# Calcareous paphs and phosphate



## Rick (May 21, 2008)

After checking out Sanderianum's choice of high phosphate fertilizer ("promoting root growth") the Antec reading room on mineral nutrition, and a bunch of articles on limestone and soil chemistry... it's starting to look like calcareous paphs may be hooked on limestone for increased phosphorous availability rather than calcium.

I looked at a few general ag articles that showed how phosphorous became much more bioavailable with the addition of humic acids and limestone. Part of the chemistry had to do with raising the pH (closer to neutral) facilitating better transfer of P to plants as well as competitive interactions freeing up P from iron and aluminum and the bioavailabilty of CaP complexes.

Also limestone has a naturally high phosphate content so as it dissolves it releases P (phosphate mines are located in karst topography). My well water and local streams have a high phosphate content, and just explode with algae if you add a little nitrogen.

Anyway in considering some of the cyclical root issues and boom and bust growth with belatulum I've experienced, and MSU fert is not well balanced for P, I was just considering a general phosphate deficiency.

More discussion encouraged.


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## cdub (May 23, 2008)

I'm no soil chemist, but it would appear from your synopsis, Rick, that the calcium and phosphorus are EQUALLY important in the affinity of some plants to calcareous substrates. The calcium compounds (in the form of carbonates?) raise the pH, which makes the phosphorus more "bioavailable." I assume this has something to do with increasing the solubility of elemental phosphorus.


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## NYEric (May 23, 2008)

Just make us a chart someone!


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## Rick (May 23, 2008)

cdub said:


> I'm no soil chemist, but it would appear from your synopsis, Rick, that the calcium and phosphorus are EQUALLY important in the affinity of some plants to calcareous substrates. The calcium compounds (in the form of carbonates?) raise the pH, which makes the phosphorus more "bioavailable." I assume this has something to do with increasing the solubility of elemental phosphorus.



We are still really talking about P as phosphates, but its easier to just say P.

In non-calcareous conditions the bioavailability of P is strongly regulated by pH, but also Al, Fe, and humic acids, and mycorrhizae. Its a complex mess, but I did dig up a paper that crop yeilds were enhanced in tropical soils by adding limestone that enhanced P availability. Also I was pointing out that many limestones (karst topography) has a naturally high P (phosphate) content.

I'm also wondering about whether P deficiencies promote Erwinia rot infections. I found one paper that showed how P and N deficient wheat was not able to ward of a bacterial challenge (not erwinia), while P&N supported wheat was able to withstand the bacterial challenge.

P for most organisms is core to their cellular energetic machinery. If P is low then anything requiring energy (flowering/rooting/fighting off disease) could be comprimised. I always thought that I had plenty of P around because I would get BG algae growing in anything with standing water, but looking at some of the symptoms and "amounts needed" charts from the ANTEC reading room indicate that my 50% use of MSU could be leaving the chids short of P


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## cnycharles (May 23, 2008)

humic acids themselves are somewhat able to (inside the plant and maybe root/soil border) sort of chelate many compounds making them more available and mobile


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## Rick (May 23, 2008)

cnycharles said:


> humic acids themselves are somewhat able to (inside the plant and maybe root/soil border) sort of chelate many compounds making them more available and mobile



Correct. In at least one article the role of humic acid (which comes from the breakdown of bark, CHC, and sphagnum moss in our mixes) to enhance the bioavailability of P in conjunction with limestone.


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## Brabantia (May 25, 2008)

Very interesting subject, but which has already tested the bone powder efficiency added to the substrat? It is an excellent source of calcium and phosphor.


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## Rick (May 25, 2008)

Brabantia said:


> Very interesting subject, but which has already tested the bone powder efficiency added to the substrat? It is an excellent source of calcium and phosphor.



Yes it is used extensively in agriculture, but I hardly ever hear it mentioned for use in orchids, let alone Paphs. I did note a warning, that many sources of bone meal contain significant amounts of lead, and that the label should be checked before using that particular source.

I was also wondering that certain vini-varieties of paphs may just be phosphorous starved populations. Hookerae and var voluntianum comes to mind.


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## Brabantia (May 26, 2008)

Brabantia said:


> Very interesting subject, but which has already tested the bone powder efficiency added to the substrat? It is an excellent source of calcium and phosphor.


I asked this question after having read this: http://www.slipperorchidforum.com/forum/showthread.php?t=944
and this:http://www.clanorchids.com/culture/nanphrag.htm


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## Rick (May 26, 2008)

Brabantia said:


> I asked this question after having read this: http://www.slipperorchidforum.com/forum/showthread.php?t=944
> and this:http://www.clanorchids.com/culture/nanphrag.htm



Your articles tend to point out that bone meal is like a long forgotten supplement that's been around in horticulture forever, but not in widespread use in recent orchid culture.

There has been allot of attention spent on nitrogen and calcium, and I've seen some debates on the pros and cons of "bloom boosting" high phosphate fertilizers. But with the big rush to MSU type fertilizers I'm wondering if phosphate is becoming the "forgotten" nutrient, and some of the poor root, rot problems, and "shrinking plant" syndromes we are seeing are the result of this.


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## SlipperFan (May 26, 2008)

Bone meals that I've seen are powders, and would tend to wash though quickly in orchid media.


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## Brabantia (Jun 15, 2008)

SlipperFan said:


> Bone meals that I've seen are powders, and would tend to wash though quickly in orchid media.


Yes, same situation with a fertilyser like 10/52/10 or 10/30/20.
For the people witch are using the MSU fertilyser: Why not to use every three or four distributions of MSU fertilizer a fertilizer with a higher concentration in phosphor such as 10/52/10 or 10/30/20 targeting 80 ppm of P as for the phalaenopsis (Prof. Wang paper)?


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## paphioboy (Jun 15, 2008)

Rick you mentioned:



> I was also wondering that certain vini-varieties of paphs may just be phosphorous starved populations.



I was just wondering what did low P/P-deficiency had to do with increasing the intensity of the flowers? Thanks...


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## Rick (Jun 15, 2008)

paphioboy said:


> Rick you mentioned:
> 
> 
> 
> I was just wondering what did low P/P-deficiency had to do with increasing the intensity of the flowers? Thanks...



It started with the Antec reading room discussion on symptoms of various nutrient deficiencies, but I found a lot of other literature that agrees with it, but apparently one symptom of phosphorus deficiency in plants is the increase in anthocyanin (purple pigment) production. Plants will turn red/purple/blue when low on phosphorus.

Plants can become low on P not only by a lack of it in their environment, but also by the pH being to high or too low. There is a pH bioavailability chart for important orchid nutrients in the Antec paper. The optimal pH range for P is narrower than for nitrogen, and tapers off pretty fast below 6 or 5.5. So this kind of goes with Sanderianums observation of armeniacum (or was it micranthum) that the pH around new growths was about neutral, but low around old flowered growths, and stolons traveled to higher pH soil.

Sounds like they could be looking for more available nutrients.

Many Barbata come from more acidic and low light sites. They may have a tolerance or adaptation for low P availability, and part of this adaptation is the production of anthocyanin. If I remember from my biochem/algology days, this pigment is somewhat photosynthetic under lower light conditions than chlorophyll. So under conditions of low light and low P, plants with anthocyanin will still be able to generate enough energy for metabolic needs. I'm not sure how much of this is genetic with regards to changing the color of flowers, but I suspect that plants with vinicolor traits may be intensified by P deficiency or able to handle lower P availability than non vinicolor varieties. 

I have been seeing some results with orchids (such as a Encyclia belezensis in my collection that developed purple tinted leaves, that when I applied the P supplement it turned green in just about a week.


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## cnycharles (Jun 15, 2008)

Rick said:


> I have been seeing some results with orchids (such as a Encyclia belezensis in my collection that developed purple tinted leaves, that when I applied the P supplement it turned green in just about a week.



in the non-orchid world, if you use low phosphorus fertilizer or withhold all fertilizer eventually pepper and tomato seedling stems will turn purple. if you resume normal fertilizing they will also turn more green again. it only applies to the stems and to a degree some of the leaves for them, however; the flowers and fruits are the usual color from what i've seen


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## Rick (Jun 15, 2008)

cnycharles said:


> in the non-orchid world, if you use low phosphorus fertilizer or withhold all fertilizer eventually pepper and tomato seedling stems will turn purple. if you resume normal fertilizing they will also turn more green again. it only applies to the stems and to a degree some of the leaves for them, however; the flowers and fruits are the usual color from what i've seen



That agrees with the literature I've read too. What's the deal with hydrangeas though?


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## cnycharles (Jun 15, 2008)

I don't specifically know, though from what little I remember of reading about it in the past it's basically the same thing as what is happening with the phalaenopsis violacea 'blue' varieties that have been being created lately. Very basic explanation I think is the greater acidity in the cell 'leads to' (very short explanation) the color changing from pink to blue. I don't remember if it is a genetic expression change or what the other explanation is


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## Rick (Jun 15, 2008)

http://www.hydrangeashydrangeas.com/colorchange.html

This was very interesting.

It discusses that low pH is necessary to get blue flowers and low pH makes aluminum (also necessary to get blue) more bioavailable. It also says that high phosphate or bone meal additions will prevent blue coloring even with adequate pH and aluminum levels. So phosphorus is a player in blue flower pigment in hydrangeas too.

I also read an article on phosphorus deficiency in tropical soils for agricultural use, and aluminum was implicated for tying up P in these soils at low pH once again.

Also in our waste treatment business we use aluminum or iron to remove excess phosphates from water.

So for hydrangeas it may be that the bottom line to get more blue is to starve it for P.

Hey, remember that post about a blue chamberlainianum that Sanderianum posted a while ago??


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## paphioboy (Jun 16, 2008)

> Hey, remember that post about a blue chamberlainianum that Sanderianum posted a while ago??



So, you're implying/speculating that that particular plant may originate from a P-starved population..? (",)


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## Rick (Jun 16, 2008)

paphioboy said:


> So, you're implying/speculating that that particular plant may originate from a P-starved population..? (",)



Or maybe low pH and aluminum rich. The effect is the same (P unavailable).

I have noted from texts that P. kalinae (more strongly colored form of victoria-regina) is found on either volcanic or granitic (can't remember which right now) hills instead of the limestone bluffs that the nominal form is found. Volcanic and granitic substrates are low pH and would also be P limiting.

The plants are apparently successful in these areas, so P limitation is apparently not lethal, and there may be genetic adaptations to offset this issue which would produce a distinct population (hence a genetic basis to define a different color form as a species/variety concept).


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