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  • From: KAKerby@aol.com
  • To: permaculture@lists.ibiblio.org
  • Subject: Re: [permaculture] pc aquaponics
  • Date: Wed, 10 Oct 2012 16:24:45 -0400 (EDT)

We had the opposite - day after day of bright sunshine, temperatures quite
warm but not hot, low humidity, and they driest summer in 65 years. A lot
of the upland farming areas where they've never had to irrigate before, had
to irrigate. We were very fortunate that our hayfields are at river
level, so the water table is at most only a few feet down. Our grass never
dried
out, but a lot of folks' pastures and fields did. We're expecting our
first serious amount of rain in over three months, this coming Friday. A
whole inch!

Aquaponics is flexible enough that the energy "footprint" can vary,
depending upon siting, climate, goals, limitations, etc. One of the
research
articles I was trying to find earlier in this conversation, and maddenly it
eluded me, was a series of studies from a Canadian university, studying the
suitability of using aquaponics during a Canadian winter, and how those
energy needs could be minimized. But one of the very first articles I read
about hydroponics (and this would apply to aquaponics too), was the
combination of feeder steers in co-housing with the plants during the
winter. They
shared a greenhouse which was (understandably) divided in half, with the
steers at one end of the greenhouse, and the plants at the other. The
steers
produced an amazing amount of both CO2 and heat, while the plants produced
an amazing amount of O2 and all the steer's feed. The only energy that
system needed was the lighting, which the steers would have needed anyway.
Even then it was just a few hours in the morning, and a few hours at night,
to supplement the short day length. I think this was in Ontario somewhere,
so the cold they had to deal with was considerable. It was a beautiful
example of what can be done without a whole lot of overly-complicated
fussing.

I'm going to need to pull away from this conversation now, because I've got
projects here waiting on my time and I've devoted a lot of time to chasing
down these issues already. But if anyone wants more information about
this-or-that topic in aquaponics, please feel free to email me and I'll see
if
I can either answer, or point you towards where you can find answers.
Thanks everyone for keeping it civil.
Kathryn Kerby
frogchorusfarm.com
Snohomish, WA


In a message dated 10/10/2012 12:00:06 P.M. Pacific Daylight Time,
dhondt@eircom.net writes:


Hi Kathryn,
we had the most impossible summer ever here in Ireland. Only two days our
temperatures were above 20 C and then not more than one or two degrees
above. And sunshine hours could be tallied up on the fingers of ones
hands.
We saw more sun in the last half of September than during the whole rest
of
the year, a bit too late for many crops. And I take it that aquaponics
would
need serious extra energy input here to make it work. Without light
especially, no photosynthesis.

I have been using your techniques of compost tea, huge diversity of crops
heavily mixed. Wind is very seldom abscent here so air circulation is
often
more than required :)

I'll have to seriously think about an aquaponic system.

John

> John, I had to chuckle when I read your note at the end about Ireland's
> dampness and resulting "fungal abundance". We have much the same climate
> here as you do. We're not quite as far north, but we've got l-o-n-g,
damp
> autumn/winter/spring, with typically only a few short weeks of warm dry
> summer. We could quite possibly be the mildew capital of the
continental
> USA.
> Early blight, late blight, fungal this-n-that are all very common here
> for
> just about everything and anything that grows.
>
> Happily, there are a variety of options in aqupaonic systems. One of my
> favorites is to inoculate the system in advance with beneficial
bacterial
> and fungal colonies, so that any wayward spore or germ has a lot of
> competition, right from the start. That can be done either in the root
> zone or
> foliar sprays or both. One very popular choice is compost tea, which I
> believe
> someone else either mentioned or asked about earlier in this
> conversation.
> Well made compost tea is just brimming full of beneficial goodness, and
> it can safely be used in aquaponic systems.
>
> Another of the strategies with aquaponic systems is to have a really
> strong
> diversity of plant populations, so that no one plant species is host for
> something which will cause problems.
>
> A third option is to have lots of moving air through the growing area.
> The stereotypical aquaponics system is generally illustrated as being
> within
> a greenhouse, and most of the systems I've seen or toured had fans that
> blew a phenomenal amount of air through that canopy. If there were
> fungal
> spores moving through, they just kept on moving. That also helped keep
> humidity down even with the fish tanks in near proximity. Some
climates
> can get
> away with aquaponics systems set up outdoors, or with only partial
> roofing
> (such as the UVI system). I don't know what sorts of tropical nasties
> they've encountered but they must have their own special population of
> pests
> down there too.
>
> I haven't done a keyword search in Google to see what sorts of disease
> problems the various universities have had in their setups; I'm sure
some
> of
> them have written up articles about this-or-that issue. That might be an
> interesting day of reading for the next rainy day we have here, which
will
> be
> sooner than I'd like. But yes, in general, there are multiple options
for
> aquaponics, just like for other forms of gardening and/or ag, which
either
> prevent, minimize or mitigate damage from fungal, bacterial or viral
> disease. It would be hard to make blanket recommendations about which
> ones
> would be the best or most appropriate, since there are so many other
> variables
> involved.
> Kathryn Kerby
> frogchorusfarm.com
> Snohomish, WA
>
>
> In a message dated 10/9/2012 4:28:43 P.M. Pacific Daylight Time,
> dhondt@eircom.net writes:
>
>
> I was obviously too fast again when I called a water environment
> basically
>
> anaerobic. That would only be the case in a static situation. Moving
water
> can have enough oxigen to enable salmon to perform very powerful leaps.
> However, if you had numbers of micro-organisms in water as high as in
> good
> soil your water would be anaerobic and it would look rather unclear and
> murky.
> Those huge numbers in soil are important because in a good ecosystem
like
> good soil, bacteria and fungi have very much closer relations with
plants
> than just turning amonia into nitrate. It is known that micro organisms
> exchange complex molecules like amino acids and vitamins (B12 has been
> known
> for this for decades) with plants for plant made sugar. In some places
> like
> India people used sugar as sole fertilizer and saw no lack of nitrogen.
I
> can well believe that for I used Sitka spruce saw dust (with virtually
no
> nitrogen) on top of rock and could not find nitrogen being a limiting
> factor. Of course we seldom have a problem with too little rain here in
> Ireland and that helps.
> Fungi/mycorrhizae live partly inside plant roots, exchange molecules and
> information and are known to protect plants from environmental stresses
> like
> acid rain and diseases caused by other fungi and bacteria.
>
> I love my soil ecosystems for they enabled me to get rid of potato
blight
> and crucifer clubroot without any chemical intervention and even without
> rotating crops much for 20 years. What do you do when your aquaponic
> system
> develops a disease problem? You probably have a better chance in Tassie
> or
> the US but here in Ireland blight and other fungal spores are
everywhere.
> Still, how would you solve disease if it occured?
> John
>
>
> G'day John & others,
>
> If I read John's reply correctly, he seems to imply that aquaponics
> systems
> are anearobic. Not so. The bacteria that convert the ammonia to
nitrites,
> and other species that convert the nitrites to nitrates, all require
> oxygen
> to thrive. Hence the use of air bubblers in most succesful system to get
> the
> dissolved oxygen (DO) levels to the maximum. And to prevent the fish
from
> going belly up, of course. DO is VITAL to the operation of aquaponics.
> This
> is further mitigated by system design, e.g. the commonly used flood and
> drain system gradually floods the growing media with poop water, then
the
> water flushes away quickly which effectively "sucks in" O2 from the air
> above the growing bed. Then the bacteria go to work to do the
conversions
> so
> that the plants can thrive. Without O2 (by definition, anearobic
> conditions), the bacteria die -> poop remains poop -> fish die of
ammonia
> poisoning. BIG PONG.
>
> Areas that get clogged up in the grow beds, e.g. tomatoes have vigorous
> root
> systems that sometimes lead to "dead" spots in the beds, get anaerobic.
> When
> you stick your hands in there, it pongs. As you would expect. These dead
> areas mean that the overall conversion efficiency of the grow bed (i.e.
> natural filter) becomes less efficient. A regular testing regime (e.g.
> weekly) for ammonia and nitrates will show you how efficiently the
> conversion is happening, and will point out when there are problems in
> the
> system. That is one reason for instance why sand is a Really Bad Growing
> Medium in aquaponics, because it simply clogs up with poop and plant
> roots
> too easily.
>
> Earth worms are often put into the growing beds, where they work further
> on
> the sludge and enable the most to be made of the nutrients contained
> therein.
>
> Lastly, there are very few places on this planet where the perfect
combo
> of
> soils & climate occur. (I happen to be in one such place, being NW
> Tasmania.) So even in organic soil-based ag, one would have to import
> micronutrients in the form of rock dusts, kelp meal etc. to get the soil
> in
> balance. This can also be done in an aquaponics system. Most systems
are
> run
> in the pH range of 6.0-6.2, which means that rock dust amendments will
> get
> dissolved by the slightly acidic water, thereby making the nutrients
> avaliable to the entire system (plants & fish). Quite commonly, sea weed
> extracts are also added for the same purpose.
>
> Cheers
>
> Pierre Marx
>
>
>
>>________________________________
>>From: John D'hondt <dhondt@eircom.net>
>>To: permaculture <permaculture@lists.ibiblio.org>
>>Sent: Tuesday, 9 October 2012 8:22 AM
>>Subject: Re: [permaculture] pc aquaponics
>>
>>
>>My problem with aquaphonics is not just disolved chemicals aka
nutrients.
>>Soil is an ecosystem consisting for at least ten % out of
microorganisms
>>and
>>often a lot more. To a large extend these soil organisms are aerobic. It
> is
>>as good as impossible to maintain a large aerobic community in water.
>>john
>>
>>> On 10/7/2012 9:52 PM, Scott Pittman wrote:
>>>> I too have serious misgivings about aquaponics. It is always
presented
>>>> as
>>>> some kind of perpetual motion machine that provides for all its needs
>>>> within
>>>> the system, which I doubt. I also do not believe that it could
>>>> possible
>>>> have the nutrients necessary for providing wholesome and nutritious
>>>> foodstuff. We are talking about the primary nutrient source being
fish
>>>> dung
>>>> in this closed system, where does the selenium, calcium and
> phosphorous
>>>> come
>>>> from? The co-evolution of plants with soil organisms and minerals
has
>>>> created the human nutrition story and without soil I think the actual
>>>> nutrient content will be woefully inadequate.
>>>
>>> I would never try to grow food for myself in an aquaponics system
>>> unless
>>> its nutrients came from extracts of soil-based systems (don't quite k
> now
>>> how that would work given the anaerobic aspects of aquaponics
systems.
>>> I
>>> did find through a Google search a site with pictures of a soil-based
>>> aquaponics system but they were growing ornamental aquatic plants in
>>> submerged perforated barrels with a soil mix in them. The root crowns
>>> of
>>> the plants were slightly above water level.
>>>
>>>> I would love to see some data on nutrient content of hydroponic vs
>>>> soil
>>>> based vegetables.
>>>
>>> There is probably no comparison with the nutrient dense food crops
>>> grown
>>> in enriched soil with balanced nutrients and minerals.
>>>
>>>> I would also point out that both the rice paddy system and chinampa
>>>> systems
>>>> are soil based systems with a lot of water to maintain growth they
are
>>>> not
>>>> by any means hydroponic or aquaponic. You might also throw in the
fast
>>>> disappearing mangroves as an example of aquaponics but again you
would
>>>> be
>>>> wrong.
>>>
>>> In Eritrea they are developing an array of sustainable farming systems
>>> that use sea water, They impound water in lagoons and grow shrimp in
>>> them. That nutrient-rich water is released down stream to fertilize
and
>>> irrigate salt-tolerant land based crops. These crops are used to
human
>>> as well as livestock feed and to make rope or cloth. They are also
>>> propagating, planting and harvesting mangroves for firewood,
livestock
>>> feed and construction wood. They are not reducing the populations of
>>> mangroves along the coastline where their project is located. There
is
>>> a
>>> PBS documentary about this well worth watching, maybe viewable online
>>> or
>>> for $$$ for the dvd.
>>>
>>> LL
>>>
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