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  • From: KAKerby@aol.com
  • To: permaculture@lists.ibiblio.org
  • Subject: Re: [permaculture] pc aquaponics
  • Date: Mon, 8 Oct 2012 21:45:14 -0400 (EDT)

OK, I've been gone for a number of hours, a bunch of emails on this topic
have come in, and I'd like to address some of these statements in turn.
But it'll be in summary form, so hopefully no one takes offense that I'm
just trying to answer things as quickly as possible.

First, aquaponics is most definitely an aerobic setup. The claims made
about faster growth are precisely because aquaponics is MUCH MORE aerobic
than standard soil-based farming. The roots are exposed to much greater
rates
and volumes of gas exchange, so poor gas exchnage is no longer a
bottleneck for plant growth rates. That exchange rate can be varied
depending on
both the system design and the cycling rate. One of the three major
hydroponic and aquaponic methods, known as flood-and-drain, features a
container of
planting media and intact plants which is repeatedly flooded, then
drained, then flooded again, at whatever cycle is appropriate for the
plants. So
you could have system conditions ranging from near-saturation to
near-desert rates of moisture for the root zone, whatever the plants need.
With that
system, each new influx of water fills the container, thus driving out any
atmosphere (mix of O2, CO2 and N2 and trace elements) from the root zone.
That "flood" stage is generally the shorter of the two phases. The longer
"drain" stage draws atmosphere back down deep into the root zone, for a
dramatically faster gas exchange rate than would ever occur in soil-based
growing. The other two most popular setups, Nutrient Flow Technique and
Floating Raft Technique, generally feature part of the root mass submerged,
and
part of the root mass in an extremely high-humidity but non-submerged
atmosphere. So again, there's no drowning or anaerobic conditions. If a
hydro-
or aquaponics system ever goes anaerobic, something is very dramatically
wrong.

Second, I concur wholeheartedly that soil is a precious commodity, and
should be treasured as such. So the comment that someone was turned off by
seeing a photo of an aquaponics system in the foreground, then very tidy
inedible landscaping in the background, is a philosophical objection I would
share. However, I have to point out that it wasn't a valid indicator on
whether aquaponics can or cannot be part of a sustainable setup. Rather, it
was merely an indication of that particular person's taste in landscaping.
You could take that same setup, and put it in a poor village in some distant
poverty-stricken nation, and perhaps feel better about the fact that it's
feeding everyone in the village. Same system. And there are countless
variations on that system to match up with needs all around the world. So
if
some aquaponics fan had a front yard that didn't meet up with your personal
preferences for landscaping, that's hardly an indictment against the
approach as a whole.

Also on the topic of soils, I would point out that merely having access to
soils does not guarantee that folks can grow what they need, as much as
they need, and when they need it, on those soils. Or even if they could
grow
what they need during ideal years, conditions might be so unpredictable
that they couldn't count on those soils to produce what they need, year after

year. We live in one of the most productive agricultural areas of the
world. We are greatly blessed that we can work with both forested and rich
fertile floodplain soils. We have a mild climate, with a nice long growing
season. But even here, there are things we can't grow reliably, including
staples like corn and alfalfa. Try feeding 100 head of livestock without
those two staples, and you'll be up at night trying to balance your feed
ration with whatever you can scrounge instead. Been there, done that. We
are
very fortunate to be able to go out and buy those materials when we can't
grow them. But other families and other farms in other places aren't nearly
that lucky. They must eat from whatever they can grow. Even when the
soils are just right in terms of fertility, tilth, moisture, temperature and
solar exposure, one storm, one flood, one early frost or late frost or any
other combo of "bad luck" events, can wreck the crop. In some fortunate
parts of the world, that's not a big deal. We buy in what we need to
replace
what we lost. Other folks aren't so lucky, and they go hungry. Aquaponics
removes a lot of that variability. That's why we want to use it here. It
would be our backup for those crops which are iffy at best even in our
prime agricultural area. And it will allow us to grow some critical crops
which, despite our near-ideal setup, we still can't grow here.

The question of equipment and volunteers and employees is a complication,
which ironically makes aquaponics shine even brighter. We are in WA state,
USA. It might surprise folks to learn that we CANNOT have farm volunteers
here. It's against state law. We can either have interns, that must be
enrolled in a public school and taking a class for credit in which we are a
formal part of the curriculum, or we can have employees, paid at least
minimum wage, and fully insured under our farm insurance coverage plan. And
now
proposed federal law, which didn't pass this year but very well might in
the future, states that family members must be "immediate family", ie,
spouse, children and parents. Cousins and aunts and uncles and
grandparents/grandkids, etc, would not be considered family, and thus would
be required to
be hired, for at least minimum wage, with full insurance coverage. So as
neat as it sounds to have some big farm in the family, working that farm
requires some careful thought because manpower is no longer quite so easy to
access.

OK, so if we can't have lots of people, let's get some large-scale
machinery in here instead. Sadly, that's not very practical either. A 70hp
tractor, and all the implements listed in a previous post, would cost more
than
our house is worth. We have a 20 hp tractor that was manufactured the same
year my dad was born. Our haying equipment was made when draft animal
power was still in use in the USA, and that equipment can be drawn either
with
our small tractor or a team. We shopped very carefully for that
equipment, and saved a great deal of money, by buying smaller than everyone
said
we'd need. We didn't finance any of it. Yet it still set us back quite a
bit
financially, and we still have repairs to make before any of it is field
ready. So yes, a lot of folks are having serious problems getting into
farming, because even if they have access to land they need either manpower
or
machinery to work it, and both of those options are not nearly as easy to
come by as they used to be.

Which brings us to aquaponics. Because machinery and manpower are both so
expensive here, we have to make the absolute best use of our time, at a
scale that we can reasonably accommodate without either equipment or
employees. One of the major questions we're facing right now with this
bigger
farm, is whether we want to take on all that extra work, knowing that we'd
have
to have employees (thankfully, we'd have access to their machinery instead
of buying it ourselves). But I can produce the same products via
aquaponics that I manage by myself, as I can with field crops requiring a lot
of
expensive equipment and/or hired help. That's because of two things.
First,
it is so much more productive per square foot than any soil-based system.
Second, it allows for harvests in small batches, rather than one
all-or-nothing harvest. I've known of growers who raise just enough feed
for their
animals to last one day with aquaponics. They plant one tray per day, they
harvest one tray per day. The rest of the trays are growing and don't
need to be messed with other than watering. The manpower is minimal, and
they're doing the work I'd have to have machinery AND manpower to
successfully
harvest in the field. And that's only if the weather cooperates. If the
weather doesn't cooperate, or the machinery breaks down, or the manpower
quits or is busy or sick or otherwise unavailable, that harvest rots.
Shucks,
that's too bad. And most years, at least one of those issues comes along.
Try telling your family that they don't get to eat because the tractor
blew a hydraulic seal. Aquaponics has its own list of woes, but they don't
tend to be quite so dramatic, so costly, or so all-or-nothing in scale.

Finally, I know a lot of folks will puzzle about this next question, but we
believe it is utter folly to farm with anything less than profitable
outcomes. We subscribe to the theory that for any farm to be truly
sustainable, it must meet the Three E's: Environmental, Ethical and
Economical
Sustainability. So everything we do here, is for the love of the land and
love
of the life, but it's also how we pay the bills. If we can't pay the bills,
for instance if we borrowed money to buy all that nice big machinery, we
won't be farming very long. And then all this nice talk about sustainable
this-n-that goes right out the window. The next guy comes along and
converts all this wonderful farmland into condos. Or a junkyard for old
cars. Or
a landfill. Or whatever. I know some folks farm because they want to.
Some folks farm because they have to, since they can't get food otherwise.
We farm because we feel called to do so, but we must meet those 3 E's in
order to continue doing so for any length of time. Again, aquaponics
removes
a lot of the harvest uncertainty, and thus the financial uncertainty, from
this gig called farming. That means it's not merely a nice tool in the
toolbox. For us that means it's borderline essential. Farming without it
is
riskier than it needs to be.

I guess after all this, I would suggest that folks can decide they're not
interested in aquaponics, and that's fine. They can decide they don't want
to use aquaponics, and that's also fine. They can decide wow there's more
here than they realized, go learn about it, and maybe implement it or maybe
not, according to their own needs and interests. All that is fine. Where
I tend to get twitchy, is when folks hear the term "aquaponics", and they
only know a little about it, and they start making assumptions about it,
and then they start making opinions and decisions based on those
assumptions.
Or worse, start advising people based on those assumptions. I would
strongly encourage folks to learn about this approach before forming
opinions
about it. Don't just go with what you've seen in the headlines, or on
Youtube, or heard someone say that someone said that someone said that it's
just
a bunch of hooey. Either learn about it, and speak from a position of
knowledge and experience. Or simply say "well, I've heard about it but
don't
know much about it, so I can't really say." That's all I ask.
Kathryn Kerby
frogchorusfarm.com
Snohomish, WA



In a message dated 10/8/2012 2:23:18 P.M. Pacific Daylight Time,
dhondt@eircom.net writes:


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 know
> 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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