Healthy soil and sustainable growing

["E. E. Mitchamore Jr" <emitch@att.net>]

In many ways, this sounds like a larger-scale version of Ecology Action's double-digging philosophy.  Carbon credits aside, it sounds useful for rangeland for at least a few years, until the soil is functioning again with deep-rooted perennial grasses.  I can't see as much benefit for annual vegetables.

 

E. E. "Mitch" Mitchamore
www.hillcountrynatives.biz

----- Original Message -----

From: David Inglis

To: 'Healthy soil and sustainable growing'

Sent: Monday, April 30, 2007 9:12 AM

Subject: Re: [Livingontheland] Carbon Farmer

> 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