[Terrapreta] Trench Method?

[David Yarrow]

i think you're on a good track with the trench method.  or pit method.  a 
pit will conserve heat better than an above-ground heap.  and make it easier 
to control air intake.

i was discussing a similar idea last week with a friend in massachusetts who 
will be clearing a lot of brush, weeds and saplings from his farm.  usually 
he piles them in a heap and reduces them to ash.  i suggested a pit he can 
cover with the weeds, then dirt.

you may still need to vent a bit of air into one end and out the other. 
also consider how to align the debris in the pit to assure air flow through 
for a smooth, thorough burn.  it is easy to completely smother the fire and 
extinguish it.  one practice that helps is to save partially burned remains 
from one burn to add to the next as charcoal starters.

wet leaves from the forest floor can also be used as a cover on the 
smoldering woody debris, then covered with dirt.  richard haard & john 
flotvik used wet cardboard and wet old hay on their heaps.

similar to the "malawi cigar" method to turn entire large logs into giant 
chunks of charcoal.

i have seen huge piles of logging debris that were burned, but parts in the 
core were incompletely combusted, leaving significant char on the ground 
after.  in two years, ash washes away leaving only the char.

try your method and let us know how it works out.  take pictures if 
possible.

for a green & peaceful planet,
David Yarrow
44 Gilligan Rd, E Greenbush, NY 12061
www.championtrees.org
www.OnondagaLakePeaceFestival.org
www.farmandfood.org


----- Original Message ----- 
From: "William Carr" <Jkirk3279 at qtm.net>
To: <Terrapreta at bioenergylists.org>
Sent: Tuesday, January 29, 2008 8:24 AM
Subject: [Terrapreta] Trench Method?
> Hi !
>
> I was reading up on the various charcoal making methods, and I
> recalled something I'd read recently.
>
> I began putting two and two together and then added some guesswork.
>
> Please let me know if this makes any sense.
>
>
>
> Apparently the original Terra Preta may have been made in pits, or
> maybe trenches.
>
> Fill the pit with wood, and get it  burning well.
>
> Smother with wet vegetation -- I suppose los indios used banana leaves.
>
>
> I'm not sure what I'd use yet.
>
>
>
> Ahhh... green wood chips?     Leftover straw bales, soaked in water
> for a week ?
>
>
>
> Then start shoveling in dirt on top.   Keep doing so until the fire
> smolders for X amount of time, then cover completely.
>
>
> The objective is usually to come back later and recover the charcoal,
> then break it up into pieces.
>
>
> Possibly los indios used the big pieces for cooking and just left the
> little bits behind.
>
>
> The reason this idea suddenly interests me is that my tomato garden
> has a soil infection called Clavibacter Michiganensis spp.
> Michiganensis.
>
>
> The safest option to kill this stuff off is to solarize the soil.
> Cover with clear plastic in May and June, the months in the Northern
> Hemisphere where the Sunlight is most intense.
>
>
> Wait two months.   The sunlight gradually heats the soil and dries it
> until temps over 140 degrees are achieved.   That's hot enough to kill
> most bacteria.
>
> I've done this and it works.   You add healthy bacteria back to the
> soil, with horse manure, for example.
>
> Plant late-season stuff in that patch, and next year you'll have
> disease free tomatoes.
>
>
> Ah .... Unfortunately the infectious bacteria get blown back onto the
> soil when the neighbor plows his fields and it re-establishes itself.
>
>
> So I need a faster way of heating the soil.   Something that can speed
> up the process to two weeks and can be done in March.
>
> And that's when I thought of doing Terra Preta in a trench.    Use
> some low-value wood, in a deep trench, and repeat firings until the
> trench is full again.
>
> Then... don't dig it up.   Leave in place.
>
> Re-inoculate the soil with healthy bacteria and add symbiotic fungi
> from FungiPerfecti.
>
>
>
> The only thing left to work out, is how to buffer the shock the soil
> will experience with the addition of the wood ash.
>
> I always forget this one... I think you add lime to counteract ash
> until you reach neutral pH.
>
> Some organic nitrogen may be necessary if a sample shows the green
> wood chips didn't all burn.   When wood chips decay they suck up
> nitrogen.
>
>
> If this idea works, it could be repeated whenever necessary.    The
> trench would eventually become a raised bed, higher than the
> surrounding dirt, and a lot richer.
>
>
> So, any thoughts?
>
> Thanks in advance.
>
>
> William  Carr
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