# Substantial K in rainforest through fall.



## Stone (Mar 6, 2014)

These two studies show a significant amount of potassium in rainfall but especially throughfall during rainy season in New guinea and Yunnan. 
Ammonium was also much higher than nitrate. (in the chinese paper)
New Guinea montane forest (abstract only) The ratio of K relative to other nutrients leaching from the canopy is high:

http://www.jstor.org/discover/10.2307/2260106?uid=3737536&uid=2&uid=4&sid=21103677463083

China:

http://als.xtbg.ac.cn/files/1981-2011/[SCI]2002-Nutrient%20fluxes%20in%20bulk%20precipitation,%20throughfall%20and%20stemflow%20in%20montane%20subtropical%20moist.pdf

Nutrients returned as litter differ in composition. It may be that if most of these minerals are taken directly as disolved ions from rainwater throughfall (very likely) we may need a re-think on the ratios of N P K Ca and Mg available?

Malaysia:

http://www.cabdirect.org/abstracts/19810673259.html;jsessionid=4CA8C81B53780ED5D20B08C2B38FFCC7

Panama:

http://cimad.org/publicaciones-MAJ/Cavelier_et_al_1997.pdf


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## Trithor (Mar 6, 2014)

Some very interesting abstracts. (I was unable to open the Chinese paper). The K is very high, way higher than I would have expected. I eagerly await the discussion that this should generate.


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## limuhead (Mar 7, 2014)

This is VERY interesting; I have no clue what it means though...


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## Stone (Mar 7, 2014)

Trithor said:


> > (I was unable to open the Chinese paper).
> 
> 
> 
> ...


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## quietaustralian (Mar 7, 2014)

I have a copy of the Chinese paper.
I'll drop it here: www.dropbox.com/sh/jga4jd7koz9t28x/uh_wOoCsOs


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## cnycharles (Mar 7, 2014)

Pollution from industrial areas?


Sent from my iPhone using Tapatalk


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## gonewild (Mar 7, 2014)

Just reading the first abstract very quickly...

The amounts of minerals are reported in kg per hectare per year.
When you consider that a hectare receives 40,000,000 liters of water per year that makes the K content less than 2ppm in the water.

Maybe my fast math is incorrect?


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## gonewild (Mar 7, 2014)

It seems that from what the through fall content applies to plants it indicates that through fall is not the source of nutrition for orchids. It certinly plays a roll but probably a small part. The results in the Panama study show K as being higher but in reality it is not much K applied to the environment. 
It comes to an amount of about 136 mg per 15cm pot per year. 

N is low in the through fall content but we know there are organisms that provide N for plants in addition to what comes with rain. 

So if through fall is a significant source for K in the plants nutrition these studies actually support the low potassium theory. ??


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## Ray (Mar 7, 2014)

Just a couple of obervations:

Those numbers are showing REALLY small loadings of mineral content. If I assume that a plant has 5 square feet of territory to absorb from, 100 kg/hectare/year (the units described in the Cambridge paper abstract) is equivalent to about one-eighth of a microgram per day for the plant.

One of the things were have not really discussed much is the relative rates of capture and absorption of the ions.


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## Trithor (Mar 7, 2014)

I accept that the actual quantities are very small, but that is to be expected on a water source as being rain, with mineral pick-up as it passes through foliage etc, but what is interesting is the ratio of one mineral to the next. Or not? What it does support is the practice of reducing feeding way down, but are the ratios of various macros correct. It is interesting to see how consistent the Ca:Mg ratios are. Or am I just being simplistic in looking at it from a ratio perspective?


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## gonewild (Mar 7, 2014)

The low content of the through fall and stem flow can not be considered as the main source of nutrients for orchids, there simply is not enough content.

The plants have to be foraging nutrients directly from soil, organic matter, or other sources such as moss, lichen, bark, ect......
For this reason I think we can not use the through fall content to predict the correct nutrient ratio the plants need and use.


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## Secundino (Mar 7, 2014)

Prediction is for weather-forecasts...
I still don't understand why the action of micorrhiza is constantly ignored. It is irrelevant of how low (IF they are low) the contents are in rain, 'through fall' (what a wonderful occurence!) and stem flow, micorrhiza traps most of it. It is not that a single plant has 'a few' micorrhiza- threads 'hanging around' its roots - the whole epiphytic community is interconnected with multiple types of miccorhizal fungi which as a whole act like an immense trap for all nutrients; over time the concentrations increase as the biomass of a given epiphytic community increases, too. 
If the epiphytes were not able to retain the nutrients, in regions with constant all-day moisture (cloud-forests) the effect would be a constant loss of minerals and biomass in the canopy. This is not what we can see in situ.

It seems to me like comparing the root system of an adult tree to the artificially reduced one of a Bonsai. Of course a Bonsai needs specific nutrition in its tiny pot! Feeding an epiphytic orchid in a 15cm pot with just plain bark does not compare to the the orchid growing on a tree.


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## Rick (Mar 7, 2014)

Trithor said:


> I accept that the actual quantities are very small, but that is to be expected on a water source as being rain, with mineral pick-up as it passes through foliage etc, but what is interesting is the ratio of one mineral to the next. Or not? What it does support is the practice of reducing feeding way down, but are the ratios of various macros correct. It is interesting to see how consistent the Ca:Mg ratios are. Or am I just being simplistic in looking at it from a ratio perspective?



These papers are only looking at bulk precip and throughfall

As already noted when converting from kg/hectare/year to the ppm per watering we apply to plants we are talking about tiny amounts. 

As per ratios, I have presented other throughfall and net flux papers from tropical forests that show more Ca than K (especially in karst forrest). 

Now if you look at leaf nutrition and plant physiology documents, then the above documents don't really change the whole low K thing.


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## Rick (Mar 7, 2014)

Secundino said:


> I still don't understand why the action of micorrhiza is constantly ignored. It is irrelevant of how low (IF they are low) the contents are in rain, 'through fall' (what a wonderful occurence!) and stem flow, micorrhiza traps most of it. It is not that a single plant has 'a few' micorrhiza- threads 'hanging around' its roots - the whole epiphytic community is interconnected with multiple types of miccorhizal fungi which as a whole act like an immense trap for all nutrients; over time the concentrations increase as the biomass of a given epiphytic community increases, too. .



Micorrhriza fungi only transfer nutrients from dead plant material to living plants. In the epiphytic system it has been shown that retained leaf litter is very low (except for places built up by ant nests). So the fungal component of nutrient recycle for adult orchids is not high either. Although as Lance points out there is significant trapping and transfer of (mostly nitrogen, but potentially all mineral nutrients) via associations of lichens/mosses/blue green algae.

Although one could also argue that lichens are already combinations of fungi and BG algae.


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## Rick (Mar 7, 2014)

Trithor said:


> I accept that the actual quantities are very small, but that is to be expected on a water source as being rain, with mineral pick-up as it passes through foliage etc, but what is interesting is the ratio of one mineral to the next. Or not? What it does support is the practice of reducing feeding way down, but are the ratios of various macros correct. It is interesting to see how consistent the Ca:Mg ratios are. Or am I just being simplistic in looking at it from a ratio perspective?



Just looking through the abstract of the New Guinea paper that despite the higher ratio of K to Ca in the throughfall water, the ratios in the standing leaf litter crop were completely reversed, indicating a greater amount of Ca that is being recycled through the system.


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## Stone (Mar 7, 2014)

Ok so you all seem to be missing the point here. Forget about the low consentrations....thats a given. What I'm talking about is the ratios relative to each other. AT THE VERY LEAST this shows that if for example you are growing Phals or Dends on cork slabs and using Klite, you are depriving them of the potassium (RELATIVE TO NITROGEN!!!!!) they are getting in the habitat. Remember that we should always look at plant nutrients in relation to N otherwise they have no meaning.

If you look at page 541 of the Chinese data, it mentions that K is the most easily leached element. This may account for the relativly low amount found in leaf litter...trees may be hoarding as much K as possible to compensate.

It also says that deposition RATIOS of K (from throughfall) is high in ALL forests.


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## Rick (Mar 7, 2014)

Stone said:


> Remember that we should always look at plant nutrients in relation to N otherwise they have no meaning.



Not true at all. Plants (not just orchids) pick up K independently of environmental N and actively (not passively) from the environment.

The inorganic constituents of plants (NPKCaMg.....) comprise less than 1% of the wet mass of the plant so applying a squirt of fert, regardless of ratios of K lite or MSU is generally overkill to what most plants pick up during active growth.

My epiphytes (of which I have a bunch of species phalaenopsis, and almost all are mounted) are doing better than ever on low K high N diet. So empirically low K holds up fine too.


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## Stone (Mar 7, 2014)

gonewild said:


> > The low content of the through fall and stem flow can not be considered as the main source of nutrients for orchids, there simply is not enough content.
> 
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> ...


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## Stone (Mar 7, 2014)

Rick said:


> > Not true at all. Plants (not just orchids) pick up K independently of environmental N and actively (not passively) from the environment.
> 
> 
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> ...


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## Rick (Mar 7, 2014)

http://www.google.com/url?sa=t&rct=...VtFf-6afvtx9bHQ&bvm=bv.62578216,d.eW0&cad=rja

Here's a link to yet another paper on nutrient flux in rainforest. A high K to Ca ratio in rain water is not universal, and it is a very small part of the picture with regard to total nutrient flux.


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## Rick (Mar 7, 2014)

Stone said:


> But you are saying that all those trials are wrong?



Not for annual food crops that are meant to maximize starch production in a 6 month time frame and get harvested. But I've also looked at trials for thing like coffee and pecan trees those are low K. I've also seen trials for turf grass that are low K high Ca.

The growth rate and production of harvest-able fruiting characteristics of orchids is irrelevant to how to feed cultivated corn and tomatoes.







Stone said:


> However neither can you say that a plant fed with a 50/50 N to K (as mine always have been) leads some sort of retardation in growth or whatever.



That's what I thought too until I changed my ways and found out otherwise. As long as you never try it, you won't notice the difference either.

My mounted Phals, Bulbos, Oncidia, Vanda... are doing light years better than by the old 50/50 N to K. And its not just my stuff either.

It's been more than 2 years for me, and I see absolutely no reason to go back to my old feeding regime. Maybe you need to figure out why so many of us are getting better results despite the low K rather than trying to convince us that its just plain old wrong and we need to go back to methods that were stunting/killing our plants.


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## Rick (Mar 7, 2014)

Stone said:


> What I'm talking about is the ratios relative to each other.



By that logic we should be able to pot up our plants directly in a jar of fertilizer and they should thrive.oke:


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## Rick (Mar 7, 2014)

Stone said:


> trees may be hoarding as much K as possible to compensate.



That Zotz paper on Panamanian epihytes you supplied a couple years ago would agree with this statement in as much as all epiphytic species (and the trees they live on) recycle most of their P and K before leaf senescence. On the flip side there is so much more Ca available in the system to start with, they don't internally recycle hardly any leaf Ca at senescence.

Another point of logic is to explain how obviously healthy in situ orchids generally have higher Ca than K leaf tissue concentrations, and we can't replicate either the growth quality or tissue concentration ratios in cultivation using the high K feeding regime you are advocating.


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## Stone (Mar 8, 2014)

Rick said:


> http://www.google.com/url?sa=t&rct=...VtFf-6afvtx9bHQ&bvm=bv.62578216,d.eW0&cad=rja
> 
> Here's a link to yet another paper on nutrient flux in rainforest. A high K to Ca ratio in rain water is not universal, and it is a very small part of the picture with regard to total nutrient flux.



Table 6 supports what I'm saying totally. K is usually higher than both N and Ca


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## Stone (Mar 8, 2014)

Rick said:


> > Maybe you need to figure out why so many of us are getting better results despite the low K rather than trying to convince us that its just plain old wrong and we need to go back to methods that were stunting/killing our plants
> 
> 
> .
> ...


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## Stone (Mar 8, 2014)

Rick said:


> By that logic we should be able to pot up our plants directly in a jar of fertilizer and they should thrive.oke:



Sorry but I have no idea what that means


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## Stone (Mar 8, 2014)

Rick said:


> > methods that were stunting/killing our plants.
> 
> 
> 
> How come my plants are not stunted or killed?


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## Stone (Mar 8, 2014)

Rick said:


> > > Another point of logic is to explain how obviously healthy in situ orchids generally have higher Ca than K leaf tissue concentrations
> >
> >
> > ,
> > ...


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## Trithor (Mar 8, 2014)

I love these tennis matches! Bravo! It is in discussions like this that most useful information come to the fore (and a little humour)
Have you ever noticed how it has a faint odour of ammonia in a tropical rainforest in the early morning. (I have never figured out why it is stronger in the morning than at other times)
One factor we don't seem to be addressing is that non-atmospheric elements are there or they are not, and that concentrations wont just change, whereas nitrogen concentrations are in constant flux, the work of the ubiquitous nitrogen fixing bacteria.


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## Stone (Mar 8, 2014)

Trithor said:


> > I love these tennis matches!
> 
> 
> 
> Me too but Rick and Lance are playing doubles :rollhappy:


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## gonewild (Mar 8, 2014)

Consider also the location of the sample points for the through fall. The samples are collected at ground level. Most orchids grow far above ground level so ground level nutrient content of through fall water is not what most species are in contact with. When I go out in the forest and look up at orchids in the canopy it appears that the water they receive is mostly from straight on rain or if from through fall the rain has had minimal exposure to the forest canopy.

To me it is obvious that most of the nutrients the plants get are from the moss and lichens and other organisms that surround the roots.
Lichens are known to extract many nutrients directly from the atmosphere and they excrete nutrients for the other plants.

I can't speak for Asian orchid species but most South American species of orchids come from forests that have very little canopy cover if any. Very few species come from forest types that these through fall studies have been done in.


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## gonewild (Mar 8, 2014)

Stone said:


> Trithor said:
> 
> 
> > Me too but Rick and Lance are playing doubles :rollhappy:
> ...


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## Trithor (Mar 8, 2014)

gonewild said:


> To me it is obvious that most of the nutrients the plants get are from the moss and lichens and other organisms that surround the roots.
> Lichens are known to extract many nutrients directly from the atmosphere and they excrete nutrients for the other plants.



I accept that, but, Where would the lichens and mosses get the nutrients from? Unless air is different there from what I studied within my MD degree, elements such as K, P, Na, Ca, Mg, are not part of the atmosphere. Nitrogen, yes, present as upwards of 70% of the atmosphere and in the presence of nitrogen fixing bacteria, can be readily converted to nitrates and ammonia (a process which I am sure lichen is actively involved in, one of the reasons why I was hesitant to compare the K to the N as a ratio in the fall through)
So surely the ratios of not atmospheric elements to each other will remain reasonably constant, but the ratio of N might well change relative to them?


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## keithrs (Mar 8, 2014)

Stone said:


> Me too but Rick and Lance are playing doubles :rollhappy:





Gonewild said:


> :rollhappy:
> 
> Do you want me to play on your side for a while?


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## Rick (Mar 8, 2014)

Stone said:


> Table 6 supports what I'm saying totally. K is usually higher than both N and Ca



Actually Table 6 is Net throughfall (how much is left after hitting the leaves).

The actual precipitation input is in Table 9 which shows about 50% of sites with significantly higher K input than Ca.

But total nutrient flux also concerns transfer through fine litterfall (direct decomp/transfer at the root level) which generally buries the K input from rain input.

You need to look at mass balance. The total sum is represented in Table 2 (above ground biomass). You can't get to the values in Table 2 by only using the values in tables 6 and 9.


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## Rick (Mar 8, 2014)

Trithor said:


> I accept that, but, Where would the lichens and mosses get the nutrients from? Unless air is different there from what I studied within my MD degree, elements such as K, P, Na, Ca, Mg, are not part of the atmosphere. Nitrogen, yes, present as upwards of 70% of the atmosphere and in the presence of nitrogen fixing bacteria, can be readily converted to nitrates and ammonia (a process which I am sure lichen is actively involved in, one of the reasons why I was hesitant to compare the K to the N as a ratio in the fall through)



There is a little bit of KPNaCaMg in the atmosphere as noted in the rain inputs data from these sites. But the bulk of these materials, especially P, Ca, and Mg, are brought up from the soil by the trees which in turn slough off/transfer via arboreal degraders (bacteria, lichens/mosses/fungi/insects/direct water erosion or leaching). Stone likes to cherry pick the data tables in these nutrient flux papers to find the high K source inputs, but thats only a small part of the total equation of what ends up in the plants.


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## Rick (Mar 8, 2014)

Trithor said:


> So surely the ratios of not atmospheric elements to each other will remain reasonably constant, but the ratio of N might well change relative to them?



Yes N is independent of the elements generally derived from soils. The arboreal nitrogen fixing capacity in the epiphytic system is fairly impressive. But N from soil degradation and uptake into the trees is also significant.

But getting out of the ratio biz, the total amount of these inorganic nutrients is still just a tiny fraction of the total biomass, and applying these materials at orders of magnitude greater than eco-relevance turned the science into a toxicology experiment.


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## gonewild (Mar 8, 2014)

Trithor said:


> I accept that, but, Where would the lichens and mosses get the nutrients from? Unless air is different there from what I studied within my MD degree, elements such as K, P, Na, Ca, Mg, are not part of the atmosphere.



It seems that new studies are showing that lichens actually extract compounds from the air and convert them into other compounds that they excrete. I don't have the links to the papers I read but they did suggest that lichens are capable of producing various nutrients for plants from the atmosphere.

Science needs to forget everything that has been published and actually look at the environment from a different perspective. Just because it is excepted scientific fact does not make it correct.... nor are the things we learned in the past necessarily correct..... 

Calcium is in the atmosphere...
http://link.springer.com/article/10.1007/BF02607214

Phosphorous is in the atmosphere... http://www.sciencedirect.com/science/article/pii/0016703779901121


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## Rick (Mar 8, 2014)

Here's a summary of the nutrient flux for PNG Montane forest from that article I posted.




Note the huge amount of Ca relative to K tied up in the above ground biomass, and the large amounts of nutrients moved around in the litterfall (also heavy in Ca).

The rainfall input doesn't come close to making a big dent on either the K or Ca, but based on net throughfall K is moving around with the rainfall easier than Ca. But net throughfall doesn't explain whats actually in the leaves and the rest of the total above ground biomass.

And certainly when boiled down to the amount each plants actually recieve per unit rainfall its all orders of magnitude less than what a basic weakly weekly feeding regime offers.


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## Stone (Mar 8, 2014)

gonewild said:


> Consider also the location of the sample points for the through fall. The samples are collected at ground level. Most orchids grow far above ground level so ground level nutrient content of through fall water is not what most species are in contact with. When I go out in the forest and look up at orchids in the canopy it appears that the water they receive is mostly from straight on rain or if from through fall the rain has had minimal exposure to the forest canopy.
> 
> To me it is obvious that most of the nutrients the plants get are from the moss and lichens and other organisms that surround the roots.
> Lichens are known to extract many nutrients directly from the atmosphere and they excrete nutrients for the other plants.
> ...



None of this changes the ratios


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## Stone (Mar 8, 2014)

keithrs said:


>



:rollhappy:Love Cary in the back:rollhappy::rollhappy:


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## gonewild (Mar 8, 2014)

Stone said:


> None of this changes the ratios



But what use are the ratios if the plants also get nutrients from other sources?
If K is high level in through fall water that hits the plant is double N,P,Ca, but the plant gets additional N,P,Ca from other sources the ratio changes to make K low.

If the only source of nutrients was from rainfall or through fall then the ratios would be a valid rate. But since all the things I mentioned add nutrients to the through fall it actually does change the ratios.


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## Rick (Mar 8, 2014)

Stone said:


> None of this changes the ratios



Ratios are BS. It's plant physiology 101. These figures are summarized from that Poole and Seeley paper you supplied a year or more ago.










The K, Ca, and Mg leaf tissue concentrations are shown for each concentration of K added in fert application. Ca was held at a constant 200 ppm. Mg was also constant. So if ratios are the all important driver then how do you get tissue ratios like this, that are so totally ass backwards from tissue concentrations in situ. (That is rhetorical ? since the paper dealing with K uptake in epiphytes was also presented years ago). 

I added the Panama leaf tissue averages to the Cattleya table for reference at eco-relevant K concentrations (~5ppm).


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## Rick (Mar 8, 2014)

gonewild said:


> But what use are the ratios if the plants also get nutrients from other sources?



Exactly. The throughfall ratios are useless when its apparent that the plants are accessing a ton of stuff through other sources.

In that PNG example you can see there's a giant Ca sink being accessed outside of the stem flow.

Plants are not nuclear reactors capable of turning Na into Caoke: It's gotta come into them somehow, and doesn't seem to be in the rain in this case.


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## Stone (Mar 8, 2014)

Rick said:


> > Here's a summary of the nutrient flux for PNG Montane forest from that article I posted.
> >
> >
> >
> ...


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## Stone (Mar 8, 2014)

gonewild said:


> > But what use are the ratios if the plants also get nutrients from other sources?
> > If K is high level in through fall water that hits the plant is double N,P,Ca, but the plant gets additional N,P,Ca from other sources the ratio changes to make K low.
> 
> 
> You're cluching at straws Lance. where the hell is an epipphyte going to get its nutrients from other than stemflow during a monsoon? When the rain stops the roots dry out and stop absorbing nutrients. Or is there a way plants take up nutrients without water that I don't know about?


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## Stone (Mar 8, 2014)

Rick said:


> > Ratios are BS.
> 
> 
> 
> ...


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## gonewild (Mar 8, 2014)

Stone said:


> The nutrients in the above ground biomas of which trees would hold the largest amount by far (in their leaves) would not be seen by the epiphytes.
> What is leached from them and the rest of the biomass however would be.



What makes you so sure that epiphyte roots can't receive nutrients directly from the bark of a tree? Not through leaching but rather through a process of ionic exchange.



> Leaf content of the canopy is irrelevant because nutrients are leached from them at different rates



Isn't the leaf content of the canopy what add nutrients to rainwater as it falls through?



> Leaf littler content also irrelevent because the epiphytes do not see it.



But there ar many species of epiphytes that grow at ground level that get leaf litter dropped on them.



> Throughfall and stemflow totally relevant as thats the only main nutrient input which they have access to.



How do you figure it is the only main nutrient source when it contains basically nothing? A couple ppms?



> As I said, things may be different at ground level however if you consider the huge amounts of rain passing through the humus layer in which the terrestrials grow, they are very likly to see similar NPK ratios as those above ground--at least during the monsoon when it rains for days on end.



Do you think that the monsoon rains produce through fall with the same nutrient content as drier times of year?


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## Stone (Mar 8, 2014)

gonewild said:


> > What makes you so sure that epiphyte roots can't receive nutrients directly from the bark of a tree? Not through leaching but rather through a process of ionic exchange.
> 
> 
> 
> ...


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## gonewild (Mar 8, 2014)

Stone said:


> You're cluching at straws Lance. where the hell is an epipphyte going to get its nutrients from other than stemflow during a monsoon?



From all the other sources that I have already mentioned several times.


> When the rain stops the roots dry out and stop absorbing nutrients.



Absolutely not correct. This only applies to plants that go dormant. 
When the monsoons stop the forest is not without moisture. It does not just stop. Condensation cycles moisture even during the dry season.



> Or is there a way plants take up nutrients without water that I don't know about?



Yes.


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## Rick (Mar 8, 2014)

Stone said:


> Rick said:
> 
> 
> > The ratios of what arrives at the plant roots is ALL IMPORTANT!
> ...


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## Stone (Mar 8, 2014)

Rick said:


> Stone said:
> 
> 
> > Apparently not since your throughfall ratios don't match the ratios in the above ground biomass.:sob:
> ...


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## Rick (Mar 8, 2014)

Stone said:


> Rick said:
> 
> 
> > (Just as Xavier once noted)
> ...


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## Stone (Mar 8, 2014)

gonewild said:


> > Absolutely not correct. This only applies to plants that go dormant.
> > When the monsoons stop the forest is not without moisture. It does not just stop. Condensation cycles moisture even during the dry season.
> 
> 
> ...


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## gonewild (Mar 8, 2014)

Stone said:


> Trees get their nutrients from the soil, sometimes deep underground. Epiphytes get theirs from what comes to them.



From the ground to the trees to the epiphytes. The tree delivers nutrients from the ground to the epiphytes. oke:


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## Rick (Mar 8, 2014)

Stone said:


> Rick said:
> 
> 
> > Epiphytes get theirs from what comes to them.
> ...


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## Stone (Mar 8, 2014)

Rick said:


> Stone said:
> 
> 
> > Even though he used tissue data extensively in his work with Orchiata bark.oke:
> ...


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## Stone (Mar 8, 2014)

gonewild said:


> From the ground to the trees to the epiphytes. The tree delivers nutrients from the ground to the epiphytes. oke:



Not the same as it takes up!!


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## gonewild (Mar 8, 2014)

Stone said:


> gonewild said:
> 
> 
> > If you look at velemen, it is designed to act as a sponge. When wet it absorbs moisture and nutrients, when dry it turns white and protects the inside from desiccation. Water=uptake no water= no uptake. Why are we even arguing this point?
> ...


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## Rick (Mar 8, 2014)

Stone said:


> Rick said:
> 
> 
> > To compare wild with cultivated as I recall and determine the difference which would also hint at the difference in nutrient ratios available.
> ...


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## Stone (Mar 8, 2014)

gonewild said:


> > If the only source of nutrients was from rainfall or through fall then the ratios would be a valid rate. But since all the things I mentioned add nutrients to the through fall it actually does change the ratios
> 
> 
> .
> ...


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## gonewild (Mar 8, 2014)

Stone said:


> Not the same as it takes up!!



No not the same as what it takes up. But what there is is what the epyphites need.


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## Stone (Mar 8, 2014)

Rick said:


> Stone said:
> 
> 
> > Had nothing to to do with wild vs cultivated plants.
> ...


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## Stone (Mar 8, 2014)

gonewild said:


> No not the same as what it takes up. But what there is is what the epyphites need.



Yep


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## gonewild (Mar 8, 2014)

Stone said:


> gonewild said:
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> > .
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## Rick (Mar 8, 2014)

http://sourcedb.xtbg.cas.cn/zw/lw/201402/P020140217559696116343.pdf

Here downloadable.

Decomposition of epiphytic moss/lichens/ferns/tree leaves for arboreal soil.

Not everything comes from the rain in the trees.


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## Stone (Mar 9, 2014)

Rick said:


> http://sourcedb.xtbg.cas.cn/zw/lw/201402/P020140217559696116343.pdf
> 
> Here downloadable.
> 
> ...



* This study was done in the very same mountains as my example therfore all the throughfall and stemflow data for that is relevant for this as well.

* The throughfall and stemflow figures obviously take into account the decomposition of the epiphytic biomass and its contribution to the final analysis.

* The epiphytic biomass obtains its nutrients from the very same rain and stemflow as that recorded at the bottom of the trees.

* Therefore this study does not change anything.


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## Trithor (Mar 9, 2014)

Wow now I understand why I had such disturbed sleep last night! You guys have been very busy with your 'tennis match' Any chance of a summary for us interested parties who have short attention spans (mine is a bit like that of a gnat)
I think quite obviously the epiphytes are exposed to another source of nutrients other than that which is in rainfall/throughfall. I think the crux of the matter is - what ratio are the macros at that the plants are exposed to, or does it not matter within a fairly rough range? We already know and accept (I think) that plants are capable of accepting different elements/compounds at different rates. (are these different rates due to ionic exchange, or is there an active pathway involved (energy driven and independent of ion exchange)?). An active pathway would enable plants to move nutrients independently of each other and independent of a concentration ratio, provided the exposure is continuous/extended (the opposite of the photograph 1/200th of a second analogy, - every photojournalist is cringing at the exposure of that fact, they plainly should only earn a miniscule fraction of what they are paid!)


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## Stone (Mar 9, 2014)

gonewild said:


> Stone said:
> 
> 
> > > I know what you are talking about. You need to not rely solely on published data and look at the reality of the forest structure.
> ...


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## Rick (Mar 9, 2014)

Trithor said:


> or is there an active pathway involved (energy driven and independent of ion exchange)?). An active pathway would enable plants to move nutrients independently of each other and independent of a concentration ratio,



Yes totally

Back when we first started this topic (May 2011) we posted a link to a paper on K uptake in bromeliads ("And then there were Three"). Using rubidium tracers the authors determined that the uptake of K includes an energy driven uptake pathway (independent of simple ion exchange).

There have not been active pathways determined for Ca Mg, with the results observed in that typical Poole and Seeley figures I posted a few posts back.

Ca deficiency in cultivated plants (not just ornamental epiphytes) has been linked to K overdose for decades in the Agri business with full understanding of that antagonistic mechanism.


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## Rick (Mar 9, 2014)

Stone said:


> * This study was done in the very same mountains as my example therfore all the throughfall and stemflow data for that is relevant for this as well.
> 
> * The throughfall and stemflow figures obviously take into account the decomposition of the epiphytic biomass and its contribution to the final analysis.
> 
> ...




Except if you notice in Table 2 the initial nutrient ratios of most of the epiphytic lichens, mosses, ferns and higher plants do not have the same ratios you hammer on for throughfall concentrations.

The moss in particular has more than 2X the Ca than K. Most of the other things are at 1:1. Out of 7 species only 2 have high K verging on the ratios in the throughfall. Also reading the text (not just the figures/tables, but Figure 2 is cool too), it sounds like the biomass of bryophytes is predominant providing a massive slow release Ca sink that's not going to loose high concentrations to the throughfall waste.

The throughfall water is the waste water with the lost leachates (not the input results). If you want to know what the plants are eating you have to determine what's in the leaves (not what washes out of them).

Do you measure the uptake in higher organisms only by measuring how much they poop or exhale? Do you know how much K a human has ingested by only measuring the concentration they pee, or that's washed off of your body in the shower?


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## TyroneGenade (Mar 9, 2014)

I'm going to change the subject a little... but wasn't there a K-light vs normal K experiment in the works? Any results thus far? These debates are getting a bit old and I'm eager for some experimental data.


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## cnycharles (Mar 9, 2014)

* the referee has called for a time-out 

If plants can draw in things actively, then a ratio of passing water isn't necessarily a primary indicator of what they need. You may say that it might be a starting point, but if a plant actively draws up potassium, then it must seemingly need to scrounge for it. This would seem to indicate that there doesn't need to be very much available sitting around, it will gather more from around. 
Another point noticed from reading these exchanges that's not mentioned in the discussions is that many orchids only grow on certain trees. Why is that? If food was only in rainwater then any tree might be good. Mychorrizae connected to roots on a damp tree can supply food from elsewhere than the flowing water. Some roots of phals go long distances and submerge in crotchets or pockets of trees where there is more moisture and food, which is diluted when it rains. Forests and trees are not homogeneous entities, so if studies include through fall from a wide area it may not be showing the specific compounds falling off of certain trees that have orchids on them. Also higher and lower elevations will have different flora, as well as those growing over different geology 


Sent from my iPhone using Tapatalk


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## Rick (Mar 9, 2014)

cnycharles said:


> * the referee has called for a time-out
> 
> If plants can draw in things actively, then a ratio of passing water isn't necessarily a primary indicator of what they need. You may say that it might be a starting point, but if a plant actively draws up potassium, then it must seemingly need to scrounge for it. This would seem to indicate that there doesn't need to be very much available sitting around, it will gather more from around.



Exactly
Low K was not based on any ratios in mind, just the means of reducing K concentration in feed to the point where antagonism with Ca is overwhelmed (which looks to be somewhere below 10ppm K). You could probably feed just about anything and get the same result as K lite as long as the overall K concentration applied was in single digit ppm with no limit on Ca in the root zone. Look at what JMPC does.

The plant has a set K demand for metabolic operation, but has adaptive mechanisms to grab and store K from very dilute sources, even for luxury storage in times of plenty. However, adaptation is conservative. High K is not a reality in the jungle on a regular basis, so plants don't have kidneys to dump excess (toxic levels) of K.


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## Rick (Mar 9, 2014)

cnycharles said:


> * the referee has called for a time-out
> 
> 
> Another point noticed from reading these exchanges that's not mentioned in the discussions is that many orchids only grow on certain trees.



The Zotz work and a few others indicated that it's not that clear cut over which trees are special or not. Some of their work suggested that it might be a secondary issue based on the preferences of certain colonial ant species. The Panamanian results were fairly inconclusive on orchid preference for certain tree species to the point where I wouldn't use the level of exclusivity you suggest Charles. But other authors may have found cleaner results.

While rooting around for the paper on lichen and moss degradation I did come across a paper on a tree species in Australia that had higher leachability characteristics of its bark (or water retention capabilities), that did seem to increase the numbers of epiphytic species that colonized it.


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## Rick (Mar 9, 2014)

TyroneGenade said:


> I'm going to change the subject a little... but wasn't there a K-light vs normal K experiment in the works? Any results thus far? These debates are getting a bit old and I'm eager for some experimental data.



That small test I'm doing with lowii seedlings is still going.

The normal K are still alive (and don't look that bad from the leaf stdpt), but there's not much in the way of roots. Half the time I walk by they fall out of their pots.

The low K in comparison are starting to pull ahead at a better rate. They are well rooted. I can pick them up pot and all by the leaves.

Although lowii can be epiphytic, I don't know if they would still qualify for answering Stones point about Asian epiphytes like Phalaes and Dendrobium.

Maybe I need to take the surviving lowii and strap them to plaques?


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## eteson (Mar 9, 2014)

We do have another experiment running in-vitro with some Plbs and tiny plants. We made 2 media, the first one with K-lite ratios and the other with MSU PW ratios. We are using epiphihes, a paphio and a phrag. In a few weeks we could have some results.


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## Rick (Mar 9, 2014)

TyroneGenade said:


> These debates are getting a bit old



I agree. I have no idea why I get hooked into them either.

I just went out into the GH ,and that stupid side by side test is wasting space that I need for some new compots coming in. I can't even water/feed without rearranging the hanging plants above to keep from contaminating that test!:sob:

Since mortality is so low now, I have dozens of seedlings still in compot that I have no space for and end up giving away before they get individually potted.

The other 99% of my collection is doing better than ever, and that's all I wanted with the program to start with. I'm turning into a neglectful orchid dad while yammering away on ST


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## TyroneGenade (Mar 9, 2014)

Can you take some photos and maybe weigh each plant. Maybe there is a detectable difference in biomass? Also measures on leaf length and breadth would be useful... 

If you need homes for those seedlings I can help you out. oke:

These threads are very good reading. Lots of drama... and always some interesting wild-plant studies.


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## gonewild (Mar 9, 2014)

Stone said:


> Where do we get the reality of the forest structure other than from published data?



Get it from looking at the forest. look at where in the forest orchids grow and look at where they might get nutrients. of course not many people can go into the forest and look at wild orchids.... but I can. You can choose to listen when I talk about what I observe or you can dismiss me as a layperson.

When I stand at the base of a big forest tree that has orchids growing on the trunk mid way up to the canopy and it is pouring down monsoon type rain and I decide to collect a "stem flow" water sample and there is no water flowing down the trunk it makes me think. When it rains in the forest the canopy acts like an umbrella and sheds falling rain water away from the trunk.
Through fall water is exactly that.. water falling through without adding much in the way of nutrients for epiphytes. This observation is in a primary type forest like those used for the studies you presented. 

But as I mentioned before most orchid species come from more open forest of even tree-less locations. The zones in the Andes that have the most orchids really don't have a forest canopy to nutrify falling rain. The orchids grow on the ground on in small shrubs or small trees. No falling nutrified rainwater. Instead the plants grow in living moss with lichens associated. Rain wets the moss and the moss environment releases nutrients. Since we can't find any university students that have researched and published this you choose to dismiss the concept. That's OK with me, it doesn't hurt my feelings.



> This study was colated over a year I think or was it two?



It still only measures the nutrient content that is diluted by a rainfall that occurs in only a fraction of the years total duration. 



> Please show me data for these ''other sources'' really! I want to see them so we can form a complete picture. Believe it or not it's the truth that interests me.



Truth is not always in published form. If you only believe something if it is printed then you only know what other people already know.
The real issue is that we will never know the truth because there are an infinite number of combinations of evolved species we have to consider. 
The nutrient process and ratios are probably different for every species of orchid.

I don't have the sources with me now, they are in California. Google about Lichens and chemicals they contain/produce. A lot of new research and discoveries are being made in Australia. Lichens have not been well studied as far as plant nutrition but people are starting to look at it.


> Your talking about the epiphytic biomass here as well as any decomposing bark and whatever dust may blow onto the branches, insects, nitrogen fixing blue green algae, other bacteria. Yes I understand the disolved nutrients will concentrate as water evaporates but how does that change their ratios?



Not all nutrients are dissolved and leach freely. Some are (may be) bound ionically to the moss, lichen, bark, dirt that the orchid roots grown in/on.

In the through fall you only see those that are loose.



> The plants can only take up what is disolved in water.



Perhaps or perhaps not. Disolved in water can also be during non rain events and the water may be in the form of condensation that does not flow.
Rain likely does not leach nutrients from lichens and the lichens may secrete the nutrients when moist but not when flooded. 
The "best" time for plants (and lichen) to grow is when there is light available. Light is low during rainfall and so plants grow between rains. Lichens do the same and so probably secrete nutrients when it is not raining and as the nutrients are secreted they are consumed by epiphytes. When the rain comes again the process slows and the "doors" close. So not all the nutrients are leached into through fall.


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## Rick (Mar 9, 2014)

TyroneGenade said:


> If you need homes for those seedlings I can help you out. oke:
> 
> .



You need to come down for a visit T. There's always door prizes:wink:

Also winter doldrums really put a damper on moving stuff around. We finally had a day I could turn off the heaters!


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## gonewild (Mar 9, 2014)

cnycharles said:


> Another point noticed from reading these exchanges that's not mentioned in the discussions is that many orchids only grow on certain trees. Why is that? If food was only in rainwater then any tree might be good. Mychorrizae connected to roots on a damp tree can supply food from elsewhere than the flowing water. Some roots of phals go long distances and submerge in crotchets or pockets of trees where there is more moisture and food, which is diluted when it rains.



I can't prove it with data but I think orchid roots can extract nutrients directly from living bark. Whether they pull the nutrients or the trees excrete the nutrients who knows. But someday someone will write a paper on this. This is the explanation of why some trees grow epiphytes and others do not.


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## Rick (Mar 9, 2014)

cnycharles said:


> . You may say that it might be a starting point, but if a plant actively draws up potassium, then it must seemingly need to scrounge for it. This would seem to indicate that there doesn't need to be very much available sitting around, it will gather more from around.



Try this analogy.

The average adult human male has a metabolic requirement (determined by physiology research) of about 1800 calories per day. This is a quantity and not a concentration.

Now you can get this from a single double bacon cheeseburger in a single sitting (and still have room for desert) or 5 heads of romaine lettuce (which I doubt most can down in a single meal).

You'd probably end up the better for the lettuce eating by having to constantly go to the bathroom to pee out the extra water, and go foraging for something "worthwhile" to occupy your bored stomachoke:

Now orchid culture equivalent; drop a 50 gallon drum of unwrapped Snickers bars on the guy each week and let him sort out how deal with it. But that's OK since we also dropped a 50 gallon drum of milk on him too for his calcium needs.:evil:

The K (or other elemental demand) is based on the size and instantaneous growth rate, which (granted) fluctuates more over a 24 hour period than a temperature regulating, non photosynthesizing homeotherm, but still its a 24/7 system not a weekly or monthly system, and not a ratio system.


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## Rick (Mar 9, 2014)

gonewild said:


> Whether they pull the nutrients or the trees excrete the nutrients who knows. But someday someone will write a paper on this. This is the explanation of why some trees grow epiphytes and others do not.



You probably missed the earlier post I made, but I passed up on a paper that was along those lines on some tree in Australia.

But it also doesn't sound like you read that last paper I linked about degradation of epiphytic lichens and mosses to create "canopy soil" for nutrient exchange in the canopy directly.

Plants aren't going to ingest solids, so you're pretty stuck needing water or gasses to move things in/out of plants. Granted it doesn't take much water for fluid transfer. Damp is fine.:wink:


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## gonewild (Mar 9, 2014)

Here is am mango tree completely covered in bromeliads, orchids and other epihytes. It gets zero through fall and stem flow.

Where do the nutrients come from to produce this mass?


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## gonewild (Mar 9, 2014)

Rick said:


> You probably missed the earlier post I made, but I passed up on a paper that was along those lines on some tree in Australia.
> 
> But it also doesn't sound like you read that last paper I linked about degradation of epiphytic lichens and mosses to create "canopy soil" for nutrient exchange in the canopy directly.
> 
> Plants aren't going to ingest solids, so you're pretty stuck needing water or gasses to move things in/out of plants. Granted it doesn't take much water for fluid transfer. Damp is fine.:wink:



I have not been able to read all the links yet, just getting back online and time to use the computer now. I'm just writing what I'm thinking not basing it on published data..... call me a trouble maker!

Yes damp is what I'm talking about. Damp is the dinner table and rain is the toilet flush.


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## Stone (Mar 9, 2014)

Ok I give up.


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## Rick (Mar 9, 2014)

gonewild said:


> Here is am mango tree completely covered in bromeliads, orchids and other epihytes. It gets zero through fall and stem flow.
> 
> Where do the nutrients come from to produce this mass?



That's wild, and right in the neighborhood too!!

There must be a lot of tree frogs pooping in that treeoke:oke:


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## TyroneGenade (Mar 9, 2014)

Rick said:


> You need to come down for a visit T. There's always door prizes:wink:



Sadly, I won't be near TN for some time. I'm heading west this summer into the Rockies.

It popped into my head that you mentioned mortality in your previous post. I study survival for a living (or I did, now I teach anatomy & physiology). If you have number feel free to share. I need the total number of plants in either experimental group and the number of plants that died and when they died. It isn't difficult working out if there is a difference in survival between the groups if there is enough data. The stats are relatively robust and make few assumptions so the statistical model has wide application.

I know what you mean about the weather... It was a glorious 11 oC today in NW Iowa. There was even some welcome humidity from all the melting snow and ice. Its going to be 15 oC tomorrow. I may need to pull the short-pants out of the storage. No. That is probably a bit much.

Lance that is one very impressive mango tree. How much bird and insect fertilizer is supplied? I doubt there would be direct feeding via bark simply because the bark is supposed to be water proof (if water can't pass then the ions can't either). Perhaps the decomposition of old bark? Any have any nutrient values for plain, boring bark? There are probably a lot of mango leaves getting caught up as well.


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## Trithor (Mar 10, 2014)

TyroneGenade said:


> but wasn't there a K-light vs normal K experiment in the works? Any results thus far? These debates are getting a bit old


My rather empirical study is nearing a full year. It has been through a full winter, and the better part of a summer. I am also looking forward to stopping it, as it is becoming a bit of a pain in the rear end. I have been feeding half the greenhouse with a 'MSU' type fertilizer, and the other half with a 'K-lite' type fertilizer. Each half has a mixture of seedlings, various species and a range of hybrids, about 2000 plants to each group.
To be honest I can not see a marked difference, but in a couple of months I will go through the RIP box and check the red and blue tags and the notes relating to their demise. Then I will repost random plants through the greenhouse and scrutinise as many plants as possible. I have a mountain of closeup photos of the benches, which I will compare to current.
Although the debates have happened often, and a lot of the same ground is covered, I would not go so far as to call them 'old'. I can see a gradual shift in some of the debates indicating a slight change in ideas, obviously K will remain a central point of contention, but if as growers we were not concerned, we would not bother discussing it any further. It is an important factor in culture, and I predict that there will be many more debates of a similar (if slightly different) nature.



Rick said:


> I agree. I have no idea why I get hooked into them either.


I guess because the topic is important to you? I for one am very glad that you continue to be involved and argue your points so strongly. Each time there is a gradual shift or refinement of the topic, with valuable information being added each time (even if it does take some wading and distillation to get them).




gonewild said:


> When it rains in the forest the canopy acts like an umbrella and sheds falling rain water away from the trunk.
> But as I mentioned before most orchid species come from more open forest of even tree-less locations. The zones in the Andes that have the most orchids really don't have a forest canopy to nutrify falling rain. The orchids grow on the ground on in small shrubs or small trees. No falling nutrified rainwater. Instead the plants grow in living moss with lichens associated. Rain wets the moss and the moss environment releases nutrients.


Every now and again a valuable point is made, sometimes obvious and simple, sometimes a bit more complex. A simple observation such as this, kind of alters the whole debate, perhaps not drastically, but it requires a definite shift. Another valuable point that has become more prevalent of late is the focus on pioneer plants such as lichens and mosses. How could we possibly address the topic of epiphytic nutrition without them being a central point in the discussion, as their influence can only be pivotal.


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## Secundino (Mar 10, 2014)

Oh god, that is so sad.
A canopy is no umbrella, its a SPONGE. (And even if it was a kind of leaky umbrella, isn't there another tree at the side where the umbrella is dripping?) Even the leaves of the tree are no clean! There are plenty of algae living there!
If those composed leaves are the trees', that tree is not a mango, and it is merely living. If those leaves are not the leaves of the tree, that trunk is completely dead. So the epifitic community will not last that long and if you could compare it with the community that lived there while tere was a canopy, you would note a shift in species. And it will gradually change to a community living on decaying wood.
It is interesting that the idea I'm with (miccorhiza) doesn't get credits because supposedly micorrhiza only functions on dead organic matter (just remember, please, that the 'other end' of the micorrhiza is attached to a living root!) but without any proof there is acceptance for the hypothesis that epiphytic roots actively suck nutrients out of living bark!
But please, go on with the nutritioned rain water and the orchid hot spots devoid of trees!


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## Rick (Mar 10, 2014)

TyroneGenade said:


> It popped into my head that you mentioned mortality in your previous post. I study survival for a living (or I did, now I teach anatomy & physiology). If you have number feel free to share.



That's funny. As an aquatic toxicologist that's all I do for a living too, and spend half of every day plugging mortality data into stat programs for analysis.:wink:

After almost 20 years I can eyeball most data without having to plug it into a stat package.

I could go back through 10 years of seedling records for flasks recieved from TM, and compare to some "remembrance" of final disposition. I could see that getting picked apart for species/lot date/parentage/losses spread out over more than 3 years....

Individual case histories (such as these lowii) will be easier.

I've had complete losses (over years) of the exact same selfing that is presently pushing blooming size with no losses (about 50 seedlings pre and post). Thats almost obvious without using stats.:wink:

Several cases straddle low K.

A flask of primulinum frittered away over 5 years till 3 survivors making it low K and then turning into blooming plants in the next year.

I purchased 2 flasks of wilhelmnea, went from about 50 to 15 plants over a couple years, but stopped the bleeding with low K and got 2 plants to blooming, and another 10 or so actually growing. I gave one to SlipperKing who says it's moving right along too.

Mastersianum got 10 to start and just sat there for the first year but turning on with low K and bloomed in less than 3 years out of flask.

2 henryanum flasks (all unrelated). Have 1 left from 1 (96% loss) but after almost dieing should bloom this fall, another flask got down to 4 plants (some given away) probably 75% + mortality loss with survivors not growing. Then having those last few turn into multigrowth bloomers in the last 2 years.

A third henry flask from a cross I did with Jason Fisher recieved after K lite (that's about 6-8 months after I started low K), are all still alive (0 mortality), and even had 1 bloom. Most are still crammed in the compot


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## Rick (Mar 10, 2014)

Secundino said:


> It is interesting that the idea I'm with (miccorhiza) doesn't get credits because supposedly micorrhiza only functions on dead organic matter (just remember, please, that the 'other end' of the micorrhiza is attached to a living root!) but without any proof there is acceptance for the hypothesis that epiphytic roots actively suck nutrients out of living bark!



I think you should also read that paper I linked on degradation of epiphytic bryophytes and lichens.

I'm sure you'll find your link to micorrhiza in the trees there:wink:


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## Rick (Mar 10, 2014)

TyroneGenade said:


> It popped into my head that you mentioned mortality in your previous post. I study survival for a living (or I did, now I teach anatomy & physiology). If you have number feel free to share.



Wow a lot worse than I thought. Went into my TM records.

First flasks (lowii) in 2003 and picked up about 32 flasks before 2008 (that's about 800 seedlings of which I can probably count the total I raised to blooming on both hands. Certainly every last lowii and philipinense are gone before getting more than 6-8 inches across. Also Phrags like pearcei and lindleyanum. I have 1 left of those original pearcei that is just now coming back after almost losing it a dozen times

The transition period 2008 to mid 2010. Another 16 flasks (~400 seedlings) are really mixed. In this group, when referenced to the 2003 thru 2007 period, you could tell that typically I burned a flask out over the coarse of about 3-4 years (never had a catastrophic complete loss in less than a month or 2). So overall compot mortality by mid 2010 was maybe 50% for flasks picked up early in 2008. Stuff picked up closer to (or in 2010) wasn't as beat up by the time low K started in mid 2011(like the mastersianum, and a bunch of supardii seedlings).

I've only picked up 5 flasks worth (~125 seedlings) since mid 2010. And Low K starting mid 2011. 3 from outside TM. Like that henry flask from OL. Except for an anomalous flask of wardii that completely cratered in a month from erwinia (it really didn't last long enough to get fed), I have had 0 losses and excellent growth from these flasks.

So it looks like max life span of any given compot would have been between 4-5 years before 2008/2009. And after 2008 (with K lite intervention in 2011) I have lots of stuff not only surviving but blooming and flourishing with no end in site after 5 years by the end of 2013.


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## gonewild (Mar 10, 2014)

Secundino said:


> Oh god, that is so sad.
> A canopy is no umbrella, its a SPONGE. (And even if it was a kind of leaky umbrella, isn't there another tree at the side where the umbrella is dripping?) Even the leaves of the tree are no clean! There are plenty of algae living there!



I compare it to an umbrella because it diverts most of the water away from the trunk. Orchids like Phalaenopsis that grow on the trunk would not receive the rainwater as through fall. Water may come down as stem flow but in reality little water flows down the trunk. Most water that you would think would run down the trunk is diverted away and flows down vines to the ground. This is one instance why analysis of through fall water may not represent nutrients that a a main supply for the epiphytes. Through fall tends to fall between trees.


> If those composed leaves are the trees', that tree is not a mango, and it is merely living. If those leaves are not the leaves of the tree, that trunk is completely dead. So the epifitic community will not last that long and if you could compare it with the community that lived there while tere was a canopy, you would note a shift in species. And it will gradually change to a community living on decaying wood.



It is a mango and still alive but declining fast due to the epiphytic overload.



> It is interesting that the idea I'm with (miccorhiza) doesn't get credits



As far as I know Miccorhiza deliver nutrients to plants but do not manufacture nutrients? Miccorhiza presence does not effect the ratios or quantities of nutrients around the plants. Perhaps miccrohiza control the ratio of nutrients a plant uptakes but that would still be limited to what nutrients are in the environment the miccrohiza has access to.

Do miccrohiza supply potassium to orchid plants?


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## Rick (Mar 10, 2014)

gonewild said:


> As far as I know Miccorhiza deliver nutrients to plants but do not manufacture nutrients? Miccorhiza presence does not effect the ratios or quantities of nutrients around the plants. Perhaps miccrohiza control the ratio of nutrients a plant uptakes but that would still be limited to what nutrients are in the environment the miccrohiza has access to.
> Do miccrohiza supply potassium to orchid plants?



K, Ca, Mg, Fe, Cu... are elements and cannot be manufactured (except maybe in a nuclear reactor or collidor from some other elements). Phosphate (oxidized P) is a basic cellular currency for energy so phosphate generally gets moved around as phosphate too. 

Fungi are the worlds great decomposers especially with bacteria. There is no shortage of viable bacterial and fungal interactions between dead plant or animal material and transfer of that breakdown/recycling with living things (orchids or anything else). Its all food chain stuff.

Not that long ago in Orchids Mag there was an article about germinating and growing orchids from seed using nothing but peat moss as substrate. The author made little gelatin (no fert added) balls of orchid seed and specific mycorrihzae inoculants, and simply set onto damp peat moss. Great germination and growth.

All nutrients supplied by the fungus breaking down the peat moss and transferring to the orchid embryo. Peat moss (dead sphagnum moss) has enough NPKCaMg.....to supply orchids at that age/size without adding external nutrients. But requires the fungus to chew it down to a transferable portion.


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## TyroneGenade (Mar 10, 2014)

Rick said:


> That's funny. As an aquatic toxicologist that's all I do for a living too, and spend half of every day plugging mortality data into stat programs for analysis.:wink:



Cool. That sounds pretty convincing for survival data. I do aging/anti-aging interventions so I like control groups rather than end-stage intervention. But you data sounds pretty convincing for: K-lite stopped my plants from dying.

Thanks for sharing the data.


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## Rick (Mar 11, 2014)

TyroneGenade said:


> Cool. That sounds pretty convincing for survival data. I do aging/anti-aging interventions so I like control groups rather than end-stage intervention. But you data sounds pretty convincing for: K-lite stopped my plants from dying.
> 
> Thanks for sharing the data.



Yup, in 2001 if I had started this hobby as a K lite project it would have had controls. Who knew it would take me 10 years before I thought of it.

I poked through my TM records a bit more to look at 5 year mortality since the first flasks showed up in 2003

2003 = 100%
2004 = 99.3 % (out of 300 seedlings:sob
2005 = 97%
2006 = 92.3%
2007 = 88% (only 25 seedlings anyway)
2008 = 74.5%
2009 = 27.2% (although only at year 4 though)
2010 = 20% (of 50 seedlings)
2011 = 0%
2012/2013 = 0% (except for that anomalous death pot).

The other thing to consider is those handful of single survivors from 2004 - 2006 were ugly/mangy, and really turned around after low K. Some had never bloomed until 2012. But that's only N of 6-10 of those >5year survivors.


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## Bjorn (Mar 11, 2014)

Wow, its amazing that you did not give up Rick! So many mortalities! Then my two cents; I know (from chemical analyses) that bark normally contains a lot of nutrients, one example is calcium, would it not be possible that much of the orchid feed came from decomposing bark possibly aided by mycorhirza and supplied by lichen etc? Have to look up the analyses when back in office.


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## Rick (Mar 11, 2014)

Bjorn said:


> Wow, its amazing that you did not give up Rick! So many mortalities! Then my two cents; I know (from chemical analyses) that bark normally contains a lot of nutrients, one example is calcium, would it not be possible that much of the orchid feed came from decomposing bark possibly aided by mycorhirza and supplied by lichen etc? Have to look up the analyses when back in office.



I do get high points for persistence in my work performance reviews

But it also makes a difference that the majority of those flasks are free in the Troy Meyers programn.oke: But I really did take a serious break in 2007 to reasess.

Yes leaf litter/bark/moss all have lots of Ca, and everyone still adds oyster shell or lime!! But as long as K is in excess, the plants will not be able to extract it from any source.

I do not add any lime based materials to my mixes any more


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## Rick (Mar 11, 2014)

Bjorn said:


> Wow, its amazing that you did not give up Rick! So many mortalities!



Besides the free aspect, when you spread out the pain over several years its not as obvious. Until I looked up the records, I really thought I had only killed about 1/3 to 1/2 of what it adds up to:sob:


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## lepetitmartien (Mar 11, 2014)

Note Rick that there's another explanation: you're a better seedling grower over time. (note: devil's advocating)

(I want to survive the Big ST Low-K Flame War, back into hiding


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## gonewild (Mar 12, 2014)

lepetitmartien said:


> Note Rick that there's another explanation: you're a better seedling grower over time. (note: devil's advocating)
> 
> (I want to survive the Big ST Low-K Flame War, back into hiding



You become a better seedling grower when you start learning about what the plants truly need and respond to and not just fertilizing with traditional concept fertilizer that everyone told you to use. :evil:


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## lepetitmartien (Mar 13, 2014)

That's exactly what we don't *_know_*, but we sure can have an educated guess or multiple educated guesses. That's why Rick's low K twist is very interesting. Modern orchid growing is an experiment going on for more than a century. Here is a new one going on, like S/H is another.

Note that we have a few growers here in France reproducing the Low K approach by their own means (no K-lite in sight) and for one who's into it for near a year it's fine for now afaik. As he may be (and I think he is) reading here, it'd be better if he talks about it by himself, so I won't speak about it (save if he wants to and I have the Kalach pointed to my back).

On the arguments :fight:, it's a bore for a long time now :snore: (really guys!:evil, but the papers showing here and there are interesting. The end reasult is what counts and it takes at least 3 full years with multiple entries to be sure. Then we can wonder why it works same or better* than orthodoxy (even if Rick has an educated guess). 

If only everyone could agree that:
- What's come in near the roots is:

maybe not what they eat but maybe partially only;
maybe a little bit more complicated than this;
still a research field without much persons working on it.
- The whole thing is still lacking scientific data on many aspects especially the intake, across multiple genus, position int he trees, location on earth.

We'd make some progress. 
Thank you 

(*If it doesn't work, we have already a sh…load of explanations.):viking:
(back into hiding, I want to survive, just trying not to be too ridiculous, Eat at Joe's)


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## Leo Schordje (Mar 13, 2014)

Wow, just read the whole thread in one sitting, no time to go through the papers posted along side. That will take at least another pot of coffee. 

One key point that is getting missed in all this. 

We are growing orchids in an artificial system, in pots at nutrition levels at least 10 time the concentrations noted in observations from the wild. When concentrations of nutrients are higher than what is typically experienced in the wild, TOXICOLOGY considerations should be taken into consideration. I think Rick Lockwood is on target. Potassium in excess of what plants have evolved to handle is a toxic chemical. In humans, and excess of vitamin D can kill a person, if I took as much Vitamin D as Vitamin C I would be dead. 

I fertilize with a roughly 900 ppm total dissolved solids solution, with the N being about 80 ppm. This is almost 100 times the concentrations that are being talked about in monsoon rain, and between 10 and 50 times more than the higher figures reported for nutrients in nature. I want my plants to grow faster. I want nutrients to not be the limiting factor for their growth. SO one year & 3 months ago I switched to K-Lite, and have had a remarkable improvement in my plants. I stopped the poisoning with excess K. 

My thoughts, the data from the wild is very relevant as a starting point, but orchids in our light gardens, windowsills, and greenhouses are in a very different and very artificial environment. The wild data does not directly translate to what we do in our growing areas. 

On mycorhizae, and the nutrients orchids get from associations with mycellium. Watch this video of Paul Stament's Ted Talk. ignore the wild flight of fancy where he says something about Dark Matter, his zeal got ahead of his normally solid scientific approach. Key is the brief but well documented 3 minutes where he talks about trees of different species sharing water, carbohydrates and nutrients with each other through the connections with their mycellium. A well developed mycellial mat is not just one species, it is a complex of many species. The mycellial matt does not connect to just one plant, it usually connects to many plants, and frequently other species of wood decomposing fungi too. This fact has far reaching implications (complications) when trying to sort out nutrient cycling in the wild. It also should give one pause to think about possible implications for cultivating our orchid species in our artificial systems. A very enjoyable 15 minute video. 

https://www.youtube.com/watch?v=jNRFxmfQNbo

Also a very inspiring read, Paul Staments 2005 book, Mycellium Running, or how Mushrooms can Save the World. Every chapter has a large number of citations to peer reviewed journals, every point made is backed by experimental data, or is clearly noted as speculation where he does speculate. A good read, and not outdated yet. Newer research has largely confirmed everything he says in this book. The book is still available on Amazon, and directly from Staments at http://www.fungiperfecti.com


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## Brabantia (Mar 13, 2014)

Leo Schordje said:


> Wow, just read the whole thread in one sitting, no time to go through the papers posted along side. That will take at least another pot of coffee.
> 
> One key point that is getting missed in all this.
> 
> ...



Very interesting Leo. All this recall me that Lance (if I remember well) recommended to add some leaves humus (leaves litter?) in substrate to cultivate Paphiopedilums. With all that was said in this subject I understand much better all importance of this addition.
This afternoon I went to a beech forest and examined what there was under leaves fallen at the end of last year. I found decomposing finely shredded leaves gone through by a whole network of white filament ... mycorhiza?
If yes I know what I need to do!

Look (on 1,2,3/4) on what are growing Paphiopedilum in Borneo *Here*


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## Rick (Mar 13, 2014)

lepetitmartien said:


> Note Rick that there's another explanation: you're a better seedling grower over time. (note: devil's advocating)



There's a couple ways to look at it (especially if you only look at parts of the data not in context with all the other observations).

The mortality differences when posted on a year to year basis have a bit of a gradual look (as if cumulative small things were being changed over the course of the last 11 years). But the mortality is based on a 3-5 year lag period, and low K hasn't been in full use since May 2011 (2.5 years). So you really need extremely good records to demonstrate the intervention on the seedlings aquired within roughly 3 years of the low K program to see things numerically as black and white what you seem to be after. Or else you need to wait 2.5 more years for seedlings I recieved after May 2011.

However, the other anecdotal part (since my records aren't as detailed on this point, is based on seedlings making it to blooming. 

So going back to everything prior to 2008, not only did they mostly die, but almost none of the survivors ever got big enough to bloom before death. 

But I've had more of my own seedlings make it to blooming in the last 2 years than in the previous 9-10 years combined. I could also include individual seedlings purchased over the years, and inflate the number even more.

Yes we learn how to navigate light/temp/humidity and gradually learn through time (years if we make the same mistakes without learning), but this has been like turning a light switch on in my growing. (And the lights still on to see whats coming in the future!!)


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## Stone (Mar 13, 2014)

Leo Schordje said:


> QUOTE] I think Rick Lockwood is on target. Potassium in excess of what plants have evolved to handle is a toxic chemical.


 No, it results in Ca/Mg deficiency if they are too low.


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## Rick (Mar 13, 2014)

Stone said:


> No, it results in Ca/Mg deficiency if they are too low.



Except all of us (including myself) were applying tons of Ca/Mg during our high K years with no positive results. I have another paper (Bangerth 1979)exclaiming the same problem with non orchid plants. This has been documented in agri science for years. The uptake of K is independent of the amount of bioavailable Ca in the environment.

The 1970's Cornell study that you supplied had soluble Ca at 200ppm and the plants preferentially pulled up K at 50, 100, 200 and 300 ppm. (So much for ratiosoke

It may not fit your personal definition of "toxicity" but in the toxicity biz, any adverse effect caused by an excess of a chemical is a toxic effect.


If orchids can't pull up Ca against a 4:1 Ca to K ratio then how much Ca do you need? With MSU at 100 ppm N that was 130 ppm K? 

So how do you get 1300ppm (for 10:1 ratio) or more soluble Ca into the system?? Ratios are BS


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## Rick (Mar 13, 2014)

lepetitmartien said:


> Modern orchid growing is an experiment going on for more than a century. Here is a new one going on, like S/H is another.



I would say that modern hobbyist orchid growing is about 100 years behind that for food crop science. And every time they think they come up with something new, the physiology is really the same.

Farmers don't apply an indiscriminate amount of K at a set concentration to a single plant. 

They apply a discreet mass of K based on how much they know is going to be utilized by an acre of plants at a known density.

Tissue analysis of root leaf and fruit was done so that the application of discreet mass of NPKCaMg could be applied to minimize waste. The studies also included optimization to find out how much was too much. You can find plenty of corn and tomato projects that look at excess as well as deficiency. I'm not sure why orchid people are in such denial of the excess side of the equation (especially since the first time I saw it in print was on the ANTEC orchid website!!)

The only thing I've done is apply the same understanding to a slow growing group of plants adapted to very low nutrient environments. 

I claim nothing more than trying to catch up hobby orchid "research" with the rest of the plant sciences"


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## Stone (Mar 14, 2014)

Rick said:


> .
> 
> 
> 
> ...


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## Stone (Mar 14, 2014)

lepetitmartien said:


> > On the arguments :fight:, it's a bore for a long time now :snore: (really guys!:evil,
> 
> 
> 
> ity: Not:fight: just oke: Please do not put mouse arrow device on thread and click :evil:


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## naoki (Mar 14, 2014)

Mike, which book is it?

I have been also wondering that the mechanism explaining why k lite works well with some people may be something else. Interference among cations seems unlikely at such low concentration. What do you two think about the Classic Poole and Sheehan 1982? They didn't see k toxicity for most orchids even at 200ppm K.

It is known P is detrimental for mycorrhizal association (K-lite is low in P, too). Lower fertilization is Also known to increase root biomass, maybe resulting in more robust plants?

Poole and Sheehan is a chapter in Orchid Biology: Reviews and Perspectives, Volume 2, Joseph Arditti (ed.) 1982 Lots of materials from this review paper is repeated in Fundamentals of Orchid Biology by Joseph Arditti (1992).


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## TyroneGenade (Mar 14, 2014)

I think we are conflating two issues.

The first is nutrient interference:




from http://nutriag.com/article/mulderschart

An imbalance of nutrients can disrupt nutrient utilization and uptake. Too much K will disrupt Mg uptake but it will also increase Iron availability so the plant can become more sensitive to iron overload. 

The second issue is toxicity and toxicity can come about in several ways. Give a human too much K and they will have a heart attack and die. Too much K is poison (very important: the dose makes the poison!). K is more tricky for plants. K is hydroscopic: it is going to draw water towards itself. If you give high K you are going to disrupt plant water uptake. The plant can only solve this one way: by taking up K so the water can follow it out of the soil. But the plant can only hold so much K... so to take up more K it has to grow. To grow it needs more N, Fe, P, Mg etc... But now these are all out of balance (i.e. too much of some, too little of others) and the K builds up in the tissue while it also builds up in the soil and this means the plant has trouble getting water... and then the roots die and the plant follows. K accumulation in the substrate (and plant) is just as toxic to the plant as Na.

It is very important, at this point, to remind everyone that water is needed to fuel photosynthesis, so once the plant can't get enough water it will begin to starve to death. It will also be less able to transport nutrients through its tissues, so in effect, too much K in the soil (and plant tissues) shuts down the plant's circulation as surely as it would give us a heart attack.


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## Rick (Mar 14, 2014)

Stone said:


> .
> If it were true we would be falling over Ca deficient plants.


 We don't trip over them because the carcasses are in the compost heap (like the 1000+ seedlings I just mentioned), or the suviving are too stunted to trip us. But this is what started this thing in the first place was admission that results are not good.




Stone said:


> Kevin Handreck Bsc, MAgrSc who has written a 500 page book on growing media and fertilizer practice?
> 
> Under Toxicities: ''There is no such thing as potassium toxicity. However, repeated heavy use of fertilizers containg potassium can interfere with magnesium supply. Any symptoms produced are those of magnesium deficiency''
> Under deficienies: Causes of calcium deficiency: *''Excessive applications of ammonium and/or potassium fertilizers



Obviously Handreck is not a toxicologist (plant or animal). Everything he describes as "deficiencies" are a classic definition of sublethal chronic toxicity.




Stone said:


> As far as ratios of N P K Ca and Mg being BS (even though the whole premise of your article was based on your belief that current fert ratios are damaging and a new ratio is needed),



Only for those obsessed with ratios. You are still missing the point (even from the earliest posts on this in 2011) its concentration not ratio. The article lists all kinds of ratio rational, but all tied to a starting application concentration of either 100 or 50 ppm N application rate. By math (which I know you dislike) that forces the K below 10 ppm using the ratios advocated. Since I know that orchid people are ratio junkies, the heavy comparison to insitu leaf tissue ratios was to pound home that wild plants are totally different from the cultivated plants (that we always gripe and frett over).
I've always said that ratios are not the point but all based on max K concentration.

http://www.slippertalk.com/forum/showthread.php?t=20716&page=3


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## gonewild (Mar 14, 2014)

Rick said:


> W
> I've always said that ratios are not the point but all based on max K concentration.



Ratio is important when the concentration is high and reaching the 'toxic" levels.


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## Stone (Mar 14, 2014)

Rick said:


> > Only for those obsessed with ratios. You are still missing the point (even from the earliest posts on this in 2011) its concentration not ratio.
> 
> 
> 
> ...


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## Stone (Mar 14, 2014)

gonewild said:


> Ratio is important when the concentration is high and reaching the 'toxic" levels.



So why the need to develop k-lite? Why not just reduce concentration?


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## Rick (Mar 14, 2014)

Stone said:


> So why the need to develop k-lite? Why not just reduce concentration?



Easily could have but no-one whats to give up their N.


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## Rick (Mar 15, 2014)

Stone said:


> Rick said:
> 
> 
> > .
> ...


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## Rick (Mar 15, 2014)

Stone said:


> Rick said:
> 
> 
> > The Wang study of K in Phals (and please spare the ''but their hybrids bred for high K'' and ''this study is flawed'' bunkum) found K/N ratios of 0.5 still showed K deficiency and I'm not surprized as stemflow is typically K/N of 1 or higher!
> ...


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## gonewild (Mar 15, 2014)

Maybe I don't understand your perspective. The ratios in the studies are clear but how do the ratios you present relate to formulating a complete fertilizer formula?



Stone said:


> Rick said:
> 
> 
> > Annual litterfall in a NG rainforest in kg/ha.
> ...


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## TyroneGenade (Mar 15, 2014)

Going back to Mulder's Chart, if you reduce K you increase Mg availability which in turn increases N availability etc... A simple dilution of a "balanced" fertilizer could be just as effective as K-light (if, as Rick points out its the K concentration that is the problem).

Again, we are blurring two separate issues: nutrient interactions and chemical toxicity. Too much K will kill you regardless of its ratio to other ions in your blood stream; but at the same time small imbalance of K relative Na will cause heart arrhythmia, muscle cramps, kidney problems etc... Same for the plants. Too much K will mess with osmolarity, ion uptake etc... which can be fatal; while an imbalance will disrupt nutrient utilization.

In this debate, I think, we have to conscious of the two separate issues we are dealing with: nutrient interactions and mineral toxicity.


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## Trithor (Mar 16, 2014)

TyroneGenade said:


> In this debate, I think, we have to conscious of the two separate issues we are dealing with: nutrient interactions and mineral toxicity.



My thinking too


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## gonewild (Mar 16, 2014)

TyroneGenade said:


> In this debate, I think, we have to conscious of the two separate issues we are dealing with: nutrient interactions and mineral toxicity.



I agree.

Nutrient interactions in that certain levels of K will inhibit other minerals.

Mineral toxicity in several concepts such as K being toxic to micro organisms that may make other nutrients available to the plant roots. So high K levels may indirectly reduce the availability of N for plants.
As well as the obesity concept that plants consume excess K and get fat....much like fast foods are bad for human health, this is toxicity....slow death.


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## Rick (Mar 16, 2014)

gonewild said:


> I agree.
> 
> Nutrient interactions in that certain levels of K will inhibit other minerals.
> 
> ...




http://www.ipipotash.org/udocs/Chap-3a_K_and_cl_in_higher_plants.pdf

Here's some lite reading on plant physiology (cellular level) as related to K interactions with other minerals. Note it's from the International Potash Assoc.


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## Rick (Mar 16, 2014)

gonewild said:


> I agree.
> 
> 
> 
> So high K levels may indirectly reduce the availability of N for plants.



Read the posted link please.

It's not a matter of "may".

K is directly competitive with NH3, Ca, Mg (all cations). 

Any impact to Nitrate (an anion) uptake is indirect.

Ammonia uptake is actually able to block K uptake (not the opposite we've been focusing on that K blocks Ca and Mg uptake).

So you can cause K deficiency with ammonium application. 

Maybe this is a reason why so many Euro slipper growers were having good results with supplementing ammonia?? (controlling K toxicity from the backside of the concentration regime?????).


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## Stone (Mar 16, 2014)

Rick said:


> > "A good balance" of Ca Mg K in soils is:
> > 60-80% Ca
> > 10-15% Mg
> > 2-5% K
> ...


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## Stone (Mar 16, 2014)

Rick said:


> Stone said:
> 
> 
> > > No the Wang study was flawed because they overdosed ammonia (one of the few things that actually controls K uptake).
> ...


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## Stone (Mar 16, 2014)

gonewild said:


> > Maybe I don't understand your perspective. The ratios in the studies are clear but how do the ratios you present relate to formulating a complete fertilizer formula
> 
> 
> 
> ...


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## Stone (Mar 16, 2014)

TyroneGenade said:


> > A simple dilution of a "balanced" fertilizer could be just as effective as K-light (if, as Rick points out its the K concentration that is the problem).
> 
> 
> 
> ...


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## Stone (Mar 16, 2014)

gonewild said:


> I agree.
> 
> 
> 
> ...


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## TyroneGenade (Mar 16, 2014)

The chemical osmotic physiology of plants and animals are identical. It is only the organs that differ. K and Na are hydroscopic salts that, if not regulated, will mess with osmosis. Once you mess with osmosis you get water balance and circulation issues. Our hearts can largely overcome some of the issues by forcing the fluid along (though our kidneys suffer greatly). Plants have a largely passive circulation system that relies on the manipulation of ions and other dissolved solutes to create pressure in one location and drive fluid movement to another.

You will have to explain why the statement is contradictory for me to reply. I see a big difference between talking about NPK balance and K concentration. It doesn't much matter how much you increase N and P to balance out the K if the K is at a toxic concentration. Alternatively, giving 1 ppm NPK every day may have no consequences compared to giving 10 ppm* NPK once a week (assuming the 10 ppm K is safe). 

I'm happy to read you at least agree that we are conflating separate issues: optimum N:K and too much K.

*Yes, I know we don't give 10 ppm NPK but I' too lazy to look up the actual values as it is irrelevant to the nature of explanation.


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## DavidCampen (Mar 16, 2014)

TyroneGenade said:


> The chemical osmotic physiology of plants and animals are identical. It is only the organs that differ. K and Na are hydroscopic salts that, if not regulated, will mess with osmosis.



K and Na are not salts but metals. Many salts of K and Na are not hygroscopic. Whether or not a substance is hygroscopic has no bearing on its effect as a solute on osmotic pressure. Your comments about osmosis have no basis in science.


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## Trithor (Mar 17, 2014)

In animals/humans, K and Na are involved in membrane stability and flux which is the basis of neural impulse transmission and muscular contraction. Sudden increase in K disrupts this, which is the reason for death/heart attack. Slow loading of a similar amount of K has no such effect as it is moved into the intra cellular space. Extended loading has a different effect and toxicity, a part of which is related to renal ion exchange. I doubt that the pathways are the same in plants, however that toxicity exists to a specific ion in most plants and animals is logical as we have all 'evolved' in a similar environmental 'soup'. Metallic ions which exist in nature in minute concentrations naturally are almost all universally toxic in raised concentrations, so we would expect disease to follow extended exposure to concentrations of more common ions which are drastically different from normal environmental concentrations that the life form has adapted to survive in.


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## Stone (Mar 17, 2014)

TyroneGenade said:


> > You will have to explain why the statement is contradictory for me to reply.
> 
> 
> 
> ...


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## naoki (Mar 17, 2014)

In addition to Poole and Sheehan (1982, I added the book name to my post in p.12), this one seems to show that not much detrimental effect of high K on Dendrobium: Determining the Nutritional Requirements for Optimizing Flowering of the Nobile Dendrobiium as a Potted Orchid. M.S. thesis by Rebecca G. Bichsel (2006) I haven't had time to read it in details, but she seems to have used up to 400ppm of K, and her data seem not to show a strong detrimental effects. Has anyone read this, and noticed if there were some issues (i.e. something which doesn't apply for hobbyist culture) with this set of experiments??? (I didn't post this originally because I wasn't sure if it was accessible from non-academic internet. Anyone should be able to access it.)


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## gonewild (Mar 17, 2014)

naoki said:


> In addition to Poole and Sheehan (1982, I added the book name to my post in p.12), this one seems to show that not much detrimental effect of high K on Dendrobium: Determining the Nutritional Requirements for Optimizing Flowering of the Nobile Dendrobiium as a Potted Orchid. M.S. thesis by Rebecca G. Bichsel (2006) I haven't had time to read it in details, but she seems to have used up to 400ppm of K, and her data seem not to show a strong detrimental effects. Has anyone read this, and noticed if there were some issues (i.e. something which doesn't apply for hobbyist culture) with this set of experiments??? (I didn't post this originally because I wasn't sure if it was accessible from non-academic internet. Anyone should be able to access it.)



I can't access the book. But most likely the difference between her trials and "hobbyist culture" is *time*. Her trial where she used 400ppm K with no detrimental effect may have lasted only one year. In one year you would not likely see any negative effect from excess K depending on the frequency of application. However in hobbyist culture where plants are to be grown for a "lifetime" the accumulative effect of excess K manifests itself as poor plant health and reduced vigor. Data from short scientific trials does not apply well to long term culture.

Aside from my comment above, in the trial you reference D.nobile was used as the subject and since it is a deciduous species how it handles excess K can not be applied to the majority of orchids in a hobbyist collection.


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## gonewild (Mar 17, 2014)

Rick said:


> Read the posted link please.
> 
> It's not a matter of "may".



Reading it now...slowly!

I used "may" to be polite, but it did not help.


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## Ray (Mar 17, 2014)

Stone said:


> TyroneGenade said:
> 
> 
> > If as Rick points out K concentration (in general ''balanced'' fertilizers) is the problem then a simple dilution of a ''balanced fertilizer'' could NOT be just as effective as k-lite. You would be diluting all other nutrients thereby reducing what is available to the plant.
> ...


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## TyroneGenade (Mar 17, 2014)

DavidCampen said:


> K and Na are not salts but metals. Many salts of K and Na are not hygroscopic. Whether or not a substance is hygroscopic has no bearing on its effect as a solute on osmotic pressure. Your comments about osmosis have no basis in science.



I concede that hydroscopy has nothing to do with calculating osmolarity. My point was that water follows Na and K ions. It will even happily descend out of the atmosphere to join the salt in your salt shaker.

See http://www.chem.purdue.edu/gchelp/howtosolveit/Solutions/osmoticpressure.html for the equation to calculate osmotic pressure. Notice the M for molar concentration of dissolved species. K+ and Na+ concentrations affect osmotic pressure. You are also going to start messing with membrane potentials and the ability of cells to move ions across their membranes.

Thank you Trithor the medical reply on Na+/K+ ion physiology. Plants maintain their turgor using K ions to move water around. See http://www.jstor.org/stable/56098 for an little article on how K concentrations are used to manipulate the flow of sap. Now what do you suppose would happen if the salts built up in the substrate and prevented the movement of water into the xylem? Will the plant be able to move water into the phloem with all that K stuck in its tissues? Yes, it could pump out the sugars and drag the water out of its cells that way but that would mean an increase in tissue salinity that would mess with protein function and kill the cell. I think we've had the discussion of K accumulating in the substrate before (several times)...

So we are all on the same page (from Webster's dictionary): toxic, containing or being poisonous material especially when capable of causing death or serious debilitation. Poison, a substance that can cause people or animals to die or to become very sick if it gets into their bodies especially by being swallowed. Too much salt will kill, ergo it is acting as a poison and is toxic.

Going back to Mulder's chart. If you decrease, for instance K, then Mg becomes more available and it acts synergistically with N. This means that you can drop the concentration of N if Mg is more available to help with its uptake. If the absolute concentration of K is the problem, causing toxicity, then by simply diluting high K fertilizers to safe K levels you can avoid the toxicity issues while promoting Mg uptake which will then increase N uptake.

Going back the articles that started this thread, note that N is very low in that rain water. N as nitrates and ammonia is, generally, very low in the environment. We don't need to give our plants massive amounts of N in the fertilizer. In the wide world outside of agriculture N is rarely a fraction of 10 ppm. (One of the greatest mysteries in the plant aquarium world is why we need to 10 ppm nitrate in our tanks to grow plants while you won't find even 0.1 ppm in rivers with luxuriant plant growth.) Simple dilution of the fertilizer may be all that is needed to avoid toxic K issues. We already accept this when we suggest to growers that they use commercial fertilizers as half and quarter strengths. What is more, when we suggest they fertilize weekly weakly (or is it weakly weekly?) we are buying into the idea that our fertilizers are too strong and we can get away with less. 

A few years ago a commercial grower spoke at the Cape Orchid Society about his Cymbidiums (heavy feeders, as we all know). He was fertilizing 1/10th daily (1/10 of already 1/2 so 1/20th) and was getting Cymbidiums from seedlings to flowering size in 2-3 years. His chief gripe was that he was getting a lot of fertilizer burn at the leaf tips. Bloody efficient things these Cyms...

We all already accept that our fertilizers are too concentrated and orchids need weaker feeding. All we are now doing is arguing which is the biggest factor of the fertilizer problem: too much K or a lack of something else. I think the data is now pretty clear that the issue is too much K.

tt4n


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## DavidCampen (Mar 17, 2014)

TyroneGenade said:


> I concede that hydroscopy has nothing to do with calculating osmolarity. My point was that water follows Na and K ions. It will even happily descend out of the atmosphere to join the salt in your salt shaker.
> 
> See http://www.chem.purdue.edu/gchelp/howtosolveit/Solutions/osmoticpressure.html for the equation to calculate osmotic pressure. Notice the M for molar concentration of dissolved species. K+ and Na+ concentrations affect osmotic pressure. You are also going to start messing with membrane potentials and the ability of cells to move ions across their membranes.
> 
> tt4n


You had no point. Your words were complete nonsense. Water also follows (your terminology) Ca, Mg and NH4 ions; so what? And, your word "hydroscopy", if it is even a word, has nothing to do with hygroscopicity which is perhaps the word that you were trying to use.


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## Rick (Mar 17, 2014)

naoki said:


> this one seems to show that not much detrimental effect of high K on Dendrobium: Determining the Nutritional Requirements for Optimizing Flowering of the Nobile Dendrobiium as a Potted Orchid. M.S. thesis by Rebecca G. Bichsel (2006) I haven't had time to read it in details, but she seems to have used up to 400ppm of K, and her data seem not to show a strong detrimental effects. Has anyone read this, and noticed if there were some issues (i.e. something which doesn't apply for hobbyist culture) with this set of experiments???




Naoki

The actual rate of application (as per figuring the dose exposure) is difficult to understand. 

Yes 0, 50,100,200 400ppm. I can deduce that the total duration of exposure to any regime is only 6,7,8 months. These are not hydoponic application but cannot determine the frequency of application (daily weekly monthly??) Only that at any given time 100 to 150 ml of nutrient solution was applied to the pot. The potting mix seems fairly open, so I would suspect they may have watered once or twice a week, but can't tell how much actually stayed in the pot.

Table 16 has the primary data of interest. For one thing nothing died (including the 0ppm application). 

Everything made it to flowering the following year (at least 4 months after termination of fert application).

Most of the metrics show that the plants maxed out by 100 ppm K (no benefits beyond that). Although the chlorophyl content parameter was significantly better for the 0ppm K application while all other doses were about the same from 50 to 400 ppm.

So no acute toxicity effects after 6-8 months of unknown application frequency (although I suspect at least weekly) at concentrations through 400 ppm. But growth leveled out after 100 ppm.

Also ratio of NH4:NO3 varied with the K exposures, but even at the extremes there was still alot more NH4 entered into the system than you would ever get in MSU RO version. That could cause K deficiency at low concentrations N and offer protection from high K concentrations in these short term experiments.


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## eteson (Mar 17, 2014)

IMO one of the easiest ways to prove detrimental effects of K is using in-vitro plants.
Is is quite easy to make a "standard" media and add the desired amount of Potassium Nitrate. (4 or 5 different concentrations).

I can add this test to the experiments already running.


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## Stone (Mar 17, 2014)

eteson said:


> IMO one of the easiest ways to prove detrimental effects of K is using in-vitro plants.
> Is is quite easy to make a "standard" media and add the desired amount of Potassium Nitrate. (4 or 5 different concentrations).
> 
> I can add this test to the experiments already running.



I think that could be very instructive eteson! :clap: Anything which adds to our knowledge is very desirable.


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## naoki (Mar 17, 2014)

Rick and Lance, you are right, those horticulture oriented papers use short-term experiments. But these do show that acute toxicity of K is rather rare even at the super-high K.

I thought the K-toxicity is mostly based on the correlation between cellular content of K vs Mg and Ca. This is well known (and in the Potash chapter Rick put the link), but is there a demonstration that this causes detrimental effects in a long term? We may have discussed it in the past (but there are too much stuff, and I can't remember everything). The shift in cellular content could be an adaptive response. Also plants have good buffering capacity (especially epiphytes), so the lower Mg and Ca might be within the range, and you may not get any phenotypic effects.

Mineral components in tissue seems to change drastically with age (e.g. more Ca in the older growth). This probably represents the change in the functionality (sexual reproduction for newer growth vs supporting the newer growth for older growth). K is a unique mineral because the majority of the molecules are not bound to a larger molecule in plants. So it is highly mobile. Mike's original papers show that canopy plants can easily get rid of K if they want to (really high enrichment of K in through fall). So I'm still puzzling about the actual mechanism how K might cause a long term "toxicity" (this topic is interesting because nobody knows the answer yet).

Eliseo's experiment would be interesting, but again, wouldn't you say that it is about the short-term effects? One issues is that the physiology of adult orchids are quite different from seedlings in flasks (e.g.,. it's shown that even the preference for NH4:NO3 can change).


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## Stone (Mar 17, 2014)

naoki said:


> Eliseo's experiment would be interesting, but again, wouldn't you say that it is about the short-term effects? One issues is that the physiology of adult orchids are quite different from seedlings in flasks (e.g.,. it's shown that even the preference for NH4:NO3 can change).



It should at least show us if high K relative to Ca and Mg reduces growth response in the seedlings compared to controls. Or alternatively, if low K concentrations increase it. I have doubts as whether the age of an orchid would drastically change any findings. However it is possible. Baby orchids do rely on mycorrhiza in the habitat for their nutrition which may differ in the P and N etc. available however older plants are less tied to this association.

It would also be interesting if we could compare epiphyte with terrestrial or at least bark epiphyte with humus grower such as Phrag or Paph or Masdevallia and Oncidium or Cattleya etc. as there does seem to be a small (probably insignificant) difference in the element ratios. Elisio??


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## Rick (Mar 17, 2014)

naoki said:


> Rick and Lance, you are right, those horticulture oriented papers use short-term experiments. But these do show that acute toxicity of K is rather rare even at the super-high K.



Not necessarily Naoki.

1) There is no 000 control, all the single 0 additions still have lots of the other 2 added. The absolute worst looking plant (closest to death) is 0 N, but 250ppm K and 200 ppm P. The 0 ppm K or 0 ppm P plants are way better looking than that 0N plant.

2) total mineral application of even the "control plants is XXX higher than we ever feed anyway.

3) even the lowest application of the target nutrient is still XXX more than environmentally relevant.

4) without tissue analysis all of the observed effects of what is deficient or excess are assumptions. Does the 0 ppm N plant look so crappy from N deficiency, K overdose, Ca or Mg deficiency form excess K uptake. No tissue concentrations were measured so the effects are all speculative.

Given the magnitude of the concentrations used in this paper (or the Wang papers) are really studies on the antagonistic interaction effects of NPK.

I'm not aware of any published truly controlled GH study with orchids working with either acute or chronic effects of NPK with environmentally relevant concentrations. 

That's were looking to mother nature is our last resort for useful info. We know that beautiful healthy orchids grow just fine in the jungle with total (N+P+K+Ca+Mg) ppm of nutrient at < 50ppm. Which makes these optimization studies so crazy when they say things like " a minimum of 50 ppm K is needed to grow orchids", base on a result where the 0 K is receiving 100ppm N and 250ppm P.


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## Rick (Mar 17, 2014)

naoki said:


> Mike's original papers show that canopy plants can easily get rid of K if they want to (really high enrichment of K in through fall). So I'm still puzzling about the actual mechanism how K might cause a long term "toxicity" (this topic is interesting because nobody knows the answer yet).



Actually there is nothing in Mikes original paper that suggests a voluntary release of K from living tissue. And when you divide out for hectares and years, "massive amounts of K" is certainly not the reality of what's getting shifted around. The moss/lichen paper that I linked (which is forest data from one of the same (Southern China) locations as Mikes throughfall paper indicates that the increase in throughfall K is from the leaching of decomposing/degrading materials in the canopy. The papers I attached years ago on bromilead K uptake and the Zotz paper on leaf senescence (actually linked by Mike 2 years ago) show that epiphytes have no brakes on taking up K, and do everything they can to retain it during growth.

There seems to be adequate literature for crop plants that excess K causes detrimental effects due to calcium and magnesium deprivation. You could look at the rice or alfalfa literature for that.


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## Rick (Mar 17, 2014)

naoki said:


> The shift in cellular content could be an adaptive response.



Yes it is well known that luxury storage of K occurs in plants as an adaptive response to living in environments where K is rare.


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## Rick (Mar 17, 2014)

naoki said:


> Mineral components in tissue seems to change drastically with age (e.g. more Ca in the older growth).



I have not seen this demonstrated for plants where K is kept high during the entire growth cycle.

I have seen this for conditions where K is pulsed initially or allowed to decline after a single large application. But K is highly mobile in live leaf tissue at all times. Ca is not readily moved around . So as long as K is high its not going to allow Ca or Mg to build into mature leaves. (That Poole and Seeley study certainly did not show increasing Ca/Mg in mature leaves).


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## Rick (Mar 17, 2014)

naoki said:


> So I'm still puzzling about the actual mechanism how K might cause a long term "toxicity" (this topic is interesting because nobody knows the answer yet).



Nobody knows the mechanism or the symptoms?

What is your definition of long term "toxicity"?

Scroll down to the symptoms of deficiency and excess. Naoki this is old school. 

http://www.ladyslipper.com/minnut.htm


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## Stone (Mar 18, 2014)

TyroneGenade said:


> QUOTE] I think the data is now pretty clear that the issue is too much K.




How could you possibly say that?

Where is it clear that the ''issue'' (and I don't even see the issue) is too much K??
Is the issue that orchids are stunted/dying/have poor roots/suffer from bacterial rots/suffer from insect attack/grow well for a while then collapse/don't do as well/don't grow as fast?

Forget about your data its just confusing you. With everything that has been said, there is still no proof that standard K formulations are any less beneficial than very low K ones. There is however vast amounts of proof that orchids can grow perfectly well WITH standard K formulations.

I can attribute all the above problems on bad culture. Too much watering, not enough water, too hot, too cold, not enough air, too much humidity, not enough humidity, feeding too much, feeding to little, ( yes that happens more often than you might think)! etc. etc. How do I know that these were the shortcomings?, because I have fixed all of them without reducing K. Ask any one who has grown orchids for 30 years or so and they will tell you the same thing.

Our club's best grower has won orchid species of the year (culture and quality) with Phrags, Paphs and others 3 or 4 times State wide. He uses an off the shelf fertilizer with high K.

And you say its pretty clear too much K is the issue? Show me the proof please!

As I have said, all the evidence points to the important factor being to determine any given species' tolerence to salinity. This varies greatly among different spp. eg. a twig epiphyte that relys mainly on tiny amounts of nutrients arriving in the mist and rain (no throughfall at all in some cases) to a huge Vanda on a tree trunk that can suck up everything which comes its way and do all the better for it. The ratios of elements changes very little.

I am willing to concede that some spp. which grow on limestone and have sparse tree cover may have evolved with less K in circulation and may perform better in cultivation with less. (Again no proof) An example might be the coastal Brachys?? But a quick look at Tanakas web sight tells you they can do extremely well with 30 30 30 spring summer and 10 30 30 fall.
He has plants in the same pot for 10 years with no loss of leaves. Is that long term enough for you?

So show me now where it is clear.

All this talk about osmotic pressure and plant physiology mechanisms is absolute nonsense. Stop over analysing and just talk to a good grower for your answers.


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## naoki (Mar 18, 2014)

Thanks for the additional comments, Rick!



Rick said:


> 1) There is no 000 control, all the single 0 additions still have lots of the other 2 added. The absolute worst looking plant (closest to death) is 0 N, but 250ppm K and 200 ppm P. The 0 ppm K or 0 ppm P plants are way better looking than that 0N plant.
> 
> 2) total mineral application of even the "control plants is XXX higher than we ever feed anyway.
> 
> ...



OK, you are right, it's not complete factorial desing, and they didn't have no fertilization treatment. However, from the pattern you see, it is difficult to see any detrimental effects, though. 100ppm K was better than 0 ppm K, then it reaches saturation above 100ppm K, but it is still a monotonic response (not a humped response). If there is a toxic effects, don't you expect that one of the higher ppm should show lower growth than the lower ppm K?

As a related note, this paper has tissue analysis of 0-fertilizer treatment vs reasonable fertilization (which would be probably super high-K in your definition). There are quite a few interesting points in this paper.

http://www.redalyc.org/pdf/1802/180215650014.pdf

It's not designed to test the proportion of fertilizer. In the normal fertilization (I wasn't sure about the exact dosage, maybe 100 total ppm for inorganic ones?, but I'm calling this "high-K" treatment), leaf K was pretty normal (not off the scale compared to no fertilizer), Ca is also within the range, Mg was a bit low. In no fertilizer treatment, it looks like there are some deprivation (or deficiency). Maybe you can interpret this better than me, though. Ca deficiency can be seen within the time of experiment.

I came across this paper when Mike was talking about organic-N vs NO3 vs NH4.



Rick said:


> I'm not aware of any published truly controlled GH study with orchids working with either acute or chronic effects of NPK with environmentally relevant concentrations.
> 
> That's were looking to mother nature is our last resort for useful info. We know that beautiful healthy orchids grow just fine in the jungle with total (N+P+K+Ca+Mg) ppm of nutrient at < 50ppm. Which makes these optimization studies so crazy when they say things like " a minimum of 50 ppm K is needed to grow orchids", base on a result where the 0 K is receiving 100ppm N and 250ppm P.



Well, you are right, they are optimizing for quick growth, more and larger flowers. These may not be the optimization for us hobbyists, which you have been pointing out, and I agree with you. We may prefer very slow growth like in nature, but lower death rate. Low rate of fertilization (and nutrident deprivation) increase root:shoot ratio (Rodriguez et al. 2010 has some data), and this could be good for long term survival for our plants in artificial environment.



Rick said:


> The moss/lichen paper that I linked (which is forest data from one of the same (Southern China) locations as Mikes throughfall paper indicates that the increase in throughfall K is from the leaching of decomposing/degrading materials in the canopy.



Oh, OK, I don't know well about nutrient cycling in ecosystem (other than N & P).



Rick said:


> The papers I attached years ago on bromilead K uptake and the Zotz paper on leaf senescence (actually linked by Mike 2 years ago) show that epiphytes have no brakes on taking up K, and do everything they can to retain it during growth.



I think Poole and Sheehan's review also mentions it, but they seem to think orchids takes up Ca and Mg similarly (no mention of detrimental effect of accumulation, though).

Quotes from p.206:
"Cattleya and other genera were shown to absorb relatively high levels of K, Ca, Mg and several of the microelements (especially Mn, in older leaves). However, there is little evidence to date which indicates that the plants (1) require high levels of these elements, (2) utilize these nutrients rather than accumulating them, or (3) benefit (in terms of survival) from these levels. In fact, analyses of upper (acropetal) leaves and lower (basipetal) halves of one- and two-year-old Cattleya leaves of plants grown under poor fertilization practices in a fir-bark medium (Poole and Sheehan 1973b) indicate that at least Ca, Mg, and Mn are preferentially translocated to the upper halves of older leaves and accumulated. This physiological response may be necessary to reduce nutrient antagnosims or imbalances in the younger and meristematic tissues. Plants in this study exhibited severe chlorosis in the upper halves of two-year old and older leaves but only slight signs in the lower halves. The leaves could possibly be showing symptoms of K deficiency caused by low K levels coupled with relatively high concentrations of Ca and Mg, especially in the upper half of the leaf. The one year old leaves were a pale but acceptable green color...."



Rick said:


> There seems to be adequate literature for crop plants that excess K causes detrimental effects due to calcium and magnesium deprivation. You could look at the rice or alfalfa literature for that.



Yes, but these are the case with extremely high level of K, right? Even though the orchids are tolerant (slow to respond, or buffered well) against nutrient deficiency, don't you expect to see Ca, Mg deficiency in those studies which uses unreasonably high amount of K? For example, Ca deficiency can be seen within 18mo of studies (with Peter's fertilizer).




Rick said:


> I have seen this for conditions where K is pulsed initially or allowed to decline after a single large application. But K is highly mobile in live leaf tissue at all times. Ca is not readily moved around . So as long as K is high its not going to allow Ca or Mg to build into mature leaves. (That Poole and Seeley study certainly did not show increasing Ca/Mg in mature leaves).



Ca not phloem-mobile is something what I have been taught, too. But see the quotes above. Epiphytes might have slightly different mechanisms to enhance their nutrient efficiency. In both Catt and Phal, data suggested Ca could be mobile. 

Quote from p.205 of PS review:
"Poole and Sheehan (1973, 1974) indicate that both Ca and Mn are preferentially translocated to and accumulated in mature leaves..." 
So tissue analysis shows higher concentration of Ca and Mg and lower concentration of N and K in older leaves than in younger leaves. Poole and Sheehan (1974) showed similar pattern in Phal leaves (p.208 and Table 6-9 of PS review). Also in the same page, a interesting quote here: "The researchers were unable to obtain a growth response with increased levels of K, and it seems therefore that Phalaenopsis can accumulate a large amount of K in the leaves in apparent "luxury consumption"". So a small amount of K is good enough for Phals, but they didn't note the detrimental effect of K, neither.



Rick said:


> Nobody knows the mechanism or the symptoms?
> 
> What is your definition of long term "toxicity"?
> 
> ...



Rick, I'm not talking about the symptom of deficiency. At the physiological and cellular level, what processes explain what you consider to be working under K-lite principle. I think you are proposing that the long-term benefit of K-lite is higher Ca/Mg concentration in the cells. I think I might not be using the terminology correctly in the field of toxicology. But for a given growth index (coming up with this can be a challenge, but let's say survival rate), I would define that toxicity as the lower growth index with increase in K. Obviously, "toxicity" is influenced by other nutritional conditions, environments, genetics etc. But for a given whatever condition, can we really see reduced growth with increased K concentration. I'm sure we'll gradually understand the complex dynamics of epiphyte nutrition in the future.

I didn't mean to write a long essay reply, and I don't feel like proof-reading it now... (so sorry, if the post doesn't make any sense...)


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## Stone (Mar 18, 2014)

naoki said:


> > We may prefer very slow growth like in nature, but lower death rate
> 
> 
> Interesting stuff naoki but I'll just make a note that orchids don't grow slowly in nature. Many Paphs mature a new growth every year. Even emersonii according to Xavier. I'm feeding the hell out of my Phal schilleriana and although its very healthy it is still slow compared to what I would expect in the habitat. Maybe not hot enough??


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## naoki (Mar 18, 2014)

Stone said:


> naoki said:
> 
> 
> > Interesting stuff naoki but I'll just make a note that orchids don't grow slowly in nature. Many Paphs mature a new growth every year. Even emersonii according to Xavier. I'm feeding the hell out of my Phal schilleriana and although its very healthy it is still slow compared to what I would expect in the habitat. Maybe not hot enough??
> ...


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## gonewild (Mar 18, 2014)

Stone said:


> naoki said:
> 
> 
> > I'm feeding the hell out of my Phal schilleriana and although its very healthy it is still slow compared to what I would expect in the habitat. Maybe not hot enough??
> ...


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## DavidCampen (Mar 18, 2014)

Rick said:


> There seems to be adequate literature for crop plants that excess K causes detrimental effects due to calcium and magnesium deprivation. You could look at the rice or alfalfa literature for that.


The only paper that you have cited in this regard, IIRC, demonstrated that rice plants grown hydroponically with KCL concentrations in excess of 1000 ppm did poorly. How do you extrapolate this as evidence that K ion concentrations of 10 ppm are toxic to orchids? From the paper that you cited, it wasn't even clear if this was due to K ion toxicity or chloride toxicity.


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## DavidCampen (Mar 18, 2014)

Rick said:


> The paper ... I attached years ago on bromilead K uptake ... show that epiphytes have no brakes on taking up K


No, that paper shows exactly the opposite. Look at figure 2. The rubidium uptake rate does not change, does not increase, over a 2 order of magnitude change in the rubidium concentration. From a change in rubidium concentration equivalent to 8 ppm potassium to 800 ppm potassium the rate of rubidium uptake does not increase at all.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2924823/


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## gonewild (Mar 18, 2014)

Excess potassium...
http://eprints.nwisrl.ars.usda.gov/917/1/652.pdf


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## limuhead (Mar 18, 2014)

gonewild said:


> Excess potassium...
> http://eprints.nwisrl.ars.usda.gov/917/1/652.pdf



The hypotheses at the end of the report indicate that the sources of the high K are due to natural sources in the soil. Not to sound like an idiot, but what does this have to do with the thread? I was under the impression that this was a post about 'Substantial K in Rainforest Through Fall'. I have followed the High K debate for a while. Seems to me more of a debate about the sake of debating; not conclusive to either side. That's just my opinion though...


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## gonewild (Mar 18, 2014)

limuhead said:


> The hypotheses at the end of the report indicate that the sources of the high K are due to natural sources in the soil. Not to sound like an idiot, but what does this have to do with the thread? I was under the impression that this was a post about 'Substantial K in Rainforest Through Fall'. I have followed the High K debate for a while. Seems to me more of a debate about the sake of debating; not conclusive to either side. That's just my opinion though...



Because there is very little data (none) published about excess potassium and it's toxicity I posted this link to show that in some plants some research has shown plants are sensitive to excess K. How this relates to orchids, who knows but it is a data source. Some debaters here feel all plants are equal in how their nutrient uptake is achieved (not me) so using data from farm land in Idaho may be just as accurate as using rainfall in China to determine the potassium reaction by orchids that don't grow in either place. 

The report illustrates that the high excess K reduces the growth, and yes at very high ppms. We don't know at what level K becomes a "toxic" nutrient for orchids but it does at some level. And now with the majority of growers reporting improved growth using the low K formula fertilizer we can consider that perhaps orchids really don't like or need muck K in their diet.

Besides it's raining hard outside and I had time to google and I read that so I posted the link.


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## naoki (Mar 18, 2014)

DavidCampen said:


> No, that paper shows exactly the opposite. Look at figure 2. The rubidium uptake rate does not change, does not increase, over a 2 order of magnitude change in the rubidium concentration. From a change in rubidium concentration equivalent to 8 ppm potassium to 800 ppm potassium the rate of rubidium uptake does not increase at all.
> 
> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2924823/



But the x-axis is the external concentration, right? So this seems to be showing that ion-transoport channel saturate event thought the concentration is high. Plants are still taking up at the maximum possible rate. But this made me think that the data is probably not saying what Rick said: "No break to K uptake". To test the break part, I would say that you have to compare the internal concentration vs uptake rate. In other words, you saturate the plant with K for a month or so, then see if the uptake rate become slower or not. But the paper does show amazing uptake capacity of epiphytes.


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## Ray (Mar 18, 2014)

limuhead said:


> The hypotheses at the end of the report indicate that the sources of the high K are due to natural sources in the soil. Not to sound like an idiot, but what does this have to do with the thread? I was under the impression that this was a post about 'Substantial K in Rainforest Through Fall'.


Aw c'mon. You're smarter than that!

It is apparently relevant because the rainfall is SO heavy that it - and the minerals in the soil - splash all the way up to the tops of the trees!


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## naoki (Mar 18, 2014)

Well, unlike Mike, I still think that there is something going on with K-lite because quite a lot of people show good results. But the reason for the success might be different from K vs Ca/Mg. So I thought that nutrient-driven morphogenesis could be the part of the reason. This may be a bit interesting with this regard:
http://jxb.oxfordjournals.org/content/47/Special_Issue/1255.full.pdf

N,P deficiency usually increase Root:shoot (R:S) ratio (more allocation toward root). Similar to how auxin addition may work. However, I didn't know that K or Mg deficiency has the opposite consequence: lower R:S ratio. This is because K (and Mg) is required to transport photosynthates to root, so deficiency cause the accumulation of sugar in the leaves.

Several literature indicate that orchids don't need lots of K (i.e. they observe no benefit of additional K, and K in the media is enough). This matches with people's observation here (orchids don't show K deficiency with K-lite). So K-lite could be as good as the conventional high-K.

But could slight deprivation of P in K-lite is the reason of improvement? Similar to auxin products, low P might be causing the vigorous root growth (without causing too much negative effect), which eventually lead to more vigorous plants. One of the big difference between nature and potted culture is the root space (well the crack dweller may be a different story). Also phosphorous controls mycorrhizae association (no association with high P). It's shown that mycorrhizae can be associated with potted plants (I learned this from ST discussion, and saw it in some papers). It is pretty speculative, but Rick's plants are amazing, and there has to be a reason of K-lite advantage (in addition to Rick's culture skill), and I'm trying to think alternative explanation.


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## Stone (Mar 20, 2014)

naoki said:


> > Well, unlike Mike, I still think that there is something going on with K-lite because quite a lot of people show good results.
> 
> 
> No one but Rick has shown good results. (some very nice mastersianums spring to mind) But I'm sure other good growers (probably not many) around the world are growing equally good mastersianums without k-lite. This would automatically negate Rick's claim that success was due to K-like and probably more to good general culture wouldn't it? All others have written short anecdotes saying similar things. Not exactly compelling evidence just yet. The difference between k-lite and high k ferts over several years is probably so small as to be almost impossible to detect without strictly controled, sided by side trials over a long period of time. So.......Don't worry.. be happy!


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## gonewild (Mar 20, 2014)

Stone said:


> No one but Rick has shown good results.



Do you read SlipperTalk?


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## Ray (Mar 20, 2014)

Stone said:


> No one but Rick has shown good results.


 I am now 29 months into the exclusive use of K-Lite, and I am thrilled with the results - I am seeing a lot of active growth and more blooming that I've seen in a while.

And not just paphs.


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## Stone (Mar 20, 2014)

gonewild said:


> Do you read SlipperTalk?



Shown!!


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## Rick (Mar 20, 2014)

Stone said:


> No one but Rick has shown good results. (



http://www.slippertalk.com/forum/showthread.php?t=32365

I guess you missed this. But seems like at least 175 folks are giving it a try.

I know of a few dozen others that make their own version too. Emydura, Paul, Ed M. Lots of folks in my society that don't get on ST

But I guess you don't like SlipperKings plants, or Dot's, or Chicago Chad's (his first CCE on a Klite grown Pleuro species), or that Fumi's Delight of Tom Kalina....
http://www.slippertalk.com/forum/showthread.php?t=31946&page=2

How bout those walls of paphs grown on calcium nitrate (no K supplementation at all) I think that was in India.

Big specimen plants are not limited to those who hog out on K.


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## Stone (Mar 21, 2014)

Rick said:


> [QUOTE]I guess you missed this. ...ge to using it. I believe some already have??


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## Ray (Mar 21, 2014)

Stone said:


> An unfair comment. I like any well grown orchid. and aren't FCCs given for flower quality?


Come on, Mike. Are you likely to get an award quality flower out of a poorly grown plant?

OK. Enough of this BS.

The fact is that VERY little is known about plant nutrition, including that related to valuable food crops, for which a great deal of study has been done. Everything we are discussing here is speculation, as we have not been able to do the extensive testing required to actually prove anything.


Are my plants doing better since moving to K-Lite? It appears so to me, but I have no scientific proof that it's the case.
Is it possible that my plants are doing better *despite* my use of K-Lite? Not likely, as I find it hard to accept that there would be an improvement upon a change to something less beneficial.
Is it possible that something else is the reason for my perceived improvement? Of course, but I'll be damned if I can figure out what that might be, as I have tried to keep the rest of my culture pretty constant.
I have a lot of respect for (most of) the participants here, but it seems to me that there is a great deal of debate-for-debate's-sake going on, rather than an exposition of fact.


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## Rick (Mar 21, 2014)

Stone said:


> Rick said:
> 
> 
> > An unfair comment. I like any w... Chad's post since it was a CCE and not a FCC


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## Rick (Mar 21, 2014)

Ray said:


> The fact is that VERY little is known about plant nutrition, including that related to valuable food crops, for which a great deal of study has been done.



Orchid nutrition is in its infancy, but probably a lot better in the commercial crop areana than we are aware.

http://www.clemson.edu/sera6/scsb394notoc.pdf

Here's a good size list of nutrient leaf tissue concentrations for crops (including nut trees and ornamentals), calibrated for "sufficiency ranges". And yes "excesses" beyond the sufficiency range have been called toxicity effects (see Figure 2 on document page 2).

You all will have to make your own decisions as to whether you think orchids are more like cantaloupe , poinsettia, pecan trees, blueberries, or fraiser fir (no orchids in this list). Also in other searchs I do have "excessive or toxic" leaf tissue concentrations for a handful of the species listed.

I would also not make the assumption that hybrid phals would be in the same range of effects as Paph emersonii, or Dendrobium cuthbertsonii .

Also its apparent from the agri research out there, that feeding schedules are manipulated by application of individual constituents (not by generic application of a balanced NPK comercial feed) to navigate crops through within these tissue concentration boundaries.


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## Rick (Mar 21, 2014)

If you take the time and actully table the values across all the different crop species.

The bulk of Panamanian epiphytic orchids in the Zotz paper are in the K deficient range for most crops (except blueberries and christmas trees).

The Phalaenopsis tissue K (exposed to 100 - 300ppm K) in the Poole and Seeley (Cornell study) are only matched by things like cantaloupe and bellpepers. Corn would actually be pretty much stopped in its tracks at the K found in those Phalae leaves.:wink:


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## Stone (Mar 21, 2014)

Ray said:


> > Everything we are discussing here is speculation, as we have not been able to do the extensive testing required to actually prove anything.
> 
> 
> I try to do as little speculation as possible although sometimes a little imagination is required due to lack of relavent data. Most of my comments however are based on reality. ie: what I actually see with my own eyes (how my and others' orchids respond to various nutrient formulations). All the material from the other (your side) is based on speculation as everything presented so far can be explained away using the reality checks mentioned above. You don't seem to mind selling a product based on the very speculation you mention. This is absolutely fine with me but, at this time, I think it is possibly misleading to suggest to people on this and other forums that lowering K such as in k-lite will solve their growing problems.


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## DavidCampen (Mar 21, 2014)

Stone said:


> I try to do as little speculation as possible although sometimes a little imagination is required due to lack of relevant data. Most of my comments however are based on reality. ie: what I actually see with my own eyes (how my and others' orchids respond to various nutrient formulations). All the material from the other (your side) is based on speculation as everything presented so far can be explained away using the reality checks mentioned above. You don't seem to mind selling a product based on the very speculation you mention. This is absolutely fine with me but, at this time, I think it is possibly misleading to suggest to people on this and other forums that lowering K such as in k-lite will solve their growing problems.


I agree.


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## SlipperFan (Mar 22, 2014)

Maybe not "solve" -- but K-lite is helping with a couple of mine. It can't be a coincidence because nothing else is changed.


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## Ray (Mar 22, 2014)

Stone said:


> Ray said:
> 
> 
> > I try to do as little speculation as possible although sometimes a little imagination is required due to lack of relavent data. Most of my comments however are based on reality. ie: what I actually see with my own eyes (how my and others' orchids respond to various nutrient formulations). All the material from the other (your side) is based on speculation as everything presented so far can be explained away using the reality checks mentioned above. You don't seem to mind selling a product based on the very speculation you mention. This is absolutely fine with me but, at this time, I think it is possibly misleading to suggest to people on this and other forums that lowering K such as in k-lite will solve their growing problems.
> ...


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## Trithor (Mar 22, 2014)

You lot have been busy! I can't say that much progress has been made though. Apart from a few testy remarks I think everyone has been playing very nicely. Both sides are to be admired for their ongoing commitment to the discussion (sometimes argument). I must point out though that there are positive results with both types of feed (just going through the posts and looking at the well grown plants, there are positives with both types of feed). I am not sure where flower quality comes into the discussion, as no amount of good growing will get a mediocre quality plant to garner an award of quality. 
I am trying both types of feed and still am unsure of the results. What I am sure of though, is that I have seen a dramatic improvement with a reduced concentration of fertilizer applied on a more regular basis rather than with higher concentrations less regularly. I am sure that there are a host of things which I can improve in my culture, without having to look at the actual fertilizer to improve my growing. Having said that, I as with most growers, would be happy if you guys could just point me in the direction of the miracle solution when you find it. In the interim, I will battle along with my mediocre culture and read this discussion with keen interest.


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## Stone (Mar 23, 2014)

Ray said:


> Stone said:
> 
> 
> > > Let's not be personally insulting here.
> ...


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## Stone (Mar 23, 2014)

Trithor said:


> ,
> 
> 
> > I as with most growers, would be happy if you guys could just point me in the direction of the miracle solution when you find it.
> ...


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## Trithor (Mar 23, 2014)

Thanks Mike, up until a year ago I was a very casual feeder, never paid much attention to what I was feeding them, or how often for that matter. My plants all seemed to grow OK, with the only problem being when my fertigator malfunctioned and for about 3 months I was feeding at about 8x the recommended strength for tomatoes (that was a near disaster, and most of my plants still carry the scars from that maltreatment a year later)
After joining ST I became a lot more critical of what they get as fertilizer, and I read all of these k-lite/MSU debates with keen interest. Not knowing enough about plant nutrition, I don't lean to either philosophy as of yet, and as mentioned elsewhere am still busy feeding my main greenhouse with both types in the hope of seeing a marked difference. Unfortunately (or fortunately, I suppose that depends on your outlook) up till now there is no discernable difference between the two sides. I am acutely aware however that there are major differences to be achieved by improving my culture first. Although I have been growing for a few decades, there is still a lot I need to learn. Some things I am aware of, but am slow to implement the changes that would improve the culture. I firmly believe that in our climate (and probably every climate around the world) that GH volume is more important that GH size, ie a high roof is beneficial, and the higher the better. The greater the volume, the more the environment is stabilized and culturural inaccuracies are smoothed over. I know that I need to improve temperature control and air circulation, and I probably need to get rid of my Gouldians (the little buggers go through flower bud destructive phases). One of the best changes that I have made is to reduce the feed concentrations and apply more often on a more regular basis, ..... Now for the miracle formulation, that I will leave up to the experts to work out (one thing I do believe is that plants and animals have developed/evolved to grow at their best in the wild in the niche that they occupy (not talking about artificial greenhouse culture), or else they would not be growing there in the first place, but somewhere else. Anyone that has collected will tell you that they occure in very narrow/specific localities on the whole, with the exceptions being those species that we call 'easy', which occure in bigger colonies with a broader niche. I believe this debate will continue until we are able to identify what is in each species environmental niche and available to those plants directly and from the association with lichens, mosses and fungi. In the interim, I suppose we can tweak our plants feeding in order to attempt to optimize their growth, but I fear that where the tweak might be right for one, does not mean it will be right for the rest.


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## Rick (Mar 23, 2014)

Trithor said:


> One of the best changes that I have made is to reduce the feed concentrations and apply more often on a more regular basis, .....I believe this debate will continue until we are able to identify what is in each species environmental niche and available to those plants directly and from the association with lichens, mosses and fungi.



Or NOT in the environment. Interesting human behavior that we first assume that something is missing that must be added.


I hope you all will take the time to check out those sufficiency standards for crop plants (the link to Clemson U agri sciences ) and compare with the scant in situ data available (from say Zotz or Naik).

By crop standards insitu orchids should be dead for lack of NPK (unless orchids are closer to blueberry than bell pepper). As you note Gary they are thriving in the wild, and that insite should be used as a guide for what they need (or at least what they don't need).


Also from looking at those sufficiency standards, all these same arguments about K usage and K toxicity could be had between the blueberry and Christmas tree growers versus the cantaloupe growers!!


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