Aquaponics Digest - Wed 10/13/99
Message 1: Field trip activities
from Adriana Gutierrez & Dennis LaGatta
Message 2: Re: Field trip activities
from "vpage"
Message 3: Re: grow beds/biofilters
from "Barry Thomas"
Message 4: Re: Field trip activities
from Marc & Marcy
Message 5: Re: Important new advances
from "Barry Thomas"
Message 6: Salmon aquaponics?, was Re: Radio Broadcast of Amazing New
Technology
from S & S Aqua Farm
Message 7: hydroponics media vs. soil
from "Jewel" <1mastiff@amigo.net>
Message 8: Re: grow beds/biofilters
from Bagelhole1
Message 9: Re: hydroponics media vs. soil
from Glen Seibert
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Subject: Field trip activities
From: Adriana Gutierrez & Dennis LaGatta
Date: Wed, 13 Oct 1999 12:48:19 -0400
I have a group of fourth graders invited to come to my greenhouse on a
field trip. Can some of you share your ideas on possible activities to
incorporate into the visit to make it as interesting as possible?
Adriana
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Subject: Re: Field trip activities
From: "vpage"
Date: Wed, 13 Oct 1999 11:36:00 -0600
If they help plant something and then return later to see the fruits of
their labours...label their particular effort..
A literature unit then would be a"What I did and what I think will
happen.....They can do a relevant unit to gain understanding of the
processes in the meantime...nutrients,light,turgidity,chlorophyll etc
A final literature unit-were my predictions correct...what really
happened...
The beauty of aquaculture is that it fits all the disciplines. If the
teacher is strong they will figure out something about themselves...what did
I like best?...the math, the biology,the hands-on work,the plumbing..etc.
It is an endless teaching opportunity with results that have value.
Victoria
----- Original Message -----
From: Adriana Gutierrez & Dennis LaGatta
To:
Sent: Wednesday, October 13, 1999 10:48 AM
Subject: Field trip activities
> I have a group of fourth graders invited to come to my greenhouse on a
> field trip. Can some of you share your ideas on possible activities to
> incorporate into the visit to make it as interesting as possible?
>
> Adriana
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Subject: Re: grow beds/biofilters
From: "Barry Thomas"
Date: Wed, 13 Oct 1999 18:35:04 +0100
Hi Wendy,
> >Do you know (or can you point to info) how the two filter
> >types compare?
> I don't have exact numbers in front of me comparing the same
> filter used as a trickle and an ebb/flow, but if you think about
> it, it just makes sense.
Sorry, I actually meant: How do shallow vs deep filters compare? But
thanks anyway. I use flood/drain for the plants in my small hydro system
for all the reasons you mention.
> The bacteria would develop in layers depending on what
>nutrients are available.
Yes, see what you mean about the layering and the automatic adaption
(given time) of the filter to varying loads is a very nice feature. But,
once the layers have been established, in order for the bio part of the
filter to increase in size, layers near the bottom of the column
(assuming top-fed filter) must migrate quite a distance to allow higher
layers room to grow - increasng reaction time of the filter?
Does anyone feed their biofilters (possibly with just the more
difficult/variable substances) to keep them slightly oversize so able to
track variations more closely?
> >Plants seem to be able to affect their rhyzospheres to a
> >significant degree, is this helpful or harmful in this situation?
>
> I would think it would depend on how that particular plant
> effected its rhizosphere. Some plants actually put out a
> type of antibiotic. Some put off chemicals that encourage
> bacterial activity. I think that is too broad a question. :-)
Yes, it probably was. What I was trying to say was that as plants -
along with their bacterial and fungal symbionts - all attempt to
influence their immediate environment (rhizosphere) to their own
collective benefit and the detriment of their enemies, it seems likely
that conflicts could occur between them and other species (which
although classed as an enemy, are still a useful/necessary part of the
breakdown of the fish/other wastes), lowering the effectiveness of all
concerned. So, determining how each type/group of organisms affects all
the others and which should be in close proximity vs which kept at more
of a distance (both physical distance and number of stages) seems fairly
important? The less energy and general resources you have available, and
the more difficult the environment, the more important it becomes.
Are the bacteria that inhabit the rhizospheres of plants commonly used
in aquaponics the same as those (or do the same job) which live in deep
biofilters? If not, and you're using only shallow, planted trays then
where do the others live?
It seems - to me - that a (relatively) small, unplanted biofilter
upstream of the planted trays (whatever) is a worthwhile enhancement?
The least it should do is to widen the choice of plants that can be
grown?
> Perhaps we could search for a plant that sucked up tons of
> nitrates, could metabolize ammonia directly (in case of a filter
> "crash"), secreted a chemical that increased fish metabolism
> resulting in massive growth rates with absolutely yummy melt-
> in-your-mouth filets, was self pollinating, and produced fruits
> that made a great side-dish or sauce for fish.
Exactly - you missed a number of things like minimal power, water and
work input; minimal waste; resistance to pests and weather effects;
possibilities for soil improvement etc etc but you've got the idea. ;)
While it may be a little optimistic to hope to find an individual plant
with these capabilities, integrated systems can and do acheive some or
all of these aims to a greater or lesser degree (I assume you have one
yourself?). What we should search for are ways to add more of these
abilities to existing systems and new designs which give these benefits
across a wider range of environments (or better specialisation for
particular demands).
> (Boy, you can sure tell I didn't sleep last night and haven't
> had breakfast yet)
Yes, you do seem to be a bit of a bear in the morning. ;)
Barry
barrythomas@crosswinds.net
PS I certainly wasn't trying to unreccomend your reccomendation.
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Subject: Re: Field trip activities
From: Marc & Marcy
Date: Wed, 13 Oct 1999 12:06:53 -0600
Adriana Gutierrez & Dennis LaGatta wrote:
>
> I have a group of fourth graders invited to come to my greenhouse on a
> field trip. Can some of you share your ideas on possible activities to
> incorporate into the visit to make it as interesting as possible?
>
> Adriana
I often ask my students about their anticipations before
class gets moving. Most often we will spend a whole class
period exploring their preconceived notions, discoverys,
questions, etc. about assigned subject matter and I couldn't
have structured it more beneficially. We get interest,
exploration, participation, ownership of the material,
social interaction/development, self structure. It's not a
free-for-all, some moderation is needed such as time "gee,
time is short so lets look at this other thing" and subject
"sky diving is interesting so what do you think about that
pirahna on the end of your finger?" subject boundaries but
my experience is that the kids are good folks and cooperate
when they trust you are leading them in a cool direction.
Marc
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Subject: Re: Important new advances
From: "Barry Thomas"
Date: Wed, 13 Oct 1999 19:44:28 +0100
> I went through a fun experimentation phase where I established a
> "natural self supporting" 32 inch deep 800 gallon pond of
> Little winter die off. Extremely attractive pond, lots of
> complements. Lots of work. Commercial interest infected/infested
> me. On to Aquaponics now.
Marc - Great description of your experiments, many thanks.
Why (in the final pond) do you think the later hatches stayed small -
fish density topped-out for this amount of filtration/aeration or other
reasons such as seasonal temps etc?
Any chance of more info of your current (aquaponic) system? How does it
compare to the simpler pond system? Is it worth the extra complexity?
Do you - or could you - run your system using only alternative/local
energy sources?
Barry
barrythomas@crosswinds.net
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Subject: Salmon aquaponics?, was Re: Radio Broadcast of Amazing New
Technology
From: S & S Aqua Farm
Date: Wed, 13 Oct 1999 14:27:51 -0500
At 08:24 AM 10/12/1999 -0700, Nick wrote:
> A news radio station here in western Washington, Puget Sound
>region, this last week aired a news segment of interest. A person was
>quoted, who said that a new salmon hatchery would be built here which would
>include a greenhouse, on-site, where the water from the hatchery would grow
>plants and filter the water.
>
> "This amazing new technology should be completed and in
>operation in about a year and a half" was part of this persons comment.
Nick - any more details available on this?
Paula
S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775 417-256-5124
Web page http://www.townsqr.com/snsaqua/
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Subject: hydroponics media vs. soil
From: "Jewel" <1mastiff@amigo.net>
Date: Wed, 13 Oct 1999 12:52:49 -0600
Hi group! Could I get some advice again?
I'm considering doing one greenhouse using soil, with the Blumat drip =
system. So I'm trying to define the differences between using soil as a =
media, or traditonal hydroponic media. =20
Does anyone know the production differences between hydroponics media =
and soil, all other things being equal? i.e., : In a greenhouse, using =
growing beds or pots, drip or flood to waste nutrient/water delivery to =
the beds/pots.=20
Also, using the above parameters still, would there be a big diff =
regarding pest and disease problems?
Jewel
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Subject: Re: grow beds/biofilters
From: Bagelhole1
Date: Wed, 13 Oct 1999 20:29:49 EDT
In a message dated 10/13/99 6:41:30 PM, barrythomas@crosswinds.net writes:
<< Perhaps we could search for a plant that sucked up tons of
> nitrates, could metabolize ammonia directly (in case of a filter
> "crash"), secreted a chemical that increased fish metabolism
> resulting in massive growth rates with absolutely yummy melt-
> in-your-mouth filets, was self pollinating, and produced fruits
> that made a great side-dish or sauce for fish.
>>
Recently, I was advised, " Clam shells (dead or alive) and water hyacinth
will do alot." Anyone know about this? Tom O (bagelhole1)
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Subject: Re: hydroponics media vs. soil
From: Glen Seibert
Date: Wed, 13 Oct 1999 17:49:07 -0700
Jewel wrote:
>
> Hi group! Could I get some advice again?
>
> I'm considering doing one greenhouse using soil, with the Blumat drip
> system. So I'm trying to define the differences between using soil as
> a media, or traditonal hydroponic media.
Hi Jewel. "All things being equal." Thats a mouthful! Almost nothing
is equal in the very divergent situations you've asked about...soil
versus sterile medium.
The discussion about the nature of soil and its role in plant nutrition
could take years (don't I know..! WHEW!) but bottom line, there are
chemical, biological, hydrological, structural and nutritional
attributes to soil that are very different in sterile media such as
Perlite or expanded clay pebbles.
When we start growing hydroponically we take responsibility for all the
stuff that usually happens naturally...the buffering of pH in nutrient
solutions, maintaining field capacity and appropriate hydrodynamic
pressure, proper osmotic concentrations of necessary elements,
appropriate light levels and durations, etc. etc. Choosing a pure
hydroponic system that includes a sterile, inert medium lets us control
all these factors (and opens more opportunities to mess up!)
In a production situation the high initial cost of a sterilizable,
reusable medium is recovered in the long run. Diseases can be kept down
but a hydroponic system with recoverable nutrient exposes all the plants
it serves to the disease of one...the vector being the nutrient water
itself.
Greenhouses are a more controlled environment for light intensity and
photoperiod, as well as heat and humidity, but the conditions also
support molds and fungi and specific pests.
I hate to keep repeating myself, but the real answer to this question,
like so many in the field, is
(*sigh*) "It Depends!"
I recommend some soil science books to you. Not hydroponics, but good ol
fashioned soil science tomes like
SOIL SCIENCE SIMPLIFIED by Helmut Kohnke. Amazon.co has it for about
$7.00. A greater understanding of soils can only make you a better
hydroponicist...understanding what you're replacing is important.
Hope this helps!
Glen Seibert
Fullerton College Hydroponics
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