"Nick Maclaren" wrote in message
...

In article ,
martin writes:
| On Tue, 11 Nov 2003 13:34:59 -0000, "Finance"
| wrote:
|
| Clay is good soil packed badly. I have heavy clay over yellow clay
over blue
| clay. After 20 years the heavy clay has been improved. The yellow clay
has
| not changed and I doubt if I will long enough to improve the blue
clay.
| Incidentally blue clay was used to puddle the bottom of ponds, so you
have
| an idea of it's use
|
| Everything you wanted to know about the microstructure of clays and
| were frightened to ask
|
http://www.tam.uiuc.edu/courses/TAM2...y_minerals.pdf

Interesting. One thing that I didn't notice it saying explicitly
is that many nutrients bind to clay particles (but not to sand,
and only a little to peat), so soils with little clay leach very
badly and are often very low on nutrients.

I wonder how non-peat material of organic origin behaves in this respect?
Well rotted manure, for example.

Don't ask me the details, except that they are along the lines
of what the paper describes, and a bit more complicated.

Franz