Substantial K in rainforest through fall.

[Stone]

:rollhappy:Love Cary in the back:rollhappy::rollhappy:

 

[gonewild]

None of this changes the ratios

But what use are the ratios if the plants also get nutrients from other sources?
If K is high level in through fall water that hits the plant is double N,P,Ca, but the plant gets additional N,P,Ca from other sources the ratio changes to make K low.

If the only source of nutrients was from rainfall or through fall then the ratios would be a valid rate. But since all the things I mentioned add nutrients to the through fall it actually does change the ratios.

 

[Rick]

None of this changes the ratios

Ratios are BS. It's plant physiology 101. These figures are summarized from that Poole and Seeley paper you supplied a year or more ago.






The K, Ca, and Mg leaf tissue concentrations are shown for each concentration of K added in fert application. Ca was held at a constant 200 ppm. Mg was also constant. So if ratios are the all important driver then how do you get tissue ratios like this, that are so totally ass backwards from tissue concentrations in situ. (That is rhetorical ? since the paper dealing with K uptake in epiphytes was also presented years ago).

I added the Panama leaf tissue averages to the Cattleya table for reference at eco-relevant K concentrations (~5ppm).

 

[Rick]

But what use are the ratios if the plants also get nutrients from other sources?

Exactly. The throughfall ratios are useless when its apparent that the plants are accessing a ton of stuff through other sources.

In that PNG example you can see there's a giant Ca sink being accessed outside of the stem flow.

Plants are not nuclear reactors capable of turning Na into Caoke: It's gotta come into them somehow, and doesn't seem to be in the rain in this case.

 

[Stone]

Here's a summary of the nutrient flux for PNG Montane forest from that article I posted.


Note the huge amount of Ca relative to K tied up in the above ground biomass, and the large amounts of nutrients moved around in the litterfall (also heavy in Ca).

The rainfall input doesn't come close to making a big dent on either the K or Ca, but based on net throughfall K is moving around with the rainfall easier than Ca. But net throughfall doesn't explain whats actually in the leaves and the rest of the total above ground biomass.

Who's Cherry picking?

The nutrients in the above ground biomas of which trees would hold the largest amount by far (in their leaves) would not be seen by the epiphytes.
What is leached from them and the rest of the biomass however would be.


Leaf content of the canopy is irrelevant because nutrients are leached from them at different rates

Leaf littler content also irrelevent because the epiphytes do not see it.

Throughfall and stemflow totally relevant as thats the only main nutrient input which they have access to.

As I said, things may be different at ground level however if you consider the huge amounts of rain passing through the humus layer in which the terrestrials grow, they are very likly to see similar NPK ratios as those above ground--at least during the monsoon when it rains for days on end.

I've done the NPKCa ratios for your NG chart

Litter P/N (P divided by N) 0.05...K/N 0.3...Ca/N 1.05

Throughfall P/N 0.08...K/N 2.3...Ca 0.3

So lets meet in the middle (very roughly) P/N 0.06...K/N 1.0...Ca/N 0.7

Now lets look at k-lite P/N 0.08...K/N 0.08...Ca/N 0.25

 

[Stone]

But what use are the ratios if the plants also get nutrients from other sources?
If K is high level in through fall water that hits the plant is double N,P,Ca, but the plant gets additional N,P,Ca from other sources the ratio changes to make K low.

You're cluching at straws Lance. where the hell is an epipphyte going to get its nutrients from other than stemflow during a monsoon? When the rain stops the roots dry out and stop absorbing nutrients. Or is there a way plants take up nutrients without water that I don't know about?

 

[Stone]

Ratios are BS.

Leaf contents are BS. (Just as Xavier once noted) Plants take up nutrients at different rates so thier leaf contents vary widely.
The ratios of what arrives at the plant roots is ALL IMPORTANT!

 

[gonewild]

The nutrients in the above ground biomas of which trees would hold the largest amount by far (in their leaves) would not be seen by the epiphytes.
What is leached from them and the rest of the biomass however would be.

What makes you so sure that epiphyte roots can't receive nutrients directly from the bark of a tree? Not through leaching but rather through a process of ionic exchange.

Leaf content of the canopy is irrelevant because nutrients are leached from them at different rates

Isn't the leaf content of the canopy what add nutrients to rainwater as it falls through?

Leaf littler content also irrelevent because the epiphytes do not see it.

But there ar many species of epiphytes that grow at ground level that get leaf litter dropped on them.

Throughfall and stemflow totally relevant as thats the only main nutrient input which they have access to.

How do you figure it is the only main nutrient source when it contains basically nothing? A couple ppms?

As I said, things may be different at ground level however if you consider the huge amounts of rain passing through the humus layer in which the terrestrials grow, they are very likly to see similar NPK ratios as those above ground--at least during the monsoon when it rains for days on end.

Do you think that the monsoon rains produce through fall with the same nutrient content as drier times of year?

 

[Stone]

What makes you so sure that epiphyte roots can't receive nutrients directly from the bark of a tree? Not through leaching but rather through a process of ionic exchange.

I have not seen that data

Isn't the leaf content of the canopy what add nutrients to rainwater as it falls through?

Not the total leaf content, only what leaches from it

But there ar many species of epiphytes that grow at ground level that get leaf litter dropped on them.

Thats why I think the ratios are probably similar to epys

How do you figure it is the only main nutrient source when it contains basically nothing? A couple ppms?

Tell me aonther and I will look at it

Do you think that the monsoon rains produce through fall with the same nutrient content as drier times of year?

No much lower consentrations.

 

[gonewild]

You're cluching at straws Lance. where the hell is an epipphyte going to get its nutrients from other than stemflow during a monsoon?

From all the other sources that I have already mentioned several times.

When the rain stops the roots dry out and stop absorbing nutrients.

Absolutely not correct. This only applies to plants that go dormant.
When the monsoons stop the forest is not without moisture. It does not just stop. Condensation cycles moisture even during the dry season.

Or is there a way plants take up nutrients without water that I don't know about?

Yes.

 

[Rick]

The ratios of what arrives at the plant roots is ALL IMPORTANT!

Apparently not since your throughfall ratios don't match the ratios in the above ground biomass.:sob:

 

[Stone]

Apparently not since your throughfall ratios don't match the ratios in the above ground biomass.:sob:

Whats the fixation with the above ground biomass. Trees get their nutrients from the soil, sometimes deep underground. Epiphytes get theirs from what comes to them.

 

[Rick]

(Just as Xavier once noted)

Even though he used tissue data extensively in his work with Orchiata bark.oke:

 

[Stone]

Absolutely not correct. This only applies to plants that go dormant.
When the monsoons stop the forest is not without moisture. It does not just stop. Condensation cycles moisture even during the dry season.

If you look at velemen, it is designed to act as a sponge. When wet it absorbs moisture and nutrients, when dry it turns white and protects the inside from desiccation. Water=uptake no water= no uptake. Why are we even arguing this point?

 

[gonewild]

Trees get their nutrients from the soil, sometimes deep underground. Epiphytes get theirs from what comes to them.

From the ground to the trees to the epiphytes. The tree delivers nutrients from the ground to the epiphytes. oke:

 

[Rick]

Epiphytes get theirs from what comes to them.

And based on tissue sample data they are getting a lot more Ca from somewhere besides the throughfall.

 

[Stone]

Even though he used tissue data extensively in his work with Orchiata bark.oke:

To compare wild with cultivated as I recall and determine the difference which would also hint at the difference in nutrient ratios available.

 

[Stone]

From the ground to the trees to the epiphytes. The tree delivers nutrients from the ground to the epiphytes. oke:

Not the same as it takes up!!

 

[gonewild]

If you look at velemen, it is designed to act as a sponge. When wet it absorbs moisture and nutrients, when dry it turns white and protects the inside from desiccation. Water=uptake no water= no uptake. Why are we even arguing this point?

Because it does not require monsoon rains to activate root functions as you implied. It does not require rain at all, only moisture. That moisture can come simply from night time humidity. Nutrients are not only delivered by flowing water (through fall).

 

[Rick]

To compare wild with cultivated as I recall and determine the difference which would also hint at the difference in nutrient ratios available.

Had nothing to to do with wild vs cultivated plants.

He essentially repeated the Cornell work (with a hybrid phal) and fixed fert concentration/application rate to look at the effect of different substrates on nutrient uptake and growth.