[compost_tea] Re: air fall volcanic ash, WAS: Forest Floors

From: Susan Cruver <scruver_at_msn.com>
Date: Fri, 19 Sep 2003 20:34:20 -0000

There are lots of volcanic ash layers in Cascade Mtn soils and
rocks. One of the thickest is from the Mt Mazama eruption which
created Crater Lake; much larger than the 1980 St Helens eruption.
Mt Rainier ash layers can be found, too, and layers from the 1980 and
previous St Helens eruptions. But ash preserved as air fall tuffs (a
rock comprised of welded volcanic material deposited from the air) go
back to 50 million years ago and pre-Cascade volcanism. I did my
masters thesis on the geology and mineralogy a pretty thick group of
these old tuff layers, from a location near Darrington WA. Many were
light to medium gray, gritty, poorly-consolidated sediments, similar
to what you describe, Mike. However, without seeing this material it
is impossible to tell what it is. It doesn't sound like duff,
however. Duff is all organic material, very soft and low density,
and all the Cascade duffs I've observed were brown.

Volcanic ash is largely very fine grained (many of our CT microbes
are larger than lots of these particles) and composed of volcanic
glass and mineraloids (partially crystalized minerals). This stuff
decomposes very easily, enriching the soil with whatever chemical
elements are in the ash. This includes iron, magnesium, potassium,
sodium, calcium and elements which are present in trace amounts,
which can be anything from Boron to rare earths. Mostly it is
silicon and aluminum. Anyway, the stuff decomposes quickly and apple
farmers noticed improved soil fertility within a few years after the
1980 eruptions.

For more information about the effect of volcanic ash on soils, see
www.fs.fed.us/gpnf/forest-research/ei/workshop/docs/tephra-
processes.doc. For information specific to 1980 Mt St Helens ash,
see Dethier, D.P., D.R. Pevear (my thesis advisor) and David Frank,
1981, Alteration of New Volcanic Deposits, in The 1980 Eruptions of
Mt St Helens, U.S. Geological Survey Professional Paper 1250. It
includes chemical analyses of many ash samples. Preparing some of
those samples put food on my table and textbooks on the shelf while I
was in grad school. Unfortunately, it's not available on the
internet, although you can order it. I'm sure it's in the library at
Central Washington University.

Is everyone else asleep yet?

Susan Cruver

--- In compost_tea_at_yahoogroups.com, "Mike Bosko" <mjbosko_at_j...> wrote:
> Hey all, I've spent that past couple weeks backpacking the
mountains.
> Having loads of compost tea group messages in my mind - I was full
of
> thought.
>
> Kind of off topic, but somewhat biology related...
>
> While sitting, listening to a couple large bull elk bugling at each
other, I
> began pulling at the duff in the forest floor. As I probed past
the top
> pine needle litter I found a grey gritty layer that went several
inches deep
> (actually, I couldn't find the bottom). Does anyone know, is this
> decomposed forest matter, or could it be the deep ash laid down by
Mt St.
> Helens' eruptions years before. I was definitely hiking in the
area of it's
> ash path.
>
> In any event, I started looking closer and saw lots of white fungus
looking
> jewels and many roots probing around in it.
>
> Any idea where I can find information scientific studies on this?
I did a
> quick internet search, but my search terms didn't get me much by
way of this
> subject. Not that I'd go mining for this stuff, but I'm curious
how this
> might work to inoculating compost / compost tea?
>
> I hear lots about rock dusts, if its from St Helens' blast - could
this
> contain some beneficial components for plant matter? Has anyone
heard of
> any tests done on this ash?
>
> If its not ash, and thats what forest duff looks like - I'd like to
look
> into this biology as well. The forest floor seemed to be thriving,
although
> dry. I always expected material high in OG to be dark, this was
lighter
> gray.
>
> Just curious, and one of the many things that circled my mind
during a
> looong, tiring, but invigorating trip into the mountains. Amazing
what goes
> through one's mind while alone in the woods.
>
> Sad to see, that of the hundred or so messages from AACT since I
had been
> out, that the standard testing thread had died. Oh well.
>
> Mike
>
>
> JMT SYSTEMS CONSULTING
> Systems Development & Network Administration
> 509 968-9015 / Fax: 509 968-9016
> http://www.jmtsystems.com


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Received on Fri Sep 19 2003 - 20:00:58 EDT

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