Skip to Content.
Sympa Menu

livingontheland - Re: [Livingontheland] Carbon Farmer

livingontheland@lists.ibiblio.org

Subject: Healthy soil and sustainable growing

List archive

Chronological Thread  
  • From: Dieter Brand <diebrand@yahoo.com>
  • To: Healthy soil and sustainable growing <livingontheland@lists.ibiblio.org>
  • Subject: Re: [Livingontheland] Carbon Farmer
  • Date: Wed, 2 May 2007 03:56:16 -0700 (PDT)


Paul,
 
My use of the term subsoil may have been a bit too liberal. I guess, I should
have said the lower part of the topsoil. There is probably a technical term
for this. Anyway, my intended meaning was that layer, in undisturbed soil,
where permanent humus can be stored under anaerobic conditions for a long
time, and which is covered by a few inches of aerobic topsoil where organic
material is broken down under aerobic conditions, but which is not yet stable
humus, even if it looks nice and black. In traditional agriculture, the inversion
of these two layers by ploughing is the principal cause for the loss of natural
soil fertility. Subsoil ploughing doesn’t of course turn the soil. I was just
curious about the effect of subsoiling on the permanent humus in this layer.
 
David,
 
I can’t judge the merit of the Keyline subsoiling since I don’t have any
direct experience with this. And I don’t know in which way the Keyline
marketing is involved with the Carbon Farmers scheme. Anyway, both
seem to emphasize grass land as the best way for soil-improvement and
CO2 sequestration. The Carbon Farmers site even has a page (which
I didn’t read) with selected quotes to argue against reforestation.
This seems to be indicative of a narrow commercial focus rather than
a broad environmental concern. I have nothing against making money,
but we have to be honest about it.
 
I will take your word that the Keyline subsoiling has improved the soil
in many cases; however, different applications and conditions (soil,
climate, etc.) require different strategies. In my case (semi-arid
climate and clay soil), I found that the best way to improve the soil
is to feed it a varied diet consisting of green annuals together with
woody perennials (including brambles, shrubs, bushes and trees),
and let the roots do the subsoiling.
 
Regards, Dieter

David Inglis <mhcsa@verizon.net> wrote:

> Nobody has evidence that subsoiling sequesters CO2.
+> There's no significant humus in the subsoil, but if there were then
aerating - >oxidizing it - would release CO2 to the atmosphere.
Really. If this was what was being done this would be correct. There is
always some turnover of Humus, the point is whether there is ultimately a
net gain or net loss of OM to the soil. Strictly speaking this is correct in
that the definition of subsoil is that it is below the 'living layer' layer
of the topsoil. Therefore even if one doubles or triples the topsoil layer
your statement is technically correct. One of the objects of the Yeoman
Keyline approach is to dramatically increase the depth of the topsoil layer
[A horizon] by transforming the subsoil [B Horizon]. Yeoman worked
extensively with the Australian University system in the 50's and 60s to
assess the impact of his approach. I have personally witnessed increases in
'total' soil OM [organic matter] through the use of Keyline ploughs in
conjunction with pastures or short term Leys. I have also seen the misuse of
the tool reduce total OM.
> >With 18 to 24 inches, the Keyline subsoilers go deep into the subsoil, it
is hard to > imagine that grass roots go as deep as that.
That is the point; to get roots to colonize areas of the soil previously not
open to them. Many pasture species will go way deeper than 18" -24". By the
way, the effect of Keyline plowing also goes way beyond the actual depth of
plowing.
> > Also, in relation to the Carbon Farmers claims, is the improved growth
really due
> >to the sequestration of CO2 from the atmosphere? Or is it due to the
aeration of the permanent humus in the subsoil?
The atmosphere, though a little of the "permanent humus in the subsoil" is
initially oxidized.
> > Claiming carbon credits for CO2 sequestration while in reality burning
> >the carbon accumulated in the permanent humus decades ago can hardly be
right.
I believe carbon credits should only be given for total increases of OM
through the whole soil profile not just the top 6". I also believe if
Farmers are to paid for this sequestering then they should also pay for
burning it up. I can not imagine a scheme like this working well under our
current world leadership who can't even 'run a bath' let alone a program
that rewards a global benefit. For it work it would have to be based on
atmospheric CO2 exploitation; we know how to exploit.
> > And how do the Carbon Farmers account for the fuel you need to subsoil
grazing
> > land with very powerful machines, an external input normally not
required for > >grazing land.
The same way we always have, by the increased production. Anyone not
familiar with the design of the Yeoman Keyline plough should know that it is
not a conventional subsoiling plough, which does require high HP, nor is it
used the way a normal subsoiling plough is used. The power requirements are
12HP for the first shank and 8HP for each additional shank, a lot less than
any other subsoiling plough I know of. I pull mine with a 23HP tractor. Also
as the soil develops under Keyline management it ploughs easier. The action
is very gentle and if it not then the operator is at fault.
The bottom line is that the big difference with Yeoman is not in the plough
but in his thinking. He believes that Humankind can have a beneficial effect
on soils and their rapid development. Yeoman does not physically prepare the
tilth of the soil with his plough but acts as a facilitator of the
development of the soil life. This is not currently PC but it does work,
though it takes longer in a continental climate than in his native Australia
which has the potential for year round soil development. I would say 6 not 3
years.
David Inglis
Mahaiwe Harvest C.S.A.



_______________________________________________
Livingontheland mailing list
Livingontheland@lists.ibiblio.org
http://lists.ibiblio.org/mailman/listinfo/livingontheland


Ahhh...imagining that irresistible "new car" smell?
Check out new cars at Yahoo! Autos.


Archive powered by MHonArc 2.6.24.

Top of Page