----- Original Message -----
From: Roger Pye <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, October 10, 2002 5:54 PM
Subject: Nutrient blockers
> Does anyone know whether aluminium locks calcium up in soils?
>
> roger
> --
> Hi Roger
Other way round!!- calcium locks up aluminium - Its a
chain of events - calcium depletion - then low pH - then the acidity makes
aluminium available - Al is a +++ so its some of the last to come unstuck.
So you are not going to have available aluminium at toxic levels unless you
have the extreme low pH that comes with a serious lack of calcium (or
magnesium in a real sandy soil). This will be at pH less than 4.5 calcium
chloride - in our red soils we can go as low as 4.2 before serious trouble -
in your country probably 4.4 would be the cutoff point. . Aluminium levels
rocket upwards as the pH drops that last half point or so. So the aluminium
is a result of a lack of available calcium not the cause of it.
Cheers
Lloyd Charles
