permaculture@lists.ibiblio.org

Subject: permaculture

List archive

[permaculture] Thanks to georg

From: "Marsha Hanzi" <hanzibra@svn.com.br>
To: <permaculture@lists.ibiblio.org>
Subject: [permaculture] Thanks to georg
Date: Sat, 30 Nov 2002 12:37:30 -0200

I first learned of the ethelyne cycle from Lea Harrison in the 1992 Hawaii
permaculture course. This is a scientific argument agains plowing , for
example, and has lots of other exciting ramifications.
I lent the paper to someone years ago and no longer could remember all the
steps in the cycle, nor found souce of explanation-- even asked on this list
some time ago, and got a partial reply from Jack Rowe.

Thank you so much ! This is really important in our agriclutural work.

Marsha Hanzi
Instituto de Permacultura da Bahia
www.permacultura-bahia.org.br

> Message: 4
> From: "georg parlow" <georg@websuxxess.com>
> To: <permaculture@lists.ibiblio.org>
> Subject: Re: [permaculture] areobic/anerobic
> Date: Fri, 29 Nov 2002 15:59:55 +0100
> Reply-To: permaculture@lists.ibiblio.org
>
> let me try to run that one by once again - admittedly i had to look
through
> my notes to get it all clear. but i am working on this so i will
eventually
> reach the point where it is all simple and easy to explain for me. ok,
here
> we go:
>
> since this is a glance into the quite complex interactive web of life,
> linear language fails me a bit. so please patiently follow my fragmented
> narrations, and put them together within your systemic mind.
>
> since us gardeners main interest is the health and production of the
> plants, i will look at it from the point of the plant. how the degradation
> of pesticides and other things tie in can then easily be concluded when
> looking onto the various aspects of the action.
>
> plants generate energy in their leaves. apparently they deposit up to 25%
of
> this energy in the soil through their roots - part as extrudates, part as
> shedding of dead matter. this apparent loss of energy in the form of
carbon
> is actually a well spent investment. microorganisms living in the
> rhizosphere gobble it all up, and due to the energy boost they multiply so
> fast, that they use up all the available oxygen. this way anaerob
> microniches are created. in order to understand why this is important we
> will have to appraoch from a different angle as well.
>
> soil is full of iron - 2 to 12% of it's weight are made up by it. in well
> aerated soils this iron exists in the trivalent form of tiny ironoxide
> crystalls. now if the microclimate turns anaerobic this fairly inert
> trivalent iron crystalls fall apart and change to the mobile bivalent
form,
> also called reduced form. and this is important for 2 reasons: one is,
that
> this reduced form of iron is needed in order to produce ethylene - when
> ethylene is generated in the soil, it stops the life processes of the
> microorganisms that fed on the energy bonus given to them by the plants.
but
> fortunately ethylene doesn't kill them, but makes them inert. when the
> microorganisms in the rhizospehere become inactive, they stop using
oxygen,
> thus oxygen can diffude back into these temporary anaerob microniches,
> making them aerobic again. the inert microorganisms wake up and become
> active, starting the cycle all over again.
>
> the second good thing that happens when the iron oxyde crystalls
> desintegrate, is this: these crystalls have a big surface and a strong
> electric charge. thus they bind phosphate, sulphate and various trace
> minerals closly to them, making those unavailable for the plant. when the
> iron oxyde crystalls fall apart, they free those nutrients into the soil
> solution, where they can be used by the roots of the plant. other
nutrients
> (namely calcium, potash, magnesium und ammonia) are tied to the surface of
> clay particles and organic matter. these high concentrations of reduced,
> mobile iron help break those nutrients free, thus making them available
for
> the plant as well.
>
> just to round the picture off (and to expose some of the folly of till
> agriculture) it might be good to take a look onto ethylene again. we need
to
> understand, that the bivalent form of iron can only make ethylene, if a
> precursing substance of ethylene is already present in the soil. this
> precursing substance is also supplied by the plant - but incidentially we
> find it only in mature leaves. so without decaying mature plant matter the
> ethylene cycle doesn't happen - the multiplying microbes are not stopped
in
> time, thus they keep going until they get killed by the lack of oxygen,
when
> they decompose in the anaerob situation substances are formed that are
> burdening the health of the plant. i guess we could say, that ethylene is
> needed in order to form a safe anaerob surrounding in the rhizoshere -
> without it anaerob situations can still happen, but then they are a sign
> that something went wrong.
>
> it is also interesting, that in natural soils close to a hundred percent
of
> nitrogen in the soil is there in the form of ammonia, only traces of
> nitrates can be found. plowing furthers a kind of bacteria that transforms
> ammonia to nitrates. plants and microbes don't mind a whole lot, they can
> use both forms. but nitrates interfere with the development of completely
> anaerob microniches - thus the nutrients stay in their unavailable form,
> because the iron oxyde crystalls never break up. also the ethylene cycle
is
> never triggered, even if everything is available, but the reduced form of
> iron never becomes available.
>
> while all this may sound quite complicated, it isn't, it is only complex.
> the very beautiful thing about this cycle is imho that the nutrients
become
> available where they are needed - in the close vicinity of the plant root.
> also it is a safe method, to make the nutrients available in their
solutible
> form in the anaerob situation - because if they are not used up or washed
> away from the root, as soon as they leave the anaerob situation, the
> bivalent iron reverts back to ironoxyde crystalls, which again tie up the
> nutrients in their immobile form.
>
> georg
>
> ----- Original Message -----
> From: "Mark Ludwig" <mpludwig@facstaff.wisc.edu>
>
> > >between aerobic and anaerobic constantly happens - this ia what makes a
> reed
> > >bed working so effectively, and the everpresent ethylene-cycle works
the
> > >same way.
> > >
> > >georg
> > interesting!
> > Would this take place better in a saturated soil like a reed bed has or
is
> > a fairly dry soil similar.
>
>
> --__--__--
>
> Message: 5
> Date: Fri, 29 Nov 2002 10:11:04 -0600
> From: Mark <mpludwig@facstaff.wisc.edu>
> Subject: Re: [permaculture] areobic/anerobic
> To: permaculture@lists.ibiblio.org
> Reply-To: permaculture@lists.ibiblio.org
>
> Excellent reply Georg, I appreciate you taking the time.
> Mark
> At 03:59 PM 11/29/02 +0100, you wrote:
> >let me try to run that one by once again - admittedly i had to look
through
> >my notes to get it all clear. but i am working on this so i will
eventually
> >reach the point where it is all simple and easy to explain for me. ok,
here
> >we go:
> >
> >since this is a glance into the quite complex interactive web of life,
> >linear language fails me a bit. so please patiently follow my fragmented
> >narrations, and put them together within your systemic mind.
> >
> >since us gardeners main interest is the health and production of the
> >plants, i will look at it from the point of the plant. how the
degradation
> >of pesticides and other things tie in can then easily be concluded when
> >looking onto the various aspects of the action.
> >
> >plants generate energy in their leaves. apparently they deposit up to 25%
of
> >this energy in the soil through their roots - part as extrudates, part as
> >shedding of dead matter. this apparent loss of energy in the form of
carbon
> >is actually a well spent investment. microorganisms living in the
> >rhizosphere gobble it all up, and due to the energy boost they multiply
so
> >fast, that they use up all the available oxygen. this way anaerob
> >microniches are created. in order to understand why this is important we
> >will have to appraoch from a different angle as well.
> >
> >soil is full of iron - 2 to 12% of it's weight are made up by it. in well
> >aerated soils this iron exists in the trivalent form of tiny ironoxide
> >crystalls. now if the microclimate turns anaerobic this fairly inert
> >trivalent iron crystalls fall apart and change to the mobile bivalent
form,
> >also called reduced form. and this is important for 2 reasons: one is,
that
> >this reduced form of iron is needed in order to produce ethylene - when
> >ethylene is generated in the soil, it stops the life processes of the
> >microorganisms that fed on the energy bonus given to them by the plants.
but
> >fortunately ethylene doesn't kill them, but makes them inert. when the
> >microorganisms in the rhizospehere become inactive, they stop using
oxygen,
> >thus oxygen can diffude back into these temporary anaerob microniches,
> >making them aerobic again. the inert microorganisms wake up and become
> >active, starting the cycle all over again.
> >
> >the second good thing that happens when the iron oxyde crystalls
> >desintegrate, is this: these crystalls have a big surface and a strong
> >electric charge. thus they bind phosphate, sulphate and various trace
> >minerals closly to them, making those unavailable for the plant. when the
> >iron oxyde crystalls fall apart, they free those nutrients into the soil
> >solution, where they can be used by the roots of the plant. other
nutrients
> >(namely calcium, potash, magnesium und ammonia) are tied to the surface
of
> >clay particles and organic matter. these high concentrations of reduced,
> >mobile iron help break those nutrients free, thus making them available
for
> >the plant as well.
> >
> >just to round the picture off (and to expose some of the folly of till
> >agriculture) it might be good to take a look onto ethylene again. we need
to
> >understand, that the bivalent form of iron can only make ethylene, if a
> >precursing substance of ethylene is already present in the soil. this
> >precursing substance is also supplied by the plant - but incidentially we
> >find it only in mature leaves. so without decaying mature plant matter
the
> >ethylene cycle doesn't happen - the multiplying microbes are not stopped
in
> >time, thus they keep going until they get killed by the lack of oxygen,
when
> >they decompose in the anaerob situation substances are formed that are
> >burdening the health of the plant. i guess we could say, that ethylene is
> >needed in order to form a safe anaerob surrounding in the rhizoshere -
> >without it anaerob situations can still happen, but then they are a sign
> >that something went wrong.
> >
> >it is also interesting, that in natural soils close to a hundred percent
of
> >nitrogen in the soil is there in the form of ammonia, only traces of
> >nitrates can be found. plowing furthers a kind of bacteria that
transforms
> >ammonia to nitrates. plants and microbes don't mind a whole lot, they can
> >use both forms. but nitrates interfere with the development of completely
> >anaerob microniches - thus the nutrients stay in their unavailable form,
> >because the iron oxyde crystalls never break up. also the ethylene cycle
is
> >never triggered, even if everything is available, but the reduced form of
> >iron never becomes available.
> >
> >while all this may sound quite complicated, it isn't, it is only complex.
> >the very beautiful thing about this cycle is imho that the nutrients
become
> >available where they are needed - in the close vicinity of the plant
root.
> >also it is a safe method, to make the nutrients available in their
solutible
> >form in the anaerob situation - because if they are not used up or
washed
> >away from the root, as soon as they leave the anaerob situation, the
> >bivalent iron reverts back to ironoxyde crystalls, which again tie up the
> >nutrients in their immobile form.
> >
> >georg
> >
> >----- Original Message -----
> >From: "Mark Ludwig" <mpludwig@facstaff.wisc.edu>
> >
> > > >between aerobic and anaerobic constantly happens - this ia what makes
a
> >reed
> > > >bed working so effectively, and the everpresent ethylene-cycle works
the
> > > >same way.
> > > >
> > > >georg
> > > interesting!
> > > Would this take place better in a saturated soil like a reed bed has
or is
> > > a fairly dry soil similar.
> >
> >_______________________________________________
> >permaculture mailing list
> >permaculture@lists.ibiblio.org
> >http://lists.ibiblio.org/mailman/listinfo/permaculture
>
> Mark P. Ludwig
> Poultry Research Lab
> University of Wisconsin -Madison
> 608-262-1730 WK
> 608-846-7125 HM
>
>
> --__--__--
>
> Message: 6
> From: "Kirby Fry" <peace@totalaccess.net>
> To: <permaculture@lists.ibiblio.org>
> Date: Fri, 29 Nov 2002 10:28:24 -0600
> Subject: [permaculture] Carbon Storage in Soil
> Reply-To: permaculture@lists.ibiblio.org
>
> This is a multi-part message in MIME format.
>
> ------=_NextPart_000_0170_01C29792.0C17C920
> Content-Type: text/plain;
> charset="iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
>
>
> Greetings,
>
>
>
> Here's another article (part of it anyway) on the capacity of soils to =
> store Carbon. Notice the high rates of carbon accumulation for =
> restoring degraded lands.
>
>
>
> The more I look, the more I learn that there is a well organized =
> contigent advocating the restoration of degraded lands, who's =
> recommendations and methods run contrary to the tree clearing ecosystem =
> restorationists of Texas. This Greening Earth Society could be a good =
> lead.
> * * * * *
>
> CARBON STORAGE IN SOIL: The Ultimate No-Regrets Policy?=20
> A Report to=20
> GREENING EARTH SOCIETY=20
> By=20
> David E. Wojick, Ph.D., P.E.=20
> Dwojick@shentel.net=20
>
> November 1, 1999=20
> =20
>
> Capacity for Soil Storage of Carbon
>
> There is tremendous capacity for storage of carbon in soil, both in =
> the United States and globally. In fact, it is estimated that about 100 =
> billion tons of carbon that was originally in the soil has been lost due =
> to human activity, especially agriculture. Most of this carbon could be =
> returned to the soil, improving the soil in the process. With mankind's =
> annual carbon emissions estimated to be just 6 to 8 billion tons this =
> signifies huge storage potential.
>
> World soils contain about 3.2 trillion tons of carbon within the top =
> six feet. An estimated 2.5 trillion tons is in the form of soil organic =
> carbon. This is the organic matter in the soil that makes it fertile. =
> The remaining 0.7 trillion tons is soil inorganic carbon.
>
> These are very large numbers. In fact the soil carbon pool is 4.2 =
> times the entire atmospheric pool, and 5.7 times the biotic pool. Thus, =
> even a relatively small increase in soil carbon, if it is taken from the =
> air, could provide a significant reduction in atmospheric carbon. =
> Moreover, because plants feed on carbon dioxide (CO2) in the air, the =
> primary way to store carbon in soil is to grow plants. Improved =
> agriculture is the key to soil storage of carbon.
>
> Soil organic matter is concentrated in the upper 12 inches of the =
> soil. So it is readily depleted by anthropogenic (human-induced) =
> disturbances such as land use changes and cultivation. The magnitude of =
> soil carbon depletion is increased by soil degradation, especially due =
> to erosion. (See figure - Soil Carbon Storage Replaces Lost Carbon)
>
> Land use changes in forests, grasslands and wetlands have transformed =
> large areas of the earth from relatively stable ecosystems to =
> agro-ecosystems under extensive and intensive use. The introduction of =
> agriculture involves land clearing, draining, sod breaking, cultivation, =
> replacing perennial vegetation with annual crops, and fertilizing. These =
> changes have had major impacts on carbon pools and fluxes around the =
> globe. In the initial phases of these transformations, major losses of =
> CO2 to the atmosphere occurred as soil carbon levels adjusted to reduced =
> carbon inputs and increased soil disturbance.
>
> Intense pressure for production also has led to serious soil =
> degradation through erosion and nutrient losses. These trends continue =
> in many areas of the world. In the U.S. and other industrialized nations =
> with available energy and technology, agricultural productivity has =
> steadily increased, land degradation has slowed or reversed, and soil =
> carbon pools have stabilized or increased. However, soil carbon levels =
> are still well below pre-agricultural levels.
>
> It is estimated that a large part (75 to 80%) of the lost carbon can =
> be re-sequestered in the soils of the earth. Of course the soil carbon =
> storage capacity is finite. Moreover, ecological factors and management =
> practices limit the rate of storage. Nevertheless, it is thought =
> possible to achieve this storage over the next 25 to 50 years. Since =
> most of the original productive capacity of the earth would be restored =
> in the process, this is indeed the ultimate "no-regrets" climate policy.
>
> The following table shows estimates of annual global soil storage of =
> carbon that might be sustained over the next 25 to 50 years. [Source: =
> Carbon Sequestration - State of the Science, U.S. Department of Energy, =
> Office of Science and the Office of Fossil Energy, February 1999 =
> available on-line at =
> http://www.fe.doe.gov/coal_power/sequestration/index.html.
>
> (carbon in billion tons per year)=20
> Agricultural lands 0.85 - 0.90=20
> Biofuel croplands 0.50 - 0.80=20
> Grasslands 0.50=20
> Rangelands 1.20=20
> Forests 1.00 - 3.00=20
> Deserts and degraded lands 0.80 - 1.30=20
> Terrestrial sediments 0.70 - 1.70=20
> Boreal peatlands and other wetlands 0.10 - 0.70=20
> Total 5.65 - 10.1=20
>
>
>
> These numbers compare favorably with total human carbon emissions due =
> to fossil fuel combustion, which are presently estimated to be six =
> billion tons per year.
>
> One of the key research questions is how long these rates of carbon =
> storage could be maintained. Also, there clearly is some maximum =
> capacity for soil storage, but that capacity is far from certain. =
> Refining such estimates should be one of the central R&D tasks in any =
> soil-carbon-storage program.
>
> While perhaps surprisingly large, these relatively high levels of =
> potential carbon storage are not unreasonable. For example, a five =
> percent increase in total carbon contained in global terrestrial =
> ecosystems and agro-ecosystems over a 25-year period would store over =
> 100 billion tons of carbon. Storing 100 billion tons over 25 years =
> requires increasing the rate of storage by an average of only 0.2 =
> percent per year - roughly one half of the amount estimated above.
>
> Entir Article at: =
> http://www.greeningearthsociety.org/Articles/1999/carbon1.htm
>
>
> ------=_NextPart_000_0170_01C29792.0C17C920
> Content-Type: text/html;
> charset="iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
>
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
> <HTML><HEAD>
> <META content=3D"text/html; charset=3Diso-8859-1" =
> http-equiv=3DContent-Type>
> <META content=3D"MSHTML 5.00.2614.3500" name=3DGENERATOR>
> <STYLE></STYLE>
> </HEAD>
> <BODY bgColor=3D#ffffff>
> <DL>
> <DT>
> <DIV align=3Dleft>Greetings,</DIV></DT>
> <DT>
> <DIV align=3Dleft> </DIV></DT>
> <DT>
> <DIV align=3Dleft>Here's another article (part of it anyway) on the =
> capacity of=20
> soils to store Carbon.  Notice the high rates of carbon =
> accumulation for=20
> restoring degraded lands.</DIV></DT>
> <DT>
> <DIV align=3Dleft> </DIV></DT>
> <DT>
> <DIV align=3Dleft>The more I look, the more I learn that there is a =
> well=20
> organized contigent advocating the restoration of degraded lands, =
> who's=20
> recommendations and methods run contrary to the tree clearing =
> ecosystem=20
> restorationists of Texas.  This Greening Earth Society could be a =
> good=20
> lead.</DIV></DT></DL>
> <DIV align=3Dleft>* * * * *</DIV>
> <DL>
> <DT>
> <DIV align=3Dleft>CARBON STORAGE IN =
> SOIL:=20
> The Ultimate No-Regrets=20
> Policy? </DIV></DT></DL>
> <DIV align=3Dleft>
> <DL>
> <DT>A Report to =
>
> <DT>GREENING EARTH =
> SOCIETY=20
> <DT>By=20
> <DT>David E. Wojick, Ph.D.,=20
> P.E.=20
> <DT><A href=3D"mailto:Dwojick@shentel.net";><FONT=20
> face=3DArial>Dwojick@shentel.net</A>=20
> <DT> November 1, =
> 1999=20
> <DT> 
> <DT>
> <A =
> name=3D1>Capacity for Soil=20
> Storage of Carbon</A>
> There is tremendous =
> capacity for=20
> storage of carbon in soil, both in the United States and globally. In =
> fact, it=20
> is estimated that about 100 billion tons of carbon that was originally =
> in the=20
> soil has been lost due to human activity, especially agriculture. Most =
> of this=20
> carbon could be returned to the soil, improving the soil in the =
> process. With=20
> mankind’s annual carbon emissions estimated to be just 6 to 8 =
> billion tons=20
> this signifies huge storage potential.
> World soils contain =
> about 3.2=20
> trillion tons of carbon within the top six feet. An estimated 2.5 =
> trillion=20
> tons is in the form of soil organic carbon. This is the organic =
> matter=20
> in the soil that makes it fertile. The remaining 0.7 trillion tons is =
> soil=20
> inorganic carbon.
> These are very large =
> numbers. In fact=20
> the soil carbon pool is 4.2 times the entire atmospheric pool, and 5.7 =
> times=20
> the biotic pool. Thus, even a relatively small increase in soil =
> carbon, if it=20
> is taken from the air, could provide a significant reduction in =
> atmospheric=20
> carbon. Moreover, because plants feed on carbon dioxide =
> (CO2) in=20
> the air, the primary way to store carbon in soil is to grow plants. =
> Improved=20
> agriculture is the key to soil storage of carbon.
> Soil organic matter is =
> concentrated=20
> in the upper 12 inches of the soil. So it is readily depleted by =
> anthropogenic=20
> (human-induced) disturbances such as land use changes and cultivation. =
> The=20
> magnitude of soil carbon depletion is increased by soil degradation,=20
> especially due to erosion. (See <A=20
> =
> href=3D"http://www.greeningearthsociety.org/Articles/1999/carbon1.htm#Fig=
> ure">figure</A>=20
> – Soil Carbon Storage Replaces Lost Carbon)
> Land use changes in =
> forests,=20
> grasslands and wetlands have transformed large areas of the earth from =
>
> relatively stable ecosystems to agro-ecosystems under extensive and =
> intensive=20
> use. The introduction of agriculture involves land clearing, draining, =
> sod=20
> breaking, cultivation, replacing perennial vegetation with annual =
> crops, and=20
> fertilizing. These changes have had major impacts on carbon pools and =
> fluxes=20
> around the globe. In the initial phases of these transformations, =
> major losses=20
> of CO2 to the atmosphere occurred as soil carbon levels =
> adjusted to=20
> reduced carbon inputs and increased soil disturbance.
> Intense pressure for =
> production also=20
> has led to serious soil degradation through erosion and nutrient =
> losses. These=20
> trends continue in many areas of the world. In the U.S. and other=20
> industrialized nations with available energy and technology, =
> agricultural=20
> productivity has steadily increased, land degradation has slowed or =
> reversed,=20
> and soil carbon pools have stabilized or increased. However, soil =
> carbon=20
> levels are still well below pre-agricultural levels.
> It is estimated that a =
> large part (75=20
> to 80%) of the lost carbon can be re-sequestered in the soils of the =
> earth. Of=20
> course the soil carbon storage capacity is finite. Moreover, =
> ecological=20
> factors and management practices limit the rate of storage. =
> Nevertheless, it=20
> is thought possible to achieve this storage over the next 25 to 50 =
> years.=20
> Since most of the original productive capacity of the earth would be =
> restored=20
> in the process, this is indeed the ultimate "no-regrets" climate=20
> policy.
> The following table =
> shows estimates=20
> of annual global soil storage of carbon that might be sustained over =
> the next=20
> 25 to 50 years. [Source: Carbon Sequestration – State of the =
> Science,=20
> U.S. Department of Energy, Office of Science and the Office of Fossil =
> Energy,=20
> February 1999 available on-line at <A=20
> =
> href=3D"http://www.fe.doe.gov/coal_power/sequestration/index.html";>http:/=
> /www.fe.doe.gov/coal_power/sequestration/index.html</A>.
> <TABLE border=3D0 cellPadding=3D0 cellSpacing=3D0 width=3D"100%">
> <TBODY>
> <TR>
> <TD width=3D"45%"></TD>
> <TD width=3D"55%">(carbon in =
> billion tons=20
> per year)</TD></TR>
> <TR>
> <TD width=3D"45%"> face=3DArial>Agricultural=20
> lands</TD>
> <TD width=3D"55%">0.85 =
> –=20
> 0.90</TD></TR>
> <TR>
> <TD width=3D"45%">Biofuel=20
> croplands</TD>
> <TD width=3D"55%">0.50 =
> –=20
> 0.80</TD></TR>
> <TR>
> <TD width=3D"45%"><FONT=20
> face=3DArial>Grasslands</TD>
> <TD width=3D"55%"><FONT=20
> face=3DArial>0.50</TD></TR>
> <TR>
> <TD width=3D"45%"><FONT=20
> face=3DArial>Rangelands</TD>
> <TD width=3D"55%"><FONT=20
> face=3DArial>1.20</TD></TR>
> <TR>
> <TD width=3D"45%"><FONT=20
> face=3DArial>Forests</TD>
> <TD width=3D"55%">1.00 =
> –=20
> 3.00</TD></TR>
> <TR>
> <TD width=3D"45%">Deserts and =
> degraded=20
> lands</TD>
> <TD width=3D"55%">0.80 =
> –=20
> 1.30</TD></TR>
> <TR>
> <TD width=3D"45%">Terrestrial =
>
> sediments</TD>
> <TD width=3D"55%">0.70 =
> –=20
> 1.70</TD></TR>
> <TR>
> <TD width=3D"45%">Boreal =
> peatlands and=20
> other wetlands</TD>
> <TD width=3D"55%">0.10 =
> –=20
> 0.70</TD></TR>
> <TR>
> <TD width=3D"45%"><FONT=20
> face=3DArial>Total</TD>
> <TD width=3D"55%">5.65 =
> –=20
> 10.1</TD></TR></TBODY></TABLE>
>  
> These numbers compare =
> favorably with=20
> total human carbon emissions due to fossil fuel combustion, which are=20
> presently estimated to be six billion tons per year.
> One of the key research =
> questions is=20
> how long these rates of carbon storage could be maintained. Also, =
> there=20
> clearly is some maximum capacity for soil storage, but that capacity =
> is far=20
> from certain. Refining such estimates should be one of the central =
> R&D=20
> tasks in any soil-carbon-storage program.
> While perhaps =
> surprisingly large,=20
> these relatively high levels of potential carbon storage are not =
> unreasonable.=20
> For example, a five percent increase in total carbon contained in =
> global=20
> terrestrial ecosystems and agro-ecosystems over a 25-year period would =
> store=20
> over 100 billion tons of carbon. Storing 100 billion tons over 25 =
> years=20
> requires increasing the rate of storage by an average of only 0.2 =
> percent per=20
> year – roughly one half of the amount estimated=20
> above.</DT></DL></DIV>
> Entir Article at:  <A=20
> href=3D"http://www.greeningearthsociety.org/Articles/1999/carbon1.htm";>ht=
> tp://www.greeningearthsociety.org/Articles/1999/carbon1.htm</A></P=
> ></BODY></HTML>
>
> ------=_NextPart_000_0170_01C29792.0C17C920--
>
>
>
> --__--__--
>
> _______________________________________________
> permaculture mailing list
> permaculture@lists.ibiblio.org
> http://lists.ibiblio.org/mailman/listinfo/permaculture
>
>
> End of permaculture Digest
>

[permaculture] Thanks to georg, Marsha Hanzi, 11/30/2002
- Re: [permaculture] Thanks to georg, Rick Valley, 11/30/2002
  - Re: [permaculture] Thanks to georg, John Schinnerer, 11/30/2002