# plants competition for resources



## IUnknown (Feb 24, 2004)

The thing I've notice in my tanks is that plants compete for resources and end up growing at different rates. I don't know if this has to do with one plant being healthier than another, or if one is 'stronger' than the other. For example, my glosso slows down when my Rotala gets real thick. I would think any phosphate that gets dosed is absorbed by the Rotala, and not much is left for the glosso. When the Rotala gets a hair cut, the glosso picks up speed and gets out of control. Anyone experience this or have input on wether this is really happening?


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## pineapple (May 4, 2004)

Does an Amano-style aquarium demand an Amano-style substrate?

Would both the Rotala sp. and Glossostigma benefit from a substrate which offers more nutrition than Flourite?

Reading Ghazanfar's post this morning has reinforced my general feelings of working with Flourite. Leaving aside the dissatisfaction with the colour and grain size and shape of Flourite, it appears to me that it does not offer a lot to plants especially in the early part when they are getting established. A more 'nutritious' substrate would ensure a nutrient supply was continually there, regardless of water fertilization. Plants in a Flourite substrate environment will be totally dependent on the water for supply of nutrients.

Pruning the Rotala removes plant material which is actively growing and consuming nutrients. Until the Rotala reestablishes new growing shoots, it is not using the same? or as much? nutrients as before and the surplus can go to other plants. I suppose that makes sense. I do notice that some plants seem to go through cycles of dominance and suppression. Pruning might be one way to change the balance, as might temperature, lighting and etc.

I wonder if there is any special nutrient plants need after pruning? The ADA line addresses this with Green Gain.

Andrew Cribb


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## Phil Edwards (Jan 22, 2004)

Yes, some plants are able to out compete others for resources. This happens all the time in the wild and is a logical guess for your aquarium given the observations. I've seen similar things in my aquariums as well. When you get a large bunch of a fast growing, or fast absorbing, plant, it's going to take up more resources than a smaller bunch of the same plant will. Personally, I'd like to find something that keeps the glosso growing slowly.


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## HeyPK (Jan 23, 2004)

> ...... For example, my glosso slows down when my Rotala gets real thick. I would think any phosphate that gets dosed is absorbed by the Rotala, and not much is left for the glosso. When the Rotala gets a hair cut, the glosso picks up speed and gets out of control........


I don't know the answer, but, if you have a repeatable effect, you can find the answer with some experiments. What could slow the glosso down when the Rotala gets thick? One hypothesis would be lack of nutrients (phosphate?) because the Rotala is out competing the glosso. This hypothesis could be tested by giving a big dose of nutrients when the Rotala is thick and seeing if the glosso gets up to speed again. Another hypothesis would be that the Rotala is shading the glosso. The way to check that one would be to make sure that some of the glosso is well illuminated and far away from from the Rotala, even if there is a lot of the Rotala. If it slows down, then we know that the light isn't limiting the growth.


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## Robert Hudson (Feb 5, 2004)

Plants take nutrients from both their roots and their leaves. If the Glosso is being outcompeted by the Rotala in the water column, it would then try to take it from the substrate. I would add NPK underneath the glosso when this appears to be happening and see what the result is.


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## plantbrain (Jan 23, 2004)

IUnknown said:


> The thing I've notice in my tanks is that plants compete for resources and end up growing at different rates. I don't know if this has to do with one plant being healthier than another, or if one is 'stronger' than the other. For example, my glosso slows down when my Rotala gets real thick. I would think any phosphate that gets dosed is absorbed by the Rotala, and not much is left for the glosso. When the Rotala gets a hair cut, the glosso picks up speed and gets out of control. Anyone experience this or have input on wether this is really happening?


Sure if things are resource limited or you run things lean.
If things are excess, this does not occur.

This is why I do not see alleopathic issues, rather, nutrient competition between plants when resources are limiting.

I suggest high levels of NO3, PO4, K, Traces for this reason.

Then there is no teter totting. You can do this with or without substrate ferts and this occurs. I used nothing in the substrate for many years, RFUG's as well. Then you can see this easily.

This is the old story that folks use to complain about in the past, they'd say such and such plant is hard or difficult while I never had a problem.
They'd come over and sure enough my plants were thriving. They knew I had nothing in the substrate.

Plants take their nutrients from the water column first, then go after the substrate if they cannot meet their demands from the water column.
You can supply the nutrients either place, but make sure there's enough overall.

Switching/bouncing back and forth also makes things difficult for the plants. Try to be consistent with the water column dosing.

Phil, try less light. 1.5-2w/gal.

Pineapple,
I've done plenty with hormones, gibs are the only hormone I've found that influences aquatic plants. It only helps once basically. Dr Kane is the best person and good friend of mine at UF on this. We discussed that several times and Dr Guy, my plant Metabolism prof. I've also simply tried it. I've never seen any effect except with gibs.
I also have no idea what is meant by "disease", I've never seen anything I would label that in aquatic plants, I suppose algae maybe......

Flourite has little in it at the start. I add peat, I add mulm. These things are in it later.

ADA may have other things beside these. That's somthing I'll be doing for ADG later in a controlled study along with some other substrates.

But......if you provide non limiting conditions in the water column, I've done this long time and kniow precisely what you are seeing , I can tell you the cause=effect will not be there, I know these plants well.

Regards, 
Tom Barr

www.BarrReport.com


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## Raul-7 (Feb 4, 2004)

Tom, then is it just a myth that Crypts and Swords need a rich substrate to thrive? But isn't it true that it is better to have Fe available in both the substrate and water column?


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## pineapple (May 4, 2004)

> Pineapple,
> I've done plenty with hormones, gibs are the only hormone I've found that influences aquatic plants. It only helps once basically. Dr Kane is the best person and good friend of mine at UF on this. We discussed that several times and Dr Guy, my plant Metabolism prof. I've also simply tried it. I've never seen any effect except with gibs.
> I also have no idea what is meant by "disease", I've never seen anything I would label that in aquatic plants, I suppose algae maybe......


Tom - Interesting post. Thanks.

Andrew Cribb


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## Jeff Kropp (Apr 25, 2004)

Greg, 

I have noticed this effect many times and Amano has mentioned the dominance of large quanities of riccia over other desirable plants in TAG.

Right now Cambomba is my dominant plant and its kinda refreshing to have so much success with this plant. Over the years I have looked for plant combinations that share similar nutritional needs. Some combinations are just very difficult while others less fussy. As Tom mentioned, running high macros is a good way to success with a wide range of species but I have found persistently high macros detrimental to longterm fish health. 

In addition to nutrient availability your post also mentions the changing plant masses of particular species. In my experience, this plant mass/species ratio is also significant in managing success with weaker species. In my experience glosso and Indica have similar needs. That you are noting differences bears testament to your close observation. Keep up the good work!
___
Jeff


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## plantbrain (Jan 23, 2004)

Raul-7 said:


> Tom, then is it just a myth that Crypts and Swords need a rich substrate to thrive? But isn't it true that it is better to have Fe available in both the substrate and water column?


Yep.
I think the roots simply have a high demand for Mn/Fe and it's easier to get them there rather than transport from the leaves to the substrate. 
I'm not _entirely sure_ why, but I'll give it some thought and discuss this in depth later when I run the Fe/Mn article in BarrReport. I will cover these in great detail.

Regards, 
Tom Barr


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## IUnknown (Feb 24, 2004)

> Sure if things are resource limited or you run things lean.
> If things are excess, this does not occur.


OK, but how long are nutrients in excess in the water column? I thought PO4 was used up within a couple of hours after dosing. I thought that plants only had the right concentration of nutrients (are happy) for 3 out of the 7 days in a week. I've always struggled at understanding the balance that goes on in the tank. I just get confused because plants are labeled as fast growers (algae busters), and that seems to me like a tug of war goes on for the resources in our tanks.


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## plantbrain (Jan 23, 2004)

24/7

You can "pulse" nutrients also, this will add "just enough" but with higher light, that becomes more difficult to add the precise amount. It take experience to hit that level, oplkants can store nutrients and use them later, so they do not "need" 24/7 concentrations but there's nothing wrong with that and does not contribute to algae over the long term even without any herbviores present at high light etc. 

Jeff, which fish seem to have issues?

Regards, 
Tom Barr


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## Raul-7 (Feb 4, 2004)

So Tom, according to your dosing schedule, you're supposed to dose 2ppm of PO4 every other day?


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## plantbrain (Jan 23, 2004)

You can, you can also use much less and dose 0.2ppm per day and likely get similar results in terms of plant growth.
Excess about .2ppm per day is just that, excess, but it'll take a life time to use up the 3 lbs of KH2PO4 I have so I really don't care, I'm more worried about running out than the excess issue.

Just enough is good for those knowing their tanks and is fun in many respects. But as far as algae is concerned, just enough for plants is a ton for the algae. Coloration, lighting, plant appearance and rate of growth are key issues when approaching that issue, not algae.

Regards, 
Tom Barr


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