# low potassium concept is not sustained by analysis



## Roth (Aug 3, 2013)

Over the course of a study sponsored by Pacific Wide/Besgrow, and carried out at Lincoln University, the following points appeared on a Phalaenopsis Sogo Yukidian 'Clone' mericlone population used for the test:

* The media and root concentration were not related. Instead, the potassium contents of the roots was related to the media type used, but not the ionic concentration of potassium.

* The foliar concentration of potassium was not related to the root concentration or the potting mix concentration. As an extract of the whole analysis:

Coir : foliar concentration 56000ppm root concentration 23600ppm, media concentration 2073ppm
Orchiata : foliar concentration 35600ppm, root concentration 8688ppm, media concentration 875ppm
New Zealand sphagnum moss foliar concentration 44000ppm, root concentration 18600ppm, media concentration 1914ppm
Us fir bark : foliar concentration 41600ppm, root concentration 10370ppm, media concentration 1100ppm

The US fir bark had the poorest leaf color of the various potting mixes tested ( here are only 4 as samples, but the total study encompassed 8 different potting mixes), with a low potassium value. There is no correlation between plant growth, quality and potassium content of the potting mix apparently...

As for the plant quality, weight, size, and leaf color have been assessed. It appears that the plant quality and strength was not related to the potassium concentration at all.

There are many more data from that study, being currently processed. However, it appears that we cannot find any intoxication by potassium, and there was no correlation between plant health and potassium. Other intermediate measurements are not included here, but plants are not intoxicated by potassium. The calcium and magnesium levels were not correlated to the potassium content either...

More will be published in the coming months out of the whole study.

We could say that maybe some other genera and species would respond well to the low K concept, but I do not use it, and many people neither. However, I use ammonium and urea in the feeding program, which always gives superior results, regardless of the potting mix used... 

The low potassium could work well in the case of an all nitrate fertilizer only, because the nitrate force an ion. However, with the use of the monovalent cation ammonium, I have the feeling that the results would be the same, but superior.


----------



## gonewild (Aug 3, 2013)

Who is Pacific Wide/Besgrow?


----------



## Roth (Aug 3, 2013)

gonewild said:


> Who is Pacific Wide/Besgrow?



www.besgrow.com 

The producers of Orchiata and NZ Sphagnum moss... We designed a study to compare the various potting mixes, from deflasking to blooming plants, to see what are the differences. 

Indeed, there are a lot of differences between the potting mixes and the feedings, which can go from simple to double size and number of flowers.


----------



## Secundino (Aug 3, 2013)

That means that root concentration of potassium is aprox. 10x (8,78-10,61) the 'media concentration' - regardless of the medium. But what exactly means 'media concentration'?


----------



## Roth (Aug 3, 2013)

Secundino said:


> That means that root concentration of potassium is aprox. 10x (8,78-10,61) the 'media concentration' - regardless of the medium. But what exactly means 'media concentration'?



Analysis of the media with total extraction, so it is the total potassium contents of the media, locked or not...


----------



## gonewild (Aug 3, 2013)

I'm not sure how these results support your thread title "low potassium concept not sustained by analysis".

What you report indicates that potassium content of the media has little effect on the leaf tissue content. But how does this relate to the low potassium content which I assume you mean to be fertilizer nutrient ratios?


----------



## Cheyenne (Aug 3, 2013)

Oooohhh....... This is going to be good. I can't wait to hear the responses. I am patiently waiting with popcorn for the show to begin!


----------



## gonewild (Aug 3, 2013)

What fertilizer was used for the trial?
How long was the trial run?


----------



## gonewild (Aug 3, 2013)

Cheyenne said:


> Oooohhh....... This is going to be good. I can't wait to hear the responses. I am patiently waiting with popcorn for the show to begin!



Would you like butter on that corn and how about a large coke?


----------



## orcoholic (Aug 3, 2013)

Thanks Roth. Please keep us updated with any information as soon as you get it. 

There has been a lot about K-lite on this site and all the results seem to have been very good. This may be due to the users paying more attention to their fertilizer regime than they did before they went to K-lite. It also could be due the amount of N is increased relative to the P & K. 

I create the K-lite be adding ammonium and Calcium nitrate to the RO Formula and the 20-10-20 Peat Lite formula. (I use both) The results I saw were so fast I could only assume it was the increase in N that caused it.

In my experience, there has been very good leaf growth, but the growth is definitely weaker and some of the tender newest leaf growth has defects. The defects could be due to the excessive heat during a couple weeks in July. I haven't been using it long enough to see flowering results.

These above observations are largely for phals. The Paphs and Phrags are putting on very good all around new growth.

Keep us informed.


----------



## Trithor (Aug 3, 2013)

Am I correct in understanding that medium concentration is a total value of the substrate and whatever has been added? (ie, if the medium was rock chips such as Kimberlite, which is an ultrapotassic igneous rock, the potassium levels would be stratospheric even if the K is not available to the plant at all?) Surely you need the free/available K level of the medium to have any grounds for comparison? Again as a carpenter, not a scientist (I too am getting my popcorn ready, and uncorking a good bottle of red wine for this debate)


----------



## Rick (Aug 3, 2013)

Yes. Please post the whole study when available.

The numbers you are posting are so far into the range of non environmentally relevant that I would not expect any normal foliar or root ratios of Ca Mg or K. Incidentally you didn't present any values of Ca and Mg to compare with tissue K. That's been the problem with all past GH studies in that they start out at already high levels of K and go on from there. 

So you are getting what's to be expected with Lance's analogy of "butter on corn".


----------



## cnycharles (Aug 3, 2013)

There must be a lot of vineyards in South Africa 


Sent from my iPhone using Tapatalk


----------



## gonewild (Aug 3, 2013)

Just to get it said and then we can debate the trial results....

A New Zealand university does a trial funded by a New Zealand company that sells new Zealand bark and the result shows that New Zealand bark is the best media and North American bark is the worst media.

Typical corporate funded trial results.

Now when it comes to the discussion about the "low potassium concept" we don't care what brand of bark is best so Roth, how do these trial results relate to the potassium content of fertilizer?


----------



## Secundino (Aug 3, 2013)

Roth said:


> Analysis of the media with total extraction, so it is the total potassium contents of the media, locked or not...



That is indeed interesting. Regardless how the potassium is present in the substrate, the plants manage a concentration (in the velamen covered roots) ten times higher. That means the roots either take potassium actively until this gradient or there is a passive potassium-trap that works the same way (or both). It makes sense to ensure the uptake of potassium for epiphytes as potassium is an essential nutrient. 
But what happened in the study when fertilizing adds soluble potassium?

This gradient makes me wonder if there are more electrolytes involved in the potassium uptake...


----------



## Roth (Aug 3, 2013)

gonewild said:


> Just to get it said and then we can debate the trial results....
> 
> A New Zealand university does a trial funded by a New Zealand company that sells new Zealand bark and the result shows that New Zealand bark is the best media and North American bark is the worst media.
> 
> ...



Honestly, it has nothing to do with the brand of the bark, and the trial was done really blinded. It was expected however that the NZ bark would perform better than the US fir bark, and this is something that is already known by the professional growers, otherwise why so many commercial pot plant nurseries, including Europe, ran internal trial and chose to use orchiata, even at an increase in cost.

The EU nurseries that made trials and are using Orchiata now pay nearly double price for orchiata compared to their old media, mostly due to transportation costs, but they are happy to do so because they see a tremendous improvement in the growth quality). So it has nothing to do with corporate funded results.

In fact, the background of the study, and what will be made public at a later time ( the analysis have been extensive, including arsenic, chromium, even lithium...), was not to promote the Orchiata or New Zealand sphagnum moss, but to try to explain why they perform better than US bark or Chile sphagnum moss. There are some elements of reply in fact in the remaining of the data. There are analysis of fresh media before potting, then media being used, then media at the end of the trial.

For the trial, it started with flasks of clone from Clone Biotech, until the plants bloomed, so it is pretty extensive.

The basis being that the sphagnum moss from New Zealand had nearly 2000ppm potassium, coir the same, yet the NZ plants were growing considerably better than the ones in coir. Orchiata had a low level of potassium, yet, the plants were identical to the NZ Sphagnum moss plants. Another media ( Dutch blend) produced good plants, and was even higher in potassium content.

For the fertilizer, it was a standard 6-3-1 20-20-20 Ca(NO3)2 MgSO4 blend, typical of the Dutch style of feeding. We decided to use that one because it is the most used type of fertilizer in the pro phalaenopsis growers, with reverse osmosis.



gonewild said:


> I'm not sure how these results support your thread title "low potassium concept not sustained by analysis".
> 
> What you report indicates that potassium content of the media has little effect on the leaf tissue content. But how does this relate to the low potassium content which I assume you mean to be fertilizer nutrient ratios?



The potassium content of the media has indeed very little effect on the foliar tissue content, and was not related to the plant appearance and quality ( on a grower's point of view, not as a disposable plant). 

On one side, Rick is right, because the load of the leaves of the plants does not depend so much of the potassium concentration in the media. so at a point, too much potassium is just a total waste.

We did the analysis for the calcium, and orchiata had much more calcium in the leaves than the others, due to the added lime. Yet, it is very interesting to note that a little bit lime was more effective in increasing the calcium foliar content than lots of calcium nitrate, providing the fertilizer was an acidifying one.

All of this has been done on a pH for the fertilizer of 5.7, which is again the standard for phalaenopsis. The fertilizer used, the 3x20, is nearly only urea with some ammonium, + the calcium nitrate, which brings some nitrate, so it is an acidifying fertilizer.

Now, to sum up a bit further about the fertilizer. I think K-Lite performed better than the MSU for some growers because in the MSU, the all nitrate ( the percentage of ammonium is ridiculous) force the plant to take up a cation, which is easier to take if it is potassium, a monovalent one. In this case, the MSU could well cause problems that the K Lite solved.

Rick solved the problem by lowering the potassium, and increasing the calcium and magnesium. But this still has the risk of potassium deficiency, and we force calcium and magnesium.

I am certain, even looking at how many growers are successful, that increasing a bit the potassium ( a high K fertilizer would seem to be foolish, because it seems that the plants have a maximal uptake level, and they cannot be intoxicated by the potassium truly), and using ammonium nitrogen instead of nitrate, at least 50/50, or using urea, would solve the whole problem. If anyone reads on the forum other posters, many report increased growth by using ammonium and urea fertilizers, and the growth will not be soft and weak.

We made a trial of an all nitrate MSU vs. the Dutch formulation given above, in several potting mixes. This is another study. And it appeared that the MSU plants looked really crappy compared to the Dutch formulation ( 202020 calcium nitrate magnesium sulfate, lots of urea and ammonium). They looked weak and starved. The only noticeable difference was the nitrogen contents of the leaves and the nitrogen source... Apparently nitrate does not so good a job to supply nitrogen compared to ammonium or even urea. 

The fertilizer results were not related to the pH or whatever, because Orchiata has lime and is buffered, the sphagnum mosses we tested had a low pH, standard for sphagnum, US bark was of low pH too, and no carbonate contents for the last 3. 

To another interesting notice, some bacteria and microorganism can make up ammoniac and ammonia therefore in the potting mix. Rick plants are indeed in excellent shape, but it could well be related to the microflora present around his greenhouse. Seaweed is being investigated, and it is a source of nitrogen, no matter the low analysis. Most of the nitrogen is available as amino acids in the seaweed ( and the potassium content is quite high in the Ascophyllum nodosium seaweed extract, like Maxicrop), and the plant takes those up readily.

So the K Lite could well benefit from increasing the potassium a bit, and adding at least 1/3 ammonium, it would be worth testing, even a K-Lite:ammonium nitrate blend at 1:1 or 2:1 if anyone wants, to see how the results are...


----------



## Trithor (Aug 3, 2013)

cnycharles said:


> There must be a lot of vineyards in South Africa
> 
> 
> Sent from my iPhone using Tapatalk



Yup, and this thread is going to require a few by the time it has run its course. 
It has begun ......


----------



## atlantis (Aug 3, 2013)

Trithor said:


> Yup, and this thread is going to require a few by the time it has run its course.
> It has begun ......



:rollhappy: I wish I liked the wine...


----------



## Rick (Aug 3, 2013)

Xavier

What are the ratios of K, Ca, Mg in the leaf and root tissues under the different regimes? In wild plants you should end up with higher concentrations of Ca than K in leaves. But as you noted, this study was working with a highly selected cultivar growing under artificial conditions (even for a Phalae).

In the old Cornell study, you could not "force" Ca and Mg into hybrid orchids as long as the available K was greater than 50ppm (the Ca was held at 200 ppm). But after 30+ years of cultivation I would expect to develop a plant capable of utilizing unnatural levels of nutrients. All kinds of salt tolerant crops are being developed every day.

These results are similar to the bromeliad study with regards to luxury uptake of K. Lots of K piling up in tissue and not related to any positive/negative growth aspects (in a 12 month study). 

You mention the aspect of microbial uptake of nitrogen (which probably accounts for the bulk of actual pot uptake in culture. 2000 mg/L of nitrifying bacteria (that would be equivalent to 2 grams of bacteria in a 4" pot. Can suck up 100's of mg of ammonia in an hour (converting it to nitrate). Unless you were feeding hydroponically the plant only has a few seconds to pick up anything while the bacteria coating/permeating the substrate will take up and convert ammonia absorbed into the media much more efficiently than the plant can utilize. Keeping the pH lower than 5 reduces the effectiveness of nitrification.

With a high % nitrate feed, fed at very low rates (under 10ppm) on a frequent basis, you will get a whole different microbial composition, which in general will be sparser, more diverse, and able to maintain a stable pH without pot supplements.

This study is still primarily dealing with pot chemistry. Much of my personal collection improvements (especially for Phaleanopsis) is for mounted plants, with virtually no complications of pot chemistry at all to consider.

I would really love to see a study of leaf tissue values on plants grown SH at environmentally relevant concentrations of nutrients.


----------



## paphioboy (Aug 3, 2013)

> But after 30+ years of cultivation I would expect to develop a plant capable of utilizing unnatural levels of nutrients. All kinds of salt tolerant crops are being developed every day.



Yes for crops, and maybe phals. But for species paphs, a large number are not likely to be beyond a couple of generations from wild-collected plants. Would the nutrient-uptaking abilities of this cultivated progeny be significantly different from their wild ancestors?


----------



## wjs2nd (Aug 3, 2013)

gonewild said:


> Just to get it said and then we can debate the trial results....
> 
> A New Zealand university does a trial funded by a New Zealand company that sells new Zealand bark and the result shows that New Zealand bark is the best media and North American bark is the worst media.
> 
> ...



I agree. 
Xavier, you sound like your just trying to sell something verses educate. You have talked about visiting the Besgrow plant in NZ often (working for them?).

I, also, don't see how this relates to low K and fertilizers. Conducting 2 studies at the same time doesn't seem very scientific. Either your testing what is the better fertilizer or what is the better growing medium.


----------



## Rick (Aug 3, 2013)

Actually the number for K retained in the bark mixes is part of what I was predicting with the original low K premise.

That all organic media have a cation exchange capacity. Assuming that all media were fed the same "high" levels of K, the Orchiata bark which is impregnated with lime exchanged and retained the lowest levels of K. So with respect to K buildup over time it would be the superior bark product. 

With respect to K exposure to the plant, the Orchiata bark would expose the plant to the shortest duration of K since it has the lowest build up between fert applications.

That seems to be in concurrence with the actual tissue values (leaf or root) which have the lowest values in the Orchiata


----------



## Rick (Aug 3, 2013)

Dang! almost perfectly linear


As media concentration goes from 875 to 2073, the root values go from 8,688 to 23,600 and leaves go from 35,600 to 56,000

That's perfect correlation, and definitely predicted by standard plant K uptake models.

Although all K application is higher than what I would advocate, you could easily make the statement that Orchiata bark "protects" the plant from excessive K exposures if that was the superior growth medium.


----------



## gonewild (Aug 3, 2013)

paphioboy said:


> Yes for crops, and maybe phals. But for species paphs, a large number are not likely to be beyond a couple of generations from wild-collected plants. Would the nutrient-uptaking abilities of this cultivated progeny be significantly different from their wild ancestors?



It could easily be different. Collect 100 wild plants and only one survives to be used for hybridization. The 1 surviving plant has traits that adapt to modern fertilizers and pass these genes on to the next generation. Only the seedlings that tolerate cultivation survive to reproduce so even more wild traits are eliminated. So in a few generations the cultivated progeny will be significantly different from their wild ancestors.

This is why after a few generations species produced in cultivation grow and bloom faster than the original wild collected.


----------



## Rick (Aug 3, 2013)

I put the K data into a spreadsheet and made a chart.

The leaf and root K concentrations correlate very well to extractable K in the potting mix. Rsq values are extremely close to parity (1.0)


----------



## Rick (Aug 3, 2013)

These pretty much parallel the results of the 1970's Cornell study results.

For their Phalea results the leaf tissue K went from 55000 to 80000 ppm as applied fert K was raised from 100 to 300 ppm (no low K trial there). Also the potting mix was the same for all fert concentration applications so exposure at the roots would parallel the fert concentrations.

As K goes up Ca and Mg in the plant tissues will go down regardless of the external Ca source. Documented in just about every green plant studied so far.

As Xavier noted the Ca concentration in Orchiata mix was the highest, but this is due to the lower overall K exposure inherent to the mix (not available Ca concentration) with subsequent reduced tissue K the plant can uptake more Ca. As he noted the plants did not pick up the Ca with increased Calcium Nitrate in other bark systems that allowed for higher tissue concentrations of K.

This work is really following the predictions of the low K system, but still operating at very high levels of K


----------



## Rick (Aug 3, 2013)

Xavier

Do you have substrate K values at T=0 before any fert application?

It would be good to know how fast the various substrates are loading K over time.


----------



## gonewild (Aug 3, 2013)

Let's debate this....




Roth said:


> Honestly, it has nothing to do with the brand of the bark, and the trial was done really blinded.



No offense but to be blind the trial would need to be finded by someone that did not care what the results were. 
The university absolutely knows who their sponsor was. And most likely the people in charge know what Orcidita looks like. But that is OK as far as the measurements are concerned but how the results are presented will be in question.



> It was expected however that the NZ bark would perform better than the US fir bark, and this is something that is already known by the professional growers, otherwise why so many commercial pot plant nurseries, including Europe, ran internal trial and chose to use orchiata, even at an increase in cost.


 
Orchidita is easily the best bark media since Fir Bark is probably the worst possible media choice for orchids. But you post here is about Potassium and not bark quality.



> The EU nurseries that made trials and are using Orchiata now pay nearly double price for orchiata compared to their old media, mostly due to transportation costs, but they are happy to do so because they see a tremendous improvement in the growth quality). So it has nothing to do with corporate funded results.



Would Besgrow have done the trial if they knew ahead that Fir bark would perform better than orchidita? Of course not, so it has something to do with corporate funding, that how the world functions.



> In fact, the background of the study, and what will be made public at a later time ( the analysis have been extensive, including arsenic, chromium, even lithium...), was not to promote the Orchiata or New Zealand sphagnum moss, but to try to explain why they perform better than US bark or Chile sphagnum moss.



OK.



> There are some elements of reply in fact in the remaining of the data. There are analysis of fresh media before potting, then media being used, then media at the end of the trial.



results about the media and not plant nutrition.



> For the trial, it started with flasks of clone from Clone Biotech, until the plants bloomed, so it is pretty extensive.



How many generations of hybridization is involved to make this clone? How many generations of this clone have been developed growing using commercial forcing techniques?

How well do the physical growing tolerances of this clone relate to plants in private collections? Has this clone been bred and grown with an addiction to Potassium? (OK not addiction but rather a higher tolerance than wild plants)



> The basis being that the sphagnum moss from New Zealand had nearly 2000ppm potassium, coir the same, yet the NZ plants were growing considerably better than the ones in coir.



I am a pretty experience grower and I pay very close attention to plant nutrition. But my personal growing experience has exact opposite results from this. So I am curious where this "basis" originates from?



> Orchiata had a low level of potassium, yet, the plants were identical to the NZ Sphagnum moss plants. Another media ( Dutch blend) produced good plants, and was even higher in potassium content.



So low level Potassium produces just as good a plant as does higher levels. 
But what determines "good plants"?
Fast growers until bloom?
Lush dark green leaves?

Is a good plant one that blooms at a young age or one that lives and blooms for 40 years?

Who determines what shade of green is the most healthiest and not just the most pretty?



> For the fertilizer, it was a standard 6-3-1 20-20-20 Ca(NO3)2 MgSO4 blend, typical of the Dutch style of feeding. We decided to use that one because it is the most used type of fertilizer in the pro phalaenopsis growers, with reverse osmosis.



But it is common knowledge that Phals produced under forced growing conditions are not the healthiest plants and live a short life unless they go through rehab after leaving the mass market shelves. 



> The potassium content of the media has indeed very little effect on the foliar tissue content, and was not related to the plant appearance and quality ( on a grower's point of view, not as a disposable plant).



Thaat is because Phalaenopsis roots in Nature don't extract nutrients from dead wood. They grow on living bark tissue and get what nutrients the can from the surface.


> On one side, Rick is right, because the load of the leaves of the plants does not depend so much of the potassium concentration in the media. so at a point, too much potassium is just a total waste.



Or toxic.


> We did the analysis for the calcium, and orchiata had much more calcium in the leaves than the others, due to the added lime. Yet, it is very interesting to note that a little bit lime was more effective in increasing the calcium foliar content than lots of calcium nitrate, providing the fertilizer was an acidifying one.



How often were the plants repotted to refresh the media during the trial



> All of this has been done on a pH for the fertilizer of 5.7, which is again the standard for phalaenopsis. The fertilizer used, the 3x20, is nearly only urea with some ammonium, + the calcium nitrate, which brings some nitrate, so it is an acidifying fertilizer.



Standard for forcing growth.



> Now, to sum up a bit further about the fertilizer. I think K-Lite performed better than the MSU for some growers because in the MSU, the all nitrate ( the percentage of ammonium is ridiculous) force the plant to take up a cation, which is easier to take if it is potassium, a monovalent one. In this case, the MSU could well cause problems that the K Lite solved.



Then the "low potassium concept" is a valid concept?


> Rick solved the problem by lowering the potassium, and increasing the calcium and magnesium. But this still has the risk of potassium deficiency, and we force calcium and magnesium.



From the trial results it seems Orchidita forces Calcium doesn't it?



> I am certain, even looking at how many growers are successful, that increasing a bit the potassium ( a high K fertilizer would seem to be foolish, because it seems that the plants have a maximal uptake level,



Even though you look at how many growers are successful with the low K level you still recommend to increase it. Why, to avoid possible K deficiency? After we see one case of K deficiency using K-lite then we should recommend increasing the K level.



> and they cannot be intoxicated by the potassium truly),



Truly? Based on what?



> and using ammonium nitrogen instead of nitrate, at least 50/50, or using urea, would solve the whole problem.



This is not true. Over the years all different combinations of Nitrogen has been tried but no one really tried decreasing the potassium so low before. This was because science said we need high K levels for healthy plant growth. (results of university trials funded by fertilizer companies).

I can assure you personally from the use of tons and tons Of Ammonium, Urea and Nitrate fertilizers that no combination has shown the improved growth as is being seen using K-lite. 




> If anyone reads on the forum other posters, many report increased growth by using ammonium and urea fertilizers, and the growth will not be soft and weak.



Of course you see increased growth when Nitrogen is increased. But increased growth is a commercial forcing concept of what is good. in this case increased growth is the same as rapid growth.



> We made a trial of an all nitrate MSU vs. the Dutch formulation given above, in several potting mixes. This is another study. And it appeared that the MSU plants looked really crappy compared to the Dutch formulation ( 202020 calcium nitrate magnesium sulfate, lots of urea and ammonium).



Crappy? If the trial produced crappy looking plants using MSU then either they purposely mis applied the MSU or know nothing about growing orchids. MSU is a very good formula.

They looked weak and starved. The only noticeable difference was the nitrogen contents of the leaves and the nitrogen source... Apparently nitrate does not so good a job to supply nitrogen compared to ammonium or even urea. 



> The fertilizer results were not related to the pH or whatever, because Orchiata has lime and is buffered, the sphagnum mosses we tested had a low pH, standard for sphagnum, US bark was of low pH too, and no carbonate contents for the last 3.



You say the results are not pH related yet the media results were all different and the pH of each was different. How do we assume the results are not pH related?



> To another interesting notice, some bacteria and microorganism can make up ammoniac and ammonia therefore in the potting mix. Rick plants are indeed in excellent shape, but it could well be related to the microflora present around his greenhouse.



But the good results are not limited to Rick's greenhouse. I doubt that Aunt Martha's windowsill has a great microorganism population. But even if the results are from the improved microflora doesn't that just prove that low K increases beneficial microflora? Doesn't it also prove (suggest) that potassium is toxic to beneficial microorganisms?

(Post too long continued)


----------



## gonewild (Aug 3, 2013)

(Continued)



> Seaweed is being investigated, and it is a source of nitrogen, no matter the low analysis. Most of the nitrogen is available as amino acids in the seaweed ( and the potassium content is quite high in the Ascophyllum nodosium seaweed extract, like Maxicrop), and the plant takes those up readily.



I think seaweed replicates what orchid plants get from Lichens and mosses in the wild. 

So the K Lite could well benefit from increasing the potassium a bit, and adding at least 1/3 ammonium, it would be worth testing, even a K-Lite:ammonium nitrate blend at 1:1 or 2:1 if anyone wants, to see how the results are...[/QUOTE]

OK I get your point about adding ammonium, in fact we have talked about that recently in some thread here. But why increase potassium until we see a reason to? No one has dis-proven the toxicity theory and how it related to plant disease (rot).


----------



## Ray (Aug 3, 2013)

I still have to wonder what role classic physics play in these ion absorption rates, referring back to my "enthalpy of hydration" Comment elsewhere. 

What the data could be demonstrating might be nothing more than a demonstration of what is taken from the solution most easily, rather than necessarily an indicator of the plant reacting differently to the substrate.


Ray Barkalow
Sent using Tapatalk


----------



## Rick (Aug 3, 2013)

Plants have to expend energy to convert nitrate to ammonia before it can be used to make amino acids (which requires phosphorus, via ATP for currency) 

Subsequently the plant will always find it energetically expedient to uptake ammonia if phosphorus is tight, and the pH is in a poor range.

However its even cheaper for the plant to uptake amino acids, and no synthesis required at all at that point.

Also like K, Ca, P, Mg..... the plant only needs a miniscule amount of N to take care of business. Given that N accounts for about 1 percent of the tissue dry weight in a healthy plant feeding much more than 10 or so ppm of N is still mostly feeding the bacteria in a pot rather than the plant. If you have cultured a huge bacterial colony in your potting mix, then the plant always be in competition with the bacteria for ammonia, and will still be relying on the nitrate reductase system for what little N it needs.


On a separate note, the leaf tissue concentrations of K in this potting mix study are equivalent to the K concentrations in Cattleya in the Cornell Study.
The value for the Orchiata bark (3.56%) is still more than 3.5X the value for your average epiphytic orchid in Panama.

Comparing Phales in this study to Phales in the Cornell study, even the highest K (5.6% for Coir) is just tickling the bottom end of what the Cornell researchers put Phales through in terms of K exposure. So the results are not unexpected.

I think this study demonstrates the dynamics of both dose concentration/duration with respect to CEC capacity of the different materials.


----------



## Secundino (Aug 3, 2013)

At the end all comes down to atmospheric pressure...
byebye folks, and good night!


----------



## Ray (Aug 3, 2013)

orcoholic said:


> There has been a lot about K-lite on this site and all the results seem to have been very good. This may be due to the users paying more attention to their fertilizer regime than they did before they went to K-lite. It also could be due the amount of N is increased relative to the P & K.



I agree that the "suddenly paying attention aspect" is fairly common in the introduction of almost anything. The casual grower can get pretty complacent, with many cultural aspects slipping, but then with the addition of something new, that interest level is rekindled, and ity's amazing what happens! However, I think many of us here are beyond the "casual grower" stage. I know that in my own case, the "diligence" aspect is pretty steady, as I feed at every watering.

When I switched from MSU to K-Lite, I also maintained the same nitrogen loading, so while the mass of that may be the same, the P & K are much lower, so maybe that does have something to do with the improved growing & blooming I've seen.


----------



## Rick (Aug 3, 2013)

Here's the Cornell study results for K Ca and Mg with increasing feed K 





Here's the Cornell study results for K Ca and Mg with increasing feed K. In this chart I added a 5ppm K to show about where wild epiphytes in Panama end up on the scale.





In both studies the Ca was held constant at 200 ppm while the K was ramped up as per the lower scale.

BTW 1% = 10,000ppm if you want to convert.


----------



## Ozpaph (Aug 3, 2013)

are there 'p values' for these lines or 'box and whiskers' plots? looking at graphs can be deceiving without statistical analysis telling us if the change is 'significant' (as I'm sure you know).
My point? Perhaps there is no real change in Calcium and magnesium with change in K+. (whatever that means)


----------



## Stone (Aug 4, 2013)

Rick said:


> > The numbers you are posting are so far into the range of non environmentally relevant that I would not expect any normal foliar or root ratios of Ca Mg or K. Incidentally you didn't present any values of Ca and Mg to compare with tissue K. That's been the problem with all past GH studies in that they start out at already high levels of K and go on from there.
> 
> 
> 
> ...


----------



## Ray (Aug 4, 2013)

Mike, I'm still not convinced it's necessary, either, but I think that proving - or disproving - the concept is a very long-term thing, and none of the data shown is of a long-enough term to tell us anything, making these debates rather senseless.

I think that if one really wanted to put some "meat" in this, it would involve raising a number of clones of different plants on diets in which the ONLY variable would be the K content, and raising them for many years.

To my mind, having fed my plants nothing but K-Lite for 19 months now and not seeing any negatives is a good thing, but not evidence that the concept is correct, even if I feel, based upon my readings and background education, that there might be something to it.


----------



## orcoholic (Aug 4, 2013)

Ray said:


> When I switched from MSU to K-Lite, I also maintained the same nitrogen loading, so while the mass of that may be the same, the P & K are much lower, so maybe that does have something to do with the improved growing & blooming I've seen.



Ray, 

Did you continue to water with the same TDS as before you changed to K-lt.? If so, by decreasing the P & K isn't that, in effect, the same thing as increasing N and keeping the TDS the same as before?


----------



## Roth (Aug 4, 2013)

So far, to make a reply over the whole thread:

- The background of those studies is simple. Many growers are using Orchiata and NZ Sphagnum moss around the world. Those are the majority of the growers in Hawaii and Japan in fact. Growers made a lot of internal trials, especially the pot plant growers, and at the end said that they are using Orchiata or NZ Sphagnum moss because their own results were far superior to the other potting mixes. Good. However some growers said that, as an example, plants in the Dutch mixes were growing very fast, then stopped growing after a while. Some other growers need technical advise to change from, let's say, fir bark (yes, some still do use it on a very large scale) to Orchiata. So we needed to have a background for the real differences, in terms of chemistry and growth, assessment. It is not a advertisement campaign at all...

- As for studies being paid by private companies, well, most studies in this world are, directly or indirectly. Many universities and research teams will do the studies in a fair way ( they have to water Orchiata or fir bark when the moisture content is such and such, etc...), so even if they know where are the Orchiata plant, they don't care, and no one can change or tamper the results. Add to that that New Zealand is one of the least corrupt countries in the world as well. I cannot think of any studies made by universities that are not done for commercial applications, or for private companies/on behalf of them/sponsored. Public money is rarely used for such studies, and the money involved is usually not spent on orchids, in that Pacific Wide did sponsor the study, to get chemical data information.

- I am technical adviser for Besgrow, indeed, and that's not a secret. I shared those results here pertaining to the potassium level. Rick found out that in Cornell they had even higher values, and no toxicity noticed at the end of their trial so far. I think the Cornell values are too excessive however, but indeed there are no 'toxic' effects.

- The results would be that people must not be afraid of potassium as an evil evenement, and the low K benefit lies mostly in a problem due to the use of an all nitrate fertilizer. In fact we found that the all nitrate fertilizer does not perform well at all. I cannot disclose more, because some are our customers for pot plant, including non phalaenopsis and quite fragile plants ( miltoniopsis), but indeed they tried nitrate as a source of nitrogen, with Orchiata, with NZ Sphagnum moss, even with coir, and even with mixes not related to Besgrow. I advised them all, and they are really huge nurseries, some of the biggest even. Their problems vanished as soon as they added ammonium. Strong, long lasting plants.

- Floricultura is growing a lot of mother plants, including masdevallias, paphs ( they have a very large collection, trust me, with some dream plants...), and many more. They apply the same feeding schedule for those as for their pot plants. Superb plants, some being decades old.

- Gonewild said * Over the years all different combinations of Nitrogen has been tried but no one really tried decreasing the potassium so low before. This was because science said we need high K levels for healthy plant growth. (results of university trials funded by fertilizer companies)*

Well, I agree that the high K formulations such as the 15-10-30 and such are not promoting anything good... However, not all different combinations of nitrogen have been tried, etc... over the years. Only very few, and it was a butchered job.

In Europe, we had nurseries with 40-50 years old plants. Using TAP water ( high in calcium), nitric acid to lower the pH, and an ammonium nitrogen source. The fertilizers used ( Hakaphos and similar...) were cheap ones, but included magnesium. There was actually nitrogen, ammonium, calcium, magnesium. Great plants. Floricultura used that feeding schedule.

Then, many nurseries changed for ALL their plants to using lime, and still an urea or ammo-urea fertilizer. Great plants. In fact many nurseries in Europe had a growth far superior to the US nurseries of the same time. names like Wichmann in Celle, Floricultura themselves, but Rohl, etc... had amazing growths.

The trials and university trials went from a NPK like a Peters, all urea, used in reverse osmosis water, and no calcium/magnesium found anywhere, to using an all nitrate calcium magnesium fertilizer, through various things, that were missing some elements.

As Ray pointed out, it is clear that the plant metabolism is not really a stupid ion uptake. Plants with lime ( I showed the Orchiata ones, but we had in the trial a Dutch blend with lime, and the calcium was really increased) always have much calcium in their tissues than plants supplemented with calcium nitrate. This is really weird...

Now I agree that Rick solved the MSU problem, and his solution is indeed good. I worry, myself, and I suggest to use a slightly higher potassium value, because different levels of potassium at the roots did not make a sharp increase in the leaves, and we failed to see anything that could be locked up, WITH THE USE of an urea/ammonium/calcium nitrate/magnesium sulfate fertilizer. That fertilizer produced stunning plants compared to the MSU.

According to my experience as a grower ( and not really a bad one  ) I strongly advise to have much more ammonium. Why no one wants to make a test... 

I think in fact that the seaweed could help a bit with the amino acids, too, and clearly I have seen improvement using seaweed on the plants. One of the best ( the best ?) growers of paphs I ever saw was using fern roots (don't tell me I am making the promotion of Orchiata), big charcoal, polystyren, seaweed and bat guano. Never seen before or since such massive plants... No mineral fertilizers, and the plants were really old.

As for what's a good growing plant, I would say that if the plant grows at the same speed or faster than in the wild, glossy juicy leaves but not weak or soft, then that's a good growing plant... 

I am not really impressed by most of what is published in terms of feeding schedules or results. In fact, I sometimes advised growers to use this and that kind of recipe for their crop. Sometimes they made foliar or run off analysis ( some are big hydroponics growers), and the lab comments ' too much' 'not enough' blabla... Even some graphs show an arrow outside of the page, because the value is way too high. Well they have one of the best crop possible, so they have a big laugh, so do I.

Back to the main problem, potassium toxicity was not found to be a problem in general, and the plant clearly takes up what it needs up to a certain point. 

I think however that ammonium would be a very welcome additive to the K Lite, as well as the use of lime in the potting mix with a 50-50 ammonium-nitrate nitrogen source. There are other unpublished results from the study, and my experience on top of that.

The potassium levels in our study were about half the ones of Cornell ( what the hell did they use ???), and this shows even further than potassium is not toxic through accumulation. It could be that, using a nitrate nitrogen fertilizer, a problem appears due to the potassium, but on a general sense, there is no problem.

My trials with MSU or the K Lite, ( and the ones of several massive nurseries, some having got real problems with the MSU type fertilizers, and even the calcium nitrate use vs. using lime in the potting mix...) were a total failure, compared to the growth standard I expect, dark green leaves, no premature leaf drop, increase in size, long roots, and long lasting, not weak or soft plants. 

In our study too, the plants with the lower K content had higher contents of sodium and lithium... so it seems that those three guys can be interchanged. Maybe Rick low K pushes more sodium in the plant ( this is not detrimental, plants need sodium anyway... and plants can be deficient in sodium clearly), or??? But definitely not a K toxicity problem per se.

I use a lot of insecticides, being in Vietnam, but so far most of the plants did not get fungicide for a really long while, despite the weather. If the plants are growing well, they are less prone to diseases.

The easiest way for some people to test would be to add ammonium nitrate to the K Lite and see how the plants performs after that. I am certain that they would grow tremendously better ( and not soft or forced after that...). Several people on the forum already reported so, with the use of urea or ammonium and a K Lite variation home made... Some others reported the same with MSU and ammonium added too.


----------



## Rick (Aug 4, 2013)

Ozpaph said:


> are there 'p values' for these lines or 'box and whiskers' plots? looking at graphs can be deceiving without statistical analysis telling us if the change is 'significant' (as I'm sure you know).
> My point? Perhaps there is no real change in Calcium and magnesium with change in K+. (whatever that means)



Correct. Mike originally linked this study (though everything was in table form and not graphical) a year or so ago now. I think I relinked it in subsequent debates. 

To answer your question, the drops in Ca were statistically significant and some of the Mg drops were significant (but not always). The K increases are also significant (but not surprising given the magnitude change compared to the Ca drops). 

In this study they also trialed the effects with a Cymbidium hybrid. Similar results

The trial duration was short (9 -12 months can't recall exactly). Nothing died, and everything was rated as "unimpaired". But they did see reduced growth in Catts over the 3 dose regimes, and leaf tip burn in cymbidium (but they chalked it up as a normal phenomena anyway). 

They also trialed changing N with everything else "constant". (Really hard to do since cations are always paired with anions, so something else must change). It's really a pretty good study of orchid response under basic cultural conditions. There was no 0 control though.


----------



## Rick (Aug 4, 2013)

So why waste all that fert if none of it makes a difference?

If we can grow great plants with and without hundreds of ppm of K then why should we waste time/money digging it out of the ground and spraying our plants with it?


----------



## Brabantia (Aug 4, 2013)

> I agree that the "suddenly paying attention aspect" is fairly common in the introduction of almost anything. The casual grower can get pretty complacent, with many cultural aspects slipping, but then with the addition of something new, that interest level is rekindled, and ity's amazing what happens!


I remember that the same situation was occurring when the MSU was introduced. Same with the AKERN RainMix here in Belgium.


----------



## gonewild (Aug 4, 2013)

Roth said:


> So far, to make a reply over the whole thread:
> 
> 
> The easiest way for some people to test would be to add ammonium nitrate to the K Lite and see how the plants performs after that. I am certain that they would grow tremendously better ( and not soft or forced after that...). Several people on the forum already reported so, with the use of urea or ammonium and a K Lite variation home made... Some others reported the same with MSU and ammonium added too.



I don't disagree or agree with the addition of ammonium or increasing the K ratio. The low potassium concept using K-lite is still in the ongoing public trial phase. So far no one has reported negative results that proved to be due to low potassium levels. In fact the observations to date have all been positive. Based on the reported observations there is no reason to think the potassium ratio should be increased.

I don't think anyone thinks that the ratios or formulation in K-lite is exactly perfect. So far the formulation for most growers is working well. If people start making changes at this point when no problems are evident the end result will be nothing learned. If and when problems arise that is the time to evaluate the problems and devise a solution.

What I do disagree with is your thread title here implies that the Besgrow trials prove that the "low potassium concept" is not correct.
The trial really has nothing to do with the relationship between fertilizer and plant nutrition since it was designed and performed with growing media as the focus. The trial did not even utilize a low potassium ratio fertilizer. What I see in the trial results that you have presented is evidence that soil media affects the amount of nutrients the plant has available and nothing that is valid to look at potassium "toxicity".

I seem to remember that when we discussed the use of ammonium in the K-lite formula and there were logistic reasons not to use it. Trying to include ammonium made it difficult to get all the ratios at desired levels and have the dry fertilizer be stable in a single package. If a growers pH is not correct for an all Nitrate fertilizer it is pretty simple to add ammonium at the time the fertilizer is mixed.

So give advice about adding ammonium but don't discredit the "low potassium concept" based on these trial results.

FYI... I appreciate your input and the chance to debate it. I also have no problem with your connection to the company selling the products you discuss.


----------



## gonewild (Aug 4, 2013)

Rick said:


> So why waste all that fert if none of it makes a difference?
> 
> If we can grow great plants with and without hundreds of ppm of K then why should we waste time/money digging it out of the ground and spraying our plants with it?



Or send it out in waste water to pollute the waterways and kill the mussels and microorganisms that do help plants grow?


----------



## naoki (Aug 4, 2013)

Roth said:


> So far, to make a reply over the whole thread:
> 
> - The results would be that people must not be afraid of potassium as an evil evenement, and the low K benefit lies mostly in a problem due to the use of an all nitrate fertilizer. In fact we found that the all nitrate fertilizer does not perform well at all. I cannot disclose more, because some are our customers for pot plant, including non phalaenopsis and quite fragile plants ( miltoniopsis), but indeed they tried nitrate as a source of nitrogen, with Orchiata, with NZ Sphagnum moss, even with coir, and even with mixes not related to Besgrow. I advised them all, and they are really huge nurseries, some of the biggest even. Their problems vanished as soon as they added ammonium. Strong, long lasting plants.
> 
> The potassium levels in our study were about half the ones of Cornell ( what the hell did they use ???), and this shows even further than potassium is not toxic through accumulation. It could be that, using a nitrate nitrogen fertilizer, a problem appears due to the potassium, but on a general sense, there is no problem.



It's interesting that the results of NH4 vs NO3 is a sharp contrast to a paper published in a peer reviewed journal. We discussed this and paphs could be different from phals, but I wonder why you get a complete opposite result from Wang (2008). It's difficult to evaluate the results until the paper is published, but maybe K concentration differed, and resulted in the contrast?

http://hortsci.ashspublications.org/content/43/2/350.short

Also, what is the physiological reason behind the NO3-K interaction? I haven't seen any published study, but again epiphytes could be different.


----------



## Rick (Aug 4, 2013)

Roth said:


> In our study too, the plants with the lower K content had higher contents of sodium and lithium... so it seems that those three guys can be interchanged. Maybe Rick low K pushes more sodium in the plant ( this is not detrimental, plants need sodium anyway... and plants can be deficient in sodium clearly), or??? But definitely not a K toxicity problem per se.




It is well known in plant physiology circles that K and Na uptake are competitive. But what cracks me up is that as long as I've been growing orchids Na has always been considered "evil" and too be avoided at all costs. Now all of a sudden its a necessary nutrientoke:oke:

In the environment Na is way more common than K. The low K system, or my personal growing practices didn't add any Na to the system to address that. So if our plants were suffering from Na deficiency then once again excess K is a culprit for causing that.


----------



## gonewild (Aug 4, 2013)

Rick said:


> It is well known in plant physiology circles that K and Na uptake are competitive. But what cracks me up is that as long as I've been growing orchids Na has always been considered "evil" and too be avoided at all costs. Now all of a sudden its a necessary nutrientoke:oke:
> 
> In the environment Na is way more common than K. The low K system, or my personal growing practices didn't add any Na to the system to address that. So if our plants were suffering from Na deficiency then once again excess K is a culprit for causing that.



Rick your plants do suffer from a serious lack of Sodium. You just don't recognize the deficiency symptoms...... Plants deficient in Sodium have green leaf tips. :evil:


----------



## Rick (Aug 4, 2013)

Roth said:


> The potassium levels in our study were about half the ones of Cornell ( what the hell did they use ???), and this shows even further than potassium is not toxic through accumulation. It could be that, using a nitrate nitrogen fertilizer, a problem appears due to the potassium, but on a general sense, there is no problem.



You should read the study. They used raw chemicals not a commercial formulation (that's the only way they were able to increase/decrease different parameters).

Also growth inhibition is a generally accepted determinant of toxicity (which they did observe at different concentrations per species per parameter.

They did not see acute toxicity (mortality), but did see differing rates of growth under different regimes.


----------



## Rick (Aug 4, 2013)

gonewild said:


> Rick your plants do suffer from a serious lack of Sodium. You just don't recognize the deficiency symptoms...... Plants deficient in Sodium have green leaf tips. :evil:




OH NO!!!! Where's the salt shaker!!!


----------



## Rick (Aug 4, 2013)

naoki said:


> Also, what is the physiological reason behind the NO3-K interaction? I haven't seen any published study, but again epiphytes could be different.



Naoki I thought I sent a link on K inhibition to photosynthesis (in BG algae). (Maybe a couple of other links on how the photosynthesis II system works)

K piling up in chloroplasts seems to increase cellular alkalinity levels dramatically(decreasing the efficiency of photosynthesis) The nitrate reductase system is part of the Photosynthesis II system (which is part of all photosynthetic plants physiology). If you cut down photosynthetic efficiency, you also retard the plants ability to convert nitrate to ammonia. Also high levels of intracellular alkalinity (bicarbonate ion) make nitrate uptake from the root zone and uphill battle if there is high alkalinity in the root zone.

Since the plant uses NO3 to make NH3 to make amino acids, then you can see you can sidestep the whole NO3 issue by going direct to NH3 or amino acids.

The next "however" is pot management of ammonia usage. Yes a more direct use by plants, but also causes more problems with pH and microbial management. Nitrate causes less pot management issues (pH or microbial).


----------



## gonewild (Aug 4, 2013)

I did a little goggleing on Phalaenopsis.

http://www.ranwild.org/Phalaenopsis/Eindex.html

After reading this well written site on Phalaenopsis species it is obvious that Phal hybrids are not a good choice to use for nutrient trials. Phal species have a very wide range of environmental requirements and now the hybrids have a mixed up genetic makeup of species with very different growing requirements. Phal hybrids do not represent the requirements of general orchid plants as found in a mixed collection.

As complete as this website is it offers very little about specific nutrient requirements of Phals but it does say the nutrient requirements are low. It does mention Nitrogen and Phosphorous but not potassium.

Nutrient trials using Phalaenopsis plants will lead to growing better commercial crops but may very well mislead growers of species and other genera.


----------



## Ray (Aug 4, 2013)

orcoholic said:


> Ray,
> 
> Did you continue to water with the same TDS as before you changed to K-lt.? If so, by decreasing the P & K isn't that, in effect, the same thing as increasing N and keeping the TDS the same as before?



Not the same TDS, the same nitrogen loading, so the TDS will be lower.


Ray Barkalow
Sent using Tapatalk


----------



## Stone (Aug 4, 2013)

Ray said:


> > Mike, I'm still not convinced it's necessary, either, but I think that proving - or disproving - the concept is a very long-term thing, and none of the data shown is of a long-enough term to tell us anything, making these debates rather senseless.
> 
> 
> 
> ...


----------



## gonewild (Aug 4, 2013)

Stone said:


> Just look at the insigne on the Specimen thread, I know for a fact that it is being fed with organic pellets which have ammonium sulphate added to boost the N and a similar amount of KS04! So I would call 20 or so years pretty long term. Not too high an EC and tons of water are the ''sectrets'' Here is what he uses, I don't like it much, I think there are much better alternatives but look at the K!
> http://www.neutrog.com.au/assets/Brochure-PDFs/Home-Garden-PDFs/NEU-SBFO-0812.pdf




This is copied from the front page of the link to Strike Back fertilizer.
_
"Neutrog commenced development of Strike Back for Orchids in early 2006"_

Can't really credit this fertilizer formula with 20 years of specimen plant growth.


----------



## gonewild (Aug 4, 2013)

Stone said:


> I don't like it much, I think there are much better alternatives but look at the K!
> http://www.neutrog.com.au/assets/Brochure-PDFs/Home-Garden-PDFs/NEU-SBFO-0812.pdf



Thanks for this link. I have never heard of this fertilizer before so I'm reading it. You are correct the K ratio is high. But note they do not recommend it's use on small plants as the formula may damage them. Instead they recommend their "Seamungus" fertilizer which is:

_Nitrogen (N) as Organic 4.0
Phosphorus (P) as Citrate Soluble 1.0
Potassium (K) as Organic 1.5_

Now look at the K!


----------



## Stone (Aug 4, 2013)

gonewild said:


> Thanks for this link. I have never heard of this fertilizer before so I'm reading it. You are correct the K ratio is high. But note they do not recommend it's use on small plants as the formula may damage them. Instead they recommend their "Seamungus" fertilizer which is:
> 
> _Nitrogen (N) as Organic 4.0
> Phosphorus (P) as Citrate Soluble 1.0
> ...



Yes the ammonium content can damage very tender plants especially in cold dark weather, nothing to do with the Koke:


----------



## Stone (Aug 4, 2013)

gonewild said:


> This is copied from the front page of the link to Strike Back fertilizer.
> _
> "Neutrog commenced development of Strike Back for Orchids in early 2006"_
> 
> Can't really credit this fertilizer formula with 20 years of specimen plant growth.



Ok 7 years then.


----------



## gonewild (Aug 4, 2013)

Stone said:


> Yes the ammonium content can damage very tender plants especially in cold dark weather, nothing to do with the Koke:



Then why do the drastically lower the K in the other recommended fertilizer? oke:


----------



## gonewild (Aug 4, 2013)

Stone said:


> Ok 7 years then.



So what fertilizer did he use to grow it to specimen size for the 30 prior years?

Just think how big it would be now if he used low K. :clap:


----------



## Stone (Aug 5, 2013)

gonewild said:


> > So what fertilizer did he use to grow it to specimen size for the 30 prior years?
> 
> 
> 
> ...


----------



## gonewild (Aug 5, 2013)

Stone said:


> gonewild said:
> 
> 
> > Send me some kovachii seed and I'll tell you
> ...


----------



## Rick (Aug 5, 2013)

Stone said:


> Ray said:
> 
> 
> > tons of water are the ''sectrets''
> ...


----------



## Roth (Aug 5, 2013)

Rick said:


> It is well known in plant physiology circles that K and Na uptake are competitive. But what cracks me up is that as long as I've been growing orchids Na has always been considered "evil" and too be avoided at all costs. Now all of a sudden its a necessary nutrientoke:oke:
> 
> In the environment Na is way more common than K. The low K system, or my personal growing practices didn't add any Na to the system to address that. So if our plants were suffering from Na deficiency then once again excess K is a culprit for causing that.



So far all the analysis I have ever seen of orchids had sodium. There has been tests on sodium deficiency, but that's very difficult to 'produce', and is virtually unknown in normal conditions in fact.

Sodium is considered now for quite a lot for crops as a required micronutrient in fact... Lithium is the third one similar to sodium and potassium that can be interchanged, at least for some processes, and only in parts. In some 

What the results showed was that the plant would have more sodium when it has less potassium in its tissues, which tends to show that it needed to replace some missing potassium by sodium, possibly. That's an hypothesis, and there could be many other reasons not yet understood.


----------



## ALToronto (Aug 5, 2013)

This sodium-potassium balance holds for people as well. Now where does lithium come into this? And does it make the plants behave better? oke:


----------



## Roth (Aug 5, 2013)

ALToronto said:


> This sodium-potassium balance holds for people as well. Now where does lithium come into this? And does it make the plants behave better? oke:



That's why we made that study too, including strange things like lead, arsenic, etc... to see if there is anything interesting outside the previous knowledge.

There are things that are, again, confirmed, like the Mn quantity being on a standard 10 times higher than the Iron. This fits most analysis of wild orchids, not only Phalaenopsis, where Mn is always much higher than Fe. 

There are new things, like the Lithium being quite 'high', or the aluminium being much higher too than the iron. The aluminium is interesting, because it appeared on all the media, and the fertilizers did not contain any aluminium, so it means the plants needed it in a way or another.

But that would require another study to know if it has any significance for the lithium.


----------



## ALToronto (Aug 5, 2013)

What about silicon? Did you test for it, or added it specifically?

Aluminum would be quite abundant in all media - clay is an alumino-silicate, and whether the media came from soil-growing plants or lava rock or LECA, there would be plenty of aluminum in all of them. But were the plants with high Al levels any different from plants with low levels?


----------



## TyroneGenade (Aug 5, 2013)

Fascinating thread.

I thought the idea of lithium for misbehaving plants very amusing, but not as amusing as the %W/W measures for the neutrog fertilizer. Just what is organic potassium? And organic ammonia? I know what organic poo is and it is rich in both... W/W measures suggest to me that 1 kg was burn to ash and then that ash was dissolved and worked back to mass fractions. Not much organic anything in a teaspoon of ash... but that is beside the point. I was using a Neutrog product on my orchids and it worked like a charm and I could dumps loads onto Catts, Cyms and Paphs (also an insigne) without trouble. This is, I think, because the various nutrients are released slowly as the pellet decomposes.

I find the conflict between the proponents of ideas of low K/high NH3 very interesting. If the plants are using the same cation transporter for K+ and NH4+ then there is little difference between talking about low K/high NH4+ and high K/higher NH4+. 

Whatever the truth of the matter, both fertilizer regimes seem to work. 

As regards correlations on graphs, I don't think them much good. All they do is show correlation, not cause and effect. Even if you had looked up the corresponding p-values for the correlation coefficients/sample sizes and got "significant" correlations this wouldn't say much about what is really going on. I think the only thing we can conclude from the experimental data is that if you are growing a commercial Phalie, with the same fertilizer mix as used in the experiment as well as other conditions... then you should probably grow in NZ sphag moss. That is all we can really conclude with any certainty from the data---and it doesn't exclude the possibility that there is a better way.


----------



## Rick (Aug 5, 2013)

ALToronto said:


> This sodium-potassium balance holds for people as well. Now where does lithium come into this? And does it make the plants behave better? oke:



Also pretty wild is that at least one study done on plant uptake of K used rubidium since it was a strong K surrogate for the plants to uptake (and easier to trace into different functions/places in the cell. But that doesn't mean that plants also have a rubidium requirement.


----------



## gonewild (Aug 5, 2013)

Rick said:


> Also pretty wild is that at least one study done on plant uptake of K used rubidium since it was a strong K surrogate for the plants to uptake (and easier to trace into different functions/places in the cell. But that doesn't mean that plants also have a rubidium requirement.



Please don't say the word rubidium or our plants will start wanting it.
Do realize how hard it will be to supply both lithium and rubidium?

What is rubidium?


----------



## Rick (Aug 5, 2013)

ALToronto said:


> What about silicon? Did you test for it, or added it specifically?
> 
> Aluminum would be quite abundant in all media - clay is an alumino-silicate, and whether the media came from soil-growing plants or lava rock or LECA, there would be plenty of aluminum in all of them. But were the plants with high Al levels any different from plants with low levels?



In my AOS article I have a table of total mineral content of leaf litter over karst geology in Sumatra.

Silicon content (8042) was 3X higher than K and Al was almost the same as K (1980 ppm Al vs 2474 ppm K). Ca and N were the most common element at 14,000ppm each.

Keeping in mind this is leaf litter and research has shown that tropical plants variably recycle minerals out of the leaves before senescence. The highest rate of recycle was for P (60% recover in Panamanian epiphytes) with about 30-40% recycle of K and N. Ca and Mg were not readily reabsorbed. I have no information about internal re-absorption of anything other than NPK Ca Mg.

Recycle rates give you an idea about what is rare and what is important to the plant to recover.


----------



## gonewild (Aug 5, 2013)

Rick said:


> Recycle rates give you an idea about what is rare and what is important to the plant to recover.



I wonder if the recycle rate is the same if the nutrient is plentiful in the media?
Will these plants not recycle if they have a ready supply to the roots?


----------



## Rick (Aug 6, 2013)

gonewild said:


> I wonder if the recycle rate is the same if the nutrient is plentiful in the media?
> Will these plants not recycle if they have a ready supply to the roots?



Don't know. But I suspect it could change for different reasons.

I see lots of Phals on high N and K feeds holding on to a lot more leaves than a normal phal (some even start to look like all out Vandas).

But then under high K, Ca and Mg (and Na!) become sparse commodities, and may need to be recycled under that regime.


----------



## naoki (Aug 6, 2013)

Rick said:


> Naoki I thought I sent a link on K inhibition to photosynthesis (in BG algae). (Maybe a couple of other links on how the photosynthesis II system works)
> 
> K piling up in chloroplasts seems to increase cellular alkalinity levels dramatically(decreasing the efficiency of photosynthesis) The nitrate reductase system is part of the Photosynthesis II system (which is part of all photosynthetic plants physiology). If you cut down photosynthetic efficiency, you also retard the plants ability to convert nitrate to ammonia. Also high levels of intracellular alkalinity (bicarbonate ion) make nitrate uptake from the root zone and uphill battle if there is high alkalinity in the root zone.
> 
> Since the plant uses NO3 to make NH3 to make amino acids, then you can see you can sidestep the whole NO3 issue by going direct to NH3 or amino acids.



Oh, yes, I remember that, but I couldn't quite figure out the effect of K on PS. I'm trying to figure this out, but it seems to be pretty complicated, and algae might have some difference in plants. So I'm reading Marschner's Mineral Nutrition of Higher Plants 3rd ed. edited by Petra Marschner (MMNHP). A couple related issues from MMNHP.

- In plants, K concentration is correlated with rate of photosynthesis and RuBP carboxylase activity (an important enzyme for carbon fixation/dark reaction). MMNHP p. 182.

"Upon illumination, additional influx of K from the cytosol [into chloroplast] is required for the maintenance of a high pH in the stroma [inside of chloroplasts but outside of thylakoid, thylakoid membrane is the place where Photosystems I & II and electron transport chain is located] necessary for optimal RuBP carboxylase activity."

- Correlation between NR activity/gene expression and photosynthesis makes sense since NR requires ATP.

- So this seems to suggest synergism between NO3 and K instead of antagonism in plants.

- Also for transportation, there seems to be synergism between NO3 and K. MMNHP p.187. "The role of K in the cation-anion balance is also reflected in nitrate metabolism, in which K often is the dominant counter ion for NO3 in long-distance transport in the xylem as well as for storage in vacuoles."


----------



## Stone (Aug 6, 2013)

gonewild said:


> Stone said:
> 
> 
> > How many kilos do you want?
> ...


----------



## naoki (Aug 6, 2013)

Rick said:


> Recycle rates give you an idea about what is rare and what is important to the plant to recover.



Among 17 essential elements, some are phloem-"mobile" (Mg, P, K, N) and others are "immobile" (B, Fe, Ca). The other 10 elements are inbetween the two extreme groups. These mobile elements are the ones which you call "recycled", right? Isn't this phloem-mobility partly determined by functions/roles of each element rather than what elements are rare/important? For example, Ca is a component of middle lamella of cell walls, and I'm guessing that it is probably energetically costly to recycle it (even cells die, cell wall could stay there and they form dead leaves).

Is Na categorized as essential elements now? It was called a beneficial element (i.e. plant can complete life-cycle without it)? Maybe my textbook is old.


----------



## Rick (Aug 6, 2013)

naoki said:


> "Upon illumination, additional influx of K from the cytosol [into chloroplast] is required for the maintenance of a high pH in the stroma [inside of chloroplasts but outside of thylakoid, thylakoid membrane is the place where Photosystems I & II and electron transport chain is located] necessary for optimal RuBP carboxylase activity."
> 
> - Correlation between NR activity/gene expression and photosynthesis makes sense since NR requires ATP.
> 
> - So this seems to suggest synergism between NO3 and K instead of antagonism in plants.



I don't get that interpretation at all. In light of this article I see nitrate reductase and pH increase by K as competitive processes.

http://link.springer.com/article/10.1007/BF00383860

Some where you need some protons to knock down all the alkalinity produced by K and nitrate reduction to generate ammonia. Given the large amounts of N (as NH3 recommended for high pH pot applications) applied to pots relative to the amount the plant actually uses, it may be another case of nitrifying bacteria to the rescue as they release protons in the process of converting NH3 to NO3.


----------



## Rick (Aug 6, 2013)

naoki said:


> Among 17 essential elements, some are phloem-"mobile" (Mg, P, K, N) and others are "immobile" (B, Fe, Ca). The other 10 elements are inbetween the two extreme groups. These mobile elements are the ones which you call "recycled", right? Isn't this phloem-mobility partly determined by functions/roles of each element rather than what elements are rare/important? For example, Ca is a component of middle lamella of cell walls, and I'm guessing that it is probably energetically costly to recycle it (even cells die, cell wall could stay there and they form dead leaves).
> 
> Is Na categorized as essential elements now? It was called a beneficial element (i.e. plant can complete life-cycle without it)? Maybe my textbook is old.



Although lots of the Ca ends up in cell walls it also is used metabolically, and yes it is a poor intracellular transport (but obviously not 0 since it ends up in the plant to the greatest degree in wild plants). However its also odd that in the case of the Panamanian epiphytes, Mg (one of the "phloem-mobile" group) was not recycled at all, while while Ca was still recycled at the rate of 15-20%. Now from an evolutionary standpoint if Ca was limiting environmentally wouldn't it make sense to come up with an energetically feasible way to recover it (instead of wasting it with growth)?

The Na thing was postulated by Xavier. My textbook is too old too.


----------



## Rick (Aug 6, 2013)

Stone said:


> gonewild said:
> 
> 
> > :rollhappy:
> ...


----------



## limuhead (Aug 6, 2013)

Rick said:


> Stone said:
> 
> 
> > Man this sounds like a coke deal:evil:
> ...


----------



## Paul (Aug 6, 2013)

Hello,

I have made my own fertilizing for a few months now, really improved for less than a couple months now. using 5:1 NK and P) ratio, both N03- and NH4+ (50-50), tap water and Mg++ supplement + oligos.
So far, fertilizing only 30ppm N, I have the very best growth I have ever had (I see it only in a couple months!!!!), and even better since I am using 2/3 rain water +1/3 tap water instead of tap water only (reduced total EC)
Growths are mostly double sized than before, what ever fertilizing I was applying in the past (MSU, urea fertilizer...)
This can be surprising, but the biggest improvment seems to be on the most vigourous plants (Catts, Paphs roths, phil, kolo...).


----------



## naoki (Aug 6, 2013)

Rick said:


> I don't get that interpretation at all. In light of this article I see nitrate reductase and pH increase by K as competitive processes.
> 
> http://link.springer.com/article/10.1007/BF00383860
> 
> Some where you need some protons to knock down all the alkalinity produced by K and nitrate reduction to generate ammonia. Given the large amounts of N (as NH3 recommended for high pH pot applications) applied to pots relative to the amount the plant actually uses, it may be another case of nitrifying bacteria to the rescue as they release protons in the process of converting NH3 to NO3.



The algae paper is coming up with the hypothesis of proton/charge balance is maintined across the plasma and chloroplast membrane by counter- and co-transportation, isn't it? I think it's trying to say that K is not involved in this process.

While I do not know why high pH is required for rubisco (RuBP carboxylase), the text says that to achieve high pH in stroma, K+ is pumped in across the chloroplast envelop, and H+ is pumped out from stroma (Wu et al 1991; Plant Physiology 97: 580-587. So inside of the chloroplast, both K+ and nitrite (NO2-) is required to have smooth light+dark reaction, so this seems to be synergism, isn't it? The nitrate reductase (which converts NO3- to NO2-) is cytosomic enzyme (not in chloroplast), and nitrite (NO2-) is transported into chloroplast, where conversion to NH4+ occurs as a part of photosynthesis electron transport chain. With regard to the overall proton balance, isn't NADP/NADPH is involved in it?

I'm still learning this (and I'm not so good at chemistry), so I may be missing your points, but it's kind of fun to learn about plant physiology through a hobby.


----------



## naoki (Aug 6, 2013)

Rick said:


> Although lots of the Ca ends up in cell walls it also is used metabolically, and yes it is a poor intracellular transport (but obviously not 0 since it ends up in the plant to the greatest degree in wild plants). However its also odd that in the case of the Panamanian epiphytes, Mg (one of the "phloem-mobile" group) was not recycled at all, while while Ca was still recycled at the rate of 15-20%. Now from an evolutionary standpoint if Ca was limiting environmentally wouldn't it make sense to come up with an energetically feasible way to recover it (instead of wasting it with growth)?
> 
> The Na thing was postulated by Xavier. My textbook is too old too.



You are right, it ends up with the cost of recycling vs the requirement/availability ratio. Even the cost of recycling is high, once required elements are not available, they should evolve to have some mechanisms of recycle (if it is possible). Here in interior Alaska, we don't really recycle paper/aluminum/plastic/metal because the cost of transporting them to recycling plants is too high. But once some necessary stuff is scarce, recycling become cost effective. Some agriculture researchers are artificially selecting for genotypes with higher recycling (White and Brown 2010; Annals of Botany 105: 1073-1080), so natural selection should work in a similar way.


----------



## Ray (Aug 6, 2013)

Rick said:


> Keeping in mind this is leaf litter and research has shown that tropical plants variably recycle minerals out of the leaves before senescence. The highest rate of recycle was for P (60% recover in Panamanian epiphytes) with about 30-40% recycle of K and N. Ca and Mg were not readily reabsorbed. I have no information about internal re-absorption of anything other than NPK Ca Mg.
> 
> Recycle rates give you an idea about what is rare and what is important to the plant to recover.


Sorry Rick. I cannot simply accept that at face value.

It seems to me that material that were accumulated to a significant degree would be the ones most likely to remain in the leaf litter. How they are accumulated can vary from active to passive, with the passive absorption being related to concentration in the local environment and the relative ease of absorption. Those easiest to absorb are probably also the easiest to extract from the leaf litter, making them available to easily absorb by living creatures.

Important? Possibly. Merely easily absorbable? Also possible.




Ray Barkalow
Sent using Tapatalk


----------



## TyroneGenade (Aug 6, 2013)

A high pH is needed for RUBISCO to function because of the organic chemistry it is catalyzing. The reactions take place only under a low proton concentration.

It is very dangerous generalizing from experiment to experiment. Plants are very diverse, biochemically speaking, and reactions that are occurring in one plant may not be occurring in another species. This is even more the case when it comes to cyanobacteria which are billions of years removed from plants. 

Also, plants have a plethora of ion channels. Some are run by ion exchange (one ion in, another out), these are antiports. Then there are synports where two ions are imported together. These can be a cation/cation, cation/anion or anion/anion. There are also channels/pumps that are run on ATP or NADH supplied energy. Some pumps/channels are doing the same job but are expressed in different locations and are also expressed by different genes. The whole story gets very complicated fast as one genus may use pump A in the chloroplast while genus B won't have that pump but a different one doing a similar reaction. We can't generalize about plant metabolism when it comes to the specifics. 

What does hold is the physics governing these pumps. This described by the Nernst Equation (taken from Wiki):




. As you can see the major effectors are the internal/external ion concentrations, the difference in charge between the membranes and the permeability of the membrane to the ions. If the movement can't occur spontaneously, then a power source is needed to drive the movement. If you keep flooding the cell with K+ then the membrane will be less permeable to NH4+ and Ca2+ etc... and more power will be needed to import these against the electrochemical gradient. This holes equally true if there is an excess of Ca2+ or NH4+ inside the cell which would make it hard to import K+ etc... 

How much the plants can vary the relative pump/channel concentrations in the membrane to transport specific ions is, in the case of Paphs, an unknown. If they can decrease K-channels and increase Ca-channels then the effect of K concentration may be of little importance... Each plant will have evolved to either cope with the change in ions in its environment by evolving the specificity of each ion to the channel or the amount of channels/available; or the plant (unable to evolve specificity or pump quantity) simply survives in a specialized niche which is just right for its delicate biochemistry. Generally, living organisms maintain their enzymes/pumps/channels etc... operating very far from the equilibrium point so organisms have a lot of flexibility to adapt to changes in the external or internal environment without bothering about changes in gene expression. I don't think we have any idea just how flexible our plants are... but the various medium and fertilizer experiment suggest that there is a range and it is not very robust.

Whether the issue is absolute K or NH4+ concentration, or how these concentrations affect the metabolism of other nutrients is very difficult to pry apart without large, well thought-out experiments. In the case of orchids these would be very expensive experiments as the plants are no as easy to work with as the normal experimental model plants that grow easily and whose roots and leaves are readily available for analysis. 

I think the best we can say is whether the fertilizer/substrate method works or not. How it works will remain a mystery until you get an orchid growing president in the white house to set up the National Orchid Research Institute funded lavishly with tax-payer dollars to benefit Dutch commercial orchid producers.


----------



## naoki (Aug 6, 2013)

Tyrone, thank you very much for the detailed explanation! After reading your earlier comment about the cation channel/transporter of K vs NH4, I was starting to read about it. These two molecules have similar size/property, so the same channel could be used, right? Also it was mentioned that in terms of transport from rhizosphere into root cells, NH4+ could compete against K uptake, but K doesn't inhibit NH4 uptake. This is partly due to gene expression regulation of a transporter genes by [NH4] but not by [K]. I thought that this is interesting, but again, as you mentioned, this may not be true in orchids. As I read more about these, I started to agree with Mike (Stone) that mixture of NO3 + NH4 seems to be the safest bet (although I have a suspicion that much higher concentration of NO3 than 50:50 is a safer bet after considering possible problems of NH4).


----------



## Brabantia (Aug 6, 2013)

naoki said:


> I started to agree with Mike (Stone) that mixture of NO3 + NH4 seems to be the safest bet (although I have a suspicion that much higher concentration of NO3 than 50:50 is a safer bet after considering possible problems of NH4).


I remember me have read someplace that ideal ratio NNH4 / Ntotal in hydroponic culture was 1/6 (83 % NNO3: 17 % NNH4). Reason is probably not physiological but chemical (pH stabilization due to both forms assimilation of nitrogen).


----------



## Stone (Aug 6, 2013)

Roth said:


> > There are things that are, again, confirmed, like the Mn quantity being on a standard 10 times higher than the Iron. This fits most analysis of wild orchids, not only Phalaenopsis, where Mn is always much higher than Fe.
> 
> 
> 
> Xavier, This relationship between Mn vs. Fe is interesting. But what is going on? is the Mn (and B for that matter) far more common in the natural substrate (available) to the plant OR is the Fe at very low levels in the substrate compared to the Mn? You mentioned some species like the early sanderianums being very susceptible to Fe toxicity. Was this due to the Fe being supplied as chelate or was Mn level supplieid to low? Obviously if the pH is too low the Fe can become toxic but so can the Mn so it must not be a pH issue.


----------



## Stone (Aug 6, 2013)

Brabantia said:


> I remember me have read someplace that ideal ratio NNH4 / Ntotal in hydroponic culture was 1/6 (83 % NNO3: 17 % NNH4). Reason is probably not physiological but chemical (pH stabilization due to both forms assimilation of nitrogen).



The reason for the high nitrate in hydroponics is because of the very low cation exchange of the solid media so the risk of NH4 toxicity is higher. Also the main way to supply the Ca is from CaN03. I think pH is adjusted automatically in big commercial setups (but not sure)


----------



## Roth (Aug 6, 2013)

Stone said:


> Roth said:
> 
> 
> > Xavier, This relationship between Mn vs. Fe is interesting. But what is going on? is the Mn (and B for that matter) far more common in the natural substrate (available) to the plant OR is the Fe at very low levels in the substrate compared to the Mn? You mentioned some species like the early sanderianums being very susceptible to Fe toxicity. Was this due to the Fe being supplied as chelate or was Mn level supplieid to low? Obviously if the pH is too low the Fe can become toxic but so can the Mn so it must not be a pH issue.
> ...


----------



## naoki (Aug 7, 2013)

Could the reason of the high concentration of Mn be that those analyzed orchids are using nitrates than ammonium as the main source of N? Traditionally, Mo requirement is thought to strongly depend on the mode of N supply, right? One of the four known Mo-containing enzymes is Nitrate Reductase, and NO3 without Mo causes severe effects on growth but NH4 doesn't seem to depend on Mn.


----------



## Brabantia (Aug 7, 2013)

Stone said:


> The reason for the high nitrate in hydroponics is because of the very low cation exchange of the solid media so the risk of NH4 toxicity is higher. Also the main way to supply the Ca is from CaN03. I think pH is adjusted automatically in big commercial setups (but not sure)


Yes in tomatos production greenhouses, pH is regulated via remote regulation system: pH electrode/computer/fine metering pumps.


----------



## Brabantia (Aug 7, 2013)

@Xavier
Now do you use the solution of micro-nutrients described in your publication " Paphiopedilum culture and distribution, concepts and guidelines "?
In this solution you have 0.4 ppm of Iron and nearly 1 ppm of Manganese.


----------



## Roth (Aug 7, 2013)

Brabantia said:


> @Xavier
> Now do you use the solution of micro-nutrients described in your publication " Paphiopedilum culture and distribution, concepts and guidelines "?
> In this solution you have 0.4 ppm of Iron and nearly 1 ppm of Manganese.



Yes indeed... I use that one still. But many hydro setups have up to 2-3 ppm of iron and 0.2-0.4 ppm of manganese, still the manganese is higher than iron in the foliar analysis... Cymbidium comes to mind. Though when I advise, I correct that quickly...


----------



## Ray (Aug 7, 2013)

So does an epiphytic order, living attached to a tree branch, naturally see more nitrate or ammonium nitrogen? How about one living in the leaf litter, or in the sediment in between rocks?


Ray Barkalow
Sent using Tapatalk


----------



## Brabantia (Aug 7, 2013)

@Xavier, thank you for your fast response.
Your values for Iron and Manganese (versus Klite or MSU) are very high but when I calculate the Total Nitrogen content of the solution with which you are feeding I find 180 ppm (NNO3 + NNH4). Probably its conductivity is around 800 µS ... very hight ... is this correct?
PS: I consider that the weights for AN, Potassium nitrate .... are also for one liter.


----------



## naoki (Aug 7, 2013)

Ray said:


> So does an epiphytic order, living attached to a tree branch, naturally see more nitrate or ammonium nitrogen? How about one living in the leaf litter, or in the sediment in between rocks?
> 
> 
> Ray Barkalow
> Sent using Tapatalk



According to this article which was mentioned before, it seems to be about 1:1 in this study (on the tree):

http://aob.oxfordjournals.org/content/75/1/5.short

and organic N is about half of NO3.

These orchids seem to show slight preference for NH4 over NO3 (according to Table 2). This paper is rather statistic-free, so the preference should be considered as just a "trend". The net absorption of organic-N was small or negative.

But I'm guessing that different host tree, region, proximity to human activity could influence the ration in stem flow. So the ones with high Mn in Xavier's study could be exposed to a different ratio.

On the ground, nitrification by bacteria could change the ratio toward NO3. Nitrification is generally rapid in warmer, well-aerated, less acidic soil. So, this is another factor.


----------



## Rick (Aug 7, 2013)

naoki said:


> The algae paper is coming up with the hypothesis of proton/charge balance is maintined across the plasma and chloroplast membrane by counter- and co-transportation, isn't it? I think it's trying to say that K is not involved in this process.



The issue missed is that plants have no way of regulating K. Plants don't have kidneys. The element is regulated via its low availability in the environment. In orchids K requirement forced adaptation of living with low carbohydrate production. Seeds and fruits with no starch storage, deceptive pollination flowers with no food rewards.....

In the algae paper K is mobilized well beyond its utilization capacity forcing pH beyond metabolic limits. In a related paper by the same author (I'm not sure if its one of the 3 or so all from the same series I linked to you), cellular pH is raised to metabolically lethal levels. This particular paper was rather detailed on the mechanisms of K inhibition on photosynthetic function.

These authors were/are planning on using K to eradicate these algae from places they are considered nuisance or detrimental. The K dose to control macrocystis would be somewhere between 200 to 300ppm. At those concentrations of K, that would also wipe out the bulk of the mollusc fauna in those waters (so sent a warning email to the authors of unintended consequences).:wink:


----------



## Rick (Aug 7, 2013)

naoki said:


> According to this article which was mentioned before, it seems to be about 1:1 in this study (on the tree):
> 
> http://aob.oxfordjournals.org/content/75/1/5.short
> 
> and organic N is about half of NO3.




Did anyone notice that the total of any one of these forms of N (ammonia, nitrate, "organo) was less than 2ppm!! Table 2 page 11

So what's going on when we apply these things at 10,50, 100, 200ppm?

You're just managing a cesspool, not growing orchidsoke:


----------

