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  1. #11
    Moderator urbanfarmer's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    Good comments dead_sled. I see you are thinking!

    Quote Originally Posted by dead_sled
    With AP, we are not a direct part of the system.
    False. Explain why you think this must always be true? You state this as a priori knowlege, yet I would question the basis for your assumption.

    Quote Originally Posted by dead_sled
    Our waste products do not stay in the system.
    Some waste products certainly do stay in the system, but some are removed; therefore, this statement is partially false.

    Quote Originally Posted by dead_sled
    How is the loss balanced without human input?
    It depends. The loss of what? Carbon, hydrogen, and oxygen are the bulk of plant matter. These can come from "the air" for most AP systems, if so designed. In fact, some are. As for the rest, it depends because it's very specific to the details of the system.



  2. #12
    Moderator urbanfarmer's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    Quote Originally Posted by 15mules
    you are trying to make when you say "False" is that duckweed is natural or organic and fish feed is full of GMO corn and chemicals??
    No. Comparing the protein content as you are doing does not take into account feed digestibility nor other nutritional requirements of the fish. Where you see it says protein on the label, it does not tell you the break down of that protein. Some raw foods have enzyme inhibitors that can cause all sorts of problems in your fish if not accounted for. Some foods have toxins that, if fed in small enough quantity, are an acceptable supplement in feed, but if fed too much cause death. There's more to consider. It's a bit of a long and winding road to properly learn about... the short answer is: use duckweed to offset SOME, but NOT ALL of your feed.

  3. #13
    Moderator urbanfarmer's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    Any as a general rule of thumb: If your duckweed is growing slow, the protein content is very low. If it's growing very fast, the protein content is very high. Obviously, feeding very low protein duckweed is going to yield slow fish growth as well. Not all duckweed is created equal!

    I was nice and found the info in the relevant literature...

    The value of duckweed as a feed resource for
    domestic animals increases with increasing crude
    protein content. In studies at the University of New
    England, Armidale, Australia, the crude protein
    content of duckweed growing on diluted effluent from
    housed pigs increased with increased water levels of
    N from about 15% crude protein with trace levels of N
    (1-4mg N/l) to 37% at between 10-15mg N/l. Above
    60mg N/l a toxic effect was noticed perhaps due to
    high levels of free ammonia in the water. Whilst few
    experiments have been undertaken on the optimum
    level of ammonia required, these results give a
    guide-line for the levels of N to be established and
    maintained in duckweed aquaculture to obtain a
    consistently high crude protein level in the dry matter.

  4. #14
    Members 15mules's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    UF, If I understood deadsleds post correctly the idea that we are not a direct part of the system, refers to what I am assuming is the "Human" removing plants and fish from the system to consume, but our waste is not returned to the system, therefore you are removing something from the system without having an input.
    As far as your explanation of the benefits of duckweed, in your opinion. I understand what you are saying, some proteins, nutrients, etc. are absorbed better by a body in different forms. I agree with that, so I think we are on the same page, as far as that is concerned. I assume and correct me if I am wrong, that your idea is that duckweed along with some other supplemental feed would make a better balanced diet for the fish and possibly promote better overall health and growth for the fish. I could also go along with that, as there is no doubt a more diversified food source would stand a better chance of meeting all of the bodies needs, than a diet based only on one nutrient source.
    However, from an economical standpoint, we need to be able to put a dollar amount on the food value of duckweed. We can then figure the investment in infrastructure, time and labor to produce x amount of duckweed. This, in order to know what the feed is costing to produce, and what the benefit is as a fish food. Without being able to do this, there is no way to accurately determine the value of duckweed, as a fish food, besides anecdotal evidence.
    Never show your ignorance, by thinking you know it all

  5. #15
    Moderator urbanfarmer's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    Quote Originally Posted by 15mules
    UF, If I understood deadsleds post correctly the idea that we are not a direct part of the system, refers to what I am assuming is the "Human" removing plants and fish from the system to consume, but our waste is not returned to the system, therefore you are removing something from the system without having an input.
    As far as your explanation of the benefits of duckweed, in your opinion. I understand what you are saying, some proteins, nutrients, etc. are absorbed better by a body in different forms. I agree with that, so I think we are on the same page, as far as that is concerned. I assume and correct me if I am wrong, that your idea is that duckweed along with some other supplemental feed would make a better balanced diet for the fish and possibly promote better overall health and growth for the fish. I could also go along with that, as there is no doubt a more diversified food source would stand a better chance of meeting all of the bodies needs, than a diet based only on one nutrient source.
    However, from an economical standpoint, we need to be able to put a dollar amount on the food value of duckweed. We can then figure the investment in infrastructure, time and labor to produce x amount of duckweed. This, in order to know what the feed is costing to produce, and what the benefit is as a fish food. Without being able to do this, there is no way to accurately determine the value of duckweed, as a fish food, besides anecdotal evidence.
    Proteins are made up of amino acids. Different organisms on this planet need different amounts of amino acids for optimal growth. Not all proteins are created equal in their composition of amino acids. The wrong balance or lack thereof will have a negative affect on growth. It is a false assumption to infer that all proteins are equal.


    You can assume the cost of the duckweed offsets the cost of your feed and calculate the cost/benefit ratio from that. Growing duckweed can be an inexpensive venture in itself.

    Quote Originally Posted by 15mules
    I just want to see some solid information on how duckweed can be economically produced and beneficial when the time, and input cost are factored in, because I just do not see it.
    If it's not a good fit for you or your business, then don't include it. For some, growing duckweed on the farm can be done inexpensively. It is very cheap to grow duckweed; so, there is potential for cost savings. Hell, you can even sell it as a premium feed product. There's plenty of hobbyists out there that would pony up for some. Make sure to put ORGANIC and HEIRLOOM real big on the package!

    Another point, fish feed is not the same price in all parts of the world nor is it the same quality. This affects the cost/benefit ratio significantly.

  6. #16
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    Re: The benefits of Duckweed/ or lack of benefits???.

    UF thanks for your ideas and the added information on the subject of duckweed. Hopefully this information along with the other threads here on duckweed will help others decide if duckweed is worth a try for them.
    Here is where I started in my thoughts on the subject of duckweed.
    #1, Duckweed is a possible miracle free food source for fish, like manna from heaven according to many threads I have read in various places.
    #2, Duckweed is the "devil" and will take over your AP system and spread to every nook and cranny, overtaking everything else, according to others.
    Now that we have had this discussion, here are my thoughts on duckweed.
    #1, Duckweed while seemingly easy to grow and relatively cheap to produce, (compared to some other fish foods), is not a miracle food that will replace all of your feed cost with a FREE food. Duckweed can however, be beneficial if feed as a supplement along with other quality fish feeds.
    #2, Whether duckweed is economical or worth the time and effort and expense to grow for YOU, is going to depend on your individual situation and many local, environmental, economical, etc. circumstances.
    #3, Thus far based on the limited information we have on duckweed, it would be difficult to accurately put a number on what the exact $$$ value of duckweed is.
    To be quite honest, I do not have the needed time or desire to carry out such an exhaustive study to determine this exact $$$ amount of value in duckweed. This is why I was hoping to learn this information from some of you who are actively using and feeding DW. Everyone is certainly free to make their own decision, as to the benefits of duckweed in their particular AP system. What I have seen, thus far, has led me to believe, if I have the spare time to experiment with duckweed it would be worth the effort, as there is potential for some benefits.
    Now having said that, I would not have high hopes going into that experiment of large $$$ gains in feed production. My best hopes in such an experiment, would be to provide a supplement that may slightly lower my feed cost, but more importantly, would provide me with healthier fish. But that is just me, you need to make up your own mind based on your unique situation.
    Again UF, thank you for your informative post on the subject. As for labeling my duckweed "ORGANIC", yea I will get right on that, and wait for the USDA folks to show up, handcuffs in hand!!!!
    Never show your ignorance, by thinking you know it all

  7. #17
    Moderator urbanfarmer's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    Quote Originally Posted by 15mules
    #1, Duckweed while seemingly easy to grow and relatively cheap to produce, (compared to some other fish foods), is not a miracle food that will replace all of your feed cost with a FREE food. Duckweed can however, be beneficial if feed as a supplement along with other quality fish feeds.
    TRUE. The "miracle food" phenomenon is simply human wonder and awe at nature. An almost microscopic organism can replicate itself in standing water with no visible input aside from the sun. This 1 lone duckweed can reproduce into millions, billions of plants that are edible and high in protein. Most plants, if first learned about, would elicit the same wonder. This is not a bad thing, it's a sign of human intelligence.

    Quote Originally Posted by 15mules
    #2, Whether duckweed is economical or worth the time and effort and expense to grow for YOU, is going to depend on your individual situation and many local, environmental, economical, etc. circumstances.
    TRUE. This is simply a shift in your paradigm of what you thought about duckweed before and how you've learned to view the economics of a system from a for-profit business viewpoint. GREAT!

    Quote Originally Posted by 15mules
    #3, Thus far based on the limited information we have on duckweed, it would be difficult to accurately put a number on what the exact $$$ value of duckweed is.
    To be quite honest, I do not have the needed time or desire to carry out such an exhaustive study to determine this exact $$$ amount of value in duckweed. This is why I was hoping to learn this information from some of you who are actively using and feeding DW. Everyone is certainly free to make their own decision, as to the benefits of duckweed in their particular AP system. What I have seen, thus far, has led me to believe, if I have the spare time to experiment with duckweed it would be worth the effort, as there is potential for some benefits.
    Now having said that, I would not have high hopes going into that experiment of large $$$ gains in feed production. My best hopes in such an experiment, would be to provide a supplement that may slightly lower my feed cost, but more importantly, would provide me with healthier fish. But that is just me, you need to make up your own mind based on your unique situation.
    Again UF, thank you for your informative post on the subject. As for labeling my duckweed "ORGANIC", yea I will get right on that, and wait for the USDA folks to show up, handcuffs in hand!!!!
    I understand not having time to invest into a full investigation into duckweed. However, I think I and others here have communicated the burden of growing duckweed a little too heavy handed. Duckweed, as the name suggests, grows like a noxious weed. It knows how to survive, out compete, and gather resources from its environment without much human input. Take a party cup and fill it with water and some duckweed. Manage that cup until you can get that sucker at capacity. Make sure you can harvest 1/2 or 1/3 of it and it comes back in 2-3 days. Upgrade to a 5 gallon bucket after that. Try it indoors/outdoors. Manage these little systems when you are having a beer or whatever. Make it something you enjoy and that doesn't impact your busy schedule, but instead augments your personal life with fun and distraction and learning... Just my 2 cents on that

    Back to commercial, how expensive would it be to dig out a long trench, let's say 4' x 100' x 1.5' deep and then put down a nice thick pond liner. Fill it with water, duckweed, and some mosquito fish (or whatever, you can even incorporate koi or something at low densities for supplemental/residual income streams). Some monitoring of water quality is required, sure, but not much. Harvest is quick and easy and requires no special training (like scooping poop, very easy). THEY DO THIS IN 3RD WORLD COUNTRIES WHERE ACCESS TO TECHNOLOGY AND AGRICULTURAL RESOURCES ARE LIMITED OR ABSENT. I don't see duckweed as creating anything short of a benefit, BUT what is the opportunity cost??? What else could you have built there, in place of that duckweed trench? What do you think?

  8. #18
    Members 15mules's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    UF What else could I have built in a 4' x 100' trench??? Another grow bed for edible plants? (No, I mean edible for people, not fish)
    Ok lets go one step more with your concept, because I think we are going in the same direction with this line of thinking. how do we accurately compare the cost. lets say I take your idea of a trough full of Duckweed and i add a little more initial coast and build that same space (assuming that space is available to me) and we grow vegetables as an additional tough in our AP system. Would the additional income form those vegetables produce enough income, to buy more (store bought feed) than the feed produced in the same time period by the duckweed?? This would be a good test of the value of DW in my opinion.
    Man, it is almost like we have ESPN or something we are thinking so much alike!!!!
    Never show your ignorance, by thinking you know it all

  9. #19
    Moderator JCO's Avatar
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    Re: The benefits of Duckweed/ or lack of benefits???.

    Great discussion. I loved every minute of it and Duckweed International salutes you all.

    However I think I can solve 15mules dilemma without much trouble here. 15mules, I know exactly where you live in Arkansas and that you are heading toward a commercial AP system for profit to be able to stay home and make money.

    Forget duckweed

    To operate properly and efficiently like a well oiled machine without any hitches, a commercial AP system must be able to depend on each facet of the operation being as close to perfect as possible and constant as possible.

    Forget duckweed

    You will not be able to grow duckweed in the winter without it taking up valuable space and resources inside your greenhouse. Resources which when used in other manners could produce more revenue than what duckweed could save you.

    Forget duckweed

    Ever hear the song:-

    "JIM DANDY TO THE RESCUE?" THAT'S ME..!
    JCO
    Irish eyes are always smiling but
    • "In the eyes of the world, you are only as good as your last success"
    so never forget
    • "MAN IS ONLY LIMITED BY HIS IMAGINATION"

  10. #20
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    Re: The benefits of Duckweed/ or lack of benefits???.

    JCO, now you went and threw another wrench in my plans!!, UF about had me convinced to forget about all of that lettuce and produce and stuff and go strait DuckWeed. That was going to be my biggest marketing Gimmick, Arkansas's only AP duckweed farm. Now you done gone and put doubt in my mind again!!!

    Oh, Well so much for Duckponics!!
    Never show your ignorance, by thinking you know it all

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