[permaculture] Fwd: [SANET-MG] phosphorus
Lawrence F. London, Jr.
venaurafarm at bellsouth.net
Fri Apr 1 10:04:27 EDT 2011
-------- Original Message --------
Subject: [SANET-MG] phosphorus
Date: Fri, 1 Apr 2011 08:30:30 -0400
From: Joel Gruver <jgruv at HOTMAIL.COM>
To: SANET-MG at LISTS.IFAS.UFL.EDU
just noticed the following typo in my early morning message:
Regarding 2 parts phosphate to 2 parts potash, a lab like Logan labs
that uses an ICP spectrophotometer...
this should read "2 parts phosphate to 1 part potash"...
It is certainly possible to load soils with P to the point that
extractable P levels are twice as high as extractable K levels but I am
not aware of any reason why one would want to do this and can think of
many ecological reasons why this would be undesirable.
In terms of food quality, crops that store P in phytate aka phytic acid
(e.g., grains) tend to have very elevated levels of phytate when soil P
levels are extremely high. My understanding is that high levels of
phytate interfere with the availability of a number of metals in human
and animal diets.
BTW here is a link to a presentation on soil phosphorus (developed for
my soil fertility class last fall) that may be of interest.
I think I posted a link to this presentation last fall during an earlier
discussion of phosphorus.
is a powerpoint file ~ 7 Mb)
link will only remain active for 1 week or 100 downloads
School of Agriculture
Western Illinois University
jgruv at hotmail.com
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