[Terrapreta] Summary of Terra Preta and Charcoal in Soil
Randy Black
rblack at hillcity.k12.sd.us
Tue Apr 24 10:28:22 CDT 2007
In answer to this quote,
"Char itself has a high fertiliser value, depending on its source.", I
would like to discuss. It seems to me, even if charcoal has some
nutrient content when it is made (and it may well have, since charcoal
is made from biomass), that when and if these nutrients become available
for uptake by plants, then they would soon be depleted, perhaps in a few
seasons of plant growth and harvesting. But, "Terra Preta" soils are
centuries old and had been there (are still there) for many many years
(again centuries). So, any original fertilizer (plant nutrient) content
in charcoal, one put into the soil and having crops grown on it, would
have been depleted long ago. Therefore, if the "Terra Preta" soils
still retain their fertility, then there must be something about the
charcoal in the soil which helps the soil maintain it's fertility.
There also must be a continual application of nutrient containing
charcoal and/or plants nutrients from another form, either organic plant
materials (composts) or other sources of plant nutrients (N, P, K, S,
Ca, Fe, Mg).".
This is a simplistic generalized summation of what I think Terra Preta
is/does.
Terra Preta soil formation is started by adding charcoal to soil. This
by itself will not make Terra Preta. You must also have a source of
organic matter, some forms of biochar, and this material must have
sufficient nutrients to start and feed a host of microbial activity.
Charcoal provided two main qualities; first is that its adsorption
properties hold on to mineral ions and keep them from both leaching and
to some extent outgasing. This keeps the mineral/nutrients in the soil
so they are available to microbes and plants. The high cation exchange
capacity (CEC), of charcoal enhanced soils means that these nutrients
are not tightly bound to the charcoal and can easily move to be
available for use by microbes and plants. This leads to the second
quality of charcoal and that is the environment it provides for
microbial life. First the nutrients/ions bound to the charcoal provide
energy/food for the microbes. Second the pores in the charcoal provide
"living spaces" for the microbes and third, and possibly most important,
the charcoal moderates the moisture content of the soil so that it makes
a better more consistent moisture environment for the microbes. Charcoal
absorbs water but only so much and helps the soil to drain excess water.
Then the charcoal releases its water at a rate that moderates the soil
moisture content so it does not get too wet or too dry for the microbes.
The need for biochar (charred non-woody material - grass, leaves,
vegetable matter, manure), is that when it ranges from partial char to
charcoal it provides food and possibly some products that help initiate
certain types of microbial growth that could be essential for Terra
Preta formation. Also charcoal will breakdown eventually and the
biochar/microbe link may be what starts some process where pure charcoal
itself slowly and microscopically breaks down providing some
carbon/energy/ion products to the Terra Preta mix. Because of the
difficulties in identifying and cataloging soil microbes and their
functions we don't have enough information to say what exact role they
play in Terra Preta. All we know is that they play a major role and
without them we don't have Terra Preta.
The need for organic soil matter is obvious because all soil to be
productive must have organic matter input to feed the necessary
microbial activity. The same can be said for nutrients and we need to
keep in mind the amount of calcium and phosphorous that the Amazonian
Indians added to their soils. Are these nutrients crucial factors in
Terra Preta formation?
The end result of charcoal, biochar, organic matter, and microbial
activity is humus formation. The role that humus plays in Terra Preta is
also not well understood but this could also be crucial to creating and
more important, sustaining Terra Preta soil.
I feel that in Terra Preta we are dealing with an interconnected living
breathing system that is as complicated and individual as a cat, dog, or
person. It is a system that starts with charcoal, biochar, organic
material, and microbes but is sustained and enhanced by first, second,
third, and fourth order effects as it cycles materials/nutrients/organic
matter and takes in water and air and produces plants.
Randy Black
-----Original Message-----
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Today's Topics:
1. Re: To compost or not; and some other points (Frank Teuton)
2. Re: Agrichar trialled in field at Wollongbar (Sean K. Barry)
----------------------------------------------------------------------
Message: 1
Date: Tue, 24 Apr 2007 01:37:22 -0400
From: Frank Teuton <fteuton at videotron.ca>
Subject: Re: [Terrapreta] To compost or not; and some other points
To: Michael Bailes <michaelangelica at gmail.com>,
terrapreta at bioenergylists.org
Message-ID: <C64B2A3FB1704295990D7AA7A098DBB8 at FrankPC>
Content-Type: text/plain; charset="iso-8859-1"
Michael,
I'm a big fan of free flowing information, so yes, feel free to re-post.
I recall having read somewhere in the literature that lower temperature
char preserves more of the original structure of the materials being
charred, and that this created better habitat for critters (crispy
carbon critter condos! ;-) and for holding water...but I can't remember
exactly where, will get back to you if I find the exact quote.
Did the 600 C chicken litter char have reduced volume compared to the
400 C char? The higher P and K values and the lower N for the high temp
char makes me think so...
Ultimately plant growth response is the final word on what's good, from
a plant's eye view, but it takes a while to build up a good database on
that. (if anyone wants to chime in with 'plants got no eyes', I just
want to say, Mr Potato Head is watching you! ;-)
Charring manures surely solves all pathogen and weed seed issues....but
I wonder how much N gets turned into NOx compounds in the bargain.
All the best,
Frank Teuton
----- Original Message -----
From: Michael Bailes
To: Frank Teuton ; terrapreta at bioenergylists.org
Sent: Saturday, April 21, 2007 12:46 AM
Subject: Re: [Terrapreta] To compost or not; and some other points
Thanks Frank
What a great post on compost
Can it be re-posted say to the Permaculture and hypography forums?
re high temp/low temp char
There is some suggestion that higher temperatures and/or activation
increase char's water holding capacity. I can't find any research to
back this up however. Any help would be appreciated!
Water is a BIG issue in Australia at the moment. Recent research by
the OZ Horticulture industry has shown that water holding
granules/polimers work well in the lab but not at all well under field
conditions. It would be nice if Charcoal could help out here.
Depends too, on what you mean by "high", temp.
BEST Energies have made Chicken Manure char at 400 and 600C (Pure,
activated charcoal is, I believe, made at much higher temps)
With these results. (Thanks to Dr Stephen Joseph of BEST Australia.)
NPK Analysis of Charred chicken litter produced at 400oC and 600oC
Temperature of Reactor
400?C
600?C
Nitrogen (wt%, db)
4.00
3.74
Phosphorus (wt%, db)
3.217
4.402
Potassium (wt%, db)
2.945
3.803
Michael Bailes
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Message: 2
Date: Tue, 24 Apr 2007 00:50:16 -0500
From: "Sean K. Barry" <sean.barry at juno.com>
Subject: Re: [Terrapreta] Agrichar trialled in field at Wollongbar
To: "terrapreta" <terrapreta at bioenergylists.org>,
<robert.prince at ngia.com.au>, "Michael Bailes"
<michaelangelica at gmail.com>
Message-ID: <AABDC5GV2AZP846S at smtp04.lax.untd.com>
Content-Type: text/plain; charset="iso-8859-1"
Hi Michael,
Interesting article.
Tom Miles was asking earlier this evening about other ways to measure
charcoal. That article had a few reasonably good suggestions I thought
...
"We will also measure the nutrient content of the agrichar, particularly
calcium and magnesium, its cation exchange capacity, pH and changes to
microbial activity and microbial biomass."
I would also suggest a "pH buffer" capacity measurement. This is
something Richard Haard mentioned the other day as a measure of soil. I
think he suggested including this type of measurement for soil enhanced
with charcoal. Your highlight in the article, Michael, "... paper mill
waste applied at a rate of 10 tonnes per hectare raised the soil pH by
one unit, making the soil 10 times less acid." points out the value of
"buffering" acidity and/or alkalinity, which charcoal can provide, when
added to soils which swing away from the ideal (is that neutral pH =
7.0?).
This quote -> "Char itself has a high fertiliser value, depending on its
source.", I would like to discuss. It seems to me, even if charcoal has
some nutrient content when it is made (and it may well have, since
charcoal is made from biomass), that when and if these nutrients become
available for uptake by plants, then they would soon be depleted,
perhaps in a few seasons of plant growth and harvesting. But, "Terra
Preta" soils are centuries old and had been there (are still there) for
many many years (again centuries). So, any original fertilizer (plant
nutrient) content in charcoal, one put into the soil and having crops
grown on it, would have been depleted long ago. Therefore, if the
"Terra Preta" soils still retain their fertility, then there must be
something about the charcoal in the soil which helps the soil maintain
it's fertility. There also must be a continual application of nutrient
containing charcoal and/or plants nutrients from another form, either
organic
plant materials (composts) or other sources of plant nutrients (N, P,
K, S, Ca, Fe, Mg).
I think I have repeated this list, (N, P, K, S, Ca, Fe, Mg), like 100
times since I have been making posts to this site. A "Plant
Propagation" professor I had a few years back told use to remember all
the "required" plant nutrients by a phrase. It includes the 3 organic
elements from air and water (Carbon, Hydrogen, Oxygen) and the 6 or 7
organic elements (Nitrogen, Phosphorus, Potassium, Sulfer, Calcium,
Iron, Magnesium, Iodine) found in soils "See (C) HOPKINS CaFe
Manager(Mg)".
Regards,
Sean K. Barry
Principal Engineer/Owner
Troposphere Energy, LLC
11170 142nd St. N.
Stillwater, MN 55082
(651) 351-0711 (Home/Fax)
(651) 285-0904 (Cell)
sean.barry at juno.com<mailto:sean.barry at juno.com>
----- Original Message -----
From: Michael Bailes<mailto:michaelangelica at gmail.com>
To: terrapreta<mailto:terrapreta at bioenergylists.org> ;
robert.prince at ngia.com.au<mailto:robert.prince at ngia.com.au>
Sent: Tuesday, April 24, 2007 12:10 AM
Subject: [Terrapreta] Agrichar trialled in field at Wollongbar
This is the first time I have seen anything on agrichar in a Oz
agriculture.
Paper mill waste has up to 70% water content. You would not get much
free electricity from in a pyrolysis process unless you added some wood
waste as well..
Paper mill waste is now dumped in landfill were it produces methane, a
greenhouse gas.
The emphasis and underlining in the article is mine.
Agrichar trialled in field at Wollongbar
From the February 2007 edition of Agriculture Today.
DPI research scientist, Lukas Van Zwieten, says charred feedlot waste
is now being applied at a rate of 20 tonnes per hectare to Wollongbar's
ferrosol soils.
After very successful pot trials, Wollongbar Agricultural Institute
researchers are undertaking field trials to assess the value of agrichar
on iron-rich ferrosols.
Agrichar is organic matter that has been burnt very slowly with little
oxygen present, a process known as pyrolysis.
In the pot trials earlier this year, research scientist, Lukas Van
Zwieten, found charred paper mill waste applied at a rate of 10 tonnes
per hectare raised the soil pH by one unit, making the soil 10 times
less acid.
The agrichar application also eliminated plant-available aluminium
which is toxic to some agricultural crops at low levels.
"The success of the pot trials encouraged us to do field trials," Dr
Van Zwieten said.
"In November we set up 36 replicated plots to investigate the benefits
of agrichar and lime on ferrosols.
"This time the agrichar is made from charred chicken and feedlot
manure.
"We applied it at a rate of 20t/ha and incorporated it by
rotary-hoeing to 15 centimetres.
"While it is extremely easy to spread because it is so light, we are
looking at ways of improving its handling and marketability.
"We have planted a peanut ground cover, arachnis pintoi, where we will
measure crop yields and hope to have results in early 2007.
"One of our main goals is to quantify carbon sequestration in soil.
"Agrichar has the potential to reverse 150 years of organic matter
decline in Australian soils.
"Results so far have been stunning.
"We will also measure the nutrient content of the agrichar,
particularly calcium and magnesium, its cation exchange capacity, pH and
changes to microbial activity and microbial biomass."
The agrichar research team has established a method for greenhouse gas
analysis to examine emissions from soils.
"Basically, we want to see if we can reduce the formation of nitrous
oxides which develop following fertiliser application," Dr Van Zwieten
said.
"We suspect agrichar may help bind the nitrogen into the soil,
reducing the biological reactions that cause loss of nitrogen.
"Char itself has a high fertiliser value, depending on its source.
"We want to know how much nutrient in char is available to plants."
The Wollongbar field trials will provide information for a similar
trial in central Vietnam next year to build soil health and provide
forage crops as part of an ACIAR aid project.
The trials will complement Best Energy Australia's US work in charring
dairy and beef feedlot wastes.
There they are harnessing the energy generated by the pyrolysis
process to dry the effluent before it is pyrolised and spread on soil.
Results of the Wollongbar trials will be announced at an international
agrichar initiative conference at Terrigal in April.
Dr Van Zwieten is on the organising committee for this conference
(website: www.iaiconference.org<http://www.iaiconference.org/>).
Contact the NSW DPI Environmental and Agricultural Health team at
www.agric.nsw.gov.au/reader/wollongbar/eah.htm<http://www.agric.nsw.gov.
au/reader/wollongbar/eah.htm>
http://www.dpi.nsw.gov.au/aboutus/news/agriculture-today/february-2007/a
grichar-trialled-wollongbar
<http://www.agric.nsw.gov.au/reader/wollongbar/eah.htm>
--
Michael Bailes.
"Human beings,
who are almost unique in having the ability to learn from the
experience of others,
are also remarkable for their apparent disinclination to do so."
Douglas Adams, "Last Chance to See"
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