permaculture

["Lawrence F. London, Jr." <lflj@bellsouth.net>]

-------- Original Message --------
Subject: [SANET-MG] Soil phosphate (was organic vrs conventional)
Date: Tue, 9 Nov 2010 21:40:33 -0800
From: Carl DuPoldt <cdupoldt@YAHOO.COM>

Soil Phosphate:

The solubility of the various inorganic phosphorus compounds directly affects the availability of phosphorus for plant 
growth. The solubility is influenced by the soil pH. Soil phosphorus is most available for plant use at pH values of 6 
to 7. When pH is less than 6, plant available phosphorus becomes increasingly tied up in aluminum phosphates. As soils 
become more acidic (pH below 5), phosphorus is fixed in iron phosphates. Some soils in the upland Prairie areas of 
Mississippi have pH values greater than 7. When pH values exceed 7.3, phosphorus is increasingly made unavailable by 
fixation in calcium phosphates.
Almost all phosphorus is taken up by plants as either of two ions. Because the pH of most Mississippi soils is below 7, 
uptake is almost totally as the H2PO4- ion. On soils with higher pH, there will be some absorption of the HPO42- ion. 
Organic forms of phosphorus are not absorbed by plants.
Phosphorus is not mobile within soils, therefore placement of phosphate fertilizers is a major management decision in 
crop production systems. No ideal special placement exists for all crops. Decisions about phosphate fertilizer placement 
depend on the intended crop, soil test P level, and environmental considerations.

On 11/10/2010 12:24 AM, Lawrence F. London, Jr. wrote:
> -------- 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.