[Terrapreta] Interesting article

[Michael Bailes]

Some say SOM is said to break down within 400 years. With the global average
being 32 years. I do get abit confused in this paer identifing just what C
is being talked about

The average global turnover time for soil organic carbon (to 1-m depth) was
>> estimated as 32 years by Raich and Schlesinger (34),
>
> Turnover times varied from 14 years to 400 years for different ecosystems
>> in their study. Radiocarbon measurements of bulk soil C, however, often show
>> that the average age of C in soils is several hundred to several thousand
>> years (35-38).
>> Both results are explained if SOM contains components that turn over
>> slower and faster than the several-decade average
>>
> There is general agreement that SOM contains at least three identifiable C
>> pools: root exudates and rapidly decomposed components of fresh plant
>> litter ("active" pool); stabilized organic matter that persists in soils
>> over several thousands of years ("passive" pool); and a poorly defined
>> "intermediate" or "slow" C pool that has turnover times in the range of
>> years to centuries (Fig. 1<http://www.pnas.org/cgi/content/full/94/16/8284?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&searchid=1&FIRSTINDEX=0&minscore=5000&resourcetype=HWCIT#F1>).
>> I will use these terms in this paper, and in addition will refer to
>> fast-cycling C as the combined active and intermediate pools (all
>> nonpassive C).
>>
>
http://www.pnas.org/cgi/content/full/94/16/8284?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&searchid=1&FIRSTINDEX=0&minscore=5000&resourcetype=HWCIT

We know soil bacteria and fungi produce about 90% of the world's natural CO2
and that charcoal hastens the decomposition of SOM
http://www.sciencedaily.com/releases/2007/10/071018123523.htm
and

> Carbon 'released, not stored' by soil
> Tuesday, 20 March 2007

http://mail.google.com/mail/#inbox/119aa05a10ee3dbe
>
> We have come along way, in 10 years, from this:-

> CSIRO MEDIA RELEASE 97/58
>> 3 April 1997
>>
>> LEGACY OF A THOUSAND BUSHFIRES
>>
>> Australia's soil is even poorer than was thought, says CSIRO Land and
>> Water researcher Jan Skjemstad. Much of our small supply of carbon - an
>> essential element in fertile soil - is in the form of useless charcoal,
>> resulting from tens of thousands of years of bushfires.
>>
>> "The charcoal is mostly carbon, but it is in a form which can't be used by
>> plants or soil organisms," said Mr Skjemstad.
>>
> Wild fire a major driver of C in your forests ? With fires every
350-100,000 years ago? Australia should be so lucky!  We would rarely go
more than a dozen years before burning forests (especially prior to European
settlement).

What is not addressed in your paper is the C02 holding proprieties of things
like Soil Algae, bacteria and AMF like glomalin which in association with
plant roots promotes growth and locks C into the soil.  In itself glomalin
is 30-40% Carbon.  It is sad to hold up to a third of the word's carbon.
http://findarticles.com/p/articles/mi_m3741/is_9_50/ai_92589768/pg_1
I gather your experimental bags were not in intimate contact with soil root
and would thus produce little glomalin, So CO2 cycling from SOM (your
'humus') could be much faster.
http://journeytoforever.org/farm_library/rayner/rayner_intro.html
Also bacteria are said to contain about 50% dry weight carbon. Lehmann and
others have suggested charcoal provides protective "housing" for bacteria.
Less predation thus  leads to higher bacterial growth in the soil.

You might also be interested in this email

> As to the 'wee beasties' or 'critters' as I like to call them, we have made
> progress on this front over the last several years. Brendan O'Neill and
> Julie Grossman in my laboratory, Sui Mai Tsai, our Brazilian collaborator at
> CENA and the University of Sao Paulo, and Biqing Liang, and many others in
> Johannes Lehmann's laboratory have been characterizing microbial populations
> in three different terra preta soils and comparing these to the adjacent,
> unmodified soils near by to them.
> Brendan found that populations of culturable bacteria and fungi are higher
> in the terra preta soils, as compared to the unmodified soils, in all cases.
> * Yet, Biqing found that the respiratory activity of these populations is
> lower (see Liang et al., 2006), even when fresh organic matter is added.*
> This alone means that the turnover of organic matter is slower in the terra
> preta soils - suggesting that the presence of black C in the terra pretas is
> helping to stabilize labile organic matter and is itself *not turning over
> in the short term.*
> All good news for C sequestration.
> * However, since the respiratory activity is lower (slower decomposition),
> * this may lead to slower release of other mineral nutrient associated
> with the fresh organic inputs.
> In some circumstances this is a good thing (maintaining nutrient release
> over the growing season),
> in other circumstances (more immobilization), perhaps not.
> We need more work on this to understand the implications of these results
> more fully.

http://hypography.com/forums/terra-preta/10703-wee-beasties-other-critters-tp-6.html#post205346


Some questions
You say "Boreal forests serve as important global sinks of carbon"  I
thought the jury was still out (-or not, yet, sent out?) on this. I have
only seen one paper saying this; and many others saying the only
'carbon-forest-sinks' are those in the tropics.


   - Was there any ash in the charcoal you used?
   - What was the C % of the humus.
   - what was the pH of you charcoal and your soil? Did this change over
   time?
   - Was there any increased plant growth?
   - Wouldn't leaching of soluble compounds be more likely to be less, (not
   more, as you suggest) with Char given its adsorption properties?
   - Could you please comment on figure 'D" in your paper. Where is the N?
   and where is it coming from?


Wish List
You paper address an important issue. Like most research it throws up more
questions than it answers.


   - It would be nice to deign a closed loop experiment controlling as many
   variables as possible and placing char in soil more naturally. This might
   need little "space capsules" around each tree as is happening in long-term
   research on trees at the University of Western Sydney. Unfortunately they
   are not looking at Charcoal's role in the soil.
   - It would be nice to look at nitrous oxide emissions for example.  A far
   more potent greenhouse gas than CO2.
   http://www.scientificblogging.com/news_releases/nitrous_oxide_forgotten_greenhouse_gas_no_laughing_matter
   - It would be nice to see how much C was captured by increased tree
   growth and soil AMF/bacteria, fungi etc encouraged by the presence of
   different amounts of charcoal.
   - It would be nice if this charcoal could me mixed with soil in a more
   natural way.
   - it would be nice to see how interacting pHs of all components in the
   experimental recipe effect  each other.
   - 50% char to humus seems high. What would 5-10% do?
   - it would be nice to know the response of mycorrhizal fungi to biochar.

While I realise researchers need to simplify and control variables in
research I have long argued here, and in other forums, that *Terra preta
Farming/gardening* needs to be seen in a Gestalt. A dynamic interaction
between charcoal (ground up and put in the soil by humans), Soil SOM will
need to be constantly added, terracotta, fish, fishbones bones and other
wastes (river algae?) are also part of the mix.
 Why are Terra preta soils said to "grow" by native Amazonian Indians? Is
this because of the increased soil life or has the Amazon got some special
"wee beasties" in its soil?


Thank you for sharing your research with us on the TP list.
You just need to gather 100 Ph.D. students to help you carry on the work!

Warmest wishes,
Michael Bailes (alias the archangel)
2008/5/5 David Wardle <David.Wardle at svek.slu.se>:

>  Not wanting to sound contrary, but I cannot agree with Gunther's comments
> *'**the conclusion that the addition of char to soil could be offset by
> the increased decomposition of litter, is* *wrong*' or '*After a century
> or* *two*, *all the litter would be expected to be metabolised,* *charcoal
> or not*.'
>
> Firstly, our litter bags contained humus and not 'litter'. Secondly, there
> is ample evidence (indeed you can find it in undergraduate textbooks on soil
> science) that there are significant pools of soil organic carbon (including
> in humus) that themselves are quite recalcitrant and take many centuries or
> millennia to break down. Therefore the claim about 'after a century or two'
> is not true.
>
>
>   ------------------------------
>
> *From:* folke Günther [mailto:folkeg at gmail.com]
> *Sent:* den 5 maj 2008 09:40
> *To:* Terra Preta; Richard Douthwaite; Exergigruppen; David Wardle
> *Subject:* Re: Interesting article
>
>
>
> Now, I have received the full article and a supplement describing the
> investigation method (attached). Actually, nothing changes my conclusions
> from yesterday; The inevitable decomposition of litter is hastened by the
> addition of charcoal, but since this would happen anyway, *the conclusion
> that the addition of char to soil could be offset by the increased
> decomposition of litter, is wrong.*
> FG
>
> 2008/5/4 folke Günther <folkeg at gmail.com>:
>
> I haven't received the pdf yet, but since there as been quite a
> discussion,I will go through the background. When I have got the pdf, I will
> go through it and give some more details.
> The basic is this:
>
>    1. *Burying charcoal in the soil always sequesters carbon (carbon
>    dioxide) from the atmosphere*
>
>
>     - This is true disregarding the route this charcoal may have taken to
>       the soil. I.e. even if the 'footprint' of this special  charcoal is larger
>       than its actual content of coal (say that it is flown around the world),
>       burying the charcoal mean that this certain amount is eliminated fro the
>       atmosphere.
>       -  I.e. If you burn it, it will return to the atmosphere, If you
>       bury it, it will stay in the soil for thousands of years
>
>
>    1. *Charcoal increase soil metabolism.*
>
>
>     - This may not come as a surprise to any of the members of this
>       list.The reasons for that, and its effects, have been discussed, and easily
>       observed, for a long time.
>
>
>    1. *If you mix litter and charcoal, the litter will decompose fasterthan if it is not mixed with charcoal.
>    *
>
>
>     - This was confirmed by the study. A large part (25% i the first two
>       years) of the litter was metabolised by the microorganisms. I do not know if
>       a simultaneous increase of the plants living in, on or near the bags was
>       observed. One could expect  that.
>
>
>    1. *In bags with only litter, some metabolism would be observed,
>    although smaller than in the litter mixed with charcoal.*
>
>
>     - This is perfectly normal.
>
>
>    1. *Thus, the presence of charcoal increase the rate of litter
>    decomposition.*
>
>
>     - Why am I not surprised?
>       - Jumping to the conclusion, however, that the presence of charcoal
>       in the soil would be offset by the increased metabolism of litter, is wrong.
>       After a century or two, *all the litter would be expected to be
>       metabolised,* *charcoal or not*.
>
>
>    1. Therefore, the sequestration effect of charcoal is *not *counteracted
>    by increased soil metabolism, since the SOM (Soil Organic Matter) is
>    ephemeral in comparison to the charcoal, and will decompose anyhow. However,
>    the in increased metabolism is reflected in a change in litter decomposition
>    rate.
>
> It would be very interesting to have the real figures, since that might
> allow a calculation of the metabolism increase. A friend observed a
> surprisingly high increase in the decomposition of a small compost heap when
> charcoal was added
>
>  2008/5/2 folke Günther <folkeg at gmail.com>:
>
> In the latest number of Sciene, (2 May), David Wardle, Marie-Charlotte
> Nilsson och Olle Zackrisson delivers an article: "Fire-Derived Charcoal
> Causes Loss of Forest Humus", where they claim that charcoal particles
> remaining after fire increase the microbial activity so they break down
> humic particles at a rate that counteracts the carbon sequestration effect
> of the carbon.
>
>
>
>
> ----------------------------------------
> Folke Günther
> Kollegievägen 19
> 224 73 Lund
> Sweden
> Phone: +46 (0)46 141429
> Cell: +46 (0)709 710306
> URL: http://www.holon.se/folke
> BLOG: http://folkegunther.blogspot.com/
>
>
>
>
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>



-- 
Michael the Archangel
"Politicians will never solve The Problem;
because they don't realise they are The Problem.".
-Robert ( Bob ) Parsons 1995
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