[Terrapreta] Terra Preta Trials 2007

[teelws at jmu.edu]

Kelpie and all,

The numbers for the amount of charcoal to put down, at least 
as far as what I have read in the terra preta lists and some 
literature searchs are pretty wide ranging, between 30 and 
140 tons per hectare, or 3 and 14 kg per square meter.  
Since the idea is new for North American soils, and we don't 
really know how quickly the results come, I am personally 
trying both low and high end numbers in a greenhouse 
experiment using home made charcoal.  My technique was not 
too different from yours, though I did the damping down in 
the woodstove by tightening air flow, then pulling it out 
and cooling it off when I thought it looked "done".  Unless 
it is tested I will have no idea the parameters of the char, 
though I doubt if that was a real concern in the Amazon 
either.

One of the hypotheses I am basing my tests on is the slow 
improvement of soil when terra preta is added.  The operates 
on the idea that the char forms a base for nutrient capture 
in the soil, reducing leaching and improving the cycling of 
nutrients throughout.  While you would still need to add 
compost or other nutrient sources to match withdrawals from 
the crop, losing nutrients to deep leaching should be 
reduced.  I do not expect an immediate response in my garden 
because the soil is already very fertile (judging by the 
worm population at any rate) but more rapid response could 
occur on less nutrient rich soils.  

The main thing is, do some small scale experiments, keep 
track of what you do, and report what you find.  This 
network will then develop good parameters for further 
testing on a larger scale, perhaps on active farms.

Wayne Teel

---- Original message ----
>Date: Sun, 25 Mar 2007 11:50:35 -0700
>From: Kelpie Wilson <kelpie at kelpiewilson.com>  
>Subject: Re: [Terrapreta] Terra Preta Trials 2007  
>To: terrapreta at bioenergylists.org
>
>   Here in the Oregon woods, we are constantly clearing
>   small trees and brush around our houses to increase
>   our fire safety. We clear the brush and then make
>   burn piles - spring and fall you will see small burn
>   piles in every back yard. I asked my husband to try
>   to make his burn pile a little cooler to make more
>   charcoal and less ash. After all the small stuff -
>   leaves and small branches - burned up, he misted it
>   with the hose to cool it down and left it smoldering
>   all night. The next day we put the fire out
>   completely with water. We ended up with a nice pile
>   of charcoal for the garden, about 3 wheelbarrow
>   loads of mixed charcoal and ash.
>
>   I figure that if nothing else, we are keeping some
>   carbon out of the atmosphere by controlling the burn
>   pile this way - we have to burn anyway.
>
>   Does anyone have any tips for how much of this
>   charcoal to put in my garden beds? They are raised
>   beds about 4 feet wide and 20 feet long. How thick a
>   charcoal layer do I need? How deep into the soil
>   should I bury it?
>
>   Thanks,
>   Kelpie
>
>   At 05:01 PM 3/24/2007, Richard Haard wrote:
>
>     On Mar 24, 2007, at 10:48 AM, Tom Miles wrote:
>
>       We learn by doing. We learn by example. And we
>       learn from each other. As far as I
>       know..........
>
>     And thank you Tom for the opportunity to interact
>     with one another and to spend time reading the
>     collection of fine articles and posts you are
>     maintaining.
>
>     Larry and I are preparing to burn about 1 1/2
>     cords of dry alder, other hardwoods and some less
>     seasoned alder and cherry wood into charcoal. He
>     is taking the lead on this and we will be using
>     our farm tractor to make a place in a fallow field
>     next Saturday morning barring a deluge of rain
>     like we are having now. We're going to attempt to
>     keep combustion temperatures low by quenching the
>     coals at intervals and smothering the fire with
>     wet  hay and sprouting willow shoots. This is my
>     first attempt at such a mission but Larry has done
>     this before and has a plan in mind.
>
>     I suppose with a burn of such a size there is no
>     way to monitor the combustion temperature but it
>     will be the proximate analysis that will follow
>     that will be the indicator of how we did.  Anyway,
>     we have invited some our local friends, interested
>     in the topic of charcoal in agriculture to drop by
>     the farm and watch two grown men burn a perfectly
>     good pile of firewood. Hopefully we will wind up
>     with enough charcoal for a treatment set in our 
>     container experiments and another batch to store
>     for a year in the forest under-story to test next
>     year as aged charcoal.
>
>     There is another element of our interest and work
>     in charcoal in agriculture, for Larry and I
>     anyway, it is fun. I call it recreational science.
>     Many years ago, Larry and I were conducting our
>     own separate researches on riparian restoration
>     with native trees and shrubs. I had developed an
>     'agricultural' approach to the topic and Larry's
>     solution was to use a lot of wood chips and create
>     in his words a structure for natural system
>     establishment. This was in the early days of our
>     local restoration movement when we were all
>     learning to do this task. He and i would have a
>     great time setting up community discussions where
>     each of us  would take our own viewpoint and
>     debate our approaches in order to get everyone  to
>     think about how they are doing their own projects.
>
>     We were having almost too much fun doing these
>     debates but I eventually came to the point of
>     realizing that Larry may indeed have the best
>     approach.  So I set up a meeting at the PUD office
>     to discuss a Washington Department of
>     Transportation mitigation project that was 2 years
>     old and involved a heavy layer of wood chip mulch
>     before planting. We had the DOT architect there
>     and would walk over to the project after the
>     meeting. I remember Larry at that meeting , eyes
>     got large and he said ' You mean I'm vindicated' ?
>
>     With our charcoal work I feel we are at the
>     beginning again and ours is a screening test of a
>     number of kinds of charcoal against combinations
>     with other additives,  and alone with commercial
>     fertilizer,  commercial compost, whatever ? , in a
>     depleted farm soil that has just finished an 2
>     year intensive cropping rotation. We might just
>     learn something from this.
>
>     Best to all
>
>     Rich Haard, Bellingham, Washington
>
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Wayne S. Teel
MSC 4102 ISAT
James Madison University
Harrisonburg, VA 22807
Tel: 540-568-2798
Fax: 540-568-2761