Re: [tomato] blights
Olin (Tomato@GlobalGarden.com)
Wed, 28 Apr 1999 17:44:11 -0700
Rock phosphate is so insoluble in alkaline soils that it is of little or no
value as a source of plant available phosphorus. I was assuming rock dust
to be a powder form of rock phosphate (not certain if that is so) and it
would also be insoluble. It is probably great for acid soils. There was a
thread on this topic 2-3 years ago on
the U of A arid_gardener listserv. The final word is from the U of A soils
department archived at
http://ag.arizona.edu/hypermail/arid_gardener/0411.html. As you suggest,
mineral depletion is not a normally problem in our desert soil with the
possible exception of iron and zinc (required by citrus) which are deficient
in some areas. -Olin
-----Original Message-----
From: Thomas Giannou <thomas@tandjenterprises.com>
Subject: Re: [tomato] blights
>... why would rock dust be inappropriate to desert soils? ... Perhaps in
your soils mineral
>depletion by plants may not be a problem? .../