[Terrapreta] Fw: Terra Preta Trials 2007

[Sean K. Barry]

----- Original Message ----- 
From: Sean K. Barry<mailto:sean.barry at juno.com> 
To: Robert Niederman<mailto:rniederman at cegworldwide.com> 
Sent: Sunday, March 25, 2007 10:13 PM
Subject: Re: [Terrapreta] Terra Preta Trials 2007


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 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 longer-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.

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 million 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 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<mailto:sean.barry at juno.com>
  ----- Original Message ----- 
  From: Robert Niederman<mailto:rniederman at cegworldwide.com> 
  To: rukurt at westnet.com.au<mailto:rukurt at westnet.com.au> ; terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Sunday, March 25, 2007 9:09 PM
  Subject: Re: [Terrapreta] Terra Preta Trials 2007


  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

  -----Original Message-----
  From: terrapreta-bounces at bioenergylists.org<mailto:terrapreta-bounces at bioenergylists.org>
  [mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of
  rukurt at westnet.com.au<mailto:rukurt at westnet.com.au>
  Sent: Sunday, March 25, 2007 4:47 PM
  To: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org>
  Subject: Re: [Terrapreta] Terra Preta Trials 2007

  Bruno M. wrote:
  > <snip>
  >
  > You can also chose to compost the stuff, no smoking stinking air 
  > pollution, no fire(-risk),
  > and a lot of useful soil amendment as a result.
  >   
  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 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.
  > Another aspect of your scenario, all the ash you put in your garden 
  > may or may not
  > be a benefit to your plants, ash makes the Ph of your soil higher, not

  > al plants like that.
  >   
  Another problem with ashes is that it may contain excess nutrients, 
  causing soil imbalances. Also, some of the nutrients, particularly 
  Potassium (K) evaporate at relatively low temperatures and will blow 
  away in the smoke.
  <snipped>

  Another thing:

   >no smoking stinking air pollution, no fire(-risk), {see above}

  A retort set up will let you make charcoal with minimal smoke and air 
  pollution. Such a system can be as simple as a 5?gallon tin in a simple 
  cob fireplace, with a simple fan supplying extra draft to the fire, or a

  good chimney. The can will need a removable lid, 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.

  Kurt

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