[Terrapreta] reduction by fire vs. water

[Kevin Chisholm]

Dear David

dyarrow at nycap.rr.com wrote:
> i'm at an organic raspberry farm in concord, MA.  when i drove in, i 
> saw a huge pile of very dark -- almost black -- organic matter, and 
> thought someone had made a giant heap of charcoal -- easily over 100 
> tons.  but it proved to be dredgings from a boggy pond.  the organic 
> matter on the pond bottom decomposes in an oxygen-deprived 
> environment, similar to a pyrolysis chamber, and thus the material is 
> reduced instead of oxidized.  hence the carbon-black residue.
>   
Wow!! Sounds like an enormous resource for your raspberries!! Could you 
consider teh possibility of running a test with the bog dredgings, as a 
"Natural TP" and another test with charcoal, for "Man-Made TP"?
> i have little notion how this water-formed, reduced carbon compares 
> physically, chemically and culturally with fire-produced char, but it 
> definitely makes a significant contribution to soil organic matter 
> content and thus fertility and productivity.  however, i would expect 
> this dark pond-bottom-muck has a much different microbial community 
> due to its watery origin and formation.  anaerobic fermentation and 
> digestion by bacteria does not seem at all like the fiery degradation 
> of pyrolysis, and would not leave behind the same kinds of volatile 
> organic compounds as nutrient sources for soil organisms.
Certainly, bog dredgings would have their own unique array of anaerobic 
life forms. And fresh char would be expected to have no content of life 
forms. Research seems to suggest that it takes 2 to 4 years for a 
charcoal based TP plot to come up to full production. A simple 
explanation could be that this is how long it takes the charcoal to get 
populated with the required life forms.
>   yet, nature 
> is forgiving, since we know muckland from drained swamps is highly 
> productive agricultural soil.  however, i believe mucklands degrade 
> rapidly with intensive use, since carbon and other organic residues 
> are rapidly oxidized and volatilized, resulting in rapid loss of that 
> rich, black topsoil.
>   
Of course, intense "robber farming" would be expected to degrade the soil.
> by contrast, degradation of organic matter by fire seems to result in 
> a carbon residue that is "recalitrant" and resists all sorts of normal 
> chemical oxidation and biological digestion.
>   
Sure, the charcoal  might be resistant to consumption under "robber 
farming" circumstances, but the productivity could be expected to drop 
also. All complete references I have seen about Terra Preta stress the 
need for replenishment of both mineral and biological nutrients.

Best wishes,

Kevin
> david
>
> ----- Original Message -----
> From: Kevin Chisholm <kchisholm at ca.inter.net>
> Date: Thursday, November 22, 2007 10:14 am
> Subject: Re: [Terrapreta] TP theft.
> To: lou gold <lou.gold at gmail.com>
>   
>> 1: There is a pond in front of where I live. In the Summer, pond 
>>     
> weed 
>   
>> drifts into a cove, and decomposes anaerobically to give a black 
>>     
> goop on 
>   
>> the bottom When stirred up, the water turns black. The pond weed is 
>>     
> not 
>   
>> consumed totally by pond life forms, but rather, a black material is 
>> left behind. It could be "black carbon."
>>
>> 2: In Northern Canada, there are millions of hectares of Humified 
>>     
> Peat, 
>   
>> where  the  the original sedges and mosses  are decomposed to the 
>> point that little or none of their original plant structure  
>>     
> remains. 
>   
>> What does remain is a "black carbon-like" material.
>>
>> 3: Many Farmers drain swampy areas, and start a Market Gardening 
>> Operation, because  vegetables grow so very well in the "black 
>>     
> earth" 
>   
>> that they uncover. Do a Google Search on "Terre Noire", "Terre 
>> Noire Canada", and "Black Earth". See also
>>     
>>> http://www.blackearth.org/History/History.html
>>>       
>> In speaking to a Member of the Historical Society, the Community of 
>> Black Earth seems to be built on a eutrophied lake. However, there 
>>     
> was 
>   
>> indeed an Indian Community well established there, long before the 
>>     
> White 
>   
>> Settlers came. The water table is very close to the surface, and 
>> buildings of any size require pilings for foundation support.
>>     
>
>