Interesting posting. Volcanic ash, its composition ie. mineralogy will
depend on the type of volcano it has been derived from. If for example
it was from a volcano that ejected lava and ash of acidic composition
one would expect minerals such as quartz, feldspars, etc. These minerals
would have elements such as silicon, calcium, potassium, sodium,
magnesium while ash from a more basic volcano would have minerals such
as amphiboles, pyroxenes, olivines, etc. These minerals are rich in
calcium, magnesium, iron, and trace elements such as chrome, vanadium.
... If this ash is old in geological terms then perhaps weathering may
have altered some of the primary minerals to clays. If this is not the
case then the ash may be a useful adjunct to the soil to assist with
increasing soil fertility.
The comment regarding the ash's ability to store nutrients due to its
concave shape is a new one on me. The storing of nutrients in a soil is
usually more to do with the cation exchange capacity of soil
colloids(clays and humus) although the actual packing structure of the
ash in a macro sense may retain some nutrients.
Anyone contemplating using ash or ground rock minerals as additives to
their soil fertility program will do well to understand that these
minerals are not very soluble and rely on soil acids and microorganism
activity to make available the elements from their host minerals. That
means either incorporating them in the soil with a green manure crop or
with compost or other biological stimulants to assist their
decomposition. If the source is local and the cost is low then ash or
crushed rock powder are useful additions to a fertility restoration
program.
Chris Alenson
Organic Advisory Service
Organic Retailers & Growers Association of Australia
----------
From: Steve Diver[SMTP:steved@ncatark.uark.edu]
Sent: Thursday, 11 June 1998 9:23:pm
To: sanet-mg@shasta.ces.ncsu.edu
Subject: Volcanic ash use in agriculture
A farmer has a deposit of volcanic ash on his farm and wants to
know
what uses or value it has in agriculture, since he has this idea
he can mine
it and sell it.
In particular, he mentioned something about the concave shape
of volcanic ash that enhances its ability to retain
nutrients....and
therefore when combined with land application of confinement
livestock manure it can prevent nutrient leaching into water?
*Are there any resources or facts associated with the
nutrient-retaining
capacity of volcanic ash?
*Are there any uses of volcanic ash in agriculture that would
make it a viable product for sale (such as a potting mix
ingredient,
soil amendment, etc?)
Thanks for any tips or resources! If there are no known uses
and
its a waste of time for him to pursue, that's good information
too.
Steve Diver
ATTRA
--
steved@ncatark.uark.edu
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