[Stoves] Stoves Digest, Vol 3, Issue 27

Philip Lloyd plloyd at mweb.co.za
Fri Nov 26 15:27:48 CST 2010


Re biochar.  I think it needs to be remembered that virtually all woodlands
need to burn at some stage in their life.  In the 'fynbos' of my local
flora, it is about once every 15 years.  Much of the life cycle is adapted
to this burning - seeds buried underground by ants only germinate when the
water reaching them contains chemicals signalling a fire has passed.

Deciduous forests also need to burn regularly.  One of the 'problems' is
that the leaf trash becomes so thick that decomposition starts to go
anaerobic, and when that happens, acid is generated.  Conifer leaves too are
very acidic - years ago I was party to a study of acid rain on  some land
planted commercially with conifers.  We found that far more acid was picked
up once the rain reached the ground than fell from the sky, all generated
from decomposition of the conifer needles.  

Another study with which I was associated looked at forests in northern
Germany.  Historically, there were layers of char in the soil about every
100 years.  These ceased in modern times - mankind didn't like forest fires
too close at hand.  However, the net result was growing acidity in the soil,
a weakening of the timber's defenses and signs of waldsterben - basically
sheer old age because the natural burn had not occurred. 

Then I reflected that ash is alkaline.  In combustion, you drive off acidic
CO2, and are left with an alkaline waste (usually rich in potash and
phosphorus).  Also, during combustion you generate quite a lot of nitrogen
oxides, and these return to earth with rain as another essential nutrient.
That is partly why land regularly recovers rapidly after fire - or why
pastoralists regularly set fire to stimulate nutrient-rich young shoots that
the grazing animals emjoy.

So yes, biochar is generally beneficial to soil.  It is usually there
naturally.

I hope this contribution helps to understand what biochar is all about.

Philip Lloyd  

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Today's Topics:

   1. Re: Biochar Projects for Science Students (Jeff Davis)
   2. Re: Biochar Projects for Science Students (steve)
   3. Re: Biochar Projects for Science Students
      (Crispin Pemberton-Pigott)
   4. Re: Biochar Projects for Science Students (Andrew C. Parker)


----------------------------------------------------------------------

Message: 1
Date: Thu, 25 Nov 2010 21:56:51 -0500
From: Jeff Davis <jeff0124 at velocity.net>
To: Discussion of biomass cooking stoves
	<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Biochar Projects for Science Students
Message-ID: <1290740211.1428.58.camel at jeff-laptop>
Content-Type: text/plain; charset="UTF-8"

Dear Kevin  and Crispin,


I doubt that all the damage done to the soil from forest fires can be blamed
on charred tree roots, maybe some, maybe not. In regards to grass fires how
much of the charcoal gets washed away, how much is ash and how much grass
char works into the soil. In the long run would the grass land been better
off without the grass fire? Does the grassland fires do as much damage to
the soil as forest fires do to the forest soil? Do these two items
accurately represent biochar? If we look hard enough we can find just about
anything in the soil from lost pocket change to beer cans... Sloppy science?
People, we're talking about thousands of years here....

This is the time for a group of real soil scientists, that are not bought
and paid for by a concern, to determine whether there could be any long term
problems down the road. Lets not find out 75 years from now. Frankly I'm not
qualified, the engineers are not qualified, the chemists are not qualified,
the hobbyists are not qualified and to say that charcoal is inert so
therefore no problem is reckless and irresponsible. We are on the verge of
making policies on a global scale and someone has to be the bad guy and ask
"if biochar persists in the soil for thousands of years and it has not been
added to the soil on a global level in any meaningful way will there be any
long term problems down the road?"

The benefits of biochar are meaningless at this point. We need to make sure
that there will not be any problems down the road. Personally I hope it
works out OK. BUT shame on me if I don't speak up!



Best regards,


Jeff


    
--
________________________________________________

www.puffergas.com

Sent from any port in the storm via  Acer netbook & Ubuntu Remix.




------------------------------

Message: 2
Date: Fri, 26 Nov 2010 08:23:53 GMT
From: "steve" <steve at thetaylorfamily.org.uk>
To: Discussion of biomass cooking stoves
	<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Biochar Projects for Science Students
Message-ID: <4cef6e99.3af.3871.347240631 at thetaylorfamily.org.uk>
Content-Type: text/plain; charset="iso-8859-1"


> 
> The benefits of biochar are meaningless at this point. We need to make 
> sure that there will not be any problems down the road. Personally I 
> hope it works out OK. BUT shame on me if I don't speak up!

I was under the impression that bio-char had been used as a soil improved in
South America from the earliest civilisations there. Surely that must count.

Steve



------------------------------

Message: 3
Date: Fri, 26 Nov 2010 23:54:16 +0800
From: "Crispin Pemberton-Pigott" <crispinpigott at gmail.com>
To: "'Discussion of biomass cooking stoves'"
	<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Biochar Projects for Science Students
Message-ID: <019201cb8d82$357dc190$a07944b0$@gmail.com>
Content-Type: text/plain;	charset="us-ascii"

Wise words, Jeff. 

It would be interesting to know if the terra preta soils were artificially
created or were the consequence of cyclical burning in a rotation (slash and
burn).

It is hard to know if the roots will burn well. When I lived in Nigeria one
of the things people had difficulty understanding was this idea of a forest
burning - inconceivable!

If the roots burn underground for some distance like they do in Canada, then
there is a lot of char produced by slash-and-burn agriculture. That does not
require premeditation and intent, even if the consequences were beneficial.

It is well known that the fertility in the jungle is in the biomass above
the ground. That means just about any available fertility is not below the
ground, or it will have been absorbed and turned into plant material.

The question is: will a biome with most of its fertility below the ground
benefit from biochar? This is a really interesting question. The answer is
bound to be complex. The char produced by stoves will have to be
characterised to see how it compares with that added as amendments. Nothing
I have seen written so far attempts to look at that so I guess it is
relatively unexplored.

Frank can you do any assessments of the contents of the char you are
producing in your tiny tube retort? Is there any reason to believe stove
char is a) variable, b) different, c) homogeneous?

Regards
Crispin




------------------------------

Message: 4
Date: Fri, 26 Nov 2010 11:05:47 -0700
From: "Andrew C. Parker" <acparker at xmission.com>
To: "'Discussion of biomass cooking stoves'"
	<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Biochar Projects for Science Students
Message-ID: <op.vmshvxz6uoov7l at user-8ezctxe031>
Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes

Crispin and All,

In regards to "accidental" terra preta, I am including a post I made to
wattsupwithat.com last January:

"Many years ago, I read a book on swithen agriculture in the upper amazon
basin and the eastern woodlands of the US. The main point of the book was
that these ecosystems supported many more times the current populations
before european agricultural and land tenure patterns were established.  
The vast majority of land cleared in the late 1700?s and early 1800?s in the
eastern woodlands has now reverted back to forest. The thin forest soils
were quickly depleted after clearing and burning, forcing families to move
West for better opportunities.

Swithen agriculture used a strictly managed rotation system that maximized
the resources of the forest ecosystem, giving the native populations a
sustained abundance of agricultural goods, forest products and wild game.  
(It is theorised that the devastating epidemics that followed the first
european explorers left remaining populations unable to maintain forest
management, which may explain why Hernando De Soto?s descriptions of the
american south differed substantially from what later explorers and settlers
found.)

I have not read much of the terra preta literature but the description of
the charcoal being found in thin layers would seem to support the idea that
the native inhabitants used a rotating swithen agriculture that could still
be found in some areas of the amazon basin thirty years ago. Nothing magic
or mysterious.

Now, I wonder if terra preta soils can be found in the eastern US?"

I still wonder about terra preta in the US.  Any soil scientists out there
that can answer the question?


Andrew Parker



On Fri, 26 Nov 2010 08:54:16 -0700, Crispin Pemberton-Pigott
<crispinpigott at gmail.com> wrote:


> It would be interesting to know if the terra preta soils were 
> artificially created or were the consequence of cyclical burning in a 
> rotation (slash and burn).



------------------------------

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