Subject: Re: Regulation of compost teas (was: NOSB loses its head)

From: Joel Gruver <[email-masked]>
Date: Mon, 21 Oct 2002 20:30:48 -0400

Hello Jeff,

I do not doubt that increasing the community of beneficial microorganisms on
leaf surfaces will often improve plant performance.
Several years ago I fortuitously discovered an article in a forestry journal
(American Forests?) that discussed phyllosphere ecology in a very clear and
captivating way. I was teaching an agroecology class at the time and I gave
the article to my students as an assigned reading.

What I am skeptical about is the benefit of increasing microbial populations
in compost teas using sugar, molasses, nutrient solutions, or aeration...

As I wrote earlier (but perhaps obscured my meaning with a typo),
the great **majority** of soil microorganisms (>95%) are unculturable using
all known types of media (let alone something very simple like glucose). Why
does selective enhancement of the "greedy"/r selected species improve the
performance of a compost tea ?

As Dale implied with his question about applying cultures of known
biocontrol species, the # of bacteria or fungi applied per square inch of
crop leaf surfaces should be less important than the species composition of
compost teas. Your goal is to promote colonization of leaf surfaces with
persistent phyllosphere adapted micoroorganisms that have the desired
effects of disease suppression and plant growth promotion, right ??.

I want to know if people have found that compost teas work better after they
have been supplemented (with sugar, nutrients, oxygen...).

Joel

Joel Gruver
Dept of Soil Science
NC State University
[email-masked]
(919) 515 4270

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From: Dale Wilson <[email-masked]>
Date: Tue, 22 Oct 2002 05:28:55 -0700

Hi Joel, jeff and Greg,

Joel wrote:
> leaf surfaces will often improve plant performance...

Compost and manure are complex and diverse materials and they are
beneficial in many ways.  But people who use compost "tea" to control
diseases are probably getting benefit by altering leaf surface flora.

> What I am skeptical about is the benefit of increasing microbial
> populations in compost teas using sugar, molasses, nutrient
> solutions, or aeration...

Well, if you add sugar and aerate compost leak water, SOMETHING is
going to grow like wildfire, and it will probably be some sort of
bacteria or yeast.  Maybe positive responses from these "teas" are
non-specific reactions to large amounts of sub-pathogenic microbial
pressure on the plant.  Maybe there are antibiotics involved.  It is
probably a very hit-or-miss game.

> the great **majority** of soil microorganisms (>95%) are unculturable
> using all known types of media (let alone something very simple like
> glucose). Why does selective enhancement of the "greedy"/r selected
> species improve the performance of a compost tea ?

What is going on may be very simple.  Probably there is some abundant,
culturable yeast or bacteria in many composts, and this is what takes
off on when they add sugar and air.  There must be some literature on
the manipulation of leaf surface flora using biocontrol agents.  I
don't have time to search right now.

> biocontrol species, the # of bacteria or fungi applied per square
> inch of crop leaf surfaces should be less important than the species
> composition of compost teas.

I don't know, maybe it is a mass-action kind of thing.  It would be
very valuable to take samples of successfully brewed compost tea and
perform dilution plating to see what is in there.  Someone must have
done this.

> have been supplemented (with sugar, nutrients, oxygen...).

Yeah, It would be nice to get comments from someone with hands-on
experience with compost tea.

Dale

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From: "Lawrence F. London, Jr." <[email-masked]>
Date: Tue, 22 Oct 2002 14:59:28 -0700

Jeff Lowenfels wrote:
> I am not sure Joel is right about 95% of soil bacteria not being
> culturable......you mean you can't grow them in a petri dish? Where do you
> get this statistic?
>
> I have my teas tested frequently and have seen the numbers. The biodiversity
> is amazing and if that is only 5 % then so be it......though, again, I doubt
> the percentage.... I would suggest Joel get in touch with

Dr. Elaine Ingham
Soil Foodweb, Incorporated
[email-masked]
http://www.soilfoodweb.com/phpweb/

or Dr.Eric Nelsonn (Cornell) to answer his questions.

-
See: GreenReleaf Novozymes
http://www.bi-chem.com/green_releaf/professional/tech_info/tech_info_backgrd.htm
 From their website:
"Soil bacteria also manufacture a suite of trigger compounds that are attractive
to other soil microbes and when present in the rhizosphere this consortium of
microbes can be extremely beneficial to plants. Plus, when beneficial bacteria
colonize the root surface they can often help exclude pathogenic microbes from
gaining access to the roots. Interestingly, when plants are grown under sterile
conditions they often do not thrive as well as when the full microbial community
is present."

--
L.F.London
[email-masked]
http://market-farming.com

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From: Dale Wilson <[email-masked]>
Date: Tue, 22 Oct 2002 12:39:10 -0700

Jeff,

> I have my teas tested frequently and have seen the numbers.

What species (or genera) predominate?

Dale

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From: "Lawrence F. London, Jr." <[email-masked]>
Date: Tue, 22 Oct 2002 14:59:28 -0700

Dr. Elaine Ingham

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