Signs of genuine macro nutrient deficiency

[scottward]

Hi,

I'm not actually having any nutrient problems at all - just thought I would post this for the sake of discussion, to better my understanding.

I've now learnt that it's usually a CO2 limitation that causes a whole host of problems, not an excess nutrient/not enough light issue as many books etc will have you otherwise believe.

But for a moment lets flip this on it's head....

Imagine we have an aquarium that is ticking along very nicely. Photoperiod is good, CO2 is non-limiting, nutrients are non-limiting (EI).

Now, let's NOT dose any nitrogen.

Given that Light, CO2 and other nutrients are good, what are the true signs of a nitrogen deficiency?

Similarly, if we only hold off dosing Phosphorous what we be the expected signs of deficiency?

And again for Potassium?

Don't want to discuss micros (...yet). ;-)

And, to keep things simple, lets assume there aren't any fish in the tank, so no fish food etc. Nutrients only come from EI dosing.

Scott.

[Gerryd]

Hi Scott,

I always think of it as a chain reaction as each of these elements work together to form other links in the chain.....

I cannot answer your question but think you would need a rigorous control to ensure that the symptoms are 100% caused by the limitation of X nutrient.

So if N is limited and it affects the K or P is it now more the reaction of the K or P that is more the cause, or the original reduction of N?

I hope/am sure Tom will chime in for this one :)

[Tom Barr]

To address CO2 issues and other factors, many use hydroponics to address this test.

You can find plenty of references for many plants done this way/method.
Many deficiencies look similar and are different on different plants.
Adding to that, no tables showing deficiencies I've ever seen.......include dissolved CO2;)

It's(dissolved CO2) just not studied in an agricultural sense.
But most aquarists simply glaringly overlook it.

This is extremely short sighted.


Regards,
Tom Barr

[Philosophos]

As Tom said, there aren't any that include CO2. I've looked a long while for it.

Here's where I refer to every now and then when I come across strange symptoms:
Nutrient Deficiency (http://www.thekrib.com/Plants/Fertilizer/nutrient-deficiency.html)

I had another one that was agricultural, and while the pictures didn't always match, the description of what happened to the plants was excellent, even for trace elements. I wish I could find it again; if I do, I'll send you the link.

-Philosophos

[baron von bubba]

this is another good link.
James' Planted Tank - Plant Deficiencies (http://www.theplantedtank.co.uk/deficiencies.htm)
pretty similar to the one philosophos posted tho


for terrestrial plants not sure of accuracy and usefulness but seems comprehensive enough!

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[scottward]

Cool; thanks guys. I will have a read...