing charcoal.  Some researchers are trying to discover if the
residual volatile matter (tars, bio-oils, etc.) left on charcoal in some way
provide a decomposable organic energy source, food, for some microorganisms
(for anaerobic bacteria for instance).  When there is available soil organic
matter and a healthy soil microorganism population, that is when the
chemical activity rises in the soil and when the CEC rises as well.

 

When charcoal is made from biomass, most , if not all of the inorganic plant
nutrients that were in the original plants are retained in the ash portion
of the charcoal (calcium, phosphorus, iron, magnesium, etc).  They do not
burn off or exit the pyrolysis reaction as gases. So, in fact, charcoal from
biomass, has nearly all of the same fertility enhancing nutrient content as
composted biomass (save for nitrogen).  But, the carbon in charcoal will not
gas off like the carbon in carbohydrates in compost.  Charcoal in soil does
not emit CO2 like compost does.

 

The tools and the research work is being done out there and in real soils,
Jim.  There are lots of researchers and lots of experiments in progress.
Not much of it seems to see the light of day on this list though.  That may
be to do with the existence of "putzi" in this group, who don't get it
and/or who want to discuss politics, economics, and fuzzy warm feelings
about TP.  I don't know why.  I'm not an expert by profession about any of
this, but my interests do lie more along the lines of applied science.  I
have found external reading far more beneficial than most anything I ever
read off of this list.

 

Regards,

 

SKB

 

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