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Aquaponics

  • - Planting recommendations

    Album Vilmorin. The vegetable garden 1850-1895
    Album Vilmorin. The vegetable garden 1850-1895. Public Domain

    This article will show which plants can be cultivated in an aquaponic system. Before going into detail about the individual plants, however, it is important to understand which systems exist in the world of aquaponicsc, as some plants work better in system A than in system B, for example. Still others, on the other hand, have proven themselves in system B. This alone makes it clear that there is no such thing as the best system or the one system, and that when setting up or planning the design, you should pay close attention to which plants the system should be suitable for.

    First of all, however, it can be said: theoretically, any plant can be cultivated in an aquaponic system. However, there are some exceptions where conventional methods work better. More on this later in the individual categories.  In this article you will find a list of experiences with individual plants.

     

    Salads and herbs
    Salads and herbs are probably the group of plants that work best in aquaponics. They are usually weak growers and are well taken care of in the aquaponic system. I have personally experienced lettuces that have grown strong, thick and robust with the help of aquaponics, so that biting into a single leaf felt like biting into a juicy piece of meat. Really crunchy.

    What's more, lettuces and herbs will grow in any system, whether standing in gravel (Steady Flow / Flood & Drain), in planters both on polystyrene or similar (DWC) or in PVC pipe (NFT).

     

    Recommended varieties:

    Any lettuces such as chard, spinach, lettuce, iceberg lettuce, endive, rocket, purslane and so on have proved successful as have herbs such as basil, parsley, thyme and oregano.

     

    Not recommended:

    Mint should be avoided in the aquaponic system because it is rampant. It loves humid locations and is like paradise in an aquaponic system. Should it have its own system in isolation, there should be no problems, but together with other plants it will have overgrown them in no time.

     

     

    Fruit vegetables
    Fruiting vegetables belong to the group of highly nutritious plants and are also very popular in the aquaponic system. However, it should be borne in mind that some fruit vegetables can grow very large. Sufficient space above and below should be provided accordingly.

    Tomato plants, for example, grow enormously. I have heard of cases where the tomato plant has grown over eight (8!) metres tall. For most people, this should represent a height that either does not fit into the desired space or makes any care of the plant an impossible task. Alternatively, cocktail tomatoes or vine tomatoes can be planted, which usually remain much smaller.

    Cucumbers and other squash plants grow very wide and quickly overgrow the entire space. Here, too, thought should be given in advance to whether this space is available.

    Furthermore, not every system is suitable for fruiting vegetables. Neither a DWC nor an NFT system is normally capable of supporting such large plants. Theoretically, this is also possible, but it would have to be readjusted regularly with supporting measures, for example with ropes or other suspensions.

     

    Recommended varieties:

    I would recommend smaller fruiting vegetables, such as chilli plants or peppers, for private households. Smaller tomato plants, such as cocktail tomatoes, are also possible.

     

    Not recommended:

    Any cucurbits, tomatoes and other plants that grow very large should only be cultivated with caution in an aquaponic system. Due to the high nutrient content in the water, enormous results can theoretically be achieved, but practically only if there is enough space.

     

    Root and tuberous plants
    Botanically not quite correct, but certainly acceptable for understanding: I count plants that develop edible parts underground as root and tuber plants, such as potatoes, carrots, beetroot, ginger, turmeric, parsnips and the like.

    Theoretically, it is also possible to cultivate these plants in an aquaponic system, but some prerequisites are necessary here.

    Soft tubers, like potatoes, should not be planted in the gravel bed (Steady Flow / Flood & Drain), as the tuber would form around the gravel. This could cause enormous toothache when eaten. Instead, for soft tubers, the Aeroponics method has proved successful.

    With harder tubers, such as ginger and turmeric, the gravel bed is again possible, as their strength gradually pushes the gravel away.

     

    Recommended varieties:

    Ginger and turmeric I can recommend at this point, but only if there is enough space.

     

    Not recommended:

    Potatoes, carrots and other plants with relatively soft tubers I can only recommend if the necessary conditions have been created - see Aeroponic.

     

    Leek plants
    Leeks include the edible onion, the winter onion, the spring onion, chives, garlic, leeks and many more. All of these grow excellently in the aquaponic system.

     

    Recommended varieties:

    Depending on personal taste, pick one or two from the list of leeks that can grow alongside. They are easy to care for and the upper parts of the plants can be harvested several times during the year.

     

    Not recommended:

    Although onions and other leeks go well with almost any dish, care should be taken not to grow too many.

     

    Exotics
    As described above, theoretically any plant can be cultivated in an aquaponic system, as long as the necessary conditions are met. There are cases where even the cultivation of a banana and papaya plant has been successful in a specially constructed aquaponic system.

     

     

    Summary:
    Theoretically, any plant can be cultivated
    Salads, herbs and allium plants grow particularly well and are easy to care for.
    In the case of fruiting vegetables, it should be considered in advance whether there is enough space and room for them to develop.
    Root and tuberous plants are only recommended under certain conditions.
    Give free rein to creativity and inventiveness

     

    ID: 130

  • - Plants in Hydroponics

    Farm and Garden Annual 1923

    Due to their design, not all plants are suitable for cultivation in aquaponics and hydroponic systems. Here is an, always incomplete, overview of suitable plants.

    Here you can find empirical values ​​on pH and EC values ​​for plants, herbs and vegetables.

    The division between fruits, vegetables and herbs is not a biological one. It also varies from culture to culture.  

    Fruits and vegetables are not generic terms for specific plant species. A clear definition is difficult. Could you say that fruit is sweet and vegetables are not? This is almost always true, but carrots, for example, can also taste sweet and you can make juice out of them. They do have a significantly lower sugar content than apples or oranges, but that's not really a satisfactory criterion. Because then you would have to set a certain sugar content as a limit and say: everything above that is considered fruit, everything else is considered vegetables. That would then be a rather arbitrary quantitative criterion.

     
    Vegetables are often annuals, fruits are perennials.
    But there is another feature that very few people think about: vegetables are almost always annual plants; They last for one season, then they have to be sown or planted again. Here too, there are many exceptions, starting with potatoes. Fruit often grows on trees or bushes that live for several years or even decades. There are exceptions to this too, but there are far fewer of them: asparagus, for example, would be such a perennial vegetable, as would artichokes.

    Mixed definition: decision on a case-by-case basis.
    In fact, we probably use a mixed definition in our heads. We have several criteria at hand and if several criteria contradict each other, we intuitively weigh them up and decide on a case-by-case basis what fits best. So: Asparagus is perennial, but it is not sweet and we don't eat the fruit, but rather the shoots - so we count it as a vegetable. Rhubarb is also perennial, we eat the shoots and even cook it – but it is eaten sweet, so we mostly count it as fruit.

    Parts of the article were taken from GÁBOR PAÁL. CC BY-NC-ND 4.0 .


    Overview of successfully grown plants in hydroponics & aquaponics

     

    Salad

    Asian salad
    Leaf lettuce
    Chicory
    Oak leaf lettuce
    Ice Cream Salad
    Endive
    Lamb's lettuce
    Green mustard
    Lettuce
    Chard
    Lollo rosso
    Mizuna
    Romaine lettuce
    Red mustard
    Arugula
    Sorrel
    Spinach
    Celery stalks
     
     
     

    Fruit vegetables

    Aubergine
    Avocado
    Bean
    Chili
    pea
    Cucumber
    Pumpkin
    Melons
    Okra
    Paprika
    Tomato
    Zucchini
     
     
     

    Soft fruit

    Strawberries
    Blueberry
     
     
     

    Cabbage

    Kale
    Kohlrabi
    Red cabbage 
    White cabbage
    Cabbage
    Savoy
    Cauliflower
    Brussels sprouts
    Chinese cabbage
    Broccoli
    Pak choi
     
     
     

    Root & tuber vegetables

    Fruit formation takes place below the carrier medium: pay attention to the system!
    Bulbous fennel
    Turmeric
    Sweet potatoes
    Potatoes
    Kohlrabi
    Beetroot
    Radish
    Spring onions
    Carrots
    Celery root
     
     
     

    Herbs

    Anise       
    Valerian
    Basil
    Savory
    Borage
    Calendula
    Curry herb
    Dill
    Echinacea
    Angelica
    Tarragon
    Fennel
    Chamomile
    Nasturtium
    Chervil
    Buttonweed
    Coriander 
    ress
    Cumin
    Lvender
    Lovage
    Dandelion
    Marjoram
    Mint
    Feverfew
    Oregano
    Parsley
    Pimpernel
    Marigold
    Rosemary
    Arugula
    Sage
    Chives
    Cut celery
    Stevia
    Thyme
    Chickweed
    Wormwood
    Hyssop
    Lemongrass
    Lemon balm
     
    Context: 
    ID: 430
  • - The fish market

    On average around the world, around 19.7 kg of fish is consumed per person per year. Annual per capita consumption in Oceania is approximately 24.8 kg, in North America 21.4 kg and in Europe 22.2 kg (Source: State of world fisheries and aquaculture, FAO, 2016). 1

     

    Germany

    In 2020, a total of 1.14 million tons of fish and seafood were consumed in Germany. This corresponds to a per capita consumption of 14.1 kg.  The market shares of fish and fishery products in Germany were broken down as follows in 2018: (3

    • 61.9% sea fish
    • 26.5% freshwater fish
    • 11.6% crustaceans and molluscs

    Per capita consumption is distributed across the following product groups:

    • 29% preserves and marinades
    • 25% frozen fish
    • 14% crustaceans and molluscs (fresh, frozen, prepared)
    • 12% fresh fish
    • 11% smoked fish
    • 6% other fish products
    • 3% fish salads

    Market shares of the most important fish, crustaceans and mollusks in percent

      2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
    Pacific pollack ( Alaska pollack ) 20.8 22.1 26.0 22.0 21.4 18.3 14.9 16.5 17.3 17.7 15.2
    Salmon 13.0 13.7 15.0 20.0 22.0 20.5 18.2 16.7 16.4 18.8 17.6
    Tuna, bonites 10.1 11.3 10.9 13.2 12.4 14.1 9.8 12.9 13.3 11.4 16.4
    herring 20.0 19.1 18.1 16.8 14.7 15.9 15.7 13.9 14.1 10.0 10.1
    shrimp 5.9 7.0 7.2 7.4 8.1
    Trout 4.9 4.2 3.4 5.5 5.9 6.2 5.4 5.8 6.2 6.8 6.9
    Köhler (trade name:  Pollock ) 3.4 2.8 1.6 2.2 1.5 1.5 2.6 2.3 2.7 2.3 1.6
    Squids 2.0 2.4 2.5 2.7 2.3
    cod 1.6 2.2 2.2 0.3 2.7 2.4 3.2 2.1 1.8 2.1 2.1
    Pangasius, catfish 5.8 5.0 3.5 3.5 2.9 2.5 1.9 1.7 1.6 1.7 1.3
    Zander 0.8 0.6 0.7 1.0 1.0 0.9 1.0 1.1 1.0 0.9 1.0
    Shellfish 1.0 1.1 1.3 0.4 1.7
    Redfish 2.5 1.5 1.0 1.6 1.4 1.7 1.3 0.7 1.1 1.5 1.1
    sardine 0.6 0.7 0.9 0.6 0.7 1.2 1.1 0.6 0.7 1.0 0.8
    hake 2.3 1.7 0.5 0.4 0.3 0.1 0.4 0.5 0.8 1.1 0.3
    mackerel 1.2 1.9 1.9 1.7 2.0 2.3 1.5 0.9 0.7 1.8 2.0
    plaice 0.8 1.0 0.8 1.1 1.2 0.8 0.9 0.8 0.7 0.6 0.4
    carp 1.2 0.8 0.6 0.8 0.8 0.6 0.8 0.8 0.6 0.6 0.5
    Dorade 0.5 0.5 0.5 0.5 0.5
    Hoki 0.3 0.7 0.3 0.5 0.1
    Halibut 0.4 0.5 0.3
    Haddock 0.6 0.6 1.0 0.7 0.7 0.5
    Tilapia 0.5 0.5 0.5 0.6 0.5 0.5 0.4 0.4 0.4 0.4
    monkfish 0.6 0.6 0.5 0.6 0.3 0.1
    Other 6.1 8.4 9.0 7.4 7.4 9.6 11.2 10.6 8.8 9.8 8.8
    86% of edible fish and fishery products are imported.
    The most important supplying countries are:  (4
    • Poland (19.2%)
    • Netherlands (11.9%)
    • Denmark (9.1%)
    • Norway (10.7%)
    • China (7.3%)

    Sources:

    1.  FOEN  (ed.):  Fish import and fish consumption.  In:  fischereistatistics.ch.  Retrieved April 18, 2021.
    2. Fish Information Center (August 13, 2021):  New consumption figures for fish and seafood .
    3. Fishing industry - data and facts 2019.  (PDF)  Accessed on September 4, 2019.
    4. https://de.wikipedia.org/wiki/Speisefisch

    Left


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    ID: 550
  • . Stocking density

    The amount of fish you can safely and legally keep in your system (fish welfare) depends on many factors. There would be, among other things:

    • Feed rate / quantity / feed type
    • Pump performance and reservoir size/circulation speed
    • Amount of water or nutrient solution
    • Water temperature
    • water flow
    • Oxygen content
    • Nitrite and nitrate content
    • Number of plants in the bed or in the hydroponic system
    • Volume of the plant bed or amount of nutrient solution
    • Fish species or species
    • Aquarium size

    Not all the decisive factors are mentioned here!

    In smaller systems but beyond your own needs , you can expect around 10-12 fish in a 1000 liter aquarium = 1m 3  = 1 IBC container (open at the top).

     

    Be sure to consult with an official veterinarian about the legal regulations before building the fish farm. These change regularly!

    Here are the regulations, some of which come from breeding in ponds because the legislature has not yet derived all the regulations for aquaponics:

     

    Stocking densities according to EU organic aquaculture regulations:

    15 kg/m³ brook trout (Salvelinus fontinalis)
    15 kg/m³ Coregonen (Whitefish Coregonus)
    15 kg/m³ trout (Oncorhynchus, Trutta)
    20 kg/m³ Arctic char (Salvelinus alpinus)
    25 kg/m³ brown and rainbow trout
    20 kg/m³ salmon: brown trout (Salmo trutta fario), lake trout (Salmo trutta lacustris), sea trout (Salmo trutta trutta), rainbow trout (Oncorhynchus mykiss)
    10 kg/m³ milkfish (Chanos chanos)
    10 kg/m³ tilapia (Oreochromis sp.)
    10 kg/m³ Mekong catfish (Pangasius sp.)
     
    Quote : The prerequisites are compliance with the ban on deterioration in water quality (2) (in accordance with Directive 2000/60/EC European Water Framework Directives), as well as an oxygen saturation of at least 7 mg/L and a minimum inflow rate of 3 seconds liters per ton of fish. Under no circumstances should the animals show injuries (e.g. to the fins) that indicate that the stocking density is too high. Tropical freshwater fish (e.g. milkfish Chanos chanos, tilapia Oreochromis sp., Mekong catfish Pangasius sp.): the stocking density in ponds and net enclosures (pens, enclosures) must not exceed 10 kg/m3 as an upper limit. 
     
    COMMISSION REGULATION (EC) No 710/2009 of 5 August 2009
    https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2009:204:0015:0034:DE:PDF
     

    Salmonids in freshwater:
    Trout (Salmo trutta) - Rainbow trout (Oncorhynchus mykiss) - Brown trout (Salvelinus fontinalis) - Salmon (Salmo salar)
    - Arctic char (Salvelinus alpinus) - Grayling (Thymallus thymallus) - American arctic char (Salvelinus namaycush) -
    Huchen (Hucho hoo)

     

    Production system: Production must take place in open systems. The water change rate must ensure an oxygen saturation of at least 60%, be tailored to the needs of the animals and ensure sufficient drainage of the water in the holding area.

    Maximum stocking density

    Salmonids other than those listed below: less than 15 kg/m 3
    Salmon: 20 kg/m 3
    Brown trout and rainbow trout: 25 kg/m 3
    Arctic char: 20 kg/m 3


    Sturgeon (Acipenseridae) in freshwater
    production system: The water flow in each housing unit must meet the physiological needs of the animals.
    The outgoing water must be of equivalent quality to the incoming water.

    Maximum stocking density 30 kg/ m3


    Carp fish (Cyprinidae) and other associated species in polyculture, including perch, pike, catfish, pike, sturgeon.

    In fish ponds, which are completely drained at regular intervals, and in lakes. Lakes must be used exclusively for organic production, including agriculture in their dry areas. The fishing area must have an inflow of fresh water and be large enough so that the animals' well-being is not impaired. After harvesting, the fish are kept in fresh water. 


    Flag shrimp (Penaeidae) and freshwater shrimp (Macrobrachium spp) 

    Establishment of production units: Settlement in areas with infertile clay soils to minimize the environmental impact of pond construction. Pond construction with the existing clay. The destruction of mangrove stands is not permitted.

    Transition time Six months per pond, corresponding to the usual lifespan of shrimp in aquaculture
    Origin of the parents: At least half of the parents must come from offspring after three years of operation of the facility. The remaining parent stock must come from pathogen-free wild stocks from sustainable fishing. The first and second generations must be screened before being introduced into the systems.
    Removal of eyestalks is prohibited
    Maximum stocking densities and production quantities


    Cultivation: maximum 22 postlarvae/m 2
    Maximum density: 240 g/m 2


    Milkfish (Chanos chanos), cichlids (Oreochromis sp.), shark catfish (Pangasius sp.)
    Production systems Ponds and net cages
    Maximum stocking density

    Shark catfish: 10 kg/m 3
    Cichlids: 20 kg/m 3


    Sources include: https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2009:204:0015:0034:DE:PDF


    Context: 

  • . Stress in Fish

    Fish are much more susceptible to disease than they are stressed. The most important are infectious diseases including parasitoses, water-related damage and stress factors in the housing conditions. Injuries, hereditary diseases, malformations and tumors also occur in fish.
     
    Some infectious diseases can lead to mass loss in fish farming. They are then referred to as fish diseases and are subject to legal measures in accordance with the Animal Health Act, special legal regulations or EU legal provisions.
     
    In Germany, four fish diseases are currently classified as notifiable animal diseases: contagious anemia of the salmon, infectious haematopoietic necrosis and viral hemorrhagic septicemia of the trout as well as the koi herpes virus infection of the carp. The infectious pancreatic necrosis of the salmonids (IPN) is subject to notification.
     
    There is a complex interdependency between the defense capabilities, the pathogens and the living conditions, which ultimately decides on the outbreak of infectious diseases. Different factors can trigger stress. This includes everything that makes fish restless and disturbs their rhythm of life, such as constant handling in the water, but also constant changing of the light-dark phases. Worsened water parameters, such as a lack or excess supply of oxygen, excessive ammonium, nitrite or CO content, are also considered a stress factor2nd, as well as unfavorable pH values, incorrect water temperature, lack of hiding places, wrong choice of species, or excessive flow.
     
    Stress weakens the animal's ability to defend itself. As a result, they cannot maintain an immune imbalance with the most ubiquitous pathogens. Only then does an infection become a breaking „disease“.
     
     
    Stress triggers:
    • High ammonia values
    • Increased nitrate levels
    • Wrong pH of the water
    • Fluctuating temperature
    • Unsuitable salinity
    • Low oxygen content
    • Harassment by other fish
    • Inadequate pool size
    • Too many fish in the pool
    • Excessive use of medication
    • Poor diet
    • Sudden changes in water chemistry
    • Improper use of water treatment agents
     
     
    Stress indicators:
     
    • Loss of appetite
    • Increased gill movements
     
    Diseases and unicellular parasites can cause a variety of symptoms in infected fish:
     
    • Some fish have difficulty swimming and lose their balance and buoyancy.
    • Sick fish often hold their fins flat against the body.
    • You may see your fish lying on the side of the tank or pond floor.
    • Some conditions can lead to higher mucus production, which leads to cloudy spots on the flanks of the fish.
    • Another symptom is an inflated stomach of the fish. Outstanding or damaged scales.
    • A fish with a weakened immune system is more likely to develop a fungal infection that can form gray growths that look like cotton on the scales.
    • Harmful bacteria can cause the gills to look red and irritated. The gills may remain open when the fish has gill mites.

    Fin rot and bacterial infections can cause the tail and fins of a fish to look frayed.
    Stressed fish cannot defend themselves against parasites such as anchor worms or lice.
    Aquatic addiction, which occurs in fish with a fluid accumulation under the scales, can also indicate the presence of bacteria.
     
     
    Stress-related illnesses:
    Because the causative agent of ichthyophthiriosis is a weak parasite and the puncture disease actually breaks out mainly when the fish is stressed, the stress for the animals in the aquarium should be reduced as much as possible. This includes stocking density, temperature, lighting, etc.
     
    This article includes. Excerpts from the Wikipedi contribution fish disease: https://de.wikipedia.org/wiki/Fischkrankheit

    Context: 
    ID: 406
  • Anadrom / Diadrom / Katadrom / Amphidrom / Potamadrom

    Hike fish are fish that spawn you habitat switch. Fish that remain in the same habitat all their lives are considered stationary designated.

    The Fish migration serves the animals primarily to find food or suitable breeding grounds. Many fish follow, for example, seasonal ones Plankton clouds through the seas. The migrations to the spawning waters can be justified by the different needs of juveniles and adult animals.

    Hiking fish are divided into:

    • diadrome Species (Greek. διά diá „ by “ and δρομάς dromás „ running “) as a generic term for species that switch between fresh and salt water. This includes
      • anadrome Hiking fish (Greek. ἀνά aná „ up “), for example the salmon, the from sea coming the river swims up to spawn
      • catadrome Hiking fish (Greek. κατά katá „ down “), for example the eel, who swims downstream into the sea to spawn there
      • amphidrome Hiking fish (Greek. ἀμφί amphi „ on both sides “), which regularly migrate between sea and fresh water or vice versa, without these migrations serving reproduction
    • potamodrome Species (Greek. ποταμός potamós „ River “) that only migrate in fresh water. 

    Context:

    ID: 421

     

     

  • Aquaponic / Hydroponic

    Aquaponics: The process

    Aquaponics is a process that combines the rearing of fish in an aquaculture system and the cultivation of crops using a hydroponic system. There are different approaches to bringing the nutrients to the plants.
    Here you will find an overview of the different types of planting.
    Such a system is always a closed circuit for fish production and a hydroponic system for plant cultivation. The system works by using the excreta from the fish farming as nutrients for plants. This is done automatically in our systems via dosing systems. By means of an appropriate control for nutrient supply - which is optimised for the respective selected plant species and the development phase. The closed cycle means that far more than 90% of the necessary nutrients, i.e. investment, can actually be found in the two end products (vegetables & fish).
    In contrast to soil-bound planting, there are the following advantages:
     
    - High yield: 500m2 yield up to 8 tons of fish and 16 tons of tomatoes per year.
    - Minimal space requirement: profitability from 500 m2
    - Weather independence: year-round operation and yield
    - Independence from precipitation: closed cycle
    - Very low water consumption
    - No pesticide use
    - No herbicide use
    - No use of medicines
    - No damage to groundwater: closed cycle
     
    Related article: What is aquaponics
    Further information and figures
    Fertiliser use in German agriculture has already exceeded the 200 tonne limit per hectare per year.
     
    Yields in organic farming: 
     
    Performance costing in crop cultivation:
     
    Yields of aquaponics: 
  • Aquaponic Diagramm

    Here is a simplified schematic representation of an aquaponics system. This consists of a fish farm that is connected to a hydroponic plant that uses the residues of fish farming for the nutritional needs. An overview of the hydroponics techniques can be found here.

    The systems can be configured as required, depending on whether the solids are to be used as fertilizer or processed separately. Space requirements in particular play, Energy consumption, Types of planting, Species of fish and more factors a role in configuration.

     

    Aquaponik Schematik 01

     

    Here is an example of how the filtered solids can be used directly as a medium for plants that are not suitable for hydroponics. These systems are technically more complex because they have a separate nutrient cycle between plants and fish. A list suitable plants can be found here.


    In some combinations of plant and fish farming, a common "water cycle" is not possible due to the different nutrient compositions. Systems with separate circuits are used here. Only after processing by biofilter can the wastewater from fish farming also be used for the plants. 

     

    Aquaponik Schematik 02

     

    We would be happy to advise you on configurations that meet your requirements.

    Kontext: 
    ID: 185
  • Aquaponics

    Aquaponics is a process that combines raising fish in an aquaculture with growing plants in hydroponics. There are different approaches to getting the nutrients to the plants.

    The idea is to use the substances released by the fish directly as fertiliser for plants. As a rule, these must first be processed, which is done via bacteria. 

    Aquaponics Nitrogen Cycle

    Graphic courtesy of I. Karonent, adapted for aquaponics by S. Friend.

    We offer control systems for the automatic management of your aquaponics and hydroponics system. Our offer ranges from systems that only serve documentation purposes to fully autonomous plant control systems.


    Context: 

     ID: 125

  • Aquaponics / Hydroponics

    Aquaponics is a process that combines the rearing of fish in aquaculture with the cultivation of plants in hydroponics. There are various approaches to transferring the nutrients produced by the fish to the plants.

    Hydroponik

    Here you will find an overview of the different types of planting.

    An overview of aquaponics system types can be seen here.

    Aquaponics Schematic 01 small

    Both aquaponics and hydroponics systems are always part of a closed-loop system. Aquaponics, for fish production, always includes a hydroponic system for plant cultivation. The system works by using the waste from fish farming as nutrients for the plants. This happens automatically in our systems via dosing systems. By appropriately controlling the nutrient supply – which is optimized for the selected plant species and development stage – the closed loop ensures that well over 90% of the necessary nutrients, i.e., the investment, are actually contained in the two final products (vegetables and fish).

    In contrast to soil-based planting, the following advantages arise

    - High yield: 500m 2 produces up to 8 tons of fish and 16 tons of tomatoes per year.

    - Minimal space requirement: Profitability from 500 m 2

    - Weather independence: Year-round operation and yieldAquaponics Schematic 02

    - Independence from precipitation: closed cycle

    - Very low water consumption

    - No use of pesticides

    - No use of herbicides

    - No use of medication

    - No damage to groundwater: closed circuit

    We offer control systems for the automated management of your aquaponics and hydroponics systems. Our offerings range from systems used solely for documentation purposes to fully autonomous system control.

    Related article: What is aquaponics?

     

     

    Aquaponics and hydroponics: situation, market demand and development

    Food production depends on the availability of resources such as land, freshwater, fossil energy, and nutrients (Conijn et al. 2018), and the current consumption or depletion of these resources exceeds their global regeneration rate (Van Vuuren et al. 2010). The concept of planetary boundaries aims to define the ecological limits within which humanity can operate with respect to finite and sometimes scarce resources (Rockström et al. 2009).

    Biochemical flow limits that restrict food supply are more stringent than climate change (Steffen et al. 2015, see figure below). In addition to nutrient recycling, dietary changes and waste prevention are essential to transforming current production (Conijn et al. 2018; Kahiluoto et al. 2014). Therefore , a major challenge is to shift the growth-oriented economic model to a balanced ecological economic paradigm—replacing infinite growth with sustainable development (Manelli 2016).

    To achieve a more balanced, practical and sustainable situation, innovative and ecological farming systems are required so that trade-offs between immediate human needs can be balanced while preserving the biosphere's ability to provide the necessary goods and services (Ehrlich and Harte 2015).

    In this context, aquaponics (aquaculture + hydroponics) has been identified as an agricultural approach that can contribute to achieving both planetary boundaries (see figure below) and sustainable development goals through nutrient and waste recycling, especially in arid regions or areas with non-agricultural soils (Goddek and Körner 2019; Appelbaum and Kotzen 2016; Kotzen and Appelbaum 2010).

    Aquaponics is also seen as a solution for utilizing marginal land in urban areas for near-market food production. Once a "backyard technology" (Bernstein 2011), aquaponics is now rapidly evolving into industrial production, as technical improvements in design and practice have significantly increased production capacity and efficiency. One such area of ​​development is coupled and decoupled aquaponics.

    Traditional designs for single-loop aquaponics systems include both aquaculture and hydroponic units, with water circulating between them. In such traditional systems, compromises are necessary regarding the conditions of the two subsystems in terms of pH, temperature, and nutrient concentration (Goddek et al. 2015; Kloas et al. 2015, Chapter 7).

    A decoupled aquaponics system can reduce the need for compromises by separating the components and allowing the conditions in each sub-system to be optimized.

    Especially the problem of complex transport

    (From the region for the region) is increasingly becoming an environmental and cost problem in cities.

    Initial experiments, such as the cultivation of herbs in hydroponic systems, which can be seen in the first supermarkets and retail stores, illustrate the potential with the effect of reducing costs by saving on transport and storage, as well as gaining customer acceptance and their interest in the problem of future supply, since the herbs can be picked on site by the customer themselves in these systems.

    The picture shows a system in a supermarket of the Edeka chain of the company Infarm / Berlin.

    Edeka Hydroponics

    According to the World Wildlife Fund for Nature (WWF), approximately 70 percent of global freshwater consumption is used for agriculture and processing. In contrast, aquaponics enables food production with 50 to 90 percent less water consumption: the savings are 50 percent compared to traditional single-circuit systems – simply due to the dual use of water.

    A dual-circuit system with water recovery even achieves savings of around 90 percent. In this production system, fresh water only needs to compensate for losses due to evaporation and the removal of biomass from the system.

     

    Available resources for nutrition

     Available resources

    Given the resource situation, a rethinking of food supply is inevitable. The current status of the control variables for seven of the planetary boundaries described by Steffen et al. (2015) is shown in the graph above.

    The green zone is the safe operating range, the yellow zone represents the zone of uncertainty (increasing risk), the red zone is a high-risk zone, and the gray zone boundaries are those that have not yet been quantified. The blue-bordered variables (i.e., land system change, freshwater use, and biochemical fluxes) indicate the planetary boundaries on which aquaponics can have a positive impact.

    This graph clearly shows that the "limits to growth" (Club of Rome, 1972) have already been reached. Traditional agriculture is already experiencing significant yield losses, not least due to soil depletion by various chemicals (such as glyphosate, see BUND study, 2013) – at least where the use of this chemical is still permitted.

     

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  • Biofilter (en)

    The heart of an aquaponics system is its biofilter. The heterotrophic and autotrophic Bacterial communities in the biofilter naturally process organic waste and deliver biologically stable water that can be recycled for months. When choosing a biofiltration system for commercial aquaculture production, the efficiency of the technology and the substrate are very important because they determine the size, cost and energy consumption of the most expensive treatment components in circulatory systems.
    Biofilter decision tree

    Figure: Aquaculture engineers have to make a number of decisions when choosing the best biofilter for a particular application. Successive decisions at each node of the "decision tree" lead to the most reliable and cost-effective filter.

    FBBs ( Floating Bead Bioclarifiers ) offer better solids separation ( 100% up to 30 µm ) as micro sieves and sedimentation tanks and at the same time avoid the problem of baking, which is typically associated with sand filters under high organic loads.

     

    Under water or over water ?

    Aerobic filters require oxygen. If the biofilm in the water that is transported to the filter can be adequately supplied with oxygen, choose an underwater filter. Otherwise, you should choose an ascending filter. Emergent (ascending) filters (EGSB) use a cascade-shaped mixture of water and air to ensure that a high oxygen content is maintained on the surface of the biofilm. Drip bodies distribute the water via a column filled with biofilter media. Rotating biological contactors - sometimes called wet / dry filters - use a more mechanical approach. They slowly turn into a water tank and out again, whereby the medium always stays wet, but is additionally aerated.

     

    Overwater filter

    Emergent filters are able to achieve an extremely high area conversion of TAN (converted TAN in grams per square meter surface), are limited by a small specific surface area (square meters of biofilm per cubic meter of unit volume). As a result, emerging filters can be 5 to 10 times larger than the submerged alternatives, and caution should be exercised with some media types to prevent possible constipation. These filters offer secondary benefits in the form of ventilation and carbon dioxide stripping. They are best suited for heavily loaded systems, where their ability to supply oxygen to the biofilm can bring some benefits.

    TAN: Total ammonia nitrogen / total ammonia nitrogen

     

    Underwater filter

    Proponents of immersion filters point out that the fish live in circulatory systems on the inlet side of the filters and that the TAN values have to be kept very low. They argue that it is not oxygen diffusion, but TAN diffusion in biofilms that limits the performance of biofiltration. Proponents of underwater filters usually focus first on maximizing the specific surface and then on biofilms and solids management to improve TAN diffusion rates.

     

    Underwater pouring bed

    The oldest biofilters consist only of a bed of submerged media through which the water is circulated. These filters generally have no biofilm or solid management functions, and little attention is paid to the specific surface. These filters are used with great success in husbandry systems for seafood, lightly polluted aquaculture, show aquariums and the like. The large, inexpensive filters do a good job until they are overloaded and get into a zone with positive bacterial growth that makes them unusable because no more water can penetrate the filter. These shortcomings in dipped bulk beds have been remedied by filters that can deal with the problem of solids accumulation.

     

    Expandable granulate filters

    Expandable granulate filters differ from other filter types by a backwash mechanism. Expandable granulate filters, which include fine sand filters, gravel filters and bead filters, have a similar backwash strategy that enables them to work in a wide range of functions. This choice controls water loss and has a major impact on how easily the filters' biofilms can be manipulated. Expandable granulate filters have the unique ability to work as mechanical filters, biofilters or bioclars. However, their effectiveness in these three areas is very different.

     

    Fine sand filter

    Fine sand filters are mainly used as mechanical filters in most applications, but contribute to a certain nitrification in circulatory systems. These filters are poorly suited as biofilters in most commercial applications because the development of a biofilm quickly overrides the washing mechanism. All sand and gravel filters require high flow rates to start their expansion, which also leads to high water losses during backwashing. These water losses can hinder biofilm management strategies that improve the performance of biofilters. Sand filters are often used as sewage treatment tanks for show aquariums, as mechanical inlet filters in aquaculture systems and as biofilters in very weakly loaded circulatory systems.Coarse sand and gravel media are used with some success because they have sufficient abrasion capacities to cut off organic flakes and to avoid the problems of baking that plague finer sandbeds.

     

    Floating bead filter

    Floating-bead filters have practically all the properties of sand and gravel filters, but reduce or eliminate the problems of biofouling and water loss. Depending on the application, bead filters can be used effectively as mechanical filters, biofilters or bioclars, at the same time intercepting solids and acting as biofilters. The backwash mechanism and the frequency of backwash of the plants are used as an instrument for managing the biofilm. Well-managed plants are therefore able to achieve volumetric TAN conversion rates that are highly competitive with other biofiltration formats. In addition, the water loss for these filters is between just over 1 percent and 10 percent of the backwash requirement for equivalent gravel filters.

     

    Expanded biofilters

    Expanded biofilters, in which sand or pearls are continuously expanded, do not catch any solids, but are used as highly effective biofilters. Biofilter with fluidized sand bed keep the sand particles in suspension evenly so that the medium behaves like a liquid. The extremely high specific surface of the fine sand medium enables the filters to operate effectively at low ammonia values of less than 0.1 mg-N per liter, even if they are exposed to unfavorable conditions such as low pH. Fine sand particles are best suited for lightly stressed systems in which very low TAN concentrations are required. For example, they are used with great success in the ornamental fish industry. However, the units tend to lose sand when the substrate content increases,and are only able to remove biofilm to a limited extent.

     

    Carrier for biofilters

    Most biofilters use media such as sand, gravel, river gravel or a form of plastic or ceramic material in the form of small pearls and rings.

    When operating a biofilter, one of the main problems is to prevent the filter material from drying out or wetting in places and thereby enable the filter bed to flow evenly. This can be achieved primarily by encapsulating the biofilters. The disadvantage is often the large space requirement of these systems, the cost-intensive fan energy to increase the pressure and permanent irrigation. Compared to other processes, such as ionization with ionization tubes, the constant biological cleaning process is often due to CO2 savings and numerous economic aspects, such as medium acquisition costs, long-term filter service life and medium operating costs, an advantage.

    Trickle filter uebergaenge

    Schematic cross section of the contact area of the bed medium in a trickling block.

     
     

    Coarse sand

    Coarse sand filters still have an excellent specific surface, are very abrasive and are well suited for higher loading capacities. Coarse sand vertebral layers support very high TAN conversions, but usually only with increased ammonia values of more than 1.5 mg-N per liter. The biofilm is overused at low substrate concentrations.

     

    The filter... which is not one

    This is not a filter in the strict sense, since the main purpose is to separate gaseous or dissolved substances and not solid particles. In contrast to the biodiesel bed reactor, on the one hand, in which a so-called biological lawn forms on installations in the reactor, which is continuously flushed, and the bio-washer on the other hand, in which the microorganisms are predominantly suspended in a washing liquid, the microorganisms in the biofilter are fixed on a matrix that partially provides the nutrient supply.

    The idea of cleaning exhaust air and waste water biologically already existed in the 1920s, and technical use took place in the 1960s at the latest. Over the years, biofilters have been optimized for a variety of applications.

     

    Biofillter type 1

    Function

    On the one hand, a biofilter filters physically undesirable solids and, on the other hand, it transforms with the help of microorganisms, among other things. the ammonia from the fish excretions into nitrate, which can therefore be used by the plants as fertilizer.

     

    Mechanical filtering

    In addition to water, solid excretions of the fish, feed residues or algae are pumped into the plant beds from the fish tank. So that the substrate of the filters does not clog, worms must either ensure that these solids are converted or the solids must be removed mechanically beforehand.

               

    Depending on the system design, there is also a sedimentation basin (also called a sedimentation system). This is an almost flow-free basin, in which water constituents are sedimented by gravity and thus a separation of removable substances from a liquid can be achieved. Here the water speed is reduced to such an extent that suspended matter can settle at the bottom. From there they can be removed with a mulm vacuum cleaner or a mechanical rake.

     

    Recycling of suspended matter by worms

    Since nutrients are also contained in the suspended matter, it is of course better (and easier) to use them. That is why worms are placed in the plant beds. Not all worms are equally suitable for this purpose. The typical „ earthworms “ from the garden need different soil depths than we can provide in aquaponics. Redworms (Eisenia foetida, Eisenia andrei, Dendrobena veneta), which are sold for worm compost or as fishing bait, are well suited.

    Permanent flooded plant beds with a simple overflow are not suitable for the use of compost worms. Regular flooding in pumped systems, on the other hand, does not harm the worms.

     

    Chemical filtering

    The substrate also forms the habitat for the bacteria, which convert ammonia excreted by the fish into nitrate in a two-stage process. The first step of this so-called nitrification takes place aerobically ( in an oxygen-containing environment ) as oxidation of the ammonia to nitrite by nitrite bacteria. 

    In the second process step, nitrate bacteria convert nitrite into nitrate by oxidation. These bacteria also live aerobic, so they need oxygen. If the filters clog through suspended matter, anaerobic zones arise in which the bacteria in the nitrification process die and use anaerobic putrefaction processes. The water receives the oxygen by pumping into the substrate and with compressed air that is added.

     

    Effect of nitrate

    Nitrate is an important plant fertilizer that mainly produces leaf growth. For salads, this is desirable to a certain extent. Amounts of nitrate that are too high are deposited in the leaves and are absorbed in the body when consumed. Nitrate and nitrite are suspected by converting them into the stomach and intestines, among others. Nitrosamines to be carcinogenic.
    In addition, an oversupply of nitrate in fruit-forming plants (e.g. tomatoes) leads to excessive leaf growth and atrophy of the fruit sets. It is therefore important to ensure a balanced ratio of biofilters to biomass fish.

     

    Environmental conditions

    A product of nitrification is acid, so water in the cycle can increasingly acidify. However, the bacteria in the biofilter need a basic to neutral environment, which is why countermeasures to stabilize the pH value must be taken as part of regular maintenance.

    Depending on the season and latitude, attention must be paid to the temperature. Depending on the microorganisms used, temperatures of 40 should be minimal0 Celsius should never be exceeded. Even under 10° Celsius some bacteria slow down their work to such an extent that they are no longer useful. From 0 ° Celsius, the bacteria in the biofilter die. Such a system must always be "run in !

     

    One more word about TAN (Total ammonia nitrogen / total ammonia nitrogen)

    Quantification of nitrification

    In the past, studies have shown nitrification rates based on the specific surface of the media, with higher SSA values being preferred. Theoretically, the larger the SSA, the more habitat for bacteria. In an ideal world, this would lead to higher nitrification rates.

    In the real world of commercial aquaculture, however, the bacteria form a biofilm that can effectively cover the medium, possibly in a way that clogs the topographical or porous features of the medium, which are intended to enlarge the specific surface. This covering of the medium essentially creates a new media topography and reduces the surface actually used by the bacteria.

     

    Volumetric TAN conversion rate

    Therefore, the theoretical nitrification capacity of a certain filter medium based on the SSA does not always reflect the nitrification actually achieved in the real world. It was recently suggested, that the nitrification rates of biofilters should be based on the TAN conversion per unit volume of the non-expanded filter medium. Designated as the volumetric TAN conversion rate ( VTR ), typical units for this standard measure of nitrification are grams of TAN removed per cubic meter of biofilter medium per day.

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  • Climate Zone

    As a guide for the temperatures at which the hydroponic part cannot be heated (greenhouse) or operated outside, the temperature ranges for all plants are given in the specialist literature. Usually you only differentiate between hardy or not. According to the vegetation cycles, this also results in an optimal time for setting the respective plant. There is one for this genetic climate classification, that provides this geographic location information. We use the standardized USDA scale for the information we use. Here is a climate overview of Europe and Central Europe:

    WHZ Europa small

    Source: https://www.jelitto.com/out/media/winterhaertezonen/europa/WHZ-Europa-big.gif

    WHZ Mitteleuropa small

    Source: https://www.jelitto.com/out/media/winterhaertezonen/europa/WHZ-Mitteleuropa-big.gif


    There is also a card for the USA. This is created by the government.

    USDA climate zones, precisely USDA Plant Hardiness Zones, are a climate classification of areas based on the average lowest annual temperature, published by the US Department of Agriculture (USDA). This classification is very helpful in determining which plants can be grown in certain areas. 

    The zones range from 1 (from − 60 ° F, approx. − 51.1 ° C) for polar regions up to 13 (up to 70 ° F, approx. 21 ° C) for the tropics, each in steps of 10 ° F (≈ 5.5 ° C). The zones can be divided into half steps a and b, each comprising 5 ° F (≈ 2.8 ° C).

    They are an international standard for the classification of the winter hardness of plants. There is also a list of indicator plants, which is divided into zones in which these plants can just survive.

    The map [see below] for the USA was first launched in 1990. It was based on an averaging period 1974 – 1986. In order to do justice to global warming, this map was created in 2012 and related to the 30-year period 1976 – 2005. The individual zones moved less than a hundred kilometers to the north, in one place the zoning changed on average by about a 5- ° F half zone.

     

    Zone division


    USDA Plant Hardiness Zone Map (USA)

    USDA-Zone
    Zonefrom °Cto °C
    1a −51,1 °C −48,3 °C
    1b −48,3 °C −45,6 °C
    2a −45,5 °C −42,8 °C
    2b −42,7 °C −40,0 °C
    3a −39,9 °C −37,3 °C
    3b −37,2 °C −34,5 °C
    4a −34,4 °C −31,7 °C
    4b −31,6 °C −28,9 °C
    5a −28,8 °C −26,2 °C
    5b −26,1 °C −23,4 °C
    6a −23,3 °C −20,5 °C
    6b −20,4 °C −17,8 °C
    7a −17,7 °C −15,0 °C
    7b −14,9 °C −12,3 °C
    USDA-Zone
    Zonefrom °Cto °C
    8a −12,2 °C −9,5 °C
    8b −9,4 °C −6,7 °C
    9a −6,6 °C −3,9 °C
    9b −3,8 °C −1,2 °C
    10a −1,1 °C +1,6 °C
    10b +1,7 °C +4,4 °C
    11a +4,5 °C +7,2 °C
    11b +7,2 °C +10,0 °C
    12a +10,0 °C +12,8 °C
    12b +12,8 °C +15,6 °C
    13a +15,6 °C +18,3 °C
    13b +18,3 °C +21,1 °C
    From USDA-ARS and Oregon State University (OSU) -
     

    Source, and others: https://de.wikipedia.org/wiki/USDA-Klimazonen

     

    CC BY-SA 4.0, From Fährtenleser, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=128106709


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    ID: 420

     
  • Comparison Costs & Benefits

    farm fan by Adam Arthur CCBY2
    By Adam Arthur CCBY2

    The choice of hydroponic system

    The choice of the type of irrigation depends on a wide variety of factors such as the cost of setting up the system, operating costs, space requirements, water consumption, desired productivity (yield) and many other aspects. To help you make a decision, we have created an example for you here that can give you a first impression of the trade-offs to be expected.

    The system used in this example is called DAR (Decision Analysis and Resolution) and comes from industry. It is a tool to precisely and accurately formulate different variants and alternatives in the realisation of a complex project, to weight the individual aspects and from this to make a decision for or against a certain variant of a project. Furthermore, it also makes it easier to summarise subjective arguments in figures and values that facilitate decision-making. In retrospect, the decision-making process can be easily understood.

    Here is just a simple overview of individual factors. Please contact us for a detailed consultation that is tailored exactly to your needs. Among others:

    • Type of system
    • Space requirement
    • Energy requirements
    • Reliability
    • Productivity
    • Construction costs
    • Operating costs
    • Break Even Point
      etc.

     

    An initial decision-making aid

    This is only a small selection of the aspects that are decisive in the planning of such plants on the way to realisation. Such a project consists of many small decisions for or against a certain approach or investment. In addition to the costs and the utilisation analysis, there are many expenses that are difficult to quantify, both in terms of time and money. These range from the search for land and the construction of the facility to training for staff and the amount of work involved.
     
    Here are some key words on this topic:
     
    • Energy costs
    • Thermal insulation overview
    • Plant types
    • Decoupled aquaponics
    • Operating modes
    • Biofilter
    We are at your disposal for the entire project with our experience and look forward to your questions.
     
    In the following file formats you will find an example of how such a complex decision-making process can be designed and also how subjective aspects can be quantified and decided on more easily in groups. Even if this is only one of many approaches, you will get a first impression of the extent to which the design and planning of an aquaponics or pure hydroponics system can take on.
     
    DAR Example

     

    TabCalc  DAR (Decision Analysis and Resolution) as Excel 97–2003 (.xls)

    TabCalc  DAR (Decision Analysis and Resolution) as Open Document (.ods)


    Our offer: Our Services

    Context: 
    ID: 53
  • Decoupled Aquaponics

    Whether decoupled Aquaponics (DAPS: Decoupled Aquaponics System) has a general advantage over conventional recirculating aquaponics systems is much debated on the internet and in academia. Finding this out has been our goal over the last few years and led to the publication "Navigating Decoupled Aquaponics Systems: A system dynamics design approach ". Following the KISS principle (Keep it simple, stupid!), I will briefly outline the main points of the publication and discuss them a bit in non-scientific jargon (without the abstract of the paper).
     
     
    DAPS Decoupled Aquaponics System ( Entkoppeltes Aquaponiksystem )
    HP Hydroponik
    RAS Rezirkulierendes Aquakultur System

     

     

     

    Abstract

    The classic working principle of aquaponics is to supply a hydroponic plant culture unit with nutrient-rich aquaculture water, which in turn purifies the water that is returned to the aquaculture tanks. A known drawback is that a compromise away from optimal growing conditions for plants and fish must be achieved to produce both crops and fish under the same environmental conditions. The aim of this study was to develop a theoretical concept of a decoupled aquaponics system (DAPS) and predict water, nutrient (N and P), fish, sludge and plant values.

    flow ras daps smallThis was addressed by developing a dynamic aquaponic system model using inputs from data in the literature covering aquaculture, hydroponics and sludge treatment. The results of the model showed the dependence of aquaculture water quality on hydroponic evapotranspiration rate. This result can be explained by the fact that DAPS is based on one-way flows. These one-way flows lead to accumulations of remineralised nutrients in the hydroponic component, which ensure optimal conditions for the plants. The study also suggests sizing the cropping area based on P availability in the hydroponic component, as P is a depletable resource and has been identified as one of the most important limiting factors for plant growth.

     

    Decoupled aquaponics

    Although many aquaponics systems are designed and operated as recirculating systems, commercial growers and researchers are expanding this initial aquaponics system design to include independent control over each system unit (i.e. RAS, hydroponics and nutrient recovery through sludge remineralisation: recirculated aquaculture systems).
    Decoupled aquaponics systems (DAPS) are systems in which fish, plants and, where appropriate, remineralisation are integrated as separate functional units consisting of individual water circuits that can be controlled independently. The difference between the concepts of one-loop and multi-loop (i.e. decoupled) aquaponics systems can be seen in Figures 1 and 2. In the context of recycling all nutrients entering the system, decoupled aquaponics can be seen as a preferred option as they avoid additional discharge.

     small recirc

    Abb. 1 - The one-loop aquaponics system is the traditional aquaponics approach. Instead of supplementing the hydroponic part with fertiliser, both components are exposed to quite similar conditions

     

    small decoupled

    Abb. 2 - In contrast to a single-loop aquaponics system, a multi-loop aquaponics system aims to create optimal conditions for both fish and plants. In this case, the fish sludge coming from the RAS is remineralised and fed to the hydroponics.

     

    Figure 3 shows a process flow drawing of a basic DAPS layout. Please note - this is only an example and can be adapted in a modular way. The blue tags in the figure include the RAS component, the green tags include the hydroponic component and the red tags include the remineralisation components. The sequence of the components is represented numerically in the tags and refers to the vertical direction in which the flow must move.
    This means that high numbers refer to high positioning and low numbers to low positioning.
     

    entkoppelte aquaponik

    Während RAS (Rezirkulierten AquakulturSysteme) und Hydroponik seit Jahrzehnten Gegenstand der Forschung sind, steckt die Remineralisierung von Fischschlamm noch in den Kinderschuhen. In der Abhandlung haben wir die Vor- und Nachteile der aeroben Vor- und Nachbehandlung der anaeroben Vergärung diskutiert, derzeit untersuchen wir jedoch die Leistung der reinen anaeroben Vergärung. Wir werden Sie auf dieser Website über unsere Ergebnisse auf dem Laufenden halten.

    Leider müssen wir alle enttäuschen, die sich dafür begeistert haben, ein entkoppeltes Aquaponik-System in ihrem Garten zu bauen. Entkoppelte Aquaponiksysteme erfordern viel Steuerungstechnik und sind nur sinnvoll, wenn man bereit ist, hohe Nährlösungen in der Hydrokultureinheit zu erzielen. Außerdem ist die Dimensionierung des Systems im Vergleich zur Dimensionierung herkömmlicher Systeme mit einer Schleife viel komplexer. Die Ermittlung der erforderlichen Evapotranspirationsrate der hydroponischen Pflanzen, die erforderlich ist, um eine Akkumulation von Stickstoffformen im RAS zu vermeiden, erhöht die Komplexität zusätzlich. Folglich sind diese Art von Systemen am besten für kommerzielle Systeme im großen Maßstab geeignet, insbesondere wegen ihrer Fähigkeit, mit kommerziellen Hydrokultursystemen zu konkurrieren.

     

    Growth benefits

    The sweet spot of aquaponics for most people is the sustainable approach as well as the symbiotic effect of the RAS water on the plants and vice versa. From a commercial point of view, you cannot convince farmers with these arguments, even though they might be valid. In recent experiments, we observed growth benefits from decoupled aquaponics systems. We observed a 39 % increase in plant growth compared to a pure hydroponic control nutrient solution when supplementing the hydroponic component with additional fertiliser. Furthermore, we were able to show that anaerobic digestate also increased plant growth. At the moment, it seems that both the RAS water and the digestate contain plant growth-promoting rhizobacteria (PGPR), which could promote plant growth. We are currently planning further experiments on this topic and will also try to identify and isolate some of these PGPR.
     

    Sensitive fish species

    In the article we explained why decoupled aquaponics is suitable for sensitive fish species. We found that the use of artificial greenhouse light leads to lower fluctuations in RAS nutrient concentrations because plant evapotranspiration is more constant. The extent to which artificial lighting pays off needs to be investigated in a harvest- and fish-dependent economic evaluation.

     

     

    Hybrid backyard approach

    The hybrid decoupled system is a combination of the one-loop and decoupled approaches (Fig. 4). Home and garden growers who still want to get into decoupled aquaponics may want to try this approach. Resizing an existing system would be obsolete, as the remineralised sludge would serve as a source of nutrients for the additional culture beds. 

    hybrid system

    Abb. 4 - Hybrides entkoppeltes Aquaponic-System. Ein Ansatz für Heimgärtner?

     

    Conclusion

    We believe that decoupled aquaponics systems have the potential to achieve similar or even higher performance than hydroponic production. We know this is a bold statement, but recent observations support these assumptions. However, whether these growth advantages of DAPS over hydroponics can still be observed under perfect growing conditions (i.e. optimal climate control, light intensity and CO2 addition) remains to be clarified. The decisive advantage, however, is the sustainable approach, which aims to recycle everything that enters the system. This aspect alone is a full justification for decoupled aquaponics.
    Regarding the remineralisation component, there is a need for further research on its remineralisation performance depending on different hydraulic retention times (HRT) and sludge retention times (SRT). In summary, while technical research in this area is important, additional geographically dependent follow-up studies are needed that address the economically feasible size of DAPS as well as comparison with equivalent hydroponic systems.

     

    Sources:
     
    This article is based on excerpts, additions, summaries and translations of various scientific publications. Among others, the following were used:
     

    MDPI and ACS Style
    Goddek, S.; Espinal, C.A.; Delaide, B.; Jijakli, M.H.; Schmautz, Z.; Wuertz, S.; Keesman, K.J. Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach. Water 2016, 8, 303. https://doi.org/10.3390/w8070303

    AMA Style
    Goddek S, Espinal CA, Delaide B, Jijakli MH, Schmautz Z, Wuertz S, Keesman KJ. Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach. Water. 2016; 8(7):303. https://doi.org/10.3390/w8070303

    Chicago/Turabian Style
    Goddek, Simon, Carlos Alberto Espinal, Boris Delaide, Mohamed Haissam Jijakli, Zala Schmautz, Sven Wuertz, and Karel J. Keesman. 2016. "Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach" Water 8, no. 7: 303. https://doi.org/10.3390/w8070303

    Decoupled Aquaponics – The Future of Food Growing?

    http://www.developonics.com/2016/07/decoupled-aquaponics/

    Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach
    https://www.mdpi.com/2073-4441/8/7/303/htm

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  • Eedible Fish

    missing
    1948 advertisement for Flair fish cutlets - Public Domain

    Edible fish  are fish species that are suitable for human consumption. Depending on their habitat, a distinction is made between freshwater fish and saltwater fish (sea fish). Some fish species occur in both saltwater and freshwater, for example eel and salmon. Not all of them are suitable for breeding in aquaponics or aquaculture. Here is an overview of the preferred fish species for aquaponics systems.


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    ID: 606

    Quelle Bild: https://www.flickr.com/photos/159358942@N07/48835684447 - Public Domain
  • Fertiliser

    1884 Standard Fertilizer Companys Food for Plants

    Fertiliser programmes

    First of all: If you receive a fertiliser recommendation without having explained exactly which plants you are growing, you can safely ignore such recommendations. There are not hundreds of fertiliser types because there is one answer.
     
    Each plant species has individual nutrient requirements that also differ according to the growth phase it is in. Furthermore, indiscriminate fertilising, over-fertilising, under-fertilising, wrong composition etc. can have devastating consequences for many plants, ranging from undersupply to specific plant diseases. In order to achieve the best nutrient mixture for a specific plant, there is no getting around an analysis of the plant itself. For cost reasons alone, we recommend preparing the nutrient composition yourself.
     

     

    Mixing hydroponic fertiliser yourself ?

    The commercially available fertilisers consist of a complete fertiliser supplemented with macronutrients. They are offered by some hydroponics and/or fertiliser companies and vary depending on the hydroponic plant. An example of a fertiliser programme is the hydroponic tomato programme offered by Hydro-Gardens.

    In this programme, growers purchase Hydro-Gardens Chem-Gro tomato formula. It has a composition of 4-18-38 and also contains magnesium and micronutrients. To make a nutrient solution, it is supplemented with calcium nitrate and magnesium sulphate, depending on the variety and/or growth stage of the plant.

     

    Advantages of fertiliser programmes

    Programmes like these are easy to use. Minimal ordering of fertilisers is required (only 3 in the Hydro-Gardens example).
    Very little or no mathematical calculations are required to prepare nutrient solutions.
     

    Disadvantages of fertiliser programmes

    Fertiliser programmes do not allow for easy adjustments of individual nutrients. For example, if the leaf analysis shows that more phosphorus is needed. When using a fertiliser programme exclusively, it is not possible to simply add phosphorus.
    Another disadvantage is that fertiliser programmes do not allow farmers to take into account the nutrients already present in the water source. For example, if a water source has a potassium content of 30 ppm, there is no way to adjust the amount of potassium added in the fertiliser programme. And too much potassium can in turn block the uptake of other nutrients.

     


     

    Fertilizer programs can be more expensive than using
    Recipes for the production of nutrient solutions.

     

    Mix recipes for nutrient solutions / hydroponics fertilizer yourself

    There are also recipes for the production of nutrient solutions. The recipes contain a certain amount of each nutrient to be added to the nutrient solution. They are specifically available for a specific crop and in a variety of sources, e.g. B. at the university advice centers, on the Internet and in specialist journals. One example is the modified Sonovelds solution for herbs (Mattson and Peters, Insidegrower) shown below.
     

     

    Modified Sonneveld recipe / herbs

    element concentration
     Nitrogen 150 ppm 
     Phosphorus  31 ppm
     Potassium  210 ppm
     Calcium 90 ppm 
     Magnesium  24 ppm
     Iron  1 ppm
     Manganese  0.25 ppm
     Zinc  0.13 ppm
     copper 0.023 ppm
     Molybdenum 0.024 ppm
     Boron 0.16 ppm

     

    It is at the discretion of the breeder which fertilizers he uses to produce a nutrient solution according to a recipe. The fertilizers commonly used include:

    fertilizerDosage, contained nutrients
     Calcium nitrate 15.5 – 0 – 0.19% calcium
     Ammonium nitrate 34 – 0 – 0
     Potassium nitrate 13 – 0 – 44
     Sequestrene 330TM 10% iron
     Potassium phosphate monobasic 0 – 52 – 34
     Magnesium sulfate 9.1% magnesium
     Borax (laundry quality) 11% boron
     Sodium molybdate 39% molybdenum
     Zinc sulfate 35.5% zinc
     Copper sulfate 25% copper
     Magnesium sulfate 31% manganese
    Farmers calculate the amount of fertilizer in the
    nutrient solution based on the amount of a nutrient
    in the fertilizer and in amount specified in the recipe.

     

    Advantages of nutrient solution recipes

    Nutritional solutions allow fertilizers to be adjusted based on the nutrients contained in water sources. An example: A gardener uses a water source with 30 ppm potassium and produces the modified Sonneveld solution for herbs that requires 210 ppm potassium. It would have to add 180 ppm potassium ( 210 ppm - 30 ppm = 180 ppm ) to the water in order to obtain the amount of potassium required in this recipe.
    With recipes, nutrients can be easily adjusted. When a leaf analysis report indicates that a plant has iron deficiency. It is easy to add more iron to the nutrient solution.
    Since recipes make it easy to adapt, fertilizers can be used more efficiently than in fertilizer programs. Using recipes can be less expensive than using fertilizer programs.


    Disadvantages of nutrient solution recipes

    It has to be calculated how much fertilizer has to be added to the nutrient solution. (Link to performing calculations). Some people may feel intimidated by the calculations involved. However, the calculations only require uncomplicated mathematical skills based on multiplication and division.
    A high-precision scale is also required for the measurement of micronutrients, since the required quantities are very small. Such a scale can be found on Amazon from 30.- €: e.g .: KUBEI 100g / 0.001g.

     

    This is about the calculation of nutrient solutions for your own needs


    Picture: Boston Public Library is licensed under CC BY 2.0


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    URL
  • Fertiliser: Calculation of nutrient solutions

    Orchilla Guano
    By Boston Public Library, license CC BY 2.0

    Calculation of the concentrations of nutrient solutions using the following two equations

    The calculation of the amount of fertilizer that has to be added to the nutrient solutions is part of a successful hydroponic production. Only multiplication, division and subtraction are used for the calculations; no advanced mathematical knowledge is required.

    If you want to know more about the compositions and concentration information, the article series can be too Stoichiometry and a look at the conversion of Mol and grams When specifying the concentration of the individual elements and connections, it is helpful to better understand the complexity of the topic.

    If you master the general process, producing nutrient solutions and adjusting the amount of nutrients is child's play.

    Fertilizer recipes for hydroponics are almost always given in ppm (in the long form: parts per million). This may differ from the fertilizer recommendations for growing vegetables and fruits outdoors, which are generally given in lb / acre (pounds per acre).

    First you have to convert ppm to mg / l (milligrams per liter) using this conversion factor: 1 ppm = 1 mg / l (1 part per million corresponds to 1 milligram per liter). For example, if 150 ppm nitrogen is required in a recipe, 150 mg / l or 150 milligrams of nitrogen in 1 liter of irrigation water are actually required.

    Ppm P (phosphorus) and ppm K (potassium) are also used in recipes for nutrient solutions. This also differs from the fertilizer recommendations for growing vegetables and fruits in the field, which use P2O5 (phosphate) and K2O (potash). The fertilizers are also given as phosphate and potash. Phosphate and potash contain oxygen, which must be taken into account in hydroponic calculations. P2O5 contains 43% P and K2O contains 83% K.

    Let us check the previous circumstances:

    1 ppm = 1 mg / l
    P2O5 = 43% P
    K2O = 83% K

    Nutrient solution tanks are usually measured in gal ( gallons ) in the United States. When we convert ppm to mg / l, we work with liters. To convert liters into gallons, use the conversion factor of 3.78 l = 1 gal ( 3.78 liters corresponds to 1 gallon ). The invoice is also given below for continental interested parties.

    Depending on the scale you use to weigh fertilizers, it may be useful to convert milligrams into grams: 1,000 mg = 1 g ( 1,000 milligrams correspond to 1 gram ). If your scale measures in pounds, you should use this conversion: 1 lb = 454 g ( 1 pound = 454 grams ).

     

    Let us summarize these circumstances:

    3.78 l = 1 gallon
    1000 mg = 1 g
    454 g = 1 lb


    Now we have all the necessary circumstances. Let's look at an example.

    How do you determine how much 20-10-20 fertilizer is needed to deliver 150 ppm N with a 5 gallon tank and a fertilizer injector that is at a concentration of 100:1 is set?

    First, write down the concentration you know you want to reach. In this case it is 150 ppm N or 150 mg N / l.

     150 mg N / 1 L Wasser

    Note that we multiply by 1. This allows you to cancel the units that are the same in the numerator and denominator. Now we can paint "mg N" and get the unit g N / l water.

    150mg1LWasser 3

    Continue this process by converting liters into gallons. Most containers are still traded in gallons ( 3.78 liters ). Entertaining here: the metric system was invented by the Britten. If you want a metric result, omit this calculation step.

    150mg1LWasser 5

    Now there are only grams of nitrogen left per gallon of water.
    We'll get closer to it. Now we want to convert grams of nitrogen into grams of fertilizer. Remember that our fertilizer is a 20-10-20, which means that it contains 20% nitrogen. It can be imagined that 100 grams of fertilizer contain 20 grams of nitrogen

    150mg1LWasser 6

    So where do we stand now? We calculated how many grams of fertilizer are needed in each gallon of irrigation water. At the moment we have a normally strong solution. Our example prompts us to calculate a concentrated solution of 100: 1. This means that for every 100 gallons of water that are applied, 1 gallon of stock solution is also applied via a fertilizer injector. We also know that our storage tank holds 5 gallons. Below see calculation for metric system (liters).

    In gallons

    150mg1LWasser 8

    In the calculator: 150 x 1: 1000 x 3.78 x 100: 20 x 100 x 5 is 1417.5 grams on 5 gallons of water (in the storage tank)

    After we have deducted everything, we have a gram of fertilizer left. This is the amount of fertilizer we need to put in our storage tank to apply 150 ppm N at a concentration of 100: 1. Multiply and divide and you get the answer 1417.5 grams of fertilizer.

    In liters

    150mg1LWasser de

    In the calculator: 150 x 1: 1000 x 100: 20 x 100 x 10 is 1500 grams per 10 liters of water ( in the storage tank )

    After we have deducted everything, we have a gram of fertilizer left. This is the amount of fertilizer we need to put in our storage tank to apply 150 ppm N at a concentration of 100: 1. Multiply and divide and you get the answer 750.0 grams of fertilizer.

    This means that for every 100 liters of water that is applied, 1 liter of stock solution is also applied via a fertilizer injector. We also know that our storage tank holds 10 liters. 

    If we measure in pounds, we have to put 0.75 kg / 1.15 lb fertilizer in our storage tank to apply 150 ppm N with a concentration of 100: 1.

    You have just completed one of the two equations. Now let's look at the other one.

    We just found that we need to add 750 grams of fertilizer to deliver 150 ppm nitrogen at a concentration of 100: 1. The fertilizer we used was a 20:10:20. In addition to nitrogen, we also add phosphorus and potassium. With the next equation we determine how much phosphorus we supply. This is basically the reversal of the first calculation.

    We start with the amount of fertilizer that we put in our tank. The final units are ppm or mg / l. As with the previous calculation, we use our specifications until we receive these units.

    1417gDuengerWasser 0

    Multiply with the concentration of the nutrient solution.

    1417gDuengerWasser 2

    Multiply to convert to liters.

    1417gDuengerWasser 3

    Next, convert milligrams of fertilizer into milligrams of phosphate.

     1417gDuengerWasser 4

    Next we will convert grams of phosphate into grams of phosphorus, assuming that phosphate contains 43% phosphorus.

    1417gDuengerWasser 5

    Finally, we convert grams of phosphorus into milligrams of phosphorus.

    1417gDuengerWasser 6

    When we calculate this, we find that we have added 32.25 mg / l P or 32.25 ppm P. This is the second equation. We can also use them to determine how much potassium we have added. 

    1417gDuengerWasser 7

    We added 124.5 mg / l K or 124.5 ppm K.

    With these two basic calculations, you can use any nutrient solution recipe program. How they are used to calculate a recipe can be seen in this article:

     


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  • Fertilizer: Calculate a nutrient recipe

    By Boston Public Library, licensed CC BY 2.0

    Now that you have the two basic equations for the production of nutrient solutions, we want to use them to calculate the amounts of fertilizer required for a nutrient solution recipe.

    If you are not familiar with the two equations, read this first: Hydroponic systems: Calculating the concentrations of nutrient solutions using the two equations.

    Here is our problem: We want to use a modified Sonneveld solution (Matson and Peters, Insidegrower) for herbs in an NFT system. We use two 5-gallon containers and injectors set to a concentration of 100: 1 and call them storage tank A and storage tank B. How much of each fertilizer do we have to put in each storage tank ?

    You may be asking: why two storage tanks? This is due to the fact that certain chemicals in our fertilizer solution react with each other as soon as they come into contact with each other. In all nutrient solutions ( fertilizer mixtures ) you have calcium, phosphates and sulfates - among other things, these three chemicals for all plants vital are. The last two react with calcium and are no longer present in the form we need in our nutrient solution. They connect to each other and fall to the bottom of the container as white flakes ( precipitates ). Therefore, phosphates and sulfates must be kept separate from calcium and, when introduced into the nutrient solution of the ( system, saved from direct mixing by means of a dosing pump or measuring cup ).

    Modified Sonneveld recipe for herbs

    element concentration
    nitrogen 150 ppm 
    phosphorus  31 ppm
    potassium  210 ppm
    calcium 90 ppm 
    magnesium  24 ppm
    iron  1 ppm
    manganese  0.25 ppm
    zinc  0.13 ppm
    copper 0.023 ppm
    Molybdenum 0.024 ppm
    boron 0.16 ppm

     

    These are the fertilizers that we will use. Some fertilizers contain more than one nutrient in the recipe, while others contain only one. Here is a small overview Commercial fertilizer from which you can put together your recipe

     

    Fertilizer
    Contained nutrients
    (Nitrogen phosphate potassium and other nutrients)
    Calcium nitrate 15.5-0-0, 19% Ca (calcium)
    Ammonium nitrate 34-0-0
    Potassium nitrate 13-0-44
    Potassium phosphate monobasic 0-52-34
    Magnesium sulfate 9.1% mg (magnesium)
    Sequestrene 330 TM 10% Fe (iron)
    Manganese sulfate 31% Mn (Mangan)
    Zinc sulfate 35.5% Zn (zinc)
    Copper sulfate 25% Cu (copper)
    Boron 11% B (Boron)
    Sodium molybdenum 39% Mo (molybdenum)

     

    The first thing you notice is that we have three sources of nitrogen (calcium nitrate, ammonium nitrate and potassium nitrate), have two sources of potassium (potassium nitrate and potassium phosphate monobasic) and one source of calcium (calcium nitrate) and phosphorus (single-base potassium phosphate). We can start calculating the calcium or phosphorus in the recipe because only one fertilizer provides each nutrient. Let's start with calcium.

    The recipe provides 90 ppm calcium. We calculate how much calcium nitrate we need to use to achieve this by using the first of our two equations.

     

    Duenger Mischung 1

    We need to add 895.3 g calcium nitrate to get 90 ppm calcium. However, calcium nitrate also contains nitrogen. We use the second equation to determine how much nitrogen should be added in ppm.

    Duenger Mischung 2

    We add 73.4 mg N / l or 73.4 ppm nitrogen. Our recipe provides 150 ppm nitrogen. If we subtract 73.4 ppm nitrogen from it, we have to add 76.6 ppm nitrogen.

    Let us now calculate how much single-base potassium phosphate we have to use to deliver 31 ppm phosphorus.

    Duenger Mischung 3

    We need to add 262 g of potassium phosphate monobed to get 31 ppm phosphorus. However, potassium phosphate also contains single-base potassium. We use the second equation to determine how much potassium should be added in ppm.

     Duenger Mischung 4

    We add 39 mg K / l or 39 ppm potassium. Our recipe provides 210 ppm potassium. If we subtract 39 ppm of potassium from it, we see that we still have to add 171 ppm of potassium.

    We have only one other source of potassium, namely potassium nitrate. Let's calculate how much we have to use of it.

    Duenger Mischung 5

    We need to add 885 g of potassium nitrate to get 171 ppm of potassium. However, potassium nitrate also contains nitrogen. We use the second equation to determine how much nitrogen should be added in ppm.

    Duenger Mischung 6

    We add 61 mg N / l or 61 ppm nitrogen. Our recipe provides 150 ppm nitrogen. We supplied 73.4 ppm nitrogen from calcium nitrate and had to add 76.6 ppm nitrogen. Now we can subtract 61 ppm nitrogen. We still have to add 15.6 ppm nitrogen. The only source of nitrogen that we have is ammonium nitrate.

    Let us now calculate how much ammonium nitrate we have to use to deliver 15.6 ppm nitrogen.

     Duenger Mischung 7

    We need to add 86.7 g of ammonium nitrate to get 15.6 ppm nitrogen.

    At this point we have completed the nitrogen, phosphorus, potassium and calcium part of the recipe. For the other nutrients, we only need to use the first equation, since the fertilizers that we use for their supply contain only one nutrient in the recipe.

    Duenger Mischung 8

    We need to add 498.5 grams of magnesium sulfate to get 24 ppm magnesium.

    Duenger Mischung 9We need to add 18.9 grams of Sequestren 330 to get 1 ppm of iron.

     Duenger Mischung 10

    We need to add 1.5 grams of manganese sulfate to get 0.25 ppm manganese.

    It is easier to weigh small amounts of fertilizers in milligrams. The conversion from milligrams to grams is therefore carried out as follows

    Duenger Mischung 11

    We need to add 692 milligrams of zinc sulfate to get 0.13 ppm zinc.

     Duenger Mischung 12

    We need to add 0.17 milligrams of copper sulfate to get 0.023 ppm copper.

     

    Duenger Mischung 13

    We need to add 2.8 milligrams of borax to get 0.16 ppm borax.

    Duenger Mischung 14

    We need to add 0.12 milligrams of sodium molybdate to get 0.024 ppm molybdenum.

     

    Summary:

     Element  Addition Nutrient Solution
     Calcium  895.3 g calcium nitrate  90 ppm calcium
     Phosphorus  262 g of potassium phosphate monobasic 31 ppm phosphorus
     Potassium  885 g potassium nitrate  171 ppm potassium
     Nitrogen   86.7 g ammonium nitrate 15.6 ppm nitrogen
     Magnesium  498.5 grams of magnesium sulfate 24 ppm magnesium
     Iron  18.9 grams of sequestrene 330 1 ppm iron
     Manganese  1.5 grams of manganese sulfate 0.25 ppm manganese
     Zinc  692 milligrams of zinc sulfate 0.13 ppm zinc
     Copper  0.17 milligrams of copper sulfate 0.023 ppm copper
     Boron  2.8 milligrams of borax 0.16 ppm boron
     Molybdenum  0.12 milligrams of sodium molybdate 0.024 ppm molybdenum

     

    Now all calculations have been completed. Now we have to decide in which storage tank, A or B, we give the individual fertilizers. In general, the calcium should be kept in a tank other than the sulfates and phosphates, as they can form precipitates that can clog the drip bodies of the irrigation system. Using this guideline, we can put the calcium nitrate in one tank and the monobasic potassium phosphate, magnesium sulfate, manganese sulfate, zinc sulfate and copper sulfate in the other tank. The rest of the fertilizers can be placed in both tanks.

    You should also consider the amount of nutrients in irrigation water. For example, if we use irrigation water that contains 10 ppm magnesium, we only need to add 14 ppm more with our fertilizer (24 ppm Mg, which are required in the recipe, minus 10 ppm Mg in water). This is a great way to use nutrients more efficiently and fine-tune your fertilizer plan.

    With some micronutrients, you have to decide for yourself what you want to add. You could do a small experiment to find out whether you need to add 0.12 milligrams of sodium molybdate to your stock solution, for example, or whether you are satisfied with the performance of your plants without this addition.

    One last point to consider. Sometimes the calculations don't work as well as here for fertilizers that contain more than one required nutrient, and you may need to add more of a nutrient, than is provided in the recipe to provide the other nutrient.

    For example, if you apply calcium nitrate to meet calcium needs, the solution may not contain enough nitrogen. In such cases, you have to decide which nutrient you want to give priority to. For example, you could apply calcium nitrate to meet the plants' nitrogen needs because the excess amount of calcium does not harm the plants. Or you choose to apply it based on the plant's calcium needs because the lack of nitrogen is just a few ppm.

    Here you will find what problems there may be with a lack and excess of fertilizer


    At this point we can give you recommendations for your plantations with modern analysis technology. Contact us...


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  • Fertilizer: Essential Nutrients, Function, Deficiency and Exces

    Deficiency symptomsHubbard Squash Rices seeds are the best

    Before we begin discussing the principles of plant nutrient systems in hydroponic systems, we need to define what we mean by "hydroponic."

    Hydroponics is the process of growing plants in water containing nutrients. Examples of this type of hydroponic systems are NFT (Nutrient Film Technique) systems and deep water floating systems where the plant roots are placed in nutrient solutions. Another definition of hydroponics is growing plants without soil. According to this definition, growing plants in soilless media (potting soil) or other types of aggregate media such as sand, gravel, and coconut shells are considered hydroponic systems. Here we use the term hydroponics for growing plants without soil.

     

    Essential nutrients

    Plants cannot function properly without these 17 essential nutrients. These nutrients are needed to allow the processes important to plant growth and development to take place. For example, magnesium is an important component of chlorophyll. Chlorophyll  (see picture) is a pigment that serves to capture light energy needed for photosynthesis. It also reflects green wavelengths and is the reason most plants are green. Magnesium is the center of the chlorophyll molecule. The table below lists the functions of the essential nutrients for plants.

    Basic structure for chlorophylls a, b and d (The designation of the rings is given.)


    Essential nutrients can be broadly divided into macronutrients and micronutrients . The classification macro (large) and micro (tiny) refers to the amounts. Both macronutrients and micronutrients are essential for the growth and development of plants. Macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium. Micronutrients include iron, manganese, zinc, boron, molybdenum, chlorine, copper, and nickel. The difference between macronutrients and micronutrients lies in the amount plants need. Macronutrients are needed in larger amounts than micronutrients. Table 1 shows the approximate content of essential nutrients in plants.

    Plants obtain carbon, hydrogen and oxygen from air and water. The remaining nutrients come from the soil or, in the case of hydroponics, from nutrient solutions or aggregate media. The sources of nutrients available to plants are listed in Table 1.

     

    Essential components of nutrient solutions, Table 1

    Nutrient (symbol) Approximate plant content (% dry weight)

    Role in the plant

    Source of nutrients available to the plant
    Carbon (C), hydrogen (H), oxygen (O) 90+ % Components of organic compounds Carbon dioxide (CO 2 ) and water (H 2 O)
    Nitrogen (N) 2–4% Component of amino acids, proteins, coenzymes, nucleic acids Nitrate (NO3-) und Ammoniak (NH4+)
    Sulfur (S) 0.50% Component of sulphur-containing amino acids, proteins, coenzyme A Sulfate (SO4-)
    Phosphor (P) 0.40% ATP, NADPMetabolic intermediates, membrane phospholipids, nucleic acids Dihydrogenphosphat (H2PO4-), Hydrogenphosphat (HPO42-)
    Potassium (K) 2.00% Enzyme activation, turgor, osmotic regulation Potassium (K + )
    Calcium (Ca) 1.50% Enzyme activation, signal transduction, cell structure Calcium (Ca2+)
    Magnesium (Mg) 0.40% Enzyme activation, component of chlorophyll Magnesium (Mg2+)
    Manganese (Mn) 0.02% Enzyme activation, important for water splitting Manganese (Mn 2+ )
    Iron (Fe) 0.02% Redox changes, photosynthesis, respiration Iron (Fe 2+ )
    Molybdenum (Mo) 0.00% Redox changes, nitrate reduction Molybdat (MoO42-)
    Copper (Cu) 0.00% Redox changes, photosynthesis, respiration Copper (Cu 2+ )
    Zink (Zn) 0.00%
    Cofactor activator for enzymes
    Alkohol-Dehydrogenase, Carboanhydrase
    Zink (Zn2+)
    Bor (Bo) 0.01% Membrane activity, cell division Borat (BO3-)
    Chlor (Cl) 0.1–2.0% Charge equalization, water splitting Chlor (Cl-)
    Nickel (Ni) 0.000005–0.0005% Component of some enzymes, biological nitrogen fixation, nitrogen metabolism Nickel (Ni2+)

     

     
    To get an idea of ​​the quantities required, here is a fertilizer quantity recommendation from the BISZ for sugar beet in arable farming. From the quantity you can see that, for example, 90 grams of copper per 1 ha (10,000 m 2 ) is only a tiny amount per square meter and a fraction of that is needed per plant. In this example: 0.009 grams per square meter. But if this element is completely missing, the plant cannot grow at all because it is essential for photosynthesis (see table above). When dry, it (copper) is no longer found due to chemical processes during drying.
     
    Nutrient requirement kg/ha
    Nitrogen 250
    Phosphor 100
    Potassium 400
    Magnesium 80
    Sulfur 20 – 30
    Calcium 60 – 80
    Nutrient requirement g/ha
    Bor 450 – 550
    Manganese 600 – 700
    Ferrum 500 – 1.500
    Copper 80 – 90
    Zinc 250 – 350

     


    PH value

    It is impossible to talk about plant nutrition without considering pH. Hydroponics is primarily concerned with the pH of the water used to prepare nutrient solutions and irrigate plants. pH is a measure of relative acidity, or hydrogen ion concentration, and plays an important role in the availability of plant nutrients. It is measured using a scale of 0 to 14 points, with 0 being the most acidic, 7 being the most neutral, and 14 being the most alkaline. The scale is logarithmic, and each unit corresponds to a 10-fold change. This means that small changes in values ​​​​mean large changes in pH. For example, a value of 7 is 10 times higher than 6 and 100 times higher than 5. In general, the optimal pH range for growing vegetables in hydroponics is 5.0 to 7.0.

    This diagram shows the relationship between nutrient availability and pH value:

    Graphic: Pennsylvania State University

     

    At the bottom of the chart, various pH levels between 4.0 and 10.0 are indicated. At the top of the chart, the relative acidity or alkalinity is indicated. Within the chart, the relative nutrient availability is represented by a bar. The wider the bar, the more relatively available the nutrient is. For example, the nitrogen bar is widest at a pH of 6.0 to 7.5. This is the pH at which it is most available to plants. Between 4.0 and 4.5, it is very narrow and not as easily available to plants.

    It is also important to consider the alkalinity of the water. Alkalinity is a measure of capacity. It measures the ability of the water to neutralize the acid. This is primarily due to the combined amount of carbonate (CO3) and bicarbonate (HCO3), but hydroxide, ammonium, borate, silicate and phosphate can also contribute.

    When total alkalinity is low, the water has a low buffering capacity. As a result, the pH changes slightly depending on what is added to the water. When total alkalinity is high, the pH of the water is high. To lower a high pH of the water, acid can be added to the irrigation water. The amount of acid needed depends on the alkalinity of the water.

     

    Nutrient antagonism and interactions

    For example, a hydroponic tomato nutrient solution recipe calls for 190 ppm nitrogen and 205 ppm potassium. Due to an error in calculating the amount of fertilizer to use, 2,050 ppm potassium is added. An excess of potassium in the solution can cause antagonism with nitrogen (and other nutrients) and result in nitrogen deficiency even if 190 ppm nitrogen was added. The table below lists common antagonisms.

     

    NutrientAntagonist of
    Nitrogen Potassium
    Phosphor Zinc
    Potassium Nitrogen, calcium, magnesium
    Sodium Potassium, calcium, magnesium
    Calcium Magnesium, Bor
    Magnesium Calcium
    Ferrum Manganese
    Zinc Ion competition: high concentrations of heavy metals, copper and phosphate reduce the uptake rate of zinc: the cause of zinc deficiency in the plant does not necessarily have to be zinc-poor soil

    See also: Interactions

     

    Problems with nutrients

    Hydroponic systems are less forgiving than soil-based systems, and nutrient problems can quickly lead to plant problems. This is why nutrient solution composition and regular monitoring of the nutrient solution and plant nutrient status are critical.

    The minimum law

    Carl Sprengel's law of the minimum states that the growth of plants is limited by the resource that is relatively scarce (nutrients, water, light, etc.). This means that a lack of nitrogen can also lead to the plant not being able to process other nutrients. On the other hand, too much of one component can have undesirable consequences: for example, too much lime inhibits the absorption of nutrients.

     

     Also pay attention to the symptoms of
    Deficiency symptoms  that often point out problems:

    Here is a brief overview of the deficiency symptoms, which can vary depending on the plant genus. 

    Symptoms N P K Ca S Mg Fe Mn B Mo Zn With  Overfertilization
    Upper leaves yellow         X   X            
    Middle leaves yellow                   X      
    Lower leaves yellow X X X     X              
    Red stems  X  X X                     
    Necrosis     X     X   X X     X  
    Points               X          
    Shoots die                 X        
    White leaf tips           X         X    
    Crumpled Wheatgrass X X X                    
    Rolled yellow leaf tips                         X
    Twisted growth                 X        



    Damage caused by soluble salts

    Cause: Soluble salt damage can be caused by over-fertilization, poor water quality, accumulation of salts in aggregate media over time, and/or inadequate leaching. Fertilizers are salts, and in hydroponic systems they are the most common fertilizer. As water evaporates, soluble salts can build up in aggregate media if they are not adequately leached. Irrigation water can also have high levels of soluble salts, contributing to the problem.

    The symptoms: Chemically induced drought can occur when the content of soluble salts in the planting substrates is too high. The result is that the plants wilt despite sufficient watering. Other symptoms include dark green foliage, dead and burned leaf edges and root death.


    Detection: Soluble salt levels can be monitored/measured by tracking the electrical conductivity (EC) of irrigation water, nutrient solutions and leachate (a nutrient solution drained from the plant container).

    Correction: Soluble salts can be leached out with plain water. First, determine the cause of the high soluble salts level and correct it. 

     
    Boron Bo
     
    The cause:  deficit in the fertilizer mixture.
     
    The symptoms:  Insufficient flower formation, the flowers are smaller and deformed. Boron deficiency affects the apical meristems (growth points). Sometimes the meristem dies completely and the side shoots start to grow (broom effect). The meristems have shorter internodes, which are often thicker and show small and deformed leaves at the tip. The shorter internodes sometimes lead to dwarfism. The stems often have breaks and cracks. The fruits are sometimes deformed and corked. Cracks or spots are also possible. Older leaves can show necrosis.
     
    Detection: leaf analysis.
     
    Correction :  Fertilizers containing boron: Borax or boric acid, but note that boric acid is highly toxic. Alternatively: If there is a general nutrient deficiency, complete fertilizers that also contain boron can be used.
     
     
     
    Boron toxicity Bo
     
    The cause: Boron toxicity is caused by too much boron applied to plants. Of the nutrients commonly applied as fertilizers, boron has the narrowest margin between deficiency and toxicity. It is easy to apply too much boron. Check the calculations of fertilizers before applying them and check again. It can also be found in irrigation water. It is important to check the boron level in a water source before use and to take into account the boron in the water when adding boron fertilizer.
     
    The symptoms: Symptoms of boron toxicity are yellow and dead spots on the leaf edges. Reduced root growth can also occur.
     
    Detection: Monitor the media and perform plant analysis.
     
    Correction : Determine the source of the excess boron and correct it.
     
     
     
    Calcium deficiency Ca
     

    The cause:  Strong temperature changes can interrupt and hinder calcium uptake. Lack of light, cold and/or too humid environmental conditions. Fertilizer level too low. Calcium deficiency can be caused by under-fertilization, a nutrient imbalance or a pH value that is too low. It is also related to moisture management, high temperatures and low air circulation. Calcium is a mobile nutrient and is transported through the plant in the water-bearing tissues. Fruits and leaves compete for water. Low relative humidity and high temperatures can lead to an increased transpiration rate and increased transport to the leaves. In this case, a calcium deficiency can develop in the fruits.

    The symptoms:  The apical meristems (these are the dividing tissues of the plant) are deformed and die off without any noticeable symptoms on the oldest leaves. The upper part of the stem and flower bud may bend. Small and deformed leaves on the upper side. Unusually dark green leaves. Premature flower and fruit drop. After a deficiency, the leaves that were developing at the time of the deficiency often show a typical deformation/drying out or a white edge. This is called tip burn and is particularly common in lettuce and strawberries. Browning of the inside of a stem/head, around the growing point like in celery (black heart). Typical symptoms are also blossom end rot on peppers and tomatoes. Symptoms usually first appear as brown leaf edges on new plants or on the underside of the fruit. Blossom end rot in tomatoes and peppers. As symptoms progress, you may see brown, dead spots on the leaves. A lack of sufficient calcium can lead to rot.

    Detection: Leaf analysis. Fruits have a poorer shelf life.

    Correction :  Make sure the pH is between 5.5 and 6.5. Add calcium nitrate or calcium chloride depending on whether you need the extra nitrogen or not. 

    In the greenhouse: Increase the temperature. More light. Without wind, the plant's nutrient transport is reduced - ensure air movement in the greenhouse. 

    Ferrum deficiency Fe
     
    The cause: The most common cause of iron deficiency is high pH in the media and/or irrigation water. It can also be caused by nutrient imbalance.
     
    The symptoms: Iron deficiency in plants shows itself as yellowing between the leaf veins. Note that this symptom appears first on new growth.
     
    Detection: Monitor the media and perform plant analysis.
     
    Correction : Correct the pH of the nutrient solution. If necessary, add iron fertilizer.
     
     
     
    Sulphur deficiency S
     

    The cause:  Too little or incorrectly proportioned fertilizer. A pH value that is too low also blocks the absorption of sulfur. At a pH value of 4.0, sulfur absorption stops completely. Too little magnesium.

    The symptoms:  Extensive yellowing  of the leaf tissue and the leaf veins. Often the younger parts of the plant first and later the whole plant. Symptoms are more likely to appear in young or freshly growing leaves at the top of the plant. Sulfur is an immobile nutrient. This means that sulfur can only be re-disposed (transported) relatively slowly by the plant. Lime green to yellow discoloration on leaves is characteristic of sulfur deficiency. It starts at the leaf stalk and moves to the leaf edges and tip. As the disease progresses, the entire leaves first turn yellow, then later brown and necrotic and then die completely. Sometimes purple/reddish leaf stalks on the affected leaves or even a purple stem. The symptoms of a mild deficiency are usually limited to the top of the plant. The middle part of the plant is hardly affected, lower leaves almost never.

    Detection: leaf analysis.

    Correction :  increase the fertilizer dose. Correct the pH: keep it well above 4.0. 5.5 to 6.5 is a good average for many plants. Enrich the soil with Epsom salt / magnesium sulfate / MgSO 4 : one teaspoon per 2 liters of water (approx. 1% concentration).

    Nitrogen deficiency N

    The cause: Nitrogen deficiency can be caused by under-fertilization, nutrient imbalance or excessive leaching.
     
    The symptoms: Typical first symptoms of nitrogen deficiency are light green foliage and a general stunting of the plants. Wilting and dead and/or yellow leaf edges can also be observed. Yellowing of the entire leaf, including the leaf veins, can be seen. The older leaves turn yellow first, but the nitrogen deficiency quickly leads to a general yellowing. Necrosis or deformation of leaves or stems does not appear in the initial stage.
    General growth retardation.
     
    Detection: Measuring/monitoring the electrical conductivity (EC) of nutrient solutions can help prevent nitrogen deficiency. Adjust the EC value if it is too low or too high.

    Correction : Determine the cause and correct it. This may mean adding more nitrogen to the nutrient solutions. It may also mean there is too much of an antagonistic nutrient in the nutrient solution.
     
     
    Potassium deficiency K
     
    The cause:  incorrectly dosed nutrient solution. Plant consumption higher than calculated: a potassium deficiency often occurs in crops that bear a large amount of fruit.
     
    The symptoms:  Wilting of the plants even at moderate temperatures. Leaf edge necrosis on the oldest leaves. Browning and curling of the lower leaf tips and yellowing (chlorosis) between the leaf veins. Purple spots may appear on the underside of the leaves. Yellowing: Yellowing also begins on the edges of the oldest leaves and develops towards the middle of the leaf. In some cases the leaf edge is not affected and the necrosis begins inside the leaf between the leaf veins.

    Detection:  Nutrient analysis and/or perform plant analysis.
     
    Correction :  Re-dose. Check antagonist concentration: nitrogen, calcium, magnesium
     
    Note: Too much potassium can cause severe stunting, redness, and poor germination. Excessive amounts of potassium can also make it difficult to absorb other ions such as calcium. 
     
     
     
    Copper deficiency Cu
     
    The cause:  incorrect fertilizer composition.
     
    The symptoms:  White discoloration in the tips of the younger leaves. The leaves curl up in a corkscrew shape. Later they may die (necrosis).
    The youngest leaves have difficulty unfolding. The youngest leaves curl up and wilt. Necrosis at the youngest growing points and the leaf margins of the youngest leaves.
     
    Correction :  Add special copper fertilizer.
     
     
     
    Magnesia deficiency Mg
     
    Cause: Magnesium can be caused by a high pH of the medium and/or a nutrient imbalance between potassium, calcium and nitrogen.
     
    The symptoms: Yellowing of the leaf tissue. The leaf veins remain green. This yellowing begins on the oldest leaves. Look for yellowing between the leaf veins as a symptom of magnesium deficiency: chlorosis or yellowing. Magnesium deficiency usually shows up first on the lower to middle leaves, which makes it easier to distinguish from iron deficiency. Premature leaf drop of the affected leaves. Sometimes the discoloration can be more brownish than yellow.
     
    Detection:  Nutrient analysis and perform plant analysis.
     
    Correction : Correct the pH of the nutrient solution. If necessary, add magnesium fertilizer. Check the dosage of competing cation suppliers (K, Ca and N).
     
     
    Manganese deficiency Mn
     
    Cause:  Too little or no fertilizer. Manganese deficiency is somewhat similar to iron deficiency: chlorosis between the leaf veins. Light green net on the leaves. It can also be confused with magnesium deficiency. With a manganese deficiency, the leaf veins (including the smaller veins) remain green, but the green stripes remain very narrow.
    With a magnesium deficiency, these green stripes around the veins are wider and the finest leaf veins also turn yellow.
     
    The symptoms:  Distinct network of green veins. Sometimes occurs on young, but already fully developed leaves (middle leaves).
     
    Correction :  Add special manganese fertilizer. Increase fertilizer dosage.
     
     
    Molybdenum deficiency Mo
    The cause:  Too little or no fertilizer. Many symptoms of a molybdenum and nitrogen deficiency are similar. The plant cannot use and process nitrogen without molybdenum.
     
    The symptoms:  The plants are smaller and show a pale green color. The discoloration can develop into yellowing first on the edges and then between the main veins. The leaf disk disappears almost completely, only the main vein of the leaf remains with small pieces of leaf. This main vein is usually also wavy. (whipstick symptoms). The leaves remain smaller and sometimes take on a spoon-like shape: wavy edge and curved main vein.
     
    Correction :  Add special molybdenum fertilizer.
     
    Phosphorus deficiency P
     
    The cause:  The pH value may not be in the optimal range of 5.5 to 6.5. There may also be an imbalance of nutrients. Check the antagonist zinc dosage. In cold periods, a build-up of sugar in the leaves can show the same symptoms as a phosphorus deficiency.
     
    The symptoms:  stunted and spindle-shaped growth, reduced leaf size and reduced number of leaves. Dull grey-green leaves with red pigments in the leaves. The phosphorus deficiency is mainly evident in the characteristic reddish to purple leaf discolouration, first on older leaves, and often the leaf veins are also affected.
    General growth retardation. Poor root development. Smaller plants than usual.
     
    Detection:  pH control and dosage monitoring. Nutrient analysis.
     
    Correction : Correct the pH value of the nutrient solution. If necessary, reduce the zinc content in the nutrient solution.
     
    Note:  An excess of phosphorus can result in a deficiency of trace elements such as Zn, Fe or Co.
     
    Zinc deficiency Zn
     
    The cause: Possibly too high a phosphorus content in the nutrient solution or too little zinc in the nutrient solution.
     
    Symptoms: The  following symptoms may occur: Chlorosis: yellowing of the leaves. Depending on the species, young leaves may be the most affected, while in others both old and new leaves are chlorotic. Necrotic spots: partial or total death of leaf tissue in areas of chlorosis. Leaf bronzing: chlorotic areas may turn bronze. Retarded plant growth: this may occur as a result of a decrease in growth rate or a decrease in the internode (the length of the shoot between two nodes). Dwarf leaves: small leaves that often show chlorosis, necrotic spots or bronzing. Malformed leaves: leaves are often narrower or have wavy edges.
     
    Detection: Monitor media and/or perform plant analysis.
     
    Correction : Correct the pH value and/or the amount of phosphorus if you know that there is enough zinc in the nutrient solution. Otherwise, add zinc in small doses. Remember: copper and phosphate reduce the absorption of zinc!
    ID: 418
    URL
  • Foreword to Plants in Aquaponics & Hydroponics

    Everlasting Sweet Pea. Lathyrus latifolius. G. Weise s. 1858
    The selection of plants plays a central role in aquaponic and hydroponic systems. Typical plant species are fast-growing vegetables such as lettuce, herbs and tomatoes. These plants are particularly suitable due to their short growth cycles and high yields. Selecting the right plants can significantly increase the efficiency and productivity of the systems.
     
    Technical manageability
    The technical requirements of hydroponic and aquaponic systems vary depending on their size and complexity. Systems such as NFT (Nutrient Film Technique) and DWC (Deep Water Culture) are technically manageable and suitable for a wide range of plants. The use of automation and sensors makes the systems easier to manage and ensures optimal growth conditions.
     

    Selection of plants in aqua and hydroponic systems

    Plant selection is a critical factor in the success of aquaponic and hydroponic systems. Different plant species have different requirements and offer specific advantages and disadvantages. It is important to select plants that are a good fit with the technical conditions and the economic goals of the grower.
     
     

    General criteria for plant selection

     
    Growth rate
    advantages:
    Crops with fast growth cycles, such as lettuce and herbs, can be harvested more frequently, increasing productivity.

    Disadvantages:
    Fast-growing plants often require a constant supply of nutrients and stable environmental conditions.
     
     
    Nutrient Requirements
    Benefits:
    Plants with low nutrient requirements are easier and less expensive to care for because they require less fertilizer.

    Disadvantages:
    Crops with higher nutrient requirements, such as tomatoes and peppers, can produce higher yields, but they require more precise nutrient management.
     
     
    Yield
    Benefits:
    High-yielding crop species offer better profitability and can increase the economic success of a system.

    Disadvantages:
    High yields can be associated with higher production costs and more intensive care.
     
    Market demand
    advantages:
    Crops that are in high demand on the market, such as tomatoes, lettuce and basil, can fetch higher prices and increase sales.

    Disadvantages:
    Growing marketable crops may also place higher demands on quality and consistency due to high demand.
     

    Economic aspects in plant selection

    Initial investment:
    The cost of setting up a hydroponic or aquaponic system can vary depending on the types of plants you choose. Fast-growing, low-maintenance plants require a lower initial investment.
     
    Operating cost:
    Plants with low nutrient requirements and low maintenance reduce ongoing operating costs. On the other hand, plants with higher lighting and nutrient requirements can increase operating costs.
     
    Earning opportunities:
    Crops that provide high yields and consistent production offer a more stable source of income. Selecting marketable crops can further increase economic success.
     
     

    Technical manageability and cost

    Simple systems:
    Plants such as lettuce and herbs are well suited to simple hydroponic systems such as NFT (Nutrient Film Technique) and DWC (Deep Water Culture). These systems are inexpensive and less technically demanding.
     
    Complex systems:
    Crops with higher demands, such as tomatoes and peppers, require more advanced systems such as ebb-and-flow or Dutch bucket systems. These systems offer more precise control options, but are also more expensive to purchase and operate.
     

    automation

    The use of automation and sensors can simplify crop care and management by ensuring optimal growing conditions. This can reduce operating costs and increase efficiency.
     
    Finally
    Choosing the right plants is crucial to the success of aquaponic and hydroponic systems. Factors such as growth rate, nutrient requirements, yield and market demand should be carefully considered. Technical feasibility and cost also play an important role. By choosing plants wisely, the economic and environmental benefits can be maximized, making aquaponic and hydroponic systems a sustainable alternative to traditional agriculture.
     

    Literature and sources

     
    Books
    - Resh, Howard M. *Hydroponic Food Production: A Definitive Guidebook for the Advanced Home Gardener and the Commercial Hydroponic Grower.* CRC Press, 2012.
    - This book provides a comprehensive overview of the different hydroponic systems and their applications.
    - Somerville, Christopher, et al. *Small-scale Aquaponic Food Production: Integrated Fish and Plant Farming.* Food and Agriculture Organization of the United Nations, 2014.
    - A detailed guide to aquaponics with a focus on small systems and their implementation.
    - Jones, Jeff. *Aquaponics: The Essential Aquaponics Guide: A Step-By-Step Aquaponics Gardening Guide to Growing Vegetables, Fruit, Herbs, and Raising Fish.* CreateSpace Independent Publishing Platform, 2017.
    - Practical instructions for implementing aquaponics systems in the home.
     
    Articles and studies
    - Graber, Andreas, and Ralf Junge. "Aquaponic Systems: Nutrient Recycling from Fish Wastewater by Vegetable Production." *Desalination* 246.1-3 (2009): 147-156.
    - This study examines the efficiency of aquaponic systems in nutrient recycling.
    - Van Os, Erik A. "Closed Soilless Growing Systems: A Sustainable Solution for Dutch Greenhouse Horticulture." *Water Science and Technology* 39.5 (1999): 105-112.
    - The article highlights the advantages of closed hydroponic systems in Dutch greenhouse production.
     
    Websites
    - FAO (Food and Agriculture Organization of the United Nations): Aquaponics: http://www.fao.org/3/a-i4021e.pdf: This FAO publication provides a comprehensive introduction to aquaponics and its applications.
    - University of Arizona - Controlled Environment Agriculture Center: Hydroponic: Lettuce Handbook: https://cals.arizona.edu/ceac/sites/cals.arizona.edu.ceac/files/hydroponic-lettuce-handbook.pdf
    - A practical handbook for growing lettuce in hydroponic systems published by the University of Arizona. These sources provide in-depth information on the origins, technology, ecological and economic aspects of aqua and hydroponic systems.

    Context: 
    ID: 586
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