[permaculture] Fwd: Re: [SANET-MG] Question for Elaine: Fwd: Re: Fwd: Re: [SANET-MG] Soil minerals and nutrition

David Muhl dmuhl65 at yahoo.com
Tue Dec 28 13:54:27 EST 2010


Excellent info...thank you. 

So it appears (as was discussed on this list in past threads) that:

a) there are myriad tests available
b) not all labs are using the same testing methods, even if the client were to ask the same questions about his/her soils.
c) there are many different variables (mineral content, organic matter, water quality and quantity, microorganisms, fungus, etc.)
d) how these variables (in their various quantities) interact with each other will determine what is available to the plants that occupy a given location (or will).
e) Some nutrients will be readily available, while others are slowly released (over various time periods).

I'm sure this list could go on for awhile, so I'll finish with the fact that each biological life form has it's own range of nutrients that is required/desired for optimal health, and that it might indeed take a "five-year PH.D. dissertation in soil chemistry and biochemistry" to piece together the absolute best combination of everything above, even for a small assortment of plantings (let alone an extended laundry list of plant materials that a permaculturist, organic market farmer, or a landscaper working with ornamentals might be working with).

Up until recently, I've been working with mostly ornamentals, and sometimes just natives for restoration work.  When I have soils tests done, the forms will ask me what I intent to plant, and based on this information (combined with the results from the testing), I will be given recommendations for specific amendments to be added (in various quantities) as part of my soil prep.  

Now, most of the labs I've used are those found at land grant universities that receive a good deal of their funding through large industrial agriculture corporations, and, suffice it to say, the recommendations virtually always suggest adding some cocktail of petrochemical fertilizers, much in the same way that doctors practicing western medicine treat symptoms of disease via "Big Pharma" rather than work towards creating a healthy body).  I could go deeper into this topic (as could most on a permaculture listserve), but my goal (starting with my original post) was to see how good of a soil I might be able to create for a specific site without the petrochemical amendments and herbicides.  

Elaine wrote about a thriving soil food web being able to make certain required nutrients available for plant uptake.  I felt if I could get at least a rough idea of my existing soil makeup, and maybe some idea of what the various living elements found in soil can do for me, then by reviewing both a standard soils test and a bio-assay, I could have a reasonable degree of confidence that I could make a few minor additions to my soil and have reasonably good success with the outcome.  Yes, each plant has it's own "ideal" conditions, and industrial mono-cropping farmers want a very specific "best recommendation" for that plant.  However, it's important to note that plants to not require the perfect set of conditions to thrive, but do well in a range of conditions (as might be illustrated by a bell curve).  Given the right project, I might (most probably would) wish to have a number of polyculture guilds present.  I should be able to (with the appropriate
 level of plant knowledge) do one or two soil amendment strategies across the site that would benefit most all of the plants I choose, which might include the addition of various bio-amendments should they be absent or insufficient in number.  Sure, a few plants might not do well, but that's only a few.  It's not like I have the same level of risk that a large monocrop farming operation has if you don't "nail it" with the absolute best conditions on the first try.

So hopefully this conversation moves beyond just a discussion of various testing strategies and why our hands are tied behind our backs and why we are helpless to solve some complex riddle even with our PhD's in hand.  Let's move to "thinking outside the box" to whatever extent possible.  Hopefully Elaine can respond as well, or others whose expertise covers the soil food web in addition to other aspects of soil science.  For that matter, let's expand this to include other questions/comments people might have.  

Cheers,

David Muhl

--- On Tue, 12/28/10, Lawrence F. London, Jr. <venaurafarm at bellsouth.net> wrote:

> From: Lawrence F. London, Jr. <venaurafarm at bellsouth.net>
> Subject: [permaculture] Fwd: Re: [SANET-MG] Question for Elaine: Fwd: Re: Fwd: Re: [SANET-MG] Soil minerals and nutrition
> To: "permaculture" <permaculture at lists.ibiblio.org>
> Date: Tuesday, December 28, 2010, 5:00 AM
> -------- Original Message --------
> Subject: Re: [SANET-MG] Question for Elaine: Fwd: Re:
> [permaculture] Fwd: Re: [SANET-MG] Soil minerals and
> nutrition
> Date: Tue, 28 Dec 2010 22:50:55 +1100
> From: James Sprunt <james.sprunt at GMAIL.COM>
> To: SANET-MG at LISTS.IFAS.UFL.EDU
> 
> A common test for soluble nutrients is a Reams type test
> using Morgan
> extracts. These use a relatively weak extractant and Reams
> wanted farmers to
> be able to conduct this test on a very regular basis.
> 
> Then there are tests for exchangeable cations(Ca, Mg, K,
> Na, H, NH4+,Al) i.e
> those adsorbed to colloids.
> 
> There are also a number of tests for the anions: P, S, N
> which some
> stronger, some weaker (some less available, some more
> available) again based
> on the ability of the extractant to extract.
> 
> There are tests for trace elements, some of which are
> cations, some anions.
> 
> Then there are the totals (largest pool), strongest
> extractant.
> 
> Note that very few labs do the exactly the same test and
> will thus have
> different results.
> 
> -----Original Message-----
> From: Sustainable Agriculture Network Discussion Group
> [mailto:SANET-MG at LISTS.IFAS.UFL.EDU]
> On Behalf Of Lawrence F. London, Jr.
> Sent: Tuesday, 28 December 2010 5:19 PM
> To: SANET-MG at LISTS.IFAS.UFL.EDU
> Subject: Re: [SANET-MG] Question for Elaine: Fwd: Re:
> [permaculture] Fwd:
> Re: [SANET-MG] Soil minerals and nutrition
> 
> On 12/27/2010 8:42 PM, James Kotcon wrote:
> > 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
> 
> Thanks very much for your thoughtful reply. I have
> forwarded it back to the permaculture list for the original
> poster,
> and everyone else interested in this, to read. Maybe some
> will subscribe to sanet-mg to read more.
> 
> This surely answers a lot of questions for me and clears up
> much confusion accumulated over the years.
> 
>  > 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.
> 
> Could you go into more explanation of this? Why wouldn't a
> weak extracting solution, mimicing plant actual uptake, not
> be the most desirable, and useful? In fact why not require
> both, the
> aggressive test to see what nutrients are in the
> soil that would not be detected by the weak extraction
> solution and that
> might become plant available at some future
> date and the less agressive test to have a more accurate
> picture of what
> nutrients one could expect to be available to
> plants in the short term?
> 
> Lawrence
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