October 26, 2009
By gary, http://www.microponics.net.au/?p=322
There are some people who would have you believe that operating an aquaponics system is just…..easy!
The people most likely to tell you that aquaponics is easy are those who want to sell you aquaponics kits or equipment – so their interest is fairly obvious. You’re much more likely to sell something to someone if you can convince them that it requires little or no effort or learning to operate.
Others like Dr Mike Nichols (a horticultural research scientist at the College of Sciences at Massey Universtity, Palmerston North NZ) have a different view.
In the March/April 2009 issue of Practical Hydroponics and Greenhouses he reported:
“Sadly, I must report that aquaponics may be too difficult for many people. Theoretically, it should involve an equal marriage of aquaculture and hydroponics in which the two separate disciplines respond synergistically, and the nutrient waste from the fish is ‘purified’ by the bacteria and the plants and the clean water is then returned to the fish. In fact, because of the difference in the skills required for aquaculture and for hydroponics, it would appear that in many cases the synergy does not exist.
The majority of the income from aquaponics comes from the horticultural component, but as the majority of aquaponics projects evolve from aquaculture there is a distinct lack of horticultural knowledge by the participants. The result is that the aquaponics producer has to compete with the specialist hydroponics grower, but without the necessary skills base. It is my view that aquaponics (except on a very small scale) requires two specialists, an aquaculture specialist and a hydroponics specialist. Without this any large project would appear to be at risk.”
While Dr Nichols makes it clear that he’s talking about commercial aquaponics systems, I believe his contention is just as applicable to any aquaponics system – large or small.
While I acknowledge that the financial cost of incompetence may be far greater in a commercial operation, the practical outcome is the same….dead fish and plants that fail to thrive…..regardless of the size of the operation.
I guess I’m puzzled (and faintly suspicious), therefore, at how quickly many people (who have no previous experience of either aquaculture or hydroponics) develop confidence in their ability to undertake aquaponics.
Their excitement and confidence is understandable when you realise that it is the product of what they are told – that that the mere combination of these two disciplines creates something which is somehow easier to comprehend than either of the component parts.
They’re told that “the fish produce waste that the bacteria convert to plant food. The fish feed the plants and the plants clean the water for the fish.”
“It can’t be that simple” say the interested onlookers. “There must be more to it than that.”
At this point, the kit maker or their agent produces a few ”guidelines” – sage little wisdoms that are easy to remember and which still leave the novice with the illusion that aquaponics is easy to do.
The ”guidelines” include:
- True aquaponics requires that the water recirculate from the fish tank through the growing system and back into the tank. See Recirculating or Open Loop?
- That you stock the system at the rate of one fingerling per 10 litres of water (according to one kit maker). See Mythconception #1 – Stocking Density
- For each litre of water in the fish tank, you must have one litre or two (depending on the source) of grow bed volume. See Mythconception #2 – Component Ratio
- Grow beds must be 300mm deep. See Mythconception #3 – Grow Bed Depth
- That you don’t need to clean out your aquaponics system because worms will turn all of that fish poop into plant nutrients. See Mythconception #4 – Removal of Solid Wastes.
Tart these ‘guidelines’ up with a few exaggerated claims about sustainability (see Mythconception #5 – Sustainability) and productivity and our onlooker is (with pen poised over the order form) rushing headlong into a Damascus Road conversion to aquaponics.
While the symbiotic relationship between fish and plants is the essence of aquaponics, the simplistic fish/plant dialogue trotted out by some vested interests is a very long way from explaining its intricacies.
My own experience of small-scale food production spans 30 years. In that time, we’ve kept all sorts of birds and animals and attempted to grow many types of plants using a variety of production systems and achieving proficiency in aquaponics has been as big a challenge as any of them…..and it is ongoing.
Now, having spent this time attempting to convince you that aquaponics is not as easy as some people would suggest, I don’t want you to believe that it’s beyond those who are prepared to make a reasonable effort to learn.
Aquaponics will, of itself, offer a reasonable return on your investment of time and money. Like any other investment, however, aquaponics may prove risky for those who are too lazy to do some basic research.
If your interest is in small-scale aquaponics, there are several books available. My personal favourite is The Urban Aquaponics Manual – 2nd Edition. While I confess to a certain bias (I wrote it), it is also the most up-to-date publication of its type in the world.
If you’re still itching for more on recirculating aquaculture – and if you’re well-healed – I’d recommend Recirculating Aquaculture Systems by Timmons, Ebeling, Wheaton, Summerfeldt and Vinci. It even contains a 40 page section on aquaponics.
Couple that with some reading about hydroponics. I recommend:
- Hydroponic Food Production by Howard Resh
- Commercial Hydroponics by John Mason
- Hydroponic Crop Production by Joe Romer
By the time you’ve digested these books, you’ll be in the top 2 percentile (in terms of your knowledge of aquaponics) in the world.
If you’re just starting out in aquaponics, you will have a distinct advantage over those who have gone before you. Notwithstanding the hocus pocus, there’s more information out there than ever before. You’ve just got to sort the wheat from the chaff (like this little gem from another kit maker)……..
“Running an aquaponic system CAN be easy… I know of people who had no idea about fish keeping and no idea about growing plants yet with a few simple guidelines they are producing and harvesting their own produce from their systems.”
And here’s my point…..everything is easy until something goes wrong. When that something happens, the simplistic little guidelines don’t prevent the fishkill……or the subsequent anguish and the inevitable loss of confidence that occurs.
Forums like www.aquaponicshq.com/forums chronicle the trials of many people who have taken such advice and had bad experiences. But for these forums, and the technical support (and the occasional bit of group therapy) that they provide, such people would simply founder and drift away from aquaponics.
To summarise, aquaponics will provide:
- crops of plants and fish for the same amount of water that it would normally take to just grow the plants.
- clean, fresh, affordable food for you and your family.
…..but, like any worthwhile pursuit, your rewards will be commensurate with your efforts. The more you know; the more you grow!
.JPG)
0 komentar:
Posting Komentar