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As to the manure thing, I think that normally applies to warm blooded manure that could carry pathogens. With Aquaponics the fish poo is not like dumping uncomposted chicken or cow manure onto crops. Is fish emulsion that is often used for organic crops "composted?"
Thanks Sylvia!
Peter, nice to see you here. Sounds like your crops are USDA certified organic, currently. Who is your certifyer and are they receptive to more aquaponics operations coming aboard with them? Maybe we should start a thread of US Certifying Agencies that are in favor of certifying aquaponic crop. As you know the certifying agency does not have to be in your home state. If we started a list of "friendly" agencies we would eliminate a lot of leg work for new growers.
Chris, I know there are many ex-students that still confuse some of the processes and principles, so most likely that person did tell you wrong information.
The nitrate regulation in our system is relatively simple. With a feed load of >40lbs a day, plenty of fine solids pass the clarifier and catch on the net in the filter tanks. If we clean the nets once per week they REALLY foul up. This creates large pockets of soilds that become anaerobic (no oxygen). The anaerobic bacteria convert Nitrates to N gas, reducing Nitrates as the water passes through the tanks. This condition favors fruiting plants that prefer lower N, allowing for a greater intake of Phos. If we change the management to cleaning nets 2X/week we maintain relatively high Nitrates. There are no anaerobic zones in the nets, so as water passes these tanks Nitrates are maintained. This condition favors vegetative plants like lettuce or basil.
When I clean the nets 1X/week my NO3 levels are 100-200ppm
When I clean the nets 2X/week my NO3 levels are 10-40ppm
The labor of cleaning nets can be nasty or can be simplified by a creative farmer, and you are right about the loss of those solids (nutrients) during the cleaning process. I prefer to have the ability to change nitrate levels and I see many uses of the sludge released during cleaning. Solids Removal is a very important process in Commercial Aquaponics.
Additionally, I think the term Better is so relative. Not every AP produce will be Better. I also don't like the term organic as it has so many definitions. of course there are other labels that can be used to identify our products as healthy, pesticide free, herbicide free, or just grown with fish poop!
As for the NOP certification, I think farms that are being certified have convinced the agencies that the plants are actually being grown in the media they are started in. I wouldn't think rockwool starts would qualify, but compost media or coco-coir seedling mixes could. The young plants are started in this media then set into the system. The system just waters the seedling that is going in the certified organic mix. I think that is the rationale on how they are being certified while really not being grown in the soil. The rules as they are written though do require animal wastes being used for fertilization to be composted for certain times and temps and turns. I'm not sure how an agency can certify knowing the plants are being fed on a manure that has not been composted. Any thoughts?
Does friendly's system have any issues with potassium or iron deficiencies?
Thanks.
Very Very Very interesting convo
I have long pondered the differences
i have one last concern, i please i do want to compare any systems.
However
In the case of solid removal i have a concern in the differences,
UVI uses a combination of a "baffle" and net filter
While i saw Mr. Murray using swirl and particulate filter- made of "spaghetti" material
now to the meat of the matter there has been a publication by Dr. Rakocy and the team from the UVI on the difference in operation of a swirl and net filter(which i have uploaded)
However is there any study in the difference between net and particulate filter and the effects on the system when cleaning is done so on
Very Very Very interesting convo
I have long pondered the differences
i have one last concern, i please i do want to compare any systems.
However
In the case of solid removal i have a concern in the differences,
UVI uses a combination of a "baffle" and net filter
While i saw Mr. Murray using swirl and particulate filter- made of "spaghetti" material
now to the meat of the matter there has been a publication by Dr. Rakocy and the team from the UVI on the difference in operation of a swirl and net filter(which i have uploaded)
However is there any study in the difference between net and particulate filter and the effects on the system when cleaning is done so on
there wont be any detail informations about UVI system, as it is Dr. Rakocys IP. Im not sure if he still offers his course at UVI (as he retired), but if he does then you will get the detail knowledge there. For Friendlys you pay 99 Bucks and you get all the informations you need. When it comes to commercial systems, knowledge is not for free - very understandable. In my oppinion is Friendlys system a modification of the UVI system, and if im not completely wrong then the Friendly owner visited a course of Dr.Rakocy at UVI :D
the FAP farm relies heavily on the use of gammarus and other detritivores to help keep their system clean. in their largest system they have a series of 3 solid settling tanks with the last one is filled with fish netting, then these dump into a degas / bubbler tank to be dispersed into 3 sets of 4 troughs...
now it was seen that in the beginning the fish waste would accumulate in the net tanks, and the netting would need to be removed and cleaned... a very dirty job. the one day a small creature was noticed in the water. not knowing exactly what it was it was left to it's own devices, but the system was put under tighter surveillance and the creatures were being researched. over time the amount of fish waste began to drop in the net tanks, and the number of these creatures began to grow.
as it turne dout the creatures were gammarus, a detritivore. (poo eating water crustacean) these little guys were actually eating the poo and mineralizing it. my guess is a bird that was swimming in a near by stream happened to drop a few of these guys into the systems... but that's not a bad thing. these guys are natural filters. this would explain why the FAP farm doesnt have complicated filtering systems.
my guess to the lack of pH swings that the FAP farm didn't have to deal with is once the systems micro biology gained a foot hold, it gave the system a bit of autonomy... meaning the things living in the system were striving for their own survival, just as they would in any new ditch of pond.... what FAP did was essentially create a lake and stream on a small scale.... fish tank would be the lake, and the grow beds the stream...
also the FAP's lowered fish density and yet proper plant growth could be attributed to the large amount of mosquito fish freely swimming about the troughs eating for free on mother natures bill... these guys would eat the mosquito eggs and larva and inturn relieve themselves directly into the troughs. this could be a bad thing... if the gammarus hadn't already made themselves at home in the troughs and handled the mosquito solid wastes as well as anything that would have found it's way into the system and died...
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