From: RiverValley (madhava@fidalgo.net)
Date: Thu Jan 16 2003 - 12:45:59 EST
Elaine,
>From this information you've presented would it be correct to say that a fe=
rmentative product like EM degrades the soil in the long run?
thanks,
daniel
----- Original Message -----
From: soilfoodweb@aol.com
To: compost_tea@yahoogroups.com
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-scien=
ce words, means they "breathe" carbon dioxide (CO2), or nitrate (NO3), nitr=
ite (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 s=
cientific colleagues just cringed when they read that, but I think it makes=
the situation more understandable to people who haven't spent years studyi=
ng 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. B=
ut why don't they tolerate anaerobic conditions?
Plants roots can do just fine in conditions that just lack of oxygen. Ro=
ots don't need oxygen, per se. Remember, plants take up CO2 and release ox=
ygen.
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 orga=
nisms do much better when oxygen is reduced, because the good guys aren't t=
here 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 aerobe=
s, but they are at the bottom of the ocean, or in thermal pools. Other env=
ironmental 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 anaerob=
ic? What is the cut off level of oxygen for the bad guys to take over beca=
use the organisms that normally grab food away from the bad guys are no lon=
ger able to grab? It depends on which bad guys you have in your soil or co=
mpost.
So, the more pathogens and bad guys you were able to kill during the comp=
osting 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 plan=
ts. It doesn't always happen, however. I think that if you have fermentat=
ive bacteria instead of putrefying bacterial species, there is less problem=
. Really bad substances aren't produced, BUT you are still setting the sta=
ge 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 ba=
cteria, you may not have alcohol production, but you have low pH organic ac=
ids produced, which harm the fungi, kill the protozoa and benefical nematod=
es. The effect is not so much a direct burn or kill of plant tissue as a s=
low 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 s=
urfaces, 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 s=
hould be able to stop spraying weekly, or even monthly, because you will ha=
ve gotten the soil back into a condition of health.
Can't happen with anaerobic teas. That's why you have to have aerobic te=
a.
Hope this helps -
Elaine
President, Soil Foodweb Inc.
www.soilfoodweb.com
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