NPK ratios?

J.E. Shields
Sun, 03 Feb 2008 04:42:23 PST
Hi Rodger and all,

Well, I changed it back and forth a couple of times.  I settled on "absorb" 
because the kaolins can do an ion exchange, switching Ca++ for K+ in the 
internal matrix of the clay.  On the other hand, ion exchange phenomena are 
probably best thought of as "adsorptions" as well, so (this morning) I tend 
to agree with you.  I have heard about the "different" clays of the North 
American West, but I've not had any personal experience gardening in them.

Jim Shields
in central Indiana (USA)

At 06:55 PM 2/2/2008 -0800, you wrote:
>On 31 Jan 08, at 9:09, J.E. Shields wrote:
> > Clays can adsorb ions on their surfaces and can absorb [sic; ITYM
> > "adsorb"] ions internally.
>Not all clays. Lateritic clays have very poor adsorption powers,
>hence the poor soils in the Oregon Coast Range (Ref: Roadside Geology
>of Oregon), Africa, and the Amazon Basin.
>For those of you on the Left Coast, there's a very nice exposure of
>bright red lateritic soil on the east side of I-5 a little north of
>Grass Pants, Oregon. Just a small cut with some erosion that exposes
>the subsoil, but quite prominent because of the brilliant color.
>Rodger Whitlock
>Victoria, British Columbia, Canada
>Maritime Zone 8, a cool Mediterranean climate
>on beautiful Vancouver Island
>pbs mailing list

Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344     or      toll-free 1-866-449-3344 in USA

More information about the pbs mailing list