permaculture

["John D'hondt" <dhondt@eircom.net>]

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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