Ethylene-oxygen cycle

Lawrence F. London, Jr. lflondon at
Thu Dec 13 00:48:26 EST 2001

I found this post from Keith in the archives:

On Tue, 22 Feb 2000 23:52:12 -0500, in permaculture Keith Johnson
<keithdj at> wrote:

To quote from an article on Soil Fertility, by Lea Harrison, in the
Activist (#26, May 92):
"Micro-organisms are extremely numerous in healthy soil; eg. one gram
of healthy
topsoil contains about 1,000 million bacteria. All the micro-organisms
that break down
organic matter, are aerobic organisms. That is, they can only function
in the presence
of oxygen. All plant pathogens, which cause plant diseases, are also
aerobic organisms.
Even in well aerated soils, aerobic organisms use up oxygen faster
than it diffuses
into the soil. This creates, at any tiime, many microsites without
oxygen, all through
the soil. Anaerobic bacteria, which function in the absence of oxygen,
grow and
multiply at these reduced microsites. They produce ethylene, which
inactivates, but
doesn't kill, aerobic micro-organisms. There is a complex rocking
backwards and
forwards between the functioning of aerobic and anerobic bacteria, all
the time, at
microsites scattered all through the soil."

In brief, the ethylene is the cycling back and forth in soils between
aerobic and
anaerobic conditions. Under both conditions nutrients are rendered
available which
would not otherwise be so. Both parts are essential for healthy
balanced soil.

Keith Johnson

L.F.London ICQ#27930345 lflondon at  london at

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