Re: Adding Clay
Glenn
I believe you have a point here with regards to the particle size and the
difference between silt and clay.
Likely in most cases you would need a B.S and lab equipment to tell the
difference. I would assume that a farmers definition of clay would be "any
of the super fine, heavy soils that tend to get very stick and slippery when
wet":)
You also bring up another good point about the wide variation in clay soil.
I have seen clay in such a wide number of colors with the majority around my
area being very grey, slightly yellow or golden or almost blue.
A past experience stands out in my mind about clay and I still curse the
stuff. My sister just built a new house this fall. At the time when they
backfilled in around the foundation they pushed all the blue clay they had
excavated for the foundation back around the house for backfill. Well this
"blue clay" while somewhat dry was ok after they first spread it, after even
the slightest shower became the "clay from hell":).
Just walking a short distance in the stuff and you would have 50 pounds
stuck on each boot. Kinda makes your legs a little "rubbery" at the end of
the day. I think it could also be used for summer skiing as I slid down a
few of the small hills around her house after wiping out in the stuff and
sliding on my butt.
Anyways just a kind of humorous clay story for the list.
Glenn
-----Original Message-----
From: LIpumpkin@aol.com <LIpumpkin@aol.com>
To: pumpkins@mallorn.com <pumpkins@mallorn.com>
Date: Sunday, December 19, 1999 10:22 AM
Subject: Re: Adding Clay
>Here's a question to all of the "CLAY" people out there with clay
questions.
>When you say "CLAY",are you sure you know what your talking about?(not
meant
>to be condescending) Let me explain......I work in the construction field
as
>a soils engineer/geotectnical consultant/inspector/slave...and have a
B.S.in
>geology.EVERYBODY is the field calls silt -clay.They call any
>thick,plastic,fine grained soil a clay soil when in fact 85% of these soils
>are silt.There is actually very few clay soils here where I live but if you
>ask around they'll tell you differently.
> Now i must admit that i'm certainly not up on Agricultural definitions of
>clay or clay soils and its probably different.But I believe that the
physical
>makeup of real clay is what creates the holding capacity of the
soil...that
>in fact the silts will make the soils look like clay soils but w/o the
>advantages of the clay.As far as I know a sieve test(where you shake a
given
>soil through various sized screens,weigh the particles held back on a given
>screen,and compare that weight to the total weight of the sample as a
>percentage) cannot and willnot give you an accurate value for clay.The 200
>screen so often used in site spec work screens out both silt AND
clay.Further
>testing is required(involving distilled water,settleing rates etc...) to
get
>the clay percentage.(It takes a couple of days for this test alone).
> Soils are made up of various sized grains...a lot of silt will make your
>soils pack,puddle,and impervious too.I just think if anyone has a
>"scientific" size definition of the clay we want it would be helpful to us
>all in cleaning up some questions.
> An added note: most of the time the terms clay-silt-sand-gravel-etc are
ONLY
>size definitions.....perhaps we're really looking for chemical compositions
>as well as size?
>also-I believe BENTONITE to be a resultant material from the further
>breakdown of volcanic ash....but I got my geology degree before the last
>iceage so things may have changed or my brain might be dead
again......Glenn
>
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