Subject: Re: Regulation of compost teas

From: Elaine Ingham <[email-masked]>
Date: Sun, 27 Oct 2002 19:06:45 EST

Hi Dale -

> You wrote:
> But don't you think that after you leach into water, add molassas, and
> aerate for a while you end up with a much simpler community?  Adding a
> soluble carbon source in a liquid culture is akin to a lab medium.  I
> don't mean to criticize the method, I just think it is simpler than
> compost per se, and that plate counts might be a useful GC tool.
>

I have data on this.  We see that all the species in compost will be
extracted (it is not a leaching process in 24 hour compost tea) into the tea.
 If you have limited species diversity in the compost, you have limited
species diversity in the tea.  High diversity in the compost, high diversity
in the tea.

But not all the individuals in the compost get extracted into the tea.  So
diversity in the tea isn't the same as diversity in the compost, but species
richness is.

The food resources in the tea come from all the soluble nutrients and food
resources in the compost, and there's a huge complexity there, not just the
food resources you add, like a simple sugar.  You are merely selecting for a
group of highly beneficial bacteria or fungi by adding an additional food
resource.

That's why testing is necessary to determine which set of beneficial bacteria
and fungi are being enhanced by addition of any food resource.  But plate
counts don't even begin to give you those answers about numbers or diversity.

We did a comparison set of plate counts, and also did direct counts, and
morphological counts.  The plate counts gave 12 species of bacteria per gram
of soil.   Six different media were used.  A total of about 30 different
species on 6 different media.  The molecular approach suggested 25,000
species, morphological analysis using direct counts gave us 20,000 different
species (extrapolated from looking at 10 different fields and determining how
many new species were observed in each field).  The molecular approach is the
way to do this work, but it's much too expensive right now.

Plate counts?  Bio-log plates?  Sorry.  They don't even begin to get a handle
on what is in soil, or compost, or compost tea.

We have a series of tests, including enzyme testing, GC work, and specific
extractants that allow us to find whether the beneficial fungi and bacteria
we know how to culture are present in a sample, and in how great numbers.
We'll be offering that starting Nov 1 on the SFI website
(www.soilfoodweb.com)

The only difference between compost and compost tea is that the non-soluble
substrates start in the compost.  So, yes, the food resources in the tea are
lower than in compost, but every species in the compost is extracted into the
tea.

Do all those species survive in tea?  If you don't feed organisms the right
foods, they tend to go to sleep and then die.  No different than people.  So,
24 hour, aerobic compost tea adds the whole diversity of organisms back into
the soil, or onto the leaf surfaces.  And they have enough food during that
short time period to stay viable.

Addition of tea or compost to soil or leaf surfaces can be a huge benefit to
both places, especially if your soil or leaf surfaces have been negatively
impacted by pesticides or salts (better known as fertilizers).

> If you had to guess, which species do you think are most
> important in a good compost tea for disease control?  It might be
> possible to add small amounts of something, like adjust the pH, SO2,
> iron, or a bit of benzakonium chloride, to tip the tea ecology one way
> or another.
>
> Dale
>

We're looking at something like 25,000 unique bacterial DNA strands in a gram
of good aerobic, highly diverse plant organic matter compost.  We don't even
have names for well over 99% of these species.   They are just numbers on the
DNA sequence list.  What does each species do?  How do you culture them?
Which ones are the ones that plant exudates feed?

Too many questions to begin talking about which ones are actually the
important ones.  To some extent, right now, we just have to let the plant do
the choosing, because its exudates feed the beneficial organisms on the leaf,
or root, surfaces.

We can assay for the beneficial bacteria and fungi we know about, but how
much of the beneficial community do we  know nothing about?

And yet, we are missing many of the beneficial species we do know about in
our agricultural soils.  Soil scientists often tell me that the bacteria and
fungi just "return to the soil - rapidly".  But they don't.  The residues in
soil, the continued plowing, the lack of organic matter in ag soil, all
contribute to even the few beneficial species we know about not being in most
ag soils.

We need to put them back.  Compost and compost tea are excellent ways to do
that.  Commercial inocula of the beneficials are useful - inocula from
companies like Helena Chemical Co, Organica Biotech Inc, Agri-Energy, EM, and
so on.  They all help.

Do we need to tip the ecology one way or another?  Sure, but which way does
addition of SO2 push you?  Beneficial to the plants you want, or beneficial
to weeds?  We don't know.   There's some work to do.  We need to educate the
public about the possibilities.

Elaine Ingham
President, Soil Foodweb Inc.

---

From: "Lawrence F. London, Jr." <[email-masked]>
Date: Mon, 28 Oct 2002 13:39:41 -0800

Is 24 hour compost tea efective in controlling fruit tree diseases (i.e.
fireblight, cedar apple rust, etc.)? Since it is cheap and easy to make
in large quantities one could cover an orchard easily with the appropriate spray
equipment or just set up an overhead sprinkler system and introduce the 24HCT
into the irrigation water.

--
L.F.London
[email-masked]
http://market-farming.com
http://www.ibiblio.org/ecolandtech/pcwiki/index.php/london

.