[Terrapreta] Terrapreta Digest, Vol 3, Issue 38

[Sean K. Barry]

Re: Terrapreta Digest, Vol 3, Issue 38Hi Rhisart,

I believe Danny Day from Eprida has published an article in the "Energy Bulletin" about Terra Preta before, in August 2004,(http://energybulletin.net/1337.html<http://energybulletin.net/1337.html>).  If you can get another article in that publication, that would be great!

SKB
  ----- Original Message ----- 
  From: Rhisiart Gwilym<mailto:Rhisiart at DDraigGoch.org> 
  To: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Tuesday, March 27, 2007 2:11 AM
  Subject: Re: [Terrapreta] Terrapreta Digest, Vol 3, Issue 38


  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
  _______________________________________________
  Terrapreta mailing list
  Terrapreta at bioenergylists.org
  http://tech.groups.yahoo.com/group/biochar/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/terrapreta_bioenergylists.org/attachments/20070327/1307a14f/attachment-0001.html