Re: [compost_tea] Information for Newcomer

From: <soilfoodweb_at_aol.com>
Date: Mon, 23 Feb 2004 15:23:22 EST

John is correct - the bottom line is how teas improve plant growth, or plant
health. What we do with tea needs to have that goal in mind.

Plant response needs to be assessed, but usually plant responses are
down-the-road, so we need a set of "early warning signals" to let us know if the tea
we are making now is going to give the plant response.

So, the biology in the tea at the beginning, when the tea is finished, is
immediate information that we can use to know that the tea will give the response
we want.

Documenting the actual plant response is important too.

When people do plate counts of bacteria to assess compost tea quality, there
is no correlation between the plate count results and improvement in plant
health. So, people doing plate counts and claiming that tells them whether the
tea is any good are just fooling themselves. Plate methods cannot the true
diversity in any sample.

Plate methods are fine for doing counts of organisms that you know grow in
certain conditions, but not for understanding diversity.

At SFI, we are doing Bio-Log determinations, where different media are used
to grow species of Pseudomonas, Bacillus, nitrogen fixing bacteria, etc in
certain conditions, and then we can tell you whether the species that grow in
those defined conditions are beneficial or not. But this is not true diversity,
just a means of telling you if you have beneficial species or
disease-organisms.

If anyone is interested in doing the Bio-Log approach, let me know, and we
can talk $$$ to get it done. But please realize the limitations of this
approach. Until we can do DNA methods, true diversity is very expensive to figure
out.

SFI in Australia is working on this issue, and the affordable DNA assay is
close - in terms of maybe a year.
 
Elaine Ingham







Received on Mon Feb 23 2004 - 23:05:28 EST

This archive was generated by hypermail 2.3.0 : Tue Feb 07 2012 - 14:15:04 EST