Re: [compost_tea] Re: measuring aeration

From: <soilfoodweb_at_aol.com>
Date: Sat, 18 Oct 2003 15:10:50 -0400

Compost doesn't vary that much on a daily basis, as long as it is mature, and you are maintaining environmental conditions.

Yes, species in compost, or any real world sample, varies daily in exact numbers of each species present, but that variation has never been demonstrated to be a critical factor in tea making.

Day-to-day variation in exact number of individuals of each species? Not important in tea making.

Much more important to know that you have the DIVERSITY of bacteria and fungi, and that you have the right balance of bacteria to fungi, that you have the nutrient cyclers, i.e., the protozoa and nematodes.

And please, listen to all the academics who, if they know anything at all about environmental samples, will agree with these statements -

Plate counts tell you nothing useful about the actual number of species present.

Plate counts are not capable of giving you information on the number of individuals of any ACTIVE, metabolically functioning species in soil, compost, compost tea, or any environmental sample you want to talk about.

Plate count information gives data on a minor subset of organisms that may or may not have been active, could have been present just as spores, and not active for decades.

Chat with Eric Nelson, whose paper on comparing plate counts with what was going on in soil or compost samples with respect to pathogens demonstrates how useless plate counts actually are.

Dr. Eric Nelson, Cornell University. The guru of
composting for in turf. Just might know what he's talking about?

His words, and as I recall this is an exact quote: "Plate counts are bogus when testing environmental samples."

Here's an example for you.

Plate count tests were done, the grower was given the data from 6 different media and told that the compost tea was good, the "index" was above 5 (what does that mean?). Fungal numbers were high.

The "fungus" was mildew. Huge numbers of spores of mildew in the "tea". In the field? Mildew was much higher in the plots "with tea". Great, mildew took out the grape vines.

It wasn't compost tea at all, was it? The tea was likely anaerobic, as it smelled. It was growing only a limited set of species of fungi. How can you call it compost tea, when what is growing is basically just mildew?

Scares me what the reputation of "compost tea" is going to get to be when we have idiots pulling off this kind of "tea making" and "tea testing".

Frightening.

Measure aeration. Make sure the tea recipe you are using allows the tea to stay aerobic.

Wish there were test strip papers we could use to dip and know that the tea was aerobic at 14, 18, and 20 hours into the brew, when, if the tea is going to go anaerobic, is when it happens.

Any one know of anything like this? Maybe we need rental oxygen probes to go to people when they start making tea with tea makers that haven't been tested properly.

But, when you use KIS brewers, we KNOW they stay aerobic if you use the amounts of foods recommended by the manufacturer. Clean after use completely. Use Monrovia tea brewers - same story.

Use EPM machines, but clean carefully, and use the recommended ingredients.

Use the Bitti-brewers, or the Alaska Giants, but clean well, and make sure you take the compost out after a couple hours. OK, numbers MIGHT not be as great, but at least you won't kill plants, and won't have the mildew debacle.

If the tea stayed aerobic, then check your total and active bacteria, total and active fungi. Right now these assays are on special, at $50 per sample instead of $100.

You learn the right way to make tea, using this approach, and after one or two tests, you know you are doing good, and you don't have to test, except for the occasional test strip, and the occasional SFI test (e.g., once at year, when you get started in the spring) to guarantee quality.

OK? No more silliness about plate counts when doing environmental samples, ok?

------
Oh, yeah - this too -

SFI is working on molecular probe testing to do the E. coli, Salmonella, Shigella, N-fixers, Pseudomonads, etc. Plate counts are not as reliable as these molecular methods, plate counts are more prone to false negatives and positives, and take longer, and cost more.

This is a no brainer.

Plate counts will soon be an outdated technology, something we think of Louis Pasteur having to do during the dawn of our understanding of microbiology. Not something anyone would use to assess numbers of anything for real world samples.

Strong language? Maybe. But coming into reality at an SFI lab near you.....

It's Sunday in Australia. :-)

Elaine Ingham
President, Soil Foodweb Inc.
SFI Corvallis, OR
SFI Port Jefferson, NY
SFI Lismore, NSW, Australia
SFI Hilversum, The Netherlands
SFI Cambridge, New Zealand
www.soilfoodweb.com

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Received on Sat Oct 18 2003 - 16:49:40 EDT

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