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Title: Re: [GreenYes] GHG and compost worms: Any thoughts, anyone?
Hi David
~
My main work task
these days is trying to help our local livestock farmers (mostly dairy) improve
the management of manure. Our focus is on phosphorus reduction, and have found a
number of management techniques result in increased nitrous oxide formation from
the manure, with the associated GHG implications.
John
PS ~ The amount of
manure per cow is huge, and the quantity of manure produced in my county swamps
the amount of solid waste produced. It's a fascinating situation, and hopefully,
we can find a way to reduce phosphorus loadings to the soil, while being able to
beneficially reuse the nitrogen, organic material, trace nutrients and water.
Interesting, indeed. This info got a lot of play
all over. Just Google it.
For what it’s worth, synthetic fertilizer,
as I understand it (and I am by no means a soil scientist or even an organics
expert), is also a significant source of nitrous oxide. Not sure of the
comparison between synthetic and natural, nor especially the lifecycle issues,
but in thinking this problem through, one clear thing to keep in mind is the
fact that soil needs nitrogen. What are the differences between naturally
occurring nitrogen and synthetic?
One fascinating thing is that it
seems pretty clear this issue has not gotten enough research and attention
vis-à-vis GHGs.
See the web pages below:
http://www.taipeitimes.com/News/editorials/archives/2003/07/20/2003060195
http://www.ghgonline.org/nitrousagri.htm
http://www.ciesin.columbia.edu/TG/AG/fertapp.html
http://www.stanford.edu/group/i-rite/statements/2001/harrison.html
db
on 7/16/07 1:53 PM,
eroyte at e@no.address wrote:
This
article appeared in the Telegraph (UK)
Wormeries 'may add to
greenhouse gases'
By Charles Clover, Environment Editor
Last
Updated: 6:01pm BST 06/07/2007
Worms may not be as environmentally
friendly as the growing number of
gardeners who use them to help compost
their kitchen scraps and grass
clippings believe, say
scientists.
In fact, the greenhouse gases emitted by a large
commercial worm composting
plant may be comparable to the global warming
potential of a landfill site
of the same scale, according to the Open
University.
This is because worms used in composting emit nitrous
oxide - a greenhouse
gas 296 times more powerful, molecule for molecule,
than carbon dioxide.
Landfill sites produce methane which is 23 times
more powerful a greenhouse
gas than carbon dioxide.
Jim
Frederickson, senior research fellow at the Open University's
faculty
of
technology, said: "We know from research in Germany that a third of
the
nitrous oxide emissions coming from the soil are associated with
worms.
"What we found from looking at large worm composting systems
is that their
emissions could be comparable in global warming potential
to the methane
from landfill sites."
The Government has said it
wants to increase the amount of waste that is
composted to 40 per cent by
2010 and 45 per cent by 2015 - which is likely
to involve more commercial
scale worm composting plants.
Red worms appear naturally in country
compost heaps but over the past
decade
or so a thriving trade has
grown up in domestic wormeries which enable
people with space as limited
as a balcony to compost their kitchen waste.
Domestic wormeries are
dustbin-sized boxes formed from several trays, with
names such as
Can-O-Worms, into which reared worms are introduced. Some are
even made
to look like beehives.
The worms are laid out on lime and vegetable
peelings. When they have
digested this material they move to another
level in search of more food.
The lower trays of compost can be used and
a tap allows the liquid
collected
to be drained off as
fertiliser.
The red worms used in composting are extremely efficient
at breaking down
decomposing material such as kitchen scraps and other
organic material but
they emit nitrous oxide in the process of digestion
in the gut.
Mr Frederickson told Materials Recycling Week said:
"Everybody loves worms
because they think they can do no harm but they
contribute to global
warming.
"The amount of worm composting is
very, very small and the amount of
landfill is huge. But landfill sites
are quite well run these days and
it is
possible to extract about
half the gas they generate and use it for
electricity
generation.
"So the amount of nitrous oxide emitted by large scale
worm composting is
something we should be looking at before we go further
down that route."
Mr Frederickson said that the research he and his
colleagues had done
was on
very large commercial worm composting
"beds" which build up large
amounts of
nitrogen which is then emitted
by the worms as gas.
It is unclear whether the same process goes on
to the same extent in
domestic worm composting bins, but Mr Frederickson
said: "We are clear they
will be producing nitrous oxide but maybe not to
the same extent. They may
be more stable.
"Worm composting bins
and compost heaps produce really good compost in a
decentralised way with
no transport to landfill sites - which is a good
thing.
"But we
must remember if we are evaluating this method against other
ways
of
getting rid of wastes, such as landfill and incineration, that
worm
composting can also be a source of greenhouse gas
emissions."
--
David Biddle,
Executive Director
<http://www.blueolives.blogspot.com>
Greater
Philadelphia Commercial Recycling Council
P.O. Box 4037
Philadelphia, PA
19118
215-247-3090 (desk)
215-432-8225 (cell)
<http://www.gpcrc.com>
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