permaculture

["Lawrence F. London, Jr." <venaurafarm@bellsouth.net>]

-------- Original Message --------
Subject: Re: [SANET-MG] Terra Preta
Date: Wed, 20 Oct 2010 02:09:37 EDT
From: Neal Van Milligen <CAVM@AOL.COM>
To: SANET-MG@LISTS.IFAS.UFL.EDU

There are any number of terra preta or bio-char production sites in
Google.  In a nutshell it is the roasting of ground organic matter to 
produce what is essentially charcoal.

The roasting process, or pyrolysis, can be polluting if done the old
fashioned low tech way.  In modern techniques the gases given off by the 
roasting or torrefaction of biomass is CO, CO2, methane and H2.  If 
ambient  air is used to stoke the process a significant amount of N will 
also be in the gas, up to 50%.  In an oxygen deprived process the gases 
will provide a valuable substitute for propane with slightly less BTU 
per scf.  If air is  used in the process the gas will be a weak but 
still valuable flammable byproduct with BTU content from 135 to 300 per 
scf..  It can be used to  power an engine or a generator or to produce 
heat for other uses such as to  distill water or cooking.

If the biomass used in the process costs $20 per green ton the  bio-char 
terra preta will have about $100 per ton cost due to loss of  moisture 
and reduction in volume.  This excludes equipment, labor, site, 
maintenance, etc, etc. However, in many cases the biomass will have a 
negative cost, you are paid to take it.

Different biomass inputs and different process techniques will result in 
different qualities of char.  There is still more art than science 
involved and experience pays good dividends in this.

Neal


In a message dated 10/19/2010 11:59:54 P.M. Central Daylight Time,
lflj@bellsouth.net writes:

On  10/20/2010 12:09 AM, Neal Van Milligen wrote:
> I read that a 140%  increase in corn yields in a study done in Columbia
> was attributed to  the use of Terra Preta or char.

(http://www.guardian.co.uk/environment/2010/sep/30/biochar-production-climate-change)

> This is stunning considering the ease with which the char can beproduced.

It is amazing for sure. Charcoal has an incredible amount of  surface 
area and can store and retain (w/o leaching) an amazing amount of 
nutrients. Initially, with a constructed biochar farmsite there is a 
deficiency of nitrogen as the charcoal soaks up to capacity N from 
surrounding  soil, then it is released to the plants. I always thought 
it was diffcult, polluting and expensive to produce.
You say otherwise. Do you know of  websites illustrating efficient 
methods of producing  biochar?

LL