soil substrate/fert questions - The Planted Tank Forum
 
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post #1 of 12 (permalink) Old 03-17-2006, 07:08 PM Thread Starter
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soil substrate/fert questions

I probably should have posted this on the substrate forum, but I put it here because it also touches the issue of fertilizing the substrate vs. water column.

I went to a local fish club meeting last week where a biology professor gave a talk on aquatic plants. I was kinda floored when he flatly stated that the best substrate was to simply dig up some soil from your vegetable or flower garden, with no preparation other than soaking it for a day or so with occasional stirring to remove excess organic matter. He said that even when he uses gravel for aesthetics, he grows his plants in soil-filled pots.

He further said that if you use soil, you have no need to dose the water column other than chelated iron. In fact, he disfavored dosing the water column, because those nutrients were accessible to rootless plants such as bolbitis - and algae.

It was hard to argue with his results, as he displayed incredible vals, lace plants, ludwigas, glosso, and more. I understand he also has a business in the area growing and selling pond plants. I have his contact info, and intend to touch bases with him in the future.

Let me preface my remarks by stating that here in Illinois we often hear that we have "the best soil in the world", so I can imagine soil as substrate may not work for other locations.

I did some amount of searching on this site and elsewhere, and didn't really find all that much specifically addressing the relative merits of a nutrient rich substrate vs. water column.
I found this site linked to from the kirb: http://home.infinet.net/teban/substrat.htm#Index
The author states “Rooted aquatic plants grow best on a mineral soil such as a silt loam with low organic matter. Rooted aquatic plants require no N, P, S, or micronutrients in the water column when grown on a fertile substrate."

The speaker's comment regarding the water column reminded me of this from Chuck Gadd's site: "Substrate fertilizers are only available to plant roots. Since algae doesn't have roots, it can't get to the nutrients buried in the substrate."

I read this recent thread:
https://www.plantedtank.net/forums/ge...e+water+column
And I intend to head back to the Aqua Botanic forums to read more of Diane W.'s writings.

But I was wondering if anyone had the comments about this. Was this lecturer off his rocker? If not, then why we not see more people recommending soil as a substrate - at least in areas with good loam?

Is anyone aware of any resource that explains which roots can obtain adequate nutrition from the substrate, as opposed to ones that REQUIRE to absorb nutrients through their stems/leaves from the water column?

Sorry if this was addressed plainly here before. I tried several variations of searches. I thank anyone in advance who can provide a link.
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post #2 of 12 (permalink) Old 03-17-2006, 07:13 PM Thread Starter
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For so reason I am unable to edit.
The last couple of paragraphs should say:

But I was wondering if anyone had [any] comments about this. Was this lecturer off his rocker? If not, then why [do] we not see more people recommending soil as a substrate - at least in areas with good loam?

Is anyone aware of any resource that explains which [plants] can obtain adequate nutrition from the substrate [through their roots], as opposed to ones that REQUIRE to absorb nutrients through their stems/leaves from the water column?
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post #3 of 12 (permalink) Old 03-17-2006, 08:44 PM
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There is more than one way to grow aquatic plants. And, there is no one way that is always the best way for everyone. You can grow plants very well in inert pool filter sand, using water fertilizing and perhaps a few root tabs for swords. But, I know from experience that backyard soil with blasting grit on top also grows plants very well. One thing is sure - the nutrients in any kind of soil will eventually be used up and the plants will then require fertilizing either by root tabs or by water fertilizing. So, why not use the method where you know what you put into the substrate - inert sand or aquatic soil of some kind - and where you know what fertilizers you are using - by adding them to the water column?

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post #4 of 12 (permalink) Old 03-17-2006, 09:07 PM Thread Starter
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Quote:
Originally Posted by Hoppy
One thing is sure - the nutrients in any kind of soil will eventually be used up and the plants will then require fertilizing either by root tabs or by water fertilizing.
Any idea how long this takes?
I mean, would make a difference if it were 1 year vs 10.
There should be SOME minerals deposited back in the soil through fish and plant waste...
I was thinking along these same lines - shoulda asked the guy, but as I said, I was kinda floored by his premise.
But I got the impression he grew plants in soil for a number of years.
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post #5 of 12 (permalink) Old 03-17-2006, 10:03 PM
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Soil substrates can go 10 years easily, I've done it.

Sean

Aquascape? I'm a crypt farmer.

It's a fine line between fishing and standing on the shore looking like an idiot.

That IS an aquascape, it's titled "The Vacant Lot".
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post #6 of 12 (permalink) Old 03-18-2006, 03:31 AM
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Read Diane Walstad's book "Ecology of the planted aquarium". I have a crypt tank set up like that right now that is doing wonderfully with no fertilization whatsoever.
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post #7 of 12 (permalink) Old 03-18-2006, 04:02 AM
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Quote:
The speaker's comment regarding the water column reminded me of this from Chuck Gadd's site: "Substrate fertilizers are only available to plant roots. Since algae doesn't have roots, it can't get to the nutrients buried in the substrate."
yes, algae does not have roots, but won't the soil leach out even if it's topped off with gravel?
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post #8 of 12 (permalink) Old 03-18-2006, 04:07 AM
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Check out this site, look for a forum entitled "El Natural" and youll find some decent info on tanks with soil substates.

Diana Walstad moderates/contributes to boot!
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post #9 of 12 (permalink) Old 03-18-2006, 08:24 AM
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Well, one thing the speaker totally missed out on, algae is not induced anymore from water column dosing than not.

Where is my algae if what he claims is true?

All substrates have some nutrient content, flux in/out of the substrate the higher concentration in the water column flows right down and into the roots as well as the foliar uptake, adding ferts to the water column allows you to measure and anticipate the levels.

Dirt works. I sure don't think it's the the greatest by any means, I also do not agree just adding it right away, you should soak it good for 2-3 weeks or boil it prior for 15 minutes or so. That and adding lots of plants from the start will ensure success.

“Rooted aquatic plants grow best on a mineral soil such as a silt loam with low organic matter. Rooted aquatic plants require no N, P, S, or micronutrients in the water column when grown on a fertile substrate."

Yea, but the plants grow better when you do and there's ample research to support that aquatic plants generally willt ake from the water column first given a choice. Even when roots were cut off, the plants had the same growth rate. I can make the same claim about fertilizing the water column, aquatic plants require no substrate ferts either if I fertilize the water column.

In general, it's not a bad idea to have nutrients in both locations and some in the substrate as a back up.

But using soil is hardly new........ and the nutrients most certainly leech out of the substrate a couple of ways no matter what you might think, and certainly more than enough to supply algae. Plant's leak quite a bit of nutrients, both from the roots and from the leaves.

As far as no fertilizer at all being added, folks, what is fish food/waste?
In non CO2 tanks, the rate of uptake and growth is slow, if you add CO2, increase growth rates...........of course you'd predict and expect and would find an increase in uptake of NO3, PO4, Fe etc.......then fish waste alone is simply not going to cut it..........and root uptake alone has it's limitations.

But for lower light tanks, non CO2 methods, soil is fine. A few use it in moderate light tanks, I fine it messy, and perfer other products but if you are careful, it can be used, also plain old ground peat works over the long term also.

"Is anyone aware of any resource that explains which roots can obtain adequate nutrition from the substrate, as opposed to ones that REQUIRE to absorb nutrients through their stems/leaves from the water column?"

Well, plants do both, so get use to it
As far as ability to get of the nutrients from one location, that's not realitistic, plants always get from both locations unless you have very specific lab set ups to isolate the water column and the substrate.
Ca/Mg/N/P/K/traces all come in from the fish waste/water changes, plants that decay(leaves etc) and get mineralized.

The real issue here is for what type of growth rates are you interested in and how much light you want to place in the tank and if you want to use CO2 or not.

For a specific growth rate, light, CO2 level the answer can go either way here regarding nutrients since these drive the system as well as fish feeding etc.

Regards,
Tom Barr




Regards,
Tom Barr
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post #10 of 12 (permalink) Old 03-20-2006, 12:13 PM
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I guess I could have posted a picture or a link to a successful "soil substrate with no dosing" tank.
https://www.plantedtank.net/forums/ph...pt-forest.html

I like that professor's thoughts, probably because he has the same basic conclusions I do. What was his name anyways?

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post #11 of 12 (permalink) Old 03-20-2006, 01:38 PM Thread Starter
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His name was Robert Steinback, he's an emoeritus professor (does that mean retired?) at Elgin Community College, NW of Chicago.
A guy wrote some detailed notes up here:
http://www.guppylog.com/section/__all__
Like I said, he has a business growing and selling pond plants.
I intend to get in touch with him - maybe trade a plant or 2 for a lily...

He was an older guy (60-ish?), and told some fun stories about his first tank and the state of the hobby probably back in the 50s or so.
I can imagine a good reason for hsi low-tech approach results from his growing plants back when much of today's aquaria technology did not exist.
He figured out a system that worked, and doesn't see the need to change it.

I don't want to come across as some whole-hog convert to el natural.
But I was a little frustrated that I did not have ready responses/explanations for all the things I am doing.
And I guess I wonder if the lower tech approach really gets enough credit/advocacy.
If you reviewed this forum, I think you would pretty much conclude that the "best" (at least most popular) substrates are eco-complete or flourite, plus ADA, Soilmaster, Schultz, etc.
When folks talk about low cost alternatives, you see more mention of sand and kitty litter, than you do of soil.

I'm no expert at this hobby - but I just kinda wonder if soil and low-tech is given enough credit.
Yes, folks link to Walstad and the like, but I always kinda sense that the tone is always, "those wacky natural low-tech folks" instead of presenting it as an equally valid - if not superior - approach.

Hey - anyone think my wife will be eager to get a new tank so I can try a natural setup?
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post #12 of 12 (permalink) Old 04-08-2006, 02:20 PM
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hey, btw, is it true that phosphates bind with soil? especially iron-rich ones?
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