permaculture

["Marsha Hanzi" <hanzibra@svn.com.br>]

Thanks Keith!  that's what I was looking for.  With plowing and exposure of
the soil , we are encouraging, it seems to me, the aerobic part of the
cycle,  thus  depressing the benefits of the anerobic part of the cycle... I
must have this Activist buried somewhere-- will look it up...

I appreciate your help...

Marsha


----- Original Message -----
From: Keith Johnson <keithdj@mindspring.com>
To: permaculture <permaculture@franklin.oit.unc.edu>
Sent: Wednesday, February 23, 2000 1:52 AM
Subject: 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.
> >
> >
>