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Re: Ethylene cycles



To quote from an article on Soil Fertility, by Lea Harrison, in the Permaculture
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



"Lawrence F. London, Jr." wrote:

> Still interested in a definition of ethylene cycles.
>
>

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