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  • From: "Lawrence F. London, Jr." <venaurafarm@bellsouth.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Fwd: Question for Elaine: Fwd: Re: Fwd: Re: [SANET-MG] Soil minerals and nutrition
  • Date: Mon, 27 Dec 2010 23:14:56 -0500

-------- Original Message --------
Subject: Question for Elaine: Fwd: Re: [permaculture] Fwd: Re: [SANET-MG] Soil minerals and nutrition
Date: Mon, 27 Dec 2010 20:42:40 -0500
From: James Kotcon <jkotcon@wvu.edu>
To: Jr. Lawrence F. London <venaurafarm@BELLSOUTH.NET>, Sustainable Agriculture Network Discussion Group <SANET-MG@LISTS.IFAS.UFL.EDU>

Soil tests from most soil test labs are based on the "extractable" nutrients, and the extracting solution is usually a fairly weak one so that what is "extracted" mimics what is available to plant roots during the current growing season. One can use stronger extracting solutions to get a larger proportion of the nutrient pool. In fact, with a mass spectrometer, you can count pretty much every molecule and atom (for a pretty high price). The concern is that, although those elements locked inside a grain of sand would eventually become "available" as the sand is weathered to silt and clay, that may require hundreds of years in the real world. Thus that kind of laboratory measurement is not a particularly useful number to tell us anything about what plants might extract during our lifetime. So while the results would be quite accurate, they would not be particularly useful from a soil fertility standpoint.

The more rational approach might be to express the nutrients based on a stronger extracting solution, but then again, the interpretation of those results would depend on the specific chemistry of the extracting solutions and the soil. Add in the variability from point to point in the field, nutrient interactions that interfere with uptake, and differences in nutrient requirements form one plant species to another, and the numbers you get might require a five-year PH.D. dissertation in soil chemistry and biochemistry to fully understand.

While it is true that soils with adequate organic matter generally will have all the nutrients required for plant growth (after all, the organic matter was originally plants), whether there is enough that becomes available in adequate amounts, at the right time and in the right balance is a different question. Knowing the "total" nutrient pool does not answer that question any better than knowing the "available" pool.

Jim Kotcon


"Lawrence F. London, Jr." <venaurafarm@BELLSOUTH.NET> 12/27/2010 8:15 PM >>>
-------- Original Message --------
Subject: Re: [permaculture] Fwd: Re: [SANET-MG] Soil minerals and nutrition
Date: Mon, 27 Dec 2010 10:41:59 -0800 (PST)
From: David Muhl <dmuhl65@yahoo.com>
To: permaculture <permaculture@lists.ibiblio.org>

Elaine,

I am assuming (correct me if I'm wrong) that it is standard practice for
soils testing labs to report soluble nutrient content, and not total
nutrient content...is this correct? If this is the case (?), can labs
even test for 'total' nutrient content (upon request) based on the
chemical composition of the submitted sample(s)? ...and if they can,
would the results be fairly accurate, or would it be more of a
'guestimate,' with the results expressed as a range?

David

--- On Mon, 12/27/10, Lawrence F. London, Jr.
<venaurafarm@bellsouth.net> wrote:

From: Lawrence F. London, Jr. <venaurafarm@bellsouth.net>
Subject: [permaculture] Fwd: Re: [SANET-MG] Soil minerals and nutrition
To: "permaculture" <permaculture@lists.ibiblio.org>, "Market Farming"
<marketfarming@lists.ibiblio.org>
Date: Monday, December 27, 2010, 5:37 AM
-------- Original Message --------
Subject: Re: [SANET-MG] Soil minerals and nutrition
Date: Mon, 27 Dec 2010 02:26:58 -0500
From: Elaine Ingham <soilfoodweb@AOL.COM>
To: SANET-MG@LISTS.IFAS.UFL.EDU

I want to make the point again that people should not
confuse SOLUBLE nutrients with total nutrients. The total
pool includes what is soluble. But do not be mislead
by chemistry reports where the only portion, and a minor
portion, of the total nutrients in a soil are reported.

I have yet to find a soil - and by that I mean something
that actually meets the definition of soil that Hans Jenny
put forward - that lacks any nutrient when TOTAL nutrient
levels are considered.


Any soil can lack nutrients in the soluble pool. But
the function of a healthy food web of organisms is to
solubilize nutrients from not-plant available into plant
available, or soluble forms. So if the biology
is properly balanced, soluble nutrients will be adequate to
supply the plant, and will be constantly replenished.

Where sand, silt, clay, aerobic organisms and adequate
organic matter is present to feed those organisms, the
nutrients required to grow plants are present.


Elaine R. Ingham
President, Soil Foodweb Inc.




  • [permaculture] Fwd: Question for Elaine: Fwd: Re: Fwd: Re: [SANET-MG] Soil minerals and nutrition, Lawrence F. London, Jr., 12/27/2010

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