yme;45696 said:
yup, I think as well
I must say didn't know this. It also explains very well why P limitation in the old days, here in Holland, worked out very well.
follow-up question:
IF you assume that in an EI based tank you are not limited for CO2, P, N, Fe and light?.... can plants then be limited by a trace element for which there is no "back-up" mechanism? which then would results in stunting/problems?
deduced from this: would it be wise to increase TMG dosage together with iron dosage? or is it also just fine to increase iron dosage alone?
practically, as jonny_ftm pointed out, one can grow just perfectly grow healthy plants with TMG alone. Which would suggest that the answer to my questions would be: no.
greets,
yme
Liebig's law applies very well regarding limitation of growth, thus all the other non limiting nutrients and very importantly => the rates of growth.
What does Tropica do? I mean mostly? Grow aquatic plants commercially for sale to hobbyist in Europe.
How do they do this?
They use the same methods used by ornamental horticulturist.
In the winter, there's not much light, so they add extra artifically.
CO2?
They use the emergent growth and mist, plastic cover the wetland species.
No CO2 issues and no algae issues. Some pest management, but nothing too bad.
Nutrients? Most use fertigation and sand/bark media or rockwool as the case for Tropica.
Virtually all use this(95% or so), not just aquatic plant growers.
So the nutrients are sprayed directly on plants emergently and in much more concentrated forms than are typical for aquariums are used.
So Tropica dilutes these formulations down.
Many aquarist do not use CO2 or have high density planted tanks.
So dosing once a week is normal.
Traces came out initially since most had plenty of N, P from tap water and from fish waste etc.
The TPN+ with macros came out from a discussion I had with Claus some 12 years ago.
Likewise, Seachem's K+, N, P all are result of talking with Greg Morin.
PMDD came about from looking at Liebig's ideas and perhaps Gerloff's/Kromboltz(Paul who still post on AGA's web site here and there but use to help on the APD mailign list in the past)
Still, Given that the CO2 is independent with emergent growth, light etc, the ability as far as a method to demonstrate deficiencies, is the very used by hydroponics researchers, Hoagland himself etc.
So we can use the commercial growers own products, or make a similar one, Hoagland's etc hydroponically and emergently to answer such questions easily.As we add more complexity to things like CO2[aq], it becomes much more difficult to say as much and to set up a test that's repeatable.
Still, the method I suggested for hydroponics is the one used as a standard method to see about particularly nutrients in controlled study.
If someone has a simple effective way to ensure independence for CO2 and can show that adding these nutrients is going to cause an issue, I'd like to hear how they are makign sure CO2 is independent.
We know changing CO2 concentration can stunt tip growth in plants. We know that at the Fe concetrations in emergent growth(even 10x higher), this does not occur
This produces lots of doubt as to Fe and points more to issues with CO2.
I've been unable to demonstrate otherwise. Maybe someone else can, but I have to view it skepticism and curiosity.
I've poked around looking citations up that might be of use.
I've not found any for the concentrations we are interested in.
I think when adjusting traces, Fe is the biggest issue due to chelation being important, the others really do not need that.
Fine if they are chelated , but not a big deal.
Still, I think adjusting all the traces, not just Fe, seems wise when adding more.
But what about copper?
Shrimps? Copper is fine for plants at higher levels to about .4ppm or so.
That kills algae well, but some sensitive species of plants too.
So less copper if the other trace are raised, and richer copper ratios for leaner dosing.
Or where critters are concerned.
Fe is easy to add independently.
Still, for all the manipulation we do with NPKCaSO4Mg etc..........few do much to traces other than brand switching and Fe spiking.
Hard to test them also.
So many leave that one alone and unknown, is it significant?
I'm not sure. I do not know.
We do know that it works well for the plants we raise.
Could we get more out of the traces?
Perhaps, but for general use and for EI dosing, we have to make some assumptions which are fairly safe, I'd worry more about CO2 than EI given what we do know and have observed, seems much more likely to be an issue for most aquarist.
You can dose more than EI also if you think it is an issue and show that it does make a significant different.
I'm not sure it does and feel pretty good that its a non limiting nutrient reference.
But what do I know?
I could be wrong for some species.
But while easy to say, it's much harder to show that I am wrong.
No one has done that yet.
Regards,
Tom Barr