Re: [compost_tea] Re: Re: Re: measuring aeration

From: Robert Norsen <bnbrew_at_yahoo.com>
Date: Tue, 14 Oct 2003 22:07:25 -0700 (PDT)

For your information - and others, Kirk Kevin and I are starting a test series with 5 Bittis and 1 BobO oriented exclusivlely to air vs nutrients with one vs water volume. Running a Bitti in a 50g. to compare identical loads 10 g vs 50 g same air. Many tests like that. Only after careful testing with D O2 meters to learn what we can about how much air is ideal ( not just enough) we will take that data to design another series of tests to send to SFI. Will we release the test methods and results? Do we have to do it on Sunday?
This ain't advertising. Sometimes I think we are shooting our image in the foot. Bob
Kirk Leonard <kirk_at_oregonatural.com> wrote:Couple posts worth repeating here, I think, and some comments. Lengthy,
same thread, but believe there are important points to make. Hopefully
successfully.

> Date: Mon, 13 Oct 2003 00:02:13 -0400
> From: soilfoodweb_at_aol.com
> Subject: Re: Re: Re: measuring aeration
[excerpted]
> The way to know if you are getting enough air is to meaure it when you use
your typical recipe and your typical compost. Start from that knowledge,
instead of from the CFM, or air pump horsepower. <
But if you don't have a DO meter (necessary if finicky tool for measuring
oxygen...), knowing pump cfm and something about
air/water volume and nutrient relationships is next best assurance you'll
stay aerobic. Per Bob's experiment, kelp makes less oxygen demand than fish
hydrolysate (wasn't it?), and we know that molasses can quickly cause
drastic DO drops. We know a lot more about nutrients than air volumes and
their value (other than air is essential...).

> I have said, over and over, that you need to have data from the makers of
the tea machines that show, with the pump, recipe and compost they
recommend, that the tea will contain the aerobic organisms needed. <
Agree, but last poll on the subject showed most folks here are making their
own machines, and most commercial makers, while providing recipe
suggestions, do not provide air volume data as far as I've seen. Bob's
recent experiment indicates that can make a lot of difference when
experimenting with recipes, which we are all encouraged to do. If TaChung
is right (I think he is), a small difference in air volume can make a big
difference in tea, especially in a smaller machine. Don't recall seeing tea
tests, though.

> I find myself getting very frustrated with all this. [Nah, really, how
come? How does this compare with USNOP?] The point is to make good tea.
Measure that end point, and determine what the CFMs need to be in YOUR
machine, in order to make good tea. <
Agree that good tea is the goal, but this sounds to me like you're treating
air volume as a dependent variable, rather than the independent one I think
it should be (I think I got that right, it's easy to add air with more
pumps/aerators, anyway, which I think is a good thing to be able to do,
generally). And it feels like an expensive, potentially damaging (see
"horrible brews" below) way to go. We need to have some baseline info on
air/water volume differences, as well as the effects of different nutrients,
and different composts. Lots of progress on nutrients and composts has been
made here. If I knew I could add 80ml of fish hydrolysate safely above some
basic a/w level, I'd be a much more comfortable camper. If I knew I could
put in inexpensive aquarium pumps/aerators for the tea, I think I'd be even
more comfortable.

Specific compost content is the most variable of variables, it seems to me.
Same composts vary season-to-season. (Thank you for some "good" compost
standards, Doc... and Jeff and others for "activation" ideas.) Nutrients
are next most variable, both in kind/form and in actual content (how many
humic or fulvic acids are in there really?). I recall having heard here
that stated manufacturer concentrations are not always accurate, even.
Water varies place to place and sometimes seasonally (and then there's that
damnable chloramine!) but that can be adjusted, once known. Temps vary,
less in a controlled environment, but the range is large, it seems, and I've
not heard of temperature-caused damage - less organisms or not right ones,
but not harmful as far as I've heard. I trust good compost and really want
to trust temperature, and atmospheric pressure...

That leaves containers, water volume, and air volume as the most
controllable variables, which is why I keep harping on air/water volumes.
Sorry for the harping but hopefully there's some context for why here.

> The point is to make tea that has the organisms in it. Aerobic organisms,
because we have even less data on anaerobic organism tea than aerobic tea,
and with certain conditionsin anaerobic tea, we can make some really
horrible brews. I've killed quite a few plants with anaerobic tea. I've
never published that data, because you don't publish negative results. <
Gotcha, Doc, but if you can do that, imagine what we can do... And on not
publishing negative results - a professor of mine wrote a book on failures
in organizations and everybody laughed when they heard that... until they
read the book and realized how valuable the insights were. Could be until
we get a better handle on "best practices," understanding what hasn't worked
is important. How much of those bad brews might have been due to not enough
air? Of the various SoilSoup failings, I think not enough air is a big one.

> Date: Thu, 2 Oct 2003 10:37:07 -0700 (PDT)
> From: Robert Norsen <bnbrew_at_yahoo.com>
> Subject: Re: Re: Air Required was: Air pump selection

> What is enough AIR? There is a suggestion in the message that air required
is related to gallons of ACTea being brewed. My experience says AIR
REQUIRED is much more related to the number and rate of activity of the
microbes needing O2. The number of microbes is related to the compost
quantity and quality AND the amount and effectivity of nutrients AND the
temperature of the brew AND how many microbes have developed in the brew at
any point in the brew cycle. Air required may also vary with the results
desired. Will the results in numbers of fungi be the same if O2 is 5.5 as
if it is held nearer 7.5? <
Great comments and question, Bob. I agree completely, and didn't mean to
imply air/water volumes were only variables, but again, they are most
controllable elements, and we do know air and water are essential... And
what is a good, safe air/water volume ratio when you add which nutrients?
It occurs to me that compost is a more predictable component than nutrients
in some respects.

> Maybe a more usefull approach is: with a given air supply the brewer
(person) must know and control the compost, nutrients and temperature to
avoid low O2 . [Absolutely Agree] With given amount of air the gallons can
increase. The concentration of microbes will decrease with more gallons.
Tests indicated an increase in total quantity of microbes produced in the
larger volume of water. Use of an O2 meter is essential to know what is
going on. <
[snip]
There's that darn DO meter again. Buggers. Beside the expense, everyone I
know who has one wonders if it's really working right much of the time, but
maybe that's mostly a learning-to-use thing. Bob's right about that, but if
those who can will look at the a/w variable via DO monitoring and tea
testing, I think we will get some serious quality control handles sooner
than later.
If Bob took those same three machines, same compost, nutrients, all else
same, too, and varied air volumes across them, seems like that would be a
real good look, for Bittis or Bobolators, anyway.

I am convinced that air/water volumes are important to the quality and
safety of compost tea, darnit, and I think they are among the easiest, most
controllable variables to test. Do I really need to mount myself on a big
petard here? DO monitoring is a great real-time way to watch that, but not
everyone has one (not to mention three!), or indeed should need one, imo.
(You can buy many good pumps for same bucks...)

And ultimately, Jeff and Elaine are right. What's actually in the tea is
most important, so tea testing - absolutely best deal I've ever seen being
the leaf assay test Doc offered up yesterday - is needed too. In the
meantime, DO on A/W by Nutes (how's that for some lingo...better than
nuk-u-lar, eh?:) is a set of tests a whole lot more folks can track and
do... hmm?

Kirk L











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Received on Wed Oct 15 2003 - 10:48:31 EDT

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