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permaculture - [permaculture] Fwd: Re: [SANET-MG] strategies for boron rich and/or hydrophobic soils

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Chronological Thread  
  • From: "Lawrence F. London, Jr." <venaurafarm@bellsouth.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Fwd: Re: [SANET-MG] strategies for boron rich and/or hydrophobic soils
  • Date: Sun, 10 Jul 2011 18:05:22 -0400



-------- Original Message --------
Subject: Re: [SANET-MG] strategies for boron rich and/or hydrophobic soils
Date: Sat, 9 Jul 2011 15:23:50 -0400
From: Michael Astera <michael.astera@GMAIL.COM>
Reply-To: Sustainable Agriculture Network Discussion Group <SANET-MG@LISTS.IFAS.UFL.EDU>, Michael Astera <michael.astera@GMAIL.COM>
To: SANET-MG@LISTS.IFAS.UFL.EDU

Mike-

Those making recommendations usually want to work with a soil test method
they are familiar with. I see tests done with many different methods; they
tell different stories and are useful for different purposes. There are a
few private labs in the US, Australia, and Europe that understand and work
with soils based on CEC calculations; I don't know of any government or
university affiliated labs that do so.

I suggested the M3 method because it's the best one I know of for measuring
actual soil reserves as opposed to what's readily available to the crop. My
experience has been that when CEC is calculated and the major cations and
other elements (including P) are adjusted/amended using M3 test results, the
response will be linear, direct, and predictable. That isn't the case with
other tests.

For soils above pH 7, excess cations will be extracted with the M3 solvent;
you have to expect that and take it into account. Above pH 7.5 I would
definitely go with a Ca saturation of 80 or 85% of "calculated" CEC and
maximum Sulfur. That alone will do a lot to compensate for any distortions
caused by free cations in the soil.

The other option would be to find a lab that first extracted and measured
the free, non-adsorbed cations, and then extracted with the Mehlich 3. That
would give a better indication of true cation exchange capacity in a high pH
soil.

Michael Astera
http://soilminerals.com





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