[Terrapreta] Effect of Washing Charcoal

[Michael Bailes]

I managed to kill some acid loving plants with pyrolysis charcoal from rice
hulls and other sources.
(I stole it from BEST)
Perhaps traditional charcoal would have ash which would raise pH
The phrase "Lowered soil acidity", is a little ambiguous.
Does it mean pH goes up or down?

Rarely people test the char- or soil- before they add char to soil/ potting
mix etc.

I am not even sure if I know what pH means any more.
The more I learn about soil science the more confused I get.
m

2008/6/27 Philip Small <psmall2008 at landprofile.com>:

> Re: [Terrapreta] list of benign effect
> On Thu, Jun 26, 2008 at 2:05 PM, Michael Bailes <michaelangelica at gmail.com>
> wrote:
>
>>
>> I am not sure about "Lowered soil acidity", that has not been my
>> experience.
>
>
> Alkalinity is a well established characteristic of charcoal.  The following
> is from The Charcoal Vision: A Win–Win–Win Scenario for Simultaneously
> Producing Bioenergy, Permanently Sequestering Carbon, while Improving Soil
> and Water Quality<http://agron.scijournals.org/cgi/content/full/100/1/178>
> *Importantly, charcoal is hypothesized to have several positive impacts on
> soils (Glaser et al., 2002). First, charcoal is ...  Fourth, charcoal is a
> liming agent that will help off set the acidifying effects of N
> fertilizers, thereby reducing the need for liming. *[emphasis added]
>
> Michael, was your charcoal washed prior to your use? If you soaked the char
> and then tossed the soak water, this could help explain your experience.
>
> Normally, adding charcoal raises soil pH (aka lowers soil acidity) and is
> thus considered a liming material.  "Lime" and "liming material"  are
> interchangeable terms for any material that will raise soil pH<http://www.soils.wisc.edu/extension/shortcourse/New_course_materials/SOILPHANDLIMING.pdf>.
> Calcium carbonate equivalent (CCE<http://hubcap.clemson.edu/%7Eblpprt/bobweb/BOBWEB2.HTM>)
> is a measure of liming ability relative to finely ground limestone.  Ash has
> a CCE of between 50% and 100%, which is fairly high, higher than coarse
> limestone.
>
> It is the ash content of the charcoal that drives its CCE<http://hubcap.clemson.edu/%7Eblpprt/bestwoodash.html>,
> and even charcoal made to minimize ash content (by burning off as little of
> the charcoal as is practical) will have a dry weight ash content starting at
> about 3%. Less efficient processes, such as my home-made charcoal, probably
> yields starting out at about 10% ash.  The alkaline constituents in ash have
> a reputation of being fast acting on soil due to their high solubility in
> water. Thus the CCE of charcoal is fairly easy to reduce with water
> processing.  This is likely why Dr. Reddy is using washed charcoal to help
> improve alkaline soils in India<http://terrapreta.bioenergylists.org/Saibaskharalkaline>
> .
>
>
> --
Michael
Most gods throw dice, but Fate plays chess,
and you don't find out til too late that he's been playing with two queens
all along.
Terry Pratchett
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