I am looking for information on using sludge as a fertilizer on pastures. My thoughts are that it would be applied as a liquid’
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What are you referring to as sludge?
I am talking about the dirty water that comes out of the swirl filter when you are commercial that sludge can amount to a considerable amount of volumn
You can certainly use it as fertilizer - just treat it like manure. Most ppl tend to put it into aerobic digesters and reintroduce it into their system (minus the solids that don’t break down like ash, etc.) to ensure complete nutrient retrieval from the fish feed/waste - especially since fish food isn’t cheap.
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yes I agree with everything that you said and that is why I was looking for some analysis or possibly a study that had been done on using it as fertilizer
Maybe this kind of study might give you some idea or lead info to what you are looking for.
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THANK YOU This was exactly
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I collect sludge and use it to either feed my earthworms or as a fertilizer in soil or AP grow beds.
Will have some pictures soon of my 2 sandponic beds ---- the system is built to pull from the bottom center of both fish tanks 5 times a day and send it to both raised beds( 17’ x 4’ x 1.25’) the sand drain water leaving the solids to build a living ‘bio-mat’ – read : McMurty 1986 paper NCU I think – been cycling for 2 weeks fishless-- soon to have some “poopers” James
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How do you plan on using the bio-mat?
Capt. I am trying to find some pictures there are several you tube videos that show the beds being flooded and the troughs are black with the solids —it stays in place as the “mat” is bio active —it stays there adding to the biological activities of the bed… wished I had saved the you tube video of biologist wading in a marsh wetlands area— the same black ‘mat’ was shown laying as the top layer in 3-4" of water… they were seeing bubbles of oxygen come out of the mat----- after reading Dr. McMurty’s paper and his research I saw this as a very straight forward way to handle the solid wastes and retain all the nutrition —the equipment to do this same function is expensive. And then the solids are either removed or added back to the media beds! — My sand beds were much less expensive to build --work just as well as media beds ( better! as they don’t get “dirty” w/ dead spots)
Have another week or 2 in my fishless cycling…as soon as the fish arrive we will start pulling solids and I will have video to share…My plumbing set up has a timer (Trolmaster Aqua X) to activate solenoid valves to ‘flip’ from recirculation to filtration…pulling water from the bottom center of the fish tanks 5 times a day James
I have been working with aquaponics for 10 yrs and I feel that what you are doing will be very effective. What I am interested in is using the sludge build up as a commercial venture. It might be possible to use the sand based bio to use as fertilizer spread on fields. Keep me informed of your progress.Thanks
Robert attached is the McMurty paper Murry in Australia has been doing AP teaching schools using this system for years- you can see him on You Tube---- I mention this as I am still working on how to test for the short comings in fish food-- there is not enough calcium, iron, magnesium and potassium for the plants… Learning how to test for these elements so I have some idea of what to add to the system. James
Mark Mc Murtry sandponic paper.pdf (429 KB)
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Thank you for that information. my limited availability of knowledge has forced me to take a hands on approach. I used two methods of collecting sludge, a swirl filter and a sand filter. I used the sludge produced on pasture grass with varying percent of dilution. the results have been rather poor. my fish weight gain is great and my peppers, tomatoes, other plants are doing great. I am even growing avocados in my grow beds. Using the sludge as a fertilizer - not so good. Not very scientific as you can see.
Had a chance to see some of the pasture management that Brahmns does here in OK… They have thousands of milk cows—the cow poop is added to water tanks and “condensed” then spread on the pastures — no info as to the before or after…
That is similar to what I was trying to accomplish. It has also been done with pond bottoms where the dirt has been removed let dry then spread with a fertilizer spreader
Robert Chinampas the floating gardens of the Aztecs… the history I read has the early Aztecs being pushed into swamp lands by other tribes taking over their better territory… they built large woven mats and used the shallow lake bottom as soil to grow crops… Seems as it worked fairly well as they became the dominant tribe when the Spanish arrived The Spaniards were blown away with the city as they recorded it as the most beautiful city with wide clean streets and the buildings were so livid with color and was larger than any city in Spain…
None of mcmurtys work has been replicated or proven at all just as a huge asterisk to his work. He has for almost 40 years refused to release basicly any useful or defendable metrics on his nutrient levels among other obvious errors.
We have an iAVs book available now, if you send me a message I can give you a free copy.