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Re: laterite mud (was "Muddy thoughts")

Well, I guess we've changed the "Subject:" to better reflect the point Steve 
wants to prove, rather than continue on with the debate about the viability
of a
mud substrate. OK. For brevity, I will paraphrase the discussion so far.  

George wrote:
>Duplarit captures nutrients pulled into the substrate by convection
currents, 
>thus making the substrate appropriately fertile. 

Steve refutes this:
>There are no scientific studies [that he knows of] to prove this,
therefore it 
>can not be true. Further, a TAG article has evidence that the plants move 
>nutrients into the substrate, thus further disproving my assertion.

It's rather clever of the plants to move nutrients into the substrate. Is
this 
like squirrels burying nuts for the winter? Making sure the other plants
don't 
get any? Keeping some in reserve for a rainy day?

Steve continues:
>What is the CEC of laterite again? [a question made even more impressive
with a
>barrage of unanswerable and irrelevant questions about nutrient flow in 
>general]. 

Now we're back to the age-old problem of "How much CEC is needed for good
plant 
growth?" Did I miss the APD were Steve quoted scientific studies that
addressed 
this question? No, I don't think I did. We are still obsessing over "Clay, 
vermiculite, [everything else except laterite] has humongous CEC values,
and we 
all know 'More is better' QED." Except, of course, for lighting, CO2,
nitrogen, 
phosphorus, trace elements, etc. 

Steve next suggests:
>Now let's send a hypothetical sample of laterite for nutrient analysis
>and a hypothetical sample of soil for analysis. Question: which one has
>more micro nutrients? which one has more macro nutrients?
>
>And then, saving us a lot of time and money, Steve quotes work done by Shaji 
>Baskar and Neil Frank (as well as using a supposed definition of laterite)
that
>proves once again plain laterite has less micro and macro nutrients than a 
>sample of "standard" garden soil. 

I don't know why this needed to be proved. It might be a bit more relevant to 
the debate if it was proven that a substrate of laterite, fed water-borne 
nutrients by convection currents, provided insufficient micro and macro 
nutrients. Not "less than mud" but INSUFFICIENT. Unless, of course, you have 
some studies up your sleeve that prove "more is better".  

Steve next provides a helpful definition of "Better growth":
>[Pointless sarcasm deleted] 
>better growth is growth which is faster. and better. healthier. colourful. 
>vibrant. huge. big. flowering.

"The 1999 Nobel Prize in Science is awarded to Stephen Pushak for his
insightful
and precise definition of Better Growth."  You may delete my pointless
sarcasm 
as needed.

Continuing on, Steve points out where I am confused:
>Sure, if you're growing Hygrophila polysperma, there doesn't seem to be
>much point in stimulating growth rates. If you are growing
>Cryptocorynes, improving the growth conditions is everything.

Steve, I haven't grown H. polysperma in years. And the "demanding" Crypt
species
have every characteristic of weeds in my tanks. I can't get rid of them.
Our one
tank has a stand of C. blassii with leaf/petiole lengths of 30" (what's
that, DOUBLE the "normal" size according to Dennerle?). Too damn big for my
taste. But impressive none the less so I tolerate them. 

Steve next disproves my assertion that his description of Duplarit is "made
up" by
quoting a landmark Dr. Dave paper on the "Preference for root uptake of P and 
N". His description of Duplarit as "slimey mud" is obviously accurate because 
"with a fertile substrate the only nutrients required in the water column are 
Ca, Mg, K and of course CO2". 

Steve, you got me there. I have no rebuttal. 

Finally, Steve shoots himself in the foot:
>"On the other side of the coin, there have been a plethora of studies
>which indicate clearly that rooted aquatic plants will not grow
>optimally on a sand or other infertile substrate no matter how richly
>you fertilize the water column (perhaps the earliest is by Pond, 1905)"

OK, let me get this straight: 
1) Plants will NOT grow optimally (or "better" at least) in an infertile 
substrate (inferring from the context of this discussion "grave+laterite")
2) ...even if I add Dupla drops and tablets to the water.  

I contend that my plants grow just fine and my website photos attest to this 
fact. If they don't take nutrients from the water and they need a fertile 
substrate to grow well, then I can only assume that somehow my infertile
gravel 
and laterite substrate has become sufficiently fertile. 

The study above indicates that plants are NOT moving nutrients into the 
substrate because the study showed poor growth with nutrients in the water 
column. If the plants moved nutrients into the substrate, it would have
become 
fertile and plants would have grown well. 

I can only conclude from your arguments that heating coils are creating 
convection currents which bring water-borne nutrients into the substrate, 
possibly being sequestered by the laterite or being used immediately by the 
plants. In either case, the gravel+laterite+heatingcoil substrate works just 
swell. QED.

George Booth, Ft. Collins, Colorado (booth at frii_com)
  Back on-line! New URL! Slightly new look! Same good data!
    http://www.frii.com/~booth/AquaticConcepts/