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  • From: "Lawrence F. London, Jr." <lflj@bellsouth.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Fwd: Re: [SANET-MG] Soil phosphate (was organic vrs conventional)
  • Date: Wed, 10 Nov 2010 00:24:08 -0500

-------- Original Message --------
Subject: Re: [SANET-MG] Soil phosphate (was organic vrs conventional)
Date: Tue, 9 Nov 2010 23:40:32 -0500
From: Lawrence F. London, Jr. <lflj@BELLSOUTH.NET>
To: SANET-MG@LISTS.IFAS.UFL.EDU

On 11/9/2010 9:22 PM, Edna Weigel wrote:
<snip>
The most important mineral nutrient being lost in the waste stream these
days is phosphate, but some good progress is being made on systems to
recover it in an almost pure form from sewage systems. As for moving the
minerals around from one place on Earth to another, I don't think Mother
Nature will mind too much if our goal is to make this a more beautiful
garden.
<snip>
I've come across enough bits of information about phosphate to leave me
thinking the following may be correct, but not
enough information to really convince me. Below is something I want to
believe. Can anyone confirm or deny it?

Soil phosphate (what is measured in a soil test and what is available to
plants--hopefully the two are the same) does
not represent all the phosphorus in the soil and other forms of phosphorus
can be converted to the bioavailable form
through microbial action in a healthy soil. If this is the case, and if the
soil contains plenty of the non-bioavailable
form(s), phosphate might not have to be added if the right conditions are
provided for the microbes to do their work and
if the grower is patient.

This idea brings back vague memories of lab experience from 30 or 40 years
ago. At the time, part of my job was to do
quality control analyses on pyrophosphate plating baths. I measured the
phosphate in part of a sample by a common wet
chemical test. I hydrolized an identical sample by boiling it with acid for a
few hours then measured the phosphate by
the same wet chemical test. The difference in the two readings represented
pyrophosphate. Someone else decided whether
the bath was good or not based on my measurements. My point is that there are
relatively inert forms of phosphate that
were changed when boiled in acid. If I could convert them to the more
reactive form of phosphate (PO4) in a few hours
using heat and acid, I can believe microbes might be able to do it in a few
months or a few years. Does anyone out there
know if this happens?
Edna

I read a Usenet post years ago reporting on red clover exuding a substance(s) that soil fungi can use which enables them to extract more phosphate from rock particles in the soil than they would otherwise be able to. I have that
article somewhere in my archives and will try to find and repost it. I
concluded that one good soil management practice
might be to add the following to gardens at the appropriate time of year:
quarry rock dusts, azomite, [as needed:
aragonite, hi cal lime, dolomitic lime], greensand, rock phosphate plus cut
weeds, herbs, hay, compost and manures.
Mix these materials together and then into the top six inches of garden soil. Follow this with a planting of red clover. A year later, plan crops in these garden beds. This procedure could be done in rotation year after year
until all gardens on a farm have been remineralized and replenished with nutrients. If plantings are done in raised beds then track cropping in them and repeat this procedure more often on beds with heavy feeders for N or P; vary proportions of materials added accordingly. Tracking could be done with a GIS system and laptop plus appropriate software. Export dataset into a spreadsheet for viewing and analysis. As with a market farm, GIS could also be a great tool for designing, implementing and maintaining permaculture systems on a working farm. This would constitute an excellent wholistic approach to farming. Bucky Fuller would say, synergistic. Chadwick would say: "We need to create the beauty and the quality first. The quantity will follow."

<>

I found the article. It refers to VAM's and red clover:

From niemirab@student.msu.edu Fri Mar 3 21:38:31 EST 1995
Article: 5512 of bionet.plants
From: niemirab@student.msu.edu (Brendan A. Niemira)
Newsgroups: bionet.plants
Subject: Re: Mycorhizzae vs. Fertilizer
Date: Thu, 02 Mar 1995 11:04 est
Organization: Michigan State University

In Article <3j30kl$s12@vixen.cso.uiuc.edu> "egrunden@prairienet.org (Eric
Grunden)" says:

> If a person was to isolate a fungus that would form a
> mycorhizzae relationship with an agronomic crop, would
> innoculation of that fungus into the field (once it
> became established) be an effective method for reducing
> the need for commercial fertilization? Wouldn't the
> "strength/abundance" of the fungi grow exponentially with
> the passing of years?

For agronomic crops, you're talking about vesicular arbuscular mycorrhizae
(VAM),
a symbiotic endomycorrhizal fungus. These are ubiquitous anyway, and not very
host-specific, so there is very little need to inoculate the field in order
to introduce them. The big trick is getting them to colonize your crop plant
to such an extent that fertilizer inputs can be reduced. You can a) build up
the population in the soil such that even moderately active fungi result in
heavy coloniazation, b) put something in the soil to stimulate the activity
of smaller populations to get heavy colonization.

Crop rotations have been shown to have a definite impact on the population
dynamics of VAM, and work is currently being done (by me, among others) to
determine how the different crop plants differentially select for certain
species of VAM among all that are available in the soil.

Other workers have shown that certain natural, plant-produced chemicals can
stimulate the existing VAM to higher levels of activity. These chemicals were
originally derived from red clover, a popular sequence in crop rotations.
This
may shed some light on why rotations are effective w/regard to VAM.

Good luck.
...........

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Brendan A. Niemira | "You know your Shelley, Bertie."
Dept. Botany and Plant Path | "Oh, am I?"
Michigan State University | P.G. Wodehouse
niemirab@student.msu.edu | *The Code of the Woosters*
All opinions expressed are entirely my own.

VAM:

http://users.sunbeach.net/users/lec/vaminfo.html
Vesicular-arbuscular and Arbuscular Mycorrhizas
by L.E. Chinnery
Vesicular-arbuscular mycorrhizas (VAM) and arbuscular mycorrhizas are
mutualistic symbioses formed between the roots of
most plants and fungi in the order Glomales.

<...>

This is the commonest type of mycorrhiza and can be found in almost all plant
communities, natural and agricultural.
Vesicular- arbuscular (VA) and arbuscular mycorrhizas are endomycorrhizas
formed by Zygomycete like fungi and the roots
of most families of Angiosperms as well as Gymnosperms, Pteridophytes and Bryophytes (liverworts). Non-mycotrophy in the Angiosperms appears to be restricted primarily to the families Amaranthaceae, Brassicaceae, Chenopodiaceae and
Zygophyllaceae, and many hemiparasitic plants. The mycorrhizal host may be
facultatively or obligately dependent on its
fungal partner. It appears that these mycorrhizal associations are
evolutionary very old and that other types of
mycorrhizas and non-mycotrophy evolved more recently. In fact, it has been
speculated that VA mycorrhizas may have been
involved in the successful invasion of land by vascular plants and played a
controlling influence on the evolution of
roots. Unlike many of the fungi involved in other types of mycorrhiza, these mycorrhizal fungi cannot be cultured in the absence of plant roots or a root organ culture.

-------- Original Message --------
Subject: Re: [SANET-MG] Soil phosphate (was organic vrs conventional)
Date: Tue, 9 Nov 2010 22:07:35 -0500
From: Jerome Rigot <jfrigot@GMAIL.COM>
To: SANET-MG@LISTS.IFAS.UFL.EDU

Hi Edna,

Mycorrhizal fungi are microorganismes that form a symbiotic relationship
with plants, providing nutrients not readily bioavailable in exchange for
sugars the plant provide. One of the main mineral nutrient these organisms
help make available to plants is phosphate. Generally, there is always a
very large amount of phosphate in the soil that is not bioavailable to
plants, but the fungi extend their hyphae much farther than the root hairs
can, and release organic acids that not only transform the phosphate into a
more bioavailable form, but transport it back to the plant.

Actually, research has shown that adding readily available phosphate
(synthetic fertilizers such as superphosphate) into the soil prevent the
mycorrhizal fungi from forming these symbiotic relationships with the
plants. Mycorrhizal fungi bring several other benefits to plants, such as a
higher resistance to diseases.

Anyway, I hope that helps.

Jerome

-------- Original Message --------
Subject: Re: [SANET-MG] Soil phosphate (was organic vrs conventional)
Date: Tue, 9 Nov 2010 20:58:17 -0800
From: Barry Lia <barrylia@COMCAST.NET>
To: SANET-MG@LISTS.IFAS.UFL.EDU

Mycorrhiza (2004) 14:145–163
Roger T. Koide · Barbara Mosse
A history of research on arbuscular mycorrhiza

Micorrhizae were first crudely described in 1842 and study of their
symbiosis taken up in ernest in the 1880's. The first evidence of
their role in phosphorus uptake came in about 1959.

My text should have read: The role of mycorrhizal fungi in phosphorus
uptake wasn't recognized in 1910...
_________________________________________
Barry Lia \ barrylia@comcast.net \ Seattle WA
_________________________________________

-------- Original Message --------
Subject: [SANET-MG] Soil erosion
Date: Tue, 9 Nov 2010 22:28:41 -0700
From: Mary-Howell & Klaas Martens <kandmhfarm@SPRINTMAIL.COM>
To: SANET-MG@LISTS.IFAS.UFL.EDU

I once reviewed a grant proposal that said: (paraphrased) "Now that I've
stopped the soil erosion on my farm by switching to no-till, I'm having
problems crossing the deep washes that are forming in my fields."

There is a lot of soil erosion on farms that is NOT caused by tillage. Well
designed crop rotations that include cover crops and soil conserving crops
can result in far less erosion, even with conventional tillage, than
continuous no-till corn and soybeans where the soil is kept bare of anything
but corn and soybeans with chemicals. There are about 7 months each year
when there is nothing growing on many chemically farmed no-till corn/soybean
fields. Soybean 'residue' is practically an oxymoron in terms of soil
protection.

If you see organic farms with heavy soil erosion, they are actually in
violation of NOP rules. If their organic system plans don't include crop
rotations that address soil erosion and organic matter depletion, they
should not be certified. A valid organic system plan should include cover
crops, and soil building crops. If they do not, then their certifiers are
not doing their job.

There is a lot more to controlling soil erosion than just reducing tillage.
The NOP standards do a pretty good job of addressing soil erosion if they
are actually being followed.




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