In article ,
"George.com" writes:
| "stuart noble" wrote in message
| ...
|
| Interesting stuff. I seem to remember that clay is slightly alkaline, so
| presumably soils that need breaking up aren't usually acidic. Don't know.
| I'm not much of a gardener, let alone a chemist :-)
|
| Gupsum (calcium sulphate) is often used to improve soils containing high
| levels of sodium. It is not a liming agent, it has a neutral or slightly
| acidic effect on soil. However by displacing sodium it will improve the
| structure of soils (including clay).

One of the things that many posters are confusing is standard
inorganic chemistry with practical soil chemistry - it is deceptive
that the terms "alkaline" and "acid" are used for soil, because they
don't mean what inorganic chemists mean by them.

Practically, "alkaline" means "with easily accessible calcium",
"without easily accessible iron" and often "without easily accessible
magnesium", and "acid" means the opposite. Don't ask me why calcium
makes iron inaccessible and, from a brief search of the literature,
don't bother about asking the experts, either - they aren't entirely
sure.


Regards,
Nick Maclaren.