[Terrapreta] Terrapreta Digest, Vol 3, Issue 38

[Rhisiart Gwilym]

Request from list-member Rhisiart Gwilym:

Dear List Members,

I want to ask for approval for a proposal. Below is an edited version 
of Volume 3, Issue 38. I've left out everyone's email addresses, 
except for Sean's who I judge is willing to get all enquiries as they 
come, since he includes all his contact information in his post.

My idea is to submit this edited version for inclusion in one of the 
sections of the regular newsflow at Energy Bulletin. The editors have 
already expressed an interest in any informed information about terra 
preta. Their website is read regularly by a wide cross-section of 
people, including many gardeners and farmers, it seems. I think that 
the ideas contained in this post are so important, and so lucidly 
expressed by the posters, that It seems to me to need disseminating 
as widely and as quickly as possible. The proposed submission to 
Energy Bulletin would read as follows:

CAN TERRA PRETA DE INDIOS SAVE THE EARTH?

In the Amazon basin, and elsewhere, there are areas of rich black 
soils, side by side with the much lighter, more barren laterite soils 
of the undisturbed forest. Current archaeology and practical soil 
research suggest that these areas of black soil were made 
deliberately from the laterite, long ago, by Native American 
communities. The three things about Terra Preta ('Black Earth' in 
Portuguese) that matter crucially today are:

1) That it is made with cheap, simple, techniques that anyone can 
learn and apply at home, on any patch of ground to which they can 
have access.

2) That it produces almost miraculously rich, long-persisting 
fertility in the soil, even starting from pretty barren substrates.

3) And that it sequesters very substantial amounts of  atmospheric 
carbon, in inert form, into the soil for - as far as anyone can 
discover - thousands of years, at least.

Long-term, massive atmospheric carbon sequestration AND spectacular 
soil fertility enhancement are clearly both eminently practical, 
using nothing more than simple 'peasant' techniques and equipment, 
whenever we start copying the ancient pioneers of the Terra Preta 
black soil of the Amazon in our gardening and farming. Potentially, 
hundreds of millions of practical, small-scale food-growers 
everywhere could be doing this any time that we want to start.

Below is a minimally-edited version of a recent thread of 
conversation taken with permission from the Terra Preta Digest, at 
terrapreta at bioenergylists.org    ----


>Hello Everyone Participating in this excellent conversation!
>
>I have a question.  I've run across this concept that making charcoal
>actually ""sequesters" carbon.  Sequester: a beautiful word.  But what
>does it actually mean when it comes to making charcoal?  Every fire I
>have seen, including those made with charcoal have lots of smoke.  Yes,
>we have carbon in the charcoal.  But we also have about half of it in
>the atmosphere. Where does the "sequestering" come in?  Are we saying
>that by making charcoal we are pulling the carbon out of the
>decomposition chain which occurs when we compost?
>
>Bob Niederman
>
>
>  I would say you have the idea behind the word "sequester" approximately
>correct. But making the charcoal is not enough, since the charcoal itself
>can be later burned.  The sequestering comes when the charcoal is
>sufficiently well mixed in the soil that it cannot be "un-mixed."
>
>  Re your last sentence, I would add that we have to also remind people
>that the photosynthesis process is taking CO2 out of the atmosphere (using
>sunlight) to create the biomass that can be pyrolyzed ("charcoaled").  You
>are of course correct about compost decomposition being prevented, and we
>need to educate that charcoal is "almost" unable to be decomposed.
>
>Most discussion on the web about "sequestration" assumes that CO2 from
>burning fossil (almost always talking coal) resources is liquified and
>"stored/sequestered" at great depths.  Despite billions of federal dollars
>in so called "clean coal" research, there are no real-world working examples
>of CCS (carbon capture and sequestration).  I exclude EOR enhanced oil
>recovery as a realistic CCS alternative, since that approach leaves lots of
>chance for release through the thousands of drill-holes in most oil and gas
>fields.  When you see the word IGCC, there is an implied CCS option about
>which there is rarely any discussion.   Terra Preta soils as an alternative
>means of sequestration avoids huge costs and uncertainties that the utility
>and coal industries have chosen to procrastinate on when they are not
>ignoring the topic.  IGCC itself has very serious cost problems - but the
>main problem is with the CCS portion of the duo.
>
>  You also give me a chance to raise the question from several weeks ago
>about placing coal dust rather than charcoal into the soil.  I have looked
>and found nothing meaningful - but think this is apt to be a real loser.
>Coal is the major source of uranium.  Coal has none of the porosity
>characteristics of charcoal.  Has anyone found anything to suggest coal
>could replace charcoal?
>
Ron

>Hi Bob and Others,
>
Yes, basically, you are right, the charcoal is carbon which will NOT 
decompose in the soil.  Charcoal is not food for the soil 
micro-organisms.  They like to digest sugars, starch, cellulose, 
lignin (complex carbohydrates).  Charcoal is more nearly pure carbon, 
like 75-93%.  The carbon is useless as food for soil microbes, but it 
does provide a haven for them to grow in and it also holds water. 

>Both of these attributes are thought to be related to the porosity 
>of the charcoal.
>
>Some think charcoal which is made at lower temperatures and 
>therefore contains some lesser decomposed "poly-aromatic 
>hydrocarbons" (sometimes called wood tars or "liquid-smoke") does 
>provide some food for microbes.  The PAH can maybe give soil 
>microbes a jump start at populating the charcoal matrix, but the PAH 
>also make charcoal less porous, perhaps.
>
>I think there may be good reason to believe that "Terra Preta" was 
>made with lower temperature charcoal, given the way it has been 
>theorized as being made; i.e. slash-and-char in the rainforest (cut 
>the trees down, start them on fire, bury them in soil, and it's 
>going to rain later in the afternoon everyday) DOES NOT make for 
>particularly hot fires (reduced oxygen supply and water added).  Do 
>you think?
>
>Plus the charcoal found in Amazonian "Terra Preta" soils still 
>retains the cell wall structures from the original trees that were 
>burned 1000s of years ago.  Very high temperature "destructive 
>distillation" or "pyrolysis" of wood has more effect on the 
>structure of the wood.  The exiting gases are more explosive and 
>more likely to shatter the cell wall structures, maybe even liquefy 
>the wood and leave it like bubbly tar before cooling to leave 
>something more "coke" like.
>
>The theoretical maximum amount of charcoal obtainable from pyrolysis 
>of biomass is like 30-45% by weight.  When it's done right, there is 
>little or no smoke (particulate carbon and cooled PAH, a.k.a. soot) 
>and the remainder of the mass from the biomass is exhausted from the 
>pyroysis reactor as hot gases (H2, CO, CH4, CO2, H2O, N2).  The 
>first 3 gases; molecular hydrogen, carbon monoxide, and methane are 
>flammable and can be used as fuels.  The others, carbon dioxide, 
>water vapor, molecular nitrogen are relatively inert and just carry 
>away heat.  Up to 60-65% of the energy that was originally in the 
>biomass can be retained in the charcoal, with the rest remaining in 
>the molecular bonds of the exhaust flammable gases or going away in 
>the radiated heat.
>
>The point is, you hit the nail on the head, charcoal (more pure 
>carbon) won't decompose, where as biomass is digested and excreted 
>(as CO2) by soil microbes.  It's not all of the carbon that was in 
>the biomass originally, but it can be like 75-93% of it.
>Once it goes into the soil, it's going to stay for a very long time 
>(a least several 1000s of years so far).  So, it is sequestering 
>carbon from the atmosphere, because the plants took in the carbon as 
>CO2 from the atmosphere, fixed (sequestered) it temporarily into the 
>plant carbohydrates, then smart men and women came along, converted 
>it to charcoal, and made a better, more long-lasting method for 
>carbon sequestration.
>
>I want to make this very important point again...
>
>Whether "Terra Preta" can actually improve soil quality or not, it 
>can very effectively sequester carbon from the atmosphere. 
>[Emphasis added]
>
>And, I have every belief that it can improve soil quality and/or 
>fertility, mostly because I don't believe the ancient Amazonian 
>people would have carried on for centuries making "Terra Preta", if 
>it did not help them feed the hundreds of thousands or millions of 
>people that it probably took to make as much "Terra Preta" as they 
>did make.
>
Lobby your favorite politicians to enact a carbon trading scheme in 
the USA [and everyhere else] as soon as possible!

>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

>Bruno M. wrote:
>
>The thing about turning the biomass into compost is that the compost
>will eventually be totally consumed, oxydised, eaten by microbes etc
>etc. All the carbon it contains will eventually be turned into CO2. (not
>a problem I know, because it is "carbon neutral" after all). The actual
>carbon the compost contained will not be left in the soil. There is
>nothing wrong with this of course, in fact it is very right because all
>the "wee beasties" in the soil need it to live and to work at extracting
>all the other nutrients from the mineral part of the soil, thus making
them available to the plantlife above.

>But then, ... you don't get charcoal to make your Terra Preta.
>
>A balanced approach, turning some (perhaps the woody bits) into
>charcoal, while making the softer stuff into compost and adding a
>mixture of the two products to the soil  [Emphasis added: mixing 
>organic plant-foods such as compost into the charcoal pieces and 
>dust helps to potentialise it quickly] will make a much better job 
>of it. It will also sequester some carbon, thus taking it out of the
>atmosphere, potentially for nearly ever. In the process the charcoal
>will also provide housing and storage for the wee beasties and some of
>their products.
>
>A retort set up will let you make charcoal with minimal smoke and air
>pollution. Such a system can be as simple as a 55 gallon drum in a simple
>cob fireplace, with a good chimney. It will need a removable lid, 
>and it will need small
>holes in the bottom for the gases to get out and feed the fire below.
Properly regulated, there will be little smoke.

>There are a number of websites describing the sort of thing I mean. Go
>googling for "charcoal retorts"
>
Kurt
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