My suggestion was that since the calcium is supplied as calcium hydrogencarbonate, the hydrogencarbonate should react with the H+ and get transformed to CO2. This will then evaporate particularly since its pumped through an impeller type pump. The remains iare then salts of sodium..
Macroelements/microelements must be a costant ratio?
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My suggestion was that since the calcium is supplied as calcium hydrogencarbonate, the hydrogencarbonate should react with the H+ and get transformed to CO2. This will then evaporate particularly since its pumped through an impeller type pump. The remains iare then salts of sodium..
A
ALToronto
Guest
The liquid phase of H2S has an affinity for D2O, while the gaseous phase attracts H2O. It's a multi-stage process that achieves over 99% purity.
myxodex
Well-Known Member
Interesting discussion. With some reservations, I go along with those that suggest not to worry too much about micro concentrations as even at higher dilutions you are probably still providing more than enough. I think the cationic transition metal micros (TMs) can potentially become toxic if allowed to build up in the medium. This toxicity may not be enough to kill the plant in normal practice but could harm the roots or at least be a source of continuous low level oxidative stress, which the roots would be happier without, especially in the context of sulphur-limited fertilization. If you let the medium partially dry out between waterings, then you could get an accumulative precipitate of TM-phosphates on the substrate which could then act like a timebomb if the medium pH subsequently drops. I guess that in the wild most orchids are probably more tolerant of pH fluctuations than they are in culture simply because of the high nutrient levels we traditionally throw on our plants.
The situation could be a bit more complicated when a particular micro is provided in excess. The TM micros do compete with each other for uptake and excess of one can cause deficiencies in another. One of the most surprising is nickel, which is thus far only known to be needed for the urea cycle (urease) and is needed in vanishingly small quantities. Producing a nickel deficiency experimentally is extremely difficult, everything that goes near the plant has to be ultra, ultra pure because the smallest trace of Ni will invalidate the experiment. The real surprise is that Ni deficiencies, although rare, do occur in agriculture, and are nearly always caused by an excess of one of the other micros, or Ca, high phosphate and pH.
Bjorn pointed out Roths comments on micros, which I agree is worth reading. The difference in element analysis of leaves of wild versus cultivated plants highlighted the lower Fe to Mn ratio in wild plants. What caught my eye in this was the lower concentration of both Zn and Cu in cultivated plants and I have a (probably crazy) idea as to why this might happen. In short the culprit might just be EDTA. Most media use EDTA to complex iron as Ferric / Fe3+ because it is the more stable chelate. The chelate stabilities for the TM micros with EDTA are as follows, Fe+++ ~ 25, Fe++ ~ 14, Mn++ ~ 14, Zn++ ~ 16.5, Cu++ ~ 18.8 (couldn't find a figure for Ni). Remember that these stability constants are on a log scale. The plant is simply not going to get the Fe+++ from the EDTA unless it is reduced to Fe++, and this is what happens in the root by the activity of iron chelate reductase. The free Zn++ and Cu++ will now displace the Fe++ from the EDTA even if they are 10 to 100 fold more dilute. Some Australian scientists have demonstrated that EDTA does enter the plant root and a proportion of this moves up to the shoots. EDTA is not broken down, it is enviromentally and physiologically persistant. One bacterium species has been found to degrade it slowly under specific conditions but this is irrevelant here, the prediction is that EDTA will accumulate, mostly in the plant roots, and this will lower the available concentration of Cu and Zn.
Just to muddy the waters even more there are the hyperaccumulator and hypertolerant plants that grow in soils that have toxic levels of say Cu, Zn, Ni etc. These are interesting because they are exceptions to the norm and have been extensively studied for the purposes of phytoremediation of metal polluted enviroments. A spin-off of this research is an increased knowledge of what "normal" is and just how variable micro concentrations and tolerances are across plant species and even between closely related species. For an extreme example, there is a hyperaccumulator in New Caledonia, Pycnandra (formally Sebertia) acuminata that produces a green latex that is up to 25% Ni dry weight. There are not many pests that will chew on that. BTW, talking of eating hyperaccumulators, there is a Mexican delicacy called "caca de luna". Not a plant, but a slime mould, Fuligo septica, (aka "dog's vomit slime mould"), can contain up to 20g/Kg dry weight Zinc and up to 15g/Kg Barium. Not high on my list of things to try.
The situation could be a bit more complicated when a particular micro is provided in excess. The TM micros do compete with each other for uptake and excess of one can cause deficiencies in another. One of the most surprising is nickel, which is thus far only known to be needed for the urea cycle (urease) and is needed in vanishingly small quantities. Producing a nickel deficiency experimentally is extremely difficult, everything that goes near the plant has to be ultra, ultra pure because the smallest trace of Ni will invalidate the experiment. The real surprise is that Ni deficiencies, although rare, do occur in agriculture, and are nearly always caused by an excess of one of the other micros, or Ca, high phosphate and pH.
Bjorn pointed out Roths comments on micros, which I agree is worth reading. The difference in element analysis of leaves of wild versus cultivated plants highlighted the lower Fe to Mn ratio in wild plants. What caught my eye in this was the lower concentration of both Zn and Cu in cultivated plants and I have a (probably crazy) idea as to why this might happen. In short the culprit might just be EDTA. Most media use EDTA to complex iron as Ferric / Fe3+ because it is the more stable chelate. The chelate stabilities for the TM micros with EDTA are as follows, Fe+++ ~ 25, Fe++ ~ 14, Mn++ ~ 14, Zn++ ~ 16.5, Cu++ ~ 18.8 (couldn't find a figure for Ni). Remember that these stability constants are on a log scale. The plant is simply not going to get the Fe+++ from the EDTA unless it is reduced to Fe++, and this is what happens in the root by the activity of iron chelate reductase. The free Zn++ and Cu++ will now displace the Fe++ from the EDTA even if they are 10 to 100 fold more dilute. Some Australian scientists have demonstrated that EDTA does enter the plant root and a proportion of this moves up to the shoots. EDTA is not broken down, it is enviromentally and physiologically persistant. One bacterium species has been found to degrade it slowly under specific conditions but this is irrevelant here, the prediction is that EDTA will accumulate, mostly in the plant roots, and this will lower the available concentration of Cu and Zn.
Just to muddy the waters even more there are the hyperaccumulator and hypertolerant plants that grow in soils that have toxic levels of say Cu, Zn, Ni etc. These are interesting because they are exceptions to the norm and have been extensively studied for the purposes of phytoremediation of metal polluted enviroments. A spin-off of this research is an increased knowledge of what "normal" is and just how variable micro concentrations and tolerances are across plant species and even between closely related species. For an extreme example, there is a hyperaccumulator in New Caledonia, Pycnandra (formally Sebertia) acuminata that produces a green latex that is up to 25% Ni dry weight. There are not many pests that will chew on that. BTW, talking of eating hyperaccumulators, there is a Mexican delicacy called "caca de luna". Not a plant, but a slime mould, Fuligo septica, (aka "dog's vomit slime mould"), can contain up to 20g/Kg dry weight Zinc and up to 15g/Kg Barium. Not high on my list of things to try.
D
DavidCampen
Guest
The formulations that I am making and using are just based on my guesses from my observations and reading but there is no scientific testing other than that I use these formulations and my plants seem to thrive.
The nitrate to ammonia ratio is 3.8 to 1, again, just a guess at what might be most beneficial.
Most commercial water soluble fertilizer formulations don't even specify the S content. I think my levels of sulfate are significantly higher than typical single package formulations and that the low levels in commercial formulations are one reason that people see beneficial effects when supplementing with epsom salts (magnesium sulfate).
To the comment re in another post about chelates. The only complexing agents that I use in my formulations are citric acid, aspartic acid and ammonia; all are very much weaker than EDTA. I add iron to my formulations as ferric ammonium citrate (green form); the concentrate that contains the ferric ammonium citrate has to be stored in an amber bottle to prevent light from causing the iron to precipitate (via conversion of the ferric ammonium citrate from its green form to its black form).
Rick
Well-Known Member
This has the potential to be a wonderful low K feeding solution, but you didn't mention what type of water they use for irrigation between.
Even if the total K content of the tree fern is relatively high (say 1% dry weight) the plant only access a tiny portion of the mount by the roots (which are not that long in this species), and they only get the K when the material is broken down . If the original mount is in good shape after 8 years then virtually no K was contributed by the tree fern. If you think tree fern has a high leachable K, then that is even more finite and short term than total K.
I can't imagine that a vertical/porous mount will hold that much osmocote (or dolomite for that matter), and osmocote is also slow release. Very little would ever be in contact with a root, and most would get washed away by the frequent misting/watering typical for a mounted Bulbo on a non-water retentive mount.
The occasional dunks in something similar to the old MSU are probably the most significant K input, and getting closer to how I treated my plant with weekly dousing at 80-100ppm N (100ppm + K). But I was dosing weekly, and I don't know what "now and then" is. Plus I was using RO water at the time, so no additional Ca inputs beyond that in MSU.
So maybe you can do more math and fill in the blanks, but I suspect my K exposure in the good old days was way higher than your friends plant has experience over the last 8 years.
Most of my Bulbos grow year round without a defined growth season, and with all being mounted, water restriction is not an option if I don't want to crispy critter them.
Rick
Well-Known Member
This area worries me more when I think about flasking medias, and how concentrated they are relative to the normal environment.
David thanks a lot for valuable input. And Myxodex the same to you. You guys got me thinking now.
As it happens I have been feeding with a fertiliser composed to be used as a foliar feed. This has been based on urea as the nitrogen source and its pH has been higher than I wanted. So, I have been using rater high amounts of citric acid to get the pH of my stock solution down to the wanted level of approximately 4. In hind sight, I realise that much of that citric acid has been consumed to complex other components of the mix, not only to suppress the pH increase caused by the (probably enzymatic) decomposition of urea into CO2 and NH3 that I have seen in the stock solution. Now, here to the point; are there any experiences connected to such a complexation in this context? Does it make the cations more (or less )available etc?
And also, and a bit on the side but related; what does such a complexation do to the conductivity of the solution? Anyone that has experiences?
Thanks in advance.
PS Myxoydex, I'd love to hear more about your culinary specialties, where are you located?
As it happens I have been feeding with a fertiliser composed to be used as a foliar feed. This has been based on urea as the nitrogen source and its pH has been higher than I wanted. So, I have been using rater high amounts of citric acid to get the pH of my stock solution down to the wanted level of approximately 4. In hind sight, I realise that much of that citric acid has been consumed to complex other components of the mix, not only to suppress the pH increase caused by the (probably enzymatic) decomposition of urea into CO2 and NH3 that I have seen in the stock solution. Now, here to the point; are there any experiences connected to such a complexation in this context? Does it make the cations more (or less )available etc?
And also, and a bit on the side but related; what does such a complexation do to the conductivity of the solution? Anyone that has experiences?
Thanks in advance.
PS Myxoydex, I'd love to hear more about your culinary specialties, where are you located?
Stone
Well-Known Member
Stone
Well-Known Member
Haven't the concentrations of nutrients in flasking media been determined as optimum? Remember it's asymbiotic culture....
:sob::sob::sob::sob::sob::sob:
D
DavidCampen
Guest
Citric acid is a very weak complexing agent for the elements we are interested in except for Fe(III).
http://george-eby-research.com/html/stability_constants.html
Interesting reading, the way I interpret the table is that a relatively weak bonding should be better for plant availability than stron bonding. The complex is less stable, but its metal more available for plant nutrition. Or am I entirely lost here, pls correct if I am wrong
D
DavidCampen
Guest
That is my opinion.
Also, as was previously mentioned, the stability constants are given as base 10 logarithms. So the difference in stability of a value of 3 compared to a value of 6 is a factor of 1000.
Yes in a sense logK is similar to pH (just that pH is the negative log). I used to be quite familiar with these things earlier. I assume the brackets are for concentration(Molar) although the text just says amount. Checked citric acid and found thatit improves availability of iron as opposed to iron sulphate when applied to citrus. Seems as if chlorosis is a big problem for citrus.
myxodex
Well-Known Member
Interesting reading, the way I interpret the table is that a relatively weak bonding should be better for plant availability than stron bonding. The complex is less stable, but its metal more available for plant nutrition. Or am I entirely lost here, pls correct if I am wrong
I wouldn't worry too much about stability constants and availability in plants, although it would probably be better if the stability constant was lower than that for nicotianamine, which is the main chelator used for transporting these metal ions in plants and has quite high constants for transition metal ions. See following papers;
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC32093/
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2004.01209.x/full
myxodex
Well-Known Member
Bjorn, I'm located in London, UK. Actually I grew up in Kwazulu Natal, South Africa before moving to London in 1982 and I'm really a bit squeamish about eating some of the unusual delicacies out there. For instance, I do like a bit of biltong (dried spicy meat) on occasion and visit a South Afican shop in London that sells some of better quality. They also sell mopani worms (another African delicacy) and I was encouraged to try them, but I just could not bring myself to eat them, despite having previously eaten fried flying ants (termites actually). I did do a course in mycology at university in SA and I do sometimes forage for wild mushrooms in late summer/autumn. One august during the late eighties I went walk-about, i.e. hiking/camping in Wales and found lots of chanterelle mushrooms in the woods. They were abundant and delicious, fried up with some garlic butter on my camp stove, and I couldn't understand why the locals didn't eat them. Later I found out that chanterelle is an accumulator of caesium, and that there was measurable (although not high) fall out of caesium-137 in Wales from the Chernobyl disaster the previous year. So I might just have eaten radioactive mushrooms ?
The information I stumbled across about "caca de luna" which means "**** of the moon" , brought back some memories of working with slime moulds for my MSc thesis project in SA. I would go out collecting them in the bush and bring them back to the lab and attempt to cultivate them axenically,... I only had success with two species, but I was unaware at the time that they are, or can be, hyperaccumulators. This group of acellular slime moulds are called myxomycetes (or at least were) ... and my pseudonym here is a nick name I had acquired from my friends at this time. For those with curious minds, a nice video of a slime mould eating fungi and of sporangia formation: https://www.youtube.com/watch?v=GY_uMH8Xpy0
Also slime moulds as self organising systems and computing research: https://www.youtube.com/watch?v=oEyWwUNj_es
BTW, the S/N ratio of David C's fertiliser is well within range, any more would most likely just be excess and not assimilated. I found the differences between different reports when doing some literature research on this were sometimes due to different conventions in expressing concentrations (S is sometimes expressed as SO3). I really dislike the oxide convention for fertilisers because it is so inconsistent. I recently dabbled in making up my own pottery glazes, and looked into ceramic glaze calculations where everything is expressed as the oxide, and in this context it makes perfect sense and is consistent, but for fertilisers, not so much.
The information I stumbled across about "caca de luna" which means "**** of the moon" , brought back some memories of working with slime moulds for my MSc thesis project in SA. I would go out collecting them in the bush and bring them back to the lab and attempt to cultivate them axenically,... I only had success with two species, but I was unaware at the time that they are, or can be, hyperaccumulators. This group of acellular slime moulds are called myxomycetes (or at least were) ... and my pseudonym here is a nick name I had acquired from my friends at this time. For those with curious minds, a nice video of a slime mould eating fungi and of sporangia formation: https://www.youtube.com/watch?v=GY_uMH8Xpy0
Also slime moulds as self organising systems and computing research: https://www.youtube.com/watch?v=oEyWwUNj_es
BTW, the S/N ratio of David C's fertiliser is well within range, any more would most likely just be excess and not assimilated. I found the differences between different reports when doing some literature research on this were sometimes due to different conventions in expressing concentrations (S is sometimes expressed as SO3). I really dislike the oxide convention for fertilisers because it is so inconsistent. I recently dabbled in making up my own pottery glazes, and looked into ceramic glaze calculations where everything is expressed as the oxide, and in this context it makes perfect sense and is consistent, but for fertilisers, not so much.
Just for your information. When I compare oligo's at equal concentration of Nitrogen the KLite have a contain two time higher in each element (and for some a little bit more) than in Cal Mg Everris (ex Peters). So I think it is enough (in KLite) also at high dilution.
PaphMadMan
phytomanic
I would assume that few media formulations have actually been optimized - maybe for major nutrients but only for one or a few test species. HUGE amount of work even then - just 3 nutrients at 5 concentrations each is 125 combinations to test, with replicates of each. And especially for micros, anything in a broad range above deficiency is probably indistinguishable.
myxodex
Well-Known Member
Exactly! ... very good point, not to mention getting the funding for orchid research.
I've been doing a lot of head scratching about this of late. I think that some of the ideas behind flasking media have been brought across from plant tissue culture/biotechnology studies mostly focused on crop plants (just a guess ... follow the money as they say).
In general for the formulations I've looked at, the replating media are more concentrated than the germination media in cases where different media are used. I guess the thinking is that you have to supply nutrients for a year or more growing time. The alternative, short of using some slow release (zeolites perhaps ?), is to use liquid culture with some suitable support for the seedlings that would allow for regular medium changes, ... although this would likely increase contamination rate and require a well equipted lab.
