[Terrapreta] Char charged vermicomposting trial---They like it!

[Frank Teuton]

So, the worms seem quite happy with the 5% by volume charcoal addition to their slurry....

To take a stab at Dan's question, my understanding is that earthworms not only are not deleterious to the formation of Terra Preta and its long lived charcoal, but may even be essential to it.

see: http://en.wikipedia.org/wiki/Terra_preta

"Topoliantz and Ponge's work, summarized in a synthetic article in "Soil Biology & Biochemistry",[30] shows that the peregrine earthworm Pontoscolex corethrurus (Oligochaeta: Glossoscolecidae), widespread in all Amazonia and notably in clearings after burning processes thanks to its high tolerance of a low content of organic matter in the soil, has been shown to ingest pieces of charcoal and to mix them in a finely ground form with the mineral soil. The authors, who experimentally verified this process, point at this as an essential element in the generation of Terra preta soils, associated with agronomic knowledge involving layering the charcoal in thin regular layers favourable to its burying by Pontoscolex corethrurus. "

It remains to be seen whether this can be duplicated or simulated via feeding epigeic worms in vermicultures, but it seems like a worthwhile try. The grinding in the earthworm's gut may be different with P. corethrurus than with E. fetida; the former may blend more mineral soil into the mix than the latter. Against this possibility I also added rock dusts (basalt, mica, rock phosphate) into my slurry to move the mix up the mineral soil content ladder. 

My understanding again is that charcoal does not readily oxidize except by burning, although some have questioned this on the list.

I also think Dan's question begs another, namely whether it is even better at all to make charcoal out of a feedstock rather than compost. It is possible to make compost in a pit under or beside a greenhouse and generate useful heat from the compost, and composting results in the conservation of about 50 percent of the C in a semi-durable form that further multiplies plant growth potential when applied. Charcoal conserves at best around 30 percent C and in its raw form is harmful to plant growth until weathering and microbial occupation has occurred. Without the full offset of the heating value of the charcoal offgasses and liquids it is difficult for me to imagine how the C losses in charring with and especially without flaring can possibly be made up for by the creation of a char product.

I think the tendency on this list is to believe that charcoal lasts virtually forever in the soil, on the one hand, and that compost is digested rather quickly in the soil, on the other....both assertions can be questioned it seems.

The list also has a seemingly incorrigible blind spot vis a vis biological reservoirs of carbon and the current excess atmospheric CO2 levels. Hear Sean K. Barry repeating the faulty mantra:

"Biomass can produce gases from combustion which are classified as GHGs.  However (and this is a critically important distinction), burning biomass CANNOT increase GHG concentrations in the atmosphere!  The cellulose, hemi-cellulose, lignin, sugars, and starch, that are in biomass are made via photosynthesis when the plants are growing and taking CO2 and H2O from the Biosphere.  Releasing those gases back into the atmosphere, there is no net gain."

This just FAILS to understand that biological reservoirs of carbon are in many cases being depleted and never restored; deforestation, soil organic matter depletion through tillage, even overfishing oceans....human behaviors involving biomass reductions which are never recovered from. The tallgrass prairies on the Great Plains are now soil eroded wheat fields; the stored carbon that was there is now mostly aloft (in an equilibrium sense). The huge forests that once occupied the eastern United States and Canada are now mere striplings compared to their former grandeur. Look at old manifests of clear lumber for the now unheard of sizes of hardwoods and softwoods....these giants are long gone.

I am interested in Terra Preta, not least because some of the land I care for is deep sand which could benefit from the charcoal component. But as I read this list I see that there is a certain level of oblivious dogmatism which wants to push Terra Preta without factual justification. As I see it Terra Preta has the ability to be 'carbon negative' if and only if the process actually replaces some fossil fuels as an energy source, if the feedstock is sustainably harvested from climax or near climax ecosystems, and if the char can be economically applied on a large scale.

Charring systems to operate a small commercial greenhouse seem not to be available yet in a practical sense; simple methods proposed by some seem to me palpably worse than not making char at all.

I am of the view that the first priority we have is to restore as much as feasibly possible the biological reservoirs of carbon; forests and other perennially based ecosystems which will store carbon both in plant material and in the soils. Only then can we look to increase the carbon storage capacity of these systems through techniques like terra preta....because the biologically active carbon, even in its most passive and durable form of long lived humus, is the basis for the long term productivity we need to capture carbon through photosynthesis in the first place. Terra preta composts can probably be valuable in restoring certain kinds of soils to productivity to reestablish absent or diminished biomes.

So, no I don't think  we need to worry about worms breaking down the charcoal. Instead we need to continue to see the forests, and to restore them, not just turn the trees into charcoal.

My two cents, 

Frank Teuton
  ----- Original Message ----- 
  From: Dan Culbertson 
  To: Terrapreta at bioenergylists.org 
  Sent: Friday, March 07, 2008 11:21 AM
  Subject: Re: [Terrapreta] Char charged vermicomposting trial


  I was just wondering about using charcoal/terrapreta in worm bins since I'm finally getting around to setting up a few vermiculture bins.  What struck me as a possible "maybe not" is the tendency (as noted by various worm publications) of earthworms to break down rock dusts and things like egg shells into more readily available nutrients.  Might that not somewhat neutralize the nutrient holding benefits of terrapreta making the casting more akin to just plain old worm compost?  In other words, I wonder if the resulting castings would be nutrient charged terrapreta  or just a very good quick release organic fertilizer for soil top dressings.  Also, just how fine will the char particles be after they go through the worms?  Would the worms gizzards make all that stored carbon oxidize faster?  I think there are some interesting questions there, especially since worms aren't just living in our worm bins but are also  a big part of the soil life in terrapreta soils and may affect the durability of the carbon and nutrient sequestration.  I wonder if there is any comprehensive analysis of all the soil fauna and how terrapreta impacts and is impacted by it.  Not just earthworms but nematodes and other critters like cutworms and slugs.  Be nice if it encouraged the good critters and suppressed the nasty ones.

  Anyhow, I'll be interested to know if the worms like living in and eating it.

  Dan
    The charcoal consisted of about 5% by volume of the total wastes run through the disposal, and the resulting grind process caused a definite color change in the final product.

    Over the next few days I will inspect the bins periodically to see how the worms respond to this new feed.



------------------------------------------------------------------------------


  _______________________________________________
  Terrapreta mailing list
  Terrapreta at bioenergylists.org
  http://tech.groups.yahoo.com/group/biochar/
  http://terrapreta.bioenergylists.org
  http://info.bioenergylists.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080314/e9d87e42/attachment.html