K-lit after 6 months

[TyroneGenade]

Your previous statement was "The experiments with CHC suggests that it will preferentially hold onto K and Na over Ca and Mg" Now you are saying the opposite.

Yes, on rereading my post I see I have fallen into the same trap as equating the cation exchange capacity (the resin element) with the chemical reactions between the phenolic matrix and Ca/Mg. This was not my attention. Rather, what was meant, is that the experiments/experiences are that the resin-character of CHC will preferentially accumulate K while absorbable Ca & Mg is either washed out or (in the case of Mg) its absorbence in inhibited by the uptake of K. This is easy to see on mediums. Ca/Mg phenolic salts are brown in color but the salt building up on organic mediums tends to be white---K and Na salts. It is these salts that accumulate in the medium.

But this discussion is useless. I have previously proposed a testable hypothesis in http://www.slippertalk.com/forum/showpost.php?p=427088&postcount=23 which was that: by feeding low-K fertilize the excess of K in the substrate is avoided and the plant can assimilate sufficient Mg and B.

Leaf/stem analysis of plants fed high and low-K fertilizers should find that the low-K plants have more Mg and B than the high-K plants. Testing the hypothesis is the only means to arrive at any certain answer. This philosophical banner is of no use for we have no certainty over the various claims. What we do have are lots of people who have switched to K-light and have seen improvements in their plants. I was looking at my Seagrow fertilize this morning and notices that is a K-lightish fertilizer with 70 g/kg N but only 15 g/Kg K (with 0.5 g/kg Ca and 1.7 g/Kg Mg).

Unless we do the experiment we can argue forever and not get anywhere.

And for the last TIME the Antec site is NOT the reference for CHC holding onto K preferentially to Ca/Mg. I am still trying find that reference again.

 

[Stone]

Mike, I agree with you, that a controlled study would be benificial. I think you are being overly sensitive to what was intended as a constructive comment.

Trithor, I reread my post to see where you may have come up with the notion of oversensitivity but it beats me! I think you may have assumed your comment was seen as offensive or critical to me in some way. Farthest thing from my mind! Not at all! I welcome all comments equally. And I agree that the more people who have the disipline to carry out such a trial the better. I just disagree with your contention that it would only apply to insigne, nothing more.
As far as being overly sensitive....Impossible!.. I'm the most insensitive person I know:rollhappy:

Anyway, you can talk about cation exchage etc but the real test is in the growing.
So who else is up for a 2 year commitment?
Minimum of 6 plants?
Minimum of 2 control?
Preferably 3 different fertilizer formulations, one with NHO4 or UREA as the main N source
Everything must be EXACTLY the same apart from the fertilizer
Plants should be the same clone the same size with a similar root system.
Fertilizer solution should have the same EC and always be applied at the same time.
Water one water all. Spray one spray all.
Plants should be positioned right next to each other
Plants should all be repotted at the same time in the exactly the same mix
Pots should be identical

 

[TyroneGenade]

Ok,

I'm still battling to find my original reference but my memory did bring be back to this: http://www.apsa.co.za/board/index.php?topic=4213.msg41180#msg41180 and http://www.sciencedirect.com/science/article/pii/S0960852401001894

First, Erik Biksa holds a diploma in agriculture with majors in fertilizer sciences and crop production and the article quoted in the above link is from Maximum Yield Magazine. Sadly, I can't find the original article.

the ScienceDirect article gives K, Na, Ca and Mg values before treatment for growing. These are respectively, on average, 24.26, 7.13, 0.82, 0.95 mol m−3. Now compare those values to the treated CHC values given by Erik. Note that the medium still contains a lot of K and Na after being treated with high concentrations of Ca. Whether CHC likes K or just continues to release cannot be told from this data but, being a cation exchanger, it accumulates what it is given and releases in proportion to the solutes in solution. If you supply high K it will accumulate more K to the resin and not be inclined to release it. The chemical process is governed solely by equilibrium kinetics and the law of mass action. That is the theory at least. And this can be tested as follows:

Take some new CHC and some old CHC fed high K and another lot of old CHC fed low K. Take 1 kg of each, dry it out and burn it. You are left with various oxides. Take 10 g of the ash and dissolve it in 100 mL of dilute 1M HCL. You will now have solutions of K, Na, Ca and Mg Cl etc... as well as insoluble precipitates. Redry the precipitate and measure the mass. 100 mL HCl would need 13.8 g of K2CO3 to neutralize the acid and precipitate the Ca and Mg salts. K2CO3 is very soluble in water (112 g/100 mL) so, again collect the precipitate to dry and weigh (this will be mostly Ca and Mg carbonate). You can again neutralize the K2CO3 with dilute HCl and then evaporate the solution. 13.8 g of K2CO3 is 7.79 g of K so the difference between the mass of the salts in solution and 7.79 g is the mass of K/Na from the CHC.

Assuming I can't find the original reference I had the above is the experiment to finally settle the issue. It would work as well for bark and LECA (except with LECA you can just wash the pellets in the acid to start with).

While we can continue to argue the issue only the experiment will reveal whose hypothesis is wrong.

 

[Ray]

Just a small caveat: Folks who are knowledgeable about crop nutrition tend to have no knowledge about epiphyte nutrition, but also tend to assume its similar - which it is obviously not.

 

[TyroneGenade]

Ok,

I have found a reference (but not the original one I found). The article is: Charlo , H.C.O., Ferreira, A.F., Vargas, P.F., Castoldi, R., Melo , D.M. and Braz, L.T. 2012. ALTERATIONS IN LEVELS OF NPK, ELECTRICAL CONDUCTIVITY AND PH OF SUBSTRATE, IN CULTIVATION OF PEPPERS. Acta Hort. (ISHS) 927:437-442
http://www.actahort.org/books/927/927_54.htm

In it potassium content of CHC is followed over 189 days. The pepper plants grown in the CHC are given (in addition to other ferts) 6.18 mmol/L K per daily (using "fertigation"). Ca and Mg are 3.96 and 1.34 mmol/L respectively. Over the 189 days the level of K in the CHC climbs from about 120 to 270 mg/L.

Another paper, from the same author: (Charlo , H.C.O., Ferreira, A.F., Castoldi, R., Vargas, P.F., Barbosa, J.C. and Braz, L.T. 2012. CHEMICAL ALTERATIONS OF SUBSTRATE IN THE CULTIVATION OF PEPPERS . Acta Hort. (ISHS) 927:443-448 http://www.actahort.org/books/927/927_55.htm) tracks changes in Ca and Mg in the CHC and that shows an increase from about 10 and 5 to 240 and 110 mg/mL.

How this fertilizer regime compares to K-light I have no idea but CHC definitely does accumulate K. Whether CHC would accumulate more K if the K concentration of the fertilizer was greater is an open question but I did find a commercial fertilizer (designed for CH products) stating that "

“The nutrient you use on coco is going to be extremely important,” said Canna’s David Hill, adding that growers should be cautious when using flowering enhancers loaded with high levels of potassium, which competes with magnesium to bind with coco, upsetting the nutrient balance in the root zone.

The K-light vs K-absorbing nature of organic mediums is a neat hypothesis that explains the better results had by K-light over K-heavy fertilizers. If there is another, better, hypothesis or direct evidence refuting this hypothesis I would like to know about it. In the mean time, experiments by which to test this hypothesis have been suggested and if anyone can do those experiments than we would know whether the hypothesis is wrong.

 

[DavidCampen]

either make your own statement about how something does or doesn't work, which is productive, or please refrain from being a dart-thrower. I am only asking politely,

If you consider challenging erroneous statements to be throwing darts then you are saying that you want to believe in fantasies.

 

[TyroneGenade]

I must confess to having a lot of appreciation for dart-throwers. Tough scrutiny makes for a stronger theory as well as uncovering the the critical question. The brilliance of Socrates was in asking the write questions. His method eventually gave us Modern Science and the various fruits it has born through Engineering, Medicine, Agriculture etc... While it irks me having to put up with nit-picking it is the price paid for thorough discussion.

 

[cnycharles]

If you consider challenging erroneous statements to be throwing darts then you are saying that you want to believe in fantasies.

When someone only spends their time trying to poke holes in other's statements, then it is largely negative. Come up with some ways on your own to discredit what you find to be inaccurate. I've already said this. Poking at me instead of coming up with a said scientific rebuttal also is dart-throwing.

 

[ALToronto]

I will repeat the offer I posted on Orchid Board, to design a statistically valid experiment that will test not only the single effects of K, Mg and Ca absorption, but interactions between different variables as well.

 

[gonewild]

I will repeat the offer I posted on Orchid Board, to design a statistically valid experiment that will test not only the single effects of K, Mg and Ca absorption, but interactions between different variables as well.

What is your offer?

 

[Markedg]

Where to buy KLite in Europe

Hi all,
This is slightly off topic but does anyone know where in Europe I could buy the KLite formula? I have read this thread and the article in March 2013 orchids magazine, and it does make sense. Some of it is over my head though. I have no issues growing cattleyas but I do have some issues with paphs/phrags. I see that Ray in the us does sell it and will ship to Europe but I would be a bit concerned that when it gets to me in Dublin, Ireland, it could be confiscated as they might think I was trying to build something else with it. Thanks.

 

[Ray]

As far as I know, firstrays.com in the US is the only commercial source. I have shipped it to any number of countries without issue, other than the seizure of a larger volume in Colombia.

 

[Stone]

I will repeat the offer I posted on Orchid Board, to design a statistically valid experiment that will test not only the single effects of K, Mg and Ca absorption, but interactions between different variables as well.

Lets have it

 

[Rick]

The K-light vs K-absorbing nature of organic mediums is a neat hypothesis that explains the better results had by K-light over K-heavy fertilizers.

The pot chemistry aspect seems to be only one facet of the benefits. I probably have roughly 50 mounted plants with little or no media around the roots and those plants have also improved dramatically. Also Ray is a SH grower with constant root immersion. That's also quite a different system from standard high absorbent organic media.

You also mentioned looking at leaf tissue data, and one of the references in my article does look at K in leaf tissues with and without K supplementation (in Bromeliads).

Two foods (for weekly feeding, with daily non feeding irrigation between feedings).

Solution with K was 45 ppm N, 90ppm PO4, 90ppmK , 14ppm Ca and 5ppm Mg
Same numbers for the non K feeding except no K (sodium subbed for the Kphosphate salts). All nitrogen came from ammonium nitrate.

Leaf tissue K definitely was increased with presence of K by a factor of 5X in younger fast growing leaves. The experiment was only run for 250 days. No difference in size and condition of plants noted at the end of the test.

The test was short, and no measurements of Ca and Mg were conducted. Leaf tissue K in wild collected plants was measured /compared in 16 species/6 different studies. All lower K than GH grown plants in above study.

Other parts of the paper include using rubidium tracers (as a K surrogate) for determination of uptake rates and mechanisms in bromeliads.

Conclusion was that bromeliads actively appropriate K (not just passive osmosis) through both roots and leaf trichomes. And K is inducted well beyond metabolic needs for luxury storage.

 

[Rick]

5. Excess K disrupts the uptake of Mg and Boron (from the chart).

Actually in most plants this has been tested on already, (rice, cotton, beans, potatoes, even some orchids), increased K generally disrupts uptake of Ca first, Mg secondarily. Phosphate when Ca and Mg are trashed. The rice paper experiment is hydroponic so doesn't take organic media effects into account.

There was a good study done by Cornell university (I think in 1977) that Stone posted a link on a ways back. It was only short term (9 months), but run on Catt, Cymbidium, and Phaleanopsis hybrids.

Leaf tissue concentrations were measure in different manipulations of increasing (separately) N P K and Mg. For the study with increasing K (everything else stable). Ca dropped (significantly) in leaf tissue in all 3 genera. Mg dropped significantly in only one or two of the genera. PO4 was not measured in the K increase study. The K concentrations ranged from 50 to 300 ppm (depending on the genus). So all concentrations above K lite range. Also Ca was held constant at 200 ppm through all manipulations, which is very high compared to growers using RO water and MSU or K lite.

Given how high the Ca was, it was interesting to see that leaf tissue K was always greater than Ca even for K doses lower than 200 ppm, and the magnitude increase in leaf tissue K with increased dose was also very strong.

The leaf tissue data actually conform well to the K uptake premiss of the bromeliad work.


Ca and Mg as K goes up Ca = 200, Mg = 25ppm


K ppm K% drW Ca%drW Mg%drW
Phaleanopsis
100 5.77 3.16 0.59
200 7.49 2.79 0.54
300 7.92 2.43 0.46

Cattleya
50 3.66 1.44 0.49
100 4.34 1.29 0.46
200 4.73 1.15 0.46

Cymbidium
50 2.48 1.05 0.38
100 3.00 0.91 0.32
200 3.31 0.88 0.30

 

[Rick]

Cut and paste of the excell data is a bit buggered up.

In each the first column is K dose
2nd column is % Dry Weight leaf K
3rd column is leaf Ca
4th column is leaf Mg

the heading notes that Ca was constant at 200 ppm and Mg at 25ppm while the K doses were manipulated as shown.

Note that even at the 50 ppm K dose, leaf K is > leaf Ca. In wild epiphytic plants it is generally opposite. I have an abstract of leaf tissue values from wild Asian/Indian orchids, and leaf K was always lower than leaf Ca and Mg.

So something is definitely weird in fertilized GH grown plants compared to their wild (unfertilized) counterparts.

 

[ALToronto]

Lets have it

First, I need to know if people here are serious about doing a trial. Then we need to figure out the logistics - who, which plants, in what growing conditions. Then I'll need input from the experts - what do we want to test, what do we want to vary, what do we want to keep constant. Only then can I start on the design matrix.

It's a serious, time consuming undertaking (designing an experiment), and I'm not going to spend time on it without commitment from enough people to make the experiment happen. If enough people want to commit, I will start a separate thread.

 

[Stone]

First, I need to know if people here are serious about doing a trial. Then we need to figure out the logistics - who, which plants, in what growing conditions. Then I'll need input from the experts - what do we want to test, what do we want to vary, what do we want to keep constant. Only then can I start on the design matrix.

It's a serious, time consuming undertaking (designing an experiment), and I'm not going to spend time on it without commitment from enough people to make the experiment happen. If enough people want to commit, I will start a separate thread.

There is no need to get too complicated. Somthing similar to what I mentioned in this thread above will do for our purposes. I do not have enough of one clone of plants to go higher than 2 to 3 for each group. Rather than equal EC as I suggested, we should instead stick to the same ppm N for each group. I would like to try 4 different fertilizer treatments for my own intrest. My control would be fed with a standard all purpose ''garden center'' fertilizer. In this case it would be an NPK of 23-3.95-14 + 6.6 S and 0.15 Mg. with most N as Urea.
Calcium and extra Mg would be supplied via 50/50 dolomite/limestone powder. This is the way most orchids are grown here so it would be a good starting point for the control.
For the other groups, one would be Klite of course, one a hydroponic formulation very similar to Klite but K/N ratio of 1.2 from memory and P/N ratio of about 0.18. with all N as Calcium nitrate form. And one should be a low P formulation as in Klite but normal K ( somewhere around 0.6 to 1 K/N ) That is important as the Klite has a P/N ratio of 0.1---the same as K/N= 0.1

That would give a good indication if the claimed klite success is from the low K or the low P. I don't see a reason to go more strict than that unless you want to make up your own formulations.

 

[TyroneGenade]

Rick, one of your claims is that seedlings fair better on the K-light (and I think your plants back this claim up nicely). If one uses deflasked seedlings for an experiment this will ensure high plant numbers needed for sound statistical analysis. Stating with seedlings also removed a lot of history from the plants that could end up being confounding factors.

I don't know, but using a CHC as the growing medium might be more telling than SH or bark. CHC from agric stores seems to come now in mostly the same standard product and I don't think many people grow in SH (though that will be my option when I start again). I think the experiment must be relevant to the "average" grower (and not the nuts the in either extreme of the bell curve).

I think 3 fertilizer regimes will be most useful to the average grower:
K-heavy without Ca/Mg supplementation
K-heavy with Ca/Mg supplementation
K-light (which I understand does come with Ca/Mg in any case)
The CHC would have been treated in Ca and Mg, but does extra Ca/Mg make a difference?

I think it is important to know how the quality of the medium changes (so we can satisfy David) so both the soil and leave mineral content would need to be tested.

Maudiae crosses seem to be very productive and good growers and have good resale protection (so some experimental costs can be recouped). So, does anyone have a bumper-crop mother flask to donate to science?

 

[Rick]

Most nursery plants are raised in bark mixes with no Ca added in the fertilizer

Also most nursery plants are watered with local surface or well waters (not RO water) with lots of soluble Ca and Mg available.

Nashville tap water has 25 ppm Ca, 9 or so ppm of Mg and 3 or so ppm K. Hardness is only 100 ppm as CaCO3 so by national standards this is not a high TDS water.

The water used for big nurseries in Florida used well waters with 3-4X these levels.

Obviously a lot of variation around the world, but it helps to know your basic local water chemistry for understanding what your plants get to see.