Re: [APD] N uptake from roots or leaves/shoot

[Thomas Barr <tcbiii at yahoo_com>]

> Is there some reason that nitrogen absorbed by the roots is
> more 
> effective than nitrogen absorbed by leaves, or any other
> nutrient?
> 
> -- 
> Jerry Baker

I would suggest that having N in both locations is best and a
little in terms of plant growth/health in both forms of N.
Likely that same can be said most any nutrient.

This way the plant would not have to transport the N from one
location to another. At higher growth rates, having nutrients in
both locations will become more important. 

The main benefit for most folks is the ease of use, it's easy to
add and not fret for the next few months about having enough N
under the sword plants etc.

But.............anyone that suggest the swords or Crypts
"prefer" root uptake, they are wrong.

You can easily use an inert sand substrate and add plenty to the
water column. Both of these genera grow like weeds.

Folks that see the effect of increase health/growth of their
Crypts/swords typically were not adding enough nutrients to
their tanks to begin with.

So if you have a nutrient limited plant, then add more nutrient,
well doh, of course you will have more increased growth, but
this does not tell you whether or not the plant grows better
with or without substrate fertilizers.

If you added more water column ferts, you would also get the
same type of increased growth response.

But folks typically do not try that treatment.

Swords and crypts get weedy and larger over time, as this
occurs, more nutrients are sucked out, what might have been fine
and provided good growth back 6 months ago is now requiring 3x
as much N and P and K to sustain the nice new growth in the
leaves.

Folks see crinkled or holes in the leaves and automatically
assume Ca or K+.

I've never had any issues with swords and Crypts using inert
substrate and no root tabs for over 15 years. As the plants take
over the tank, then you see such responses, and these same
responses can be mitagated with water column ferts or adding a
root tab. Or you may do both.

If these plants prefer root tabs/rich substrates, then why do
swords and Crypts do so well for me and many other folks?

That statement does not match with the observations and there is
a poor assumption in that statement since it does not address
the status of the water column. Few folks that use such lower
tech methods ever test and realize what is happening in the
water column, they typically do not wnat to be bothered, but
then say things like the plants prefer this or that without
knowing nor testing to see if the hypothesis is right, then we
get a myth.

I used a simple method of EI to make sure things in the water
ciolumn were in good non limiting shape and never had any
issues, very simple and there's no need to test to see if things
are limiting because there's always plenty of all the nutrients,
good CO2 as well, so then the plants do fine.

This is a very easy test to do and lets the aquarist know if
there is or is not a preference.

The next step is use a combination of both the water column and
the substrate.

This seems to help some plants better than others, I would
expect this.

ADA aqua soil+ EI dosing is nice as it does this without making
so much mess, looks nice and is highly effective for all plant
species and preferences.

Mineralized Soil and EI works very well as does soaked in ferts
Kitty litter and EI.

You can go lighter on the EI part, or lighter on the amount of
substrate ferts you add, each one allows more flexibility in the
other and less demand from each source.
 
So it's much less about one or the other locations for the
nutrients and rather, an overall nutrient source for the plants.
Personal conveinences seems to also play a large role as well.

Generally, if you want less work, go non CO2 and/or go lower
light.

Instead, folks complain on the forums and boards about their
high light 4.5 w/gal powercompact system and all this algae when
they cannot balance things and they end up neglecting things or
not adding enough plants from the start, limiting their plants
growth via CO2/nutrients etc.

The success rates with non CO2 tanks are extremely high.
Some complain you cannot grow certain plants, but most you can
if......you also add a little nutrient to the water column as
well, typically once a week is all that's needed.
Then you can grow most all plants fairly well.
Slow, but well.

And that's what many seek.

 
Regards, 
Tom Barr

www.BarrReport.com

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