Elaine,
From this
information you've presented would it be correct to say that a fermentative
product like EM degrades the soil in the long run?
thanks,
daniel
----- Original Message -----
Sent: Wednesday, January 15, 2003 8:36
AM
Subject: Re: [compost_tea] What do the
nasties breathe?
Bob asked "what do the nasties breathe?"
Most of them ones we can't have in tea are autotrophs, which in
non-science words, means they "breathe" carbon dioxide (CO2), or nitrate
(NO3), nitrite (NO2), sulfate (SO4), and other materials containing oxygen
tied up in chemical forms. If you notice, all those chemical formulas
contain oxygen, but not in gaseous form. They use "solid oxygen", if you
will. (All my scientific colleagues just cringed when they read that,
but I think it makes the situation more understandable to people who haven't
spent years studying the subject, OK?)
The problem isn't so much what
the nasties breathe, as what they produce.
So, to consider this,
we need to go back to understanding plants. Plant growth is the whole
reason we are fussing about all this, right? What does the plant
need?
And, oh, yeah, we can't have any human pathogens in the tea
either.
So, how do we set the stage so that the plant gets a
soil condition that it needs, and we exit any human pathogens?
Back to plants. Roots of plants do not tolerate anaerobic
conditions. But why don't they tolerate anaerobic conditions?
Plants roots can do just fine in conditions that just lack of
oxygen. Roots don't need oxygen, per se. Remember, plants take up
CO2 and release oxygen.
So, lack of oxygen is not the
problem. Number one consideration is what the anaerobic bacteria
produce. Number two consideration is the fact that the good guys that
outcompete the bad guys require aerobic conditions. If you don't have
the organisms that compete with the disease organisms, then the diseases
"win". Almost all (please read that, ALMOST all) disease organisms do
much better when oxygen is reduced, because the good guys aren't there to
prevent the bad guys from doing well. Simple competition. Aerobic
enzymes are better at grabbing foods than enzymes produced by facultative or
true anaerobes.
Generalization however. A few anaerobic
organisms are better than aerobes, but they are at the bottom of the ocean, or
in thermal pools. Other environmental factors keep them out of your
soil. Unless you have a pH 3 soil, or you have high reduced iron, or
high sulfate, for example.
How reduced does the oxygen have to be to
"go over the edge" into anaerobic? What is the cut off level of oxygen
for the bad guys to take over because the organisms that normally grab food
away from the bad guys are no longer able to grab? It depends on which
bad guys you have in your soil or compost.
So, the more pathogens and
bad guys you were able to kill during the composting operation, either by
proper heating regime in thermal composting, or by enough passes through
earthworm guts, the less you have to worry about anything during the tea
brewing cycle.
But what is the cut-off? It depends is not a
really useful answer. What we have seen, based on plant responses to
tea, is that 5.5 to 6 mg oxygen per liter is a safe cut-off level. Below
5.5 to 6 we often see production of substances that can cause leaf-curl,
root-death, and burning of the plants. It doesn't always happen,
however. I think that if you have fermentative bacteria instead of
putrefying bacterial species, there is less problem. Really bad
substances aren't produced, BUT you are still setting the stage on plant
surfaces and in the soil that are less than beneficial for the plants.
The beneficial fungi are all strict aerobes. If you have
fermentative bacteria, you may not have alcohol production, but you have low
pH organic acids produced, which harm the fungi, kill the protozoa and
benefical nematodes. The effect is not so much a direct burn or kill of
plant tissue as a slow decline in soil health, as you lose the organisms that
combat Pythium (wilts), Phytopthora (blights, mildews), Rhizoctonia (root
rots), etc.
So, if you have fermentative bacteria in the tea
brew, lack of oxygen may not result in directly toxic materials, but the
organisms you add are not the beneficials from a plant's point of view.
You did alot of work making and spraying tea, got a little benefit from
competition for foods on leaf surfaces, but went backwards in the soil.
And that's where we're trying to head - to soil health, so you don't
have to keep putting out the teas even. As time goes by, with GOOD TEAS,
you should be able to stop spraying weekly, or even monthly, because you will
have gotten the soil back into a condition of health.
Can't happen with
anaerobic teas. That's why you have to have aerobic tea.
Hope this helps -
Elaine President, Soil Foodweb
Inc. www.soilfoodweb.com
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