has anybody heard of this idea? that is what is recommended to me...help...

http://www.texassodiumbentonite.com/

The salt takes the place of the water molecule between the clay layers and doesn't allow the clay to shrink and crack when it dries out.

bentonite I've heard of, plain salt, no.

If you have plenty of clay minerals already in your soil, just adding salt can (notice I say can, not will) help seal it up and minimize future cracking. It works better when mixed with bentonite and applied already hydrated, but it can work with existing clays. But you have to be careful not to overdo it and wind up with a saline pond for a while.

Correct...that is why he asked about mixing salt with clay. Clay minerals, like bentonite, have layers that form bonds with water molecules in between the layers, which is what causes them to swell. When the water evaporates out, the layers shrink back together. When you add salt, the sodium takes the place of the water to keep the clay "swelled". Since the sodium can't evaporate out, the clay doesn't shrink. You are correct that if there are no clays in the existing soil, it won't work...it only works with shrink swell clays already in place. But if there is already clay there, it will definitely help.

thanks for the info txags92... never heard that before.

hmm so hypothetically I could make my tank super salt water while it is full and protect against cracks in my bentonite sealant during droughts?

You don't need a lot of salt...and I suspect that is why it isn't used really frequently...you can make the water too salty with excess salt in the pond if you aren't careful. I am aware of it being used on industrial ponds around the great salt lake where they could just pump in lake water and then pump it back out to get a dose of salt on the liner.

Like I said it is better done as part of an aqueous application where the salt is added to a bentonite slurry before it is laid down. Trying to add the salt after the fact can be dicey and I wouldn't do it without talking to an expert.

hmmm, dang its a complicated issue like everything else. who might be an expert in these areas? because I've never heard of that solution, wish I had heard about the slurry application with sodium when we put down the bentonite!

ahhhh this will be fun! Ill wander the halls of Zachry and unintentionally piss off civil engineers until I find the one that would love to talk all about it saline aqueous applications to clay base water reservoirs!

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It will just add salt to your soil & water.

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You're using the Na+ to replace the Ca+ in the clay molecule. I don't remember all of the exact chemistry.

Clay's have a film of water that is adsorbed around each molecule. This is one reason that clay's make it harder for plants to remove water from them. In addition to their lower permeability, the clay molecules will compete with the plant root for that water molecule. Certain clay's (bentonite being one in particular) are highly dispersive. When the ionic chemistry of that adsorbed water is correct, high in Ca+ I believe, the molecules will actually repel each other in fresh water. Replacing that Ca+ with Na+ eliminates this phenomena.

Those of you that took Agro 301 covered this. I also did a Science Fair project on it back in 7th and 8th grade, mapping these clay's in Harris County.

If dispersive clay's are causing a continually cloudy, muddy pond adding salt to the water will actually work to clear the water as well.

Dr. Murray ****ord flashback moment

Edit: LOL, Dr. Murray M I L Ford

what the heck?

[This message has been edited by SPI-FlatsCatter 84 (edited 9/11/2012 5:18p).]

TA from that class royally ticked me off. I am supposedly one of the few to ace that final, and I still got a B (on an 88.9). TA gave me a zero on a lab, but it was the soil judging lab and I was good at that. This was the semester A&M got picky about who could drive university vans. By shear coincidence, I was the only one allowed to drive university vans in the lab section. The TA had something pressing, so lab reports had to be turned in immediately after returning. Well, I was driving. She told me not to worry about it. Get it back the next week and I had a zero, and said no excuses accepted. Loved Dr. M il ford, he said he had to support his TA, and the TA didn't remember it that way.

"Good rock gone bad" is also not the definition of soil that Dr Mi lford was looking for when he asks during the first class period...

IHIOGA that neither is the answer to contain any form of the word "dirt"

I had him in 1983 and without benefit of having EVER taken any HS or College chemistry. He and his TA helped me "B" that class.

We had a couple of clown CT's that were always inserting slides of bikini clad girls into his slide show. Might not seem funny if you never had him but to those that did can you imagine??? and I mean whoever it was did it about 8 or 10 times over the course of the semester.

For Smectite clays, there is a net negative charge on the flat, sheet-like surfaces of each particle and this net negative charge can attract anything with a positive charge. In the absence of any cations, the positive polar end of a water molecule will be attracted to the clay particles creating a relatively thick inter-particle water layer. When cations (Na+ Ca++ Mg+++) are introduced, the negative surface charge is more effectively satisfied than with pure water.

By reducing the thickness of the water layer, the clay particles can come closer to one another and increase the density of the soil as a whole. This is why lime stabilization of clay soils works for road construction and with respect to the question at hand, the densification of the clay particles would reduce the permeability through the soil.

Ask the Agronomist (TM) says ......

Usually no need to use salt with bentonite. Salt WILL work when there is plenty of clay present, but excessive calcium present. The calcium promotes flocculation, while sodium disperses clay particles "sealing" a pond. The NRCS has a standard dealing with this very thing. Contact the local office. If they can't answer, try one of their engineers (James Smith in Hallettsville is a good Ag and a good engineer).

so any tips for salt concentrations introduced into existing pond? otherwise I guess I'll start contacting experts after I do some calculations on water loss numbers and make sure I'm not just seeing a little seepage and mostly evaporation

we put drilling mud in our tanks to stop them from leaking.