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{{merge to|Aquaponics|date=May 2024}}
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[[File:Iavs schematic diagram.png|thumb|right|iAVs Schematic Diagram]]
[[File:Iavs schematic diagram.png|thumb|right|iAVs Schematic Diagram]]
The '''Integrated Aqua-Vegeculture System''' (iAVs),also informally known as Sandponics, is a food production method that combines [[aquaculture]] and [[horticulture]] ([[olericulture]]) within a closed system.{{Citation needed|date=July 2024}} It was developed in the 1980s by Dr. Mark McMurtry and colleagues at [[North Carolina State University]] including Professor Doug Sanders, Paul V. Nelson and [[The Land (Epcot)#Contributions of Merle Jensen|Dr. Merle Jensen]]. This system is one of the earliest instances of a closed-loop [[Aquaponics|aquaponic]] system.<ref name=":0">{{Cite journal |last1=Okomoda |first1=Victor Tosin |last2=Oladimeji |first2=Sunday Abraham |last3=Solomon |first3=Shola Gabriel |last4=Olufeagba |first4=Samuel Olabode |last5=Ogah |first5=Samuel Ijabo |last6=Ikhwanuddin |first6=Mhd |date=2022-12-18 |title=Aquaponics production system: A review of historical perspective, opportunities, and challenges of its adoption |journal=Food Science & Nutrition |volume=11 |issue=3 |pages=1157–1165 |doi=10.1002/fsn3.3154 |issn=2048-7177 |pmid=36911833|pmc=10002891 }}</ref>
The '''Integrated Aqua-Vegeculture System''' (iAVs),also informally known as Sandponics,<ref name=":5">{{Cite journal |last1=Sewilam |first1=Hani |last2=Kimera |first2=Fahad |last3=Nasr |first3=Peter |last4=Dawood |first4=Mahmoud |date=2022-06-30 |title=A sandponics comparative study investigating different sand media based integrated aqua vegeculture systems using desalinated water |journal=Scientific Reports |language=en |volume=12 |issue=1 |pages=11093 |bibcode=2022NatSR..1211093S |doi=10.1038/s41598-022-15291-7 |issn=2045-2322 |pmc=9247079 |pmid=35773314}}</ref> is a food production method that combines [[aquaculture]] and [[horticulture]] ([[olericulture]]).<ref name=":3" /> It was developed in the 1980s by Dr. Mark McMurtry and colleagues at [[North Carolina State University]] including Professor Doug Sanders, Paul V. Nelson and [[The Land (Epcot)#Contributions of Merle Jensen|Dr. Merle Jensen]]. This system is one of the earliest instances of a closed-loop [[Aquaponics|aquaponic]] system.<ref name=":0">{{Cite journal |last1=Okomoda |first1=Victor Tosin |last2=Oladimeji |first2=Sunday Abraham |last3=Solomon |first3=Shola Gabriel |last4=Olufeagba |first4=Samuel Olabode |last5=Ogah |first5=Samuel Ijabo |last6=Ikhwanuddin |first6=Mhd |date=2022-12-18 |title=Aquaponics production system: A review of historical perspective, opportunities, and challenges of its adoption |journal=Food Science & Nutrition |volume=11 |issue=3 |pages=1157–1165 |doi=10.1002/fsn3.3154 |issn=2048-7177 |pmid=36911833|pmc=10002891 }}</ref>


Many of the modern developments and discoveries of aquaponics are generally attributed to the [[New Alchemy Institute]] and North Carolina State University.<ref name=":0" /> Further research on aquaponics at North Carolina State University was discontinued due to the fact that the system was ready for commercial application.<ref>{{Cite thesis |title=Aquaponics : community and economic development |url=https://dspace.mit.edu/handle/1721.1/67227 |publisher=Massachusetts Institute of Technology |date=2011 |degree=Thesis |first=Elisha R. (Elisha Renee) |last=Goodman|hdl=1721.1/67227 }}</ref> Today's flood-and-drain systems, as favoured by backyard practitioners, are derived from this model.<ref>{{Cite web |last=Aqu@teach |date=2020-09-03 |title=History of aquaponics |url=https://learn.farmhub.ag/resources/aquateach/1-aquaponic-technology/history-of-aquaponics/ |access-date=2024-05-05 |website=learn.farmhub.ag |language=en}}</ref>
Many of the modern developments and discoveries of aquaponics are generally attributed to the [[New Alchemy Institute]] and North Carolina State University.<ref name=":0" /> Further research on aquaponics at North Carolina State University was discontinued due to the fact that the system was ready for commercial application.<ref>{{Cite thesis |title=Aquaponics : community and economic development |url=https://dspace.mit.edu/handle/1721.1/67227 |publisher=Massachusetts Institute of Technology |date=2011 |degree=Thesis |first=Elisha R. (Elisha Renee) |last=Goodman|hdl=1721.1/67227 }}</ref> Today's flood-and-drain systems, as favoured by backyard practitioners, are derived from this model.<ref>{{Cite web |last=Aqu@teach |date=2020-09-03 |title=History of aquaponics |url=https://learn.farmhub.ag/resources/aquateach/1-aquaponic-technology/history-of-aquaponics/ |access-date=2024-05-05 |website=learn.farmhub.ag |language=en}}</ref>

Before the Integrated AquaVegeculture System, other systems that combined fish and vegetable farming used special tanks called clarifiers to remove solid waste from the water before it was given to the plants. While this process cleaned the water, it also took away important nutrients that plants need to grow well. As a result, these systems often had to add extra supplements to make up for the missing nutrients. iAVs is different because it uses sand to filter the water, which keeps the essential nutrients in the system. This means the plants get all the natural nutrients they need without needing extra supplements.<ref name=":3">{{Cite web |title=Food Value, Water Use Efficiency, and Economic Productivity of an Integrated Aquaculture-Olericulture System as Influenced by Tank to Biofilter Ratio – iAVs (Sandponics) |url=https://iavs.info/food-value-water-use-efficiency-and-economic-productivity-of-an-integrated-aquaculture-olericulture-system-as-influenced-by-tank-to-biofilter-ratio/ |access-date=2024-07-27 |language=en-AU}}</ref>
[[File:IAVs_research_day_1.png|left|thumb|Tomato transplants in a biofilter (composed of sand, bacteria and plants) shown being irrigated with aquacultural water for the first time.]]
[[File:IAVs_research_day_1.png|left|thumb|Tomato transplants in a biofilter (composed of sand, bacteria and plants) shown being irrigated with aquacultural water for the first time.]]


One benefit is the production of high quality food products in close proximity to center of need, and reduction of operating costs.{{Citation needed|date=July 2024}}
One benefit is the production of high quality food products in close proximity to center of need, and reduction of operating costs.{{Citation needed|date=July 2024}}


In an iAVs, fish are raised in tanks, and the nutrient-rich water from these tanks is used to irrigate and fertilize grow beds filled with plants that take up the nutrients, purifying the water, which is then recirculated back to the fish tanks. The system uses sand-based grow beds to perform multiple functions, including plant support, [[Filtration#Biological filtration|biofiltration]], particulate removal, and nutrient delivery to plants, without the need for separate biofilters.{{Citation needed|date=July 2024}} This multi-functional use of sand beds contributes to the relative simplicity of the iAVs design compared to other aquaponic systems.
In an iAVs, fish are raised in tanks, and their nutrient-rich water irrigates and fertilizes sand-based grow beds that support plant growth, act as [[Biofilter|biofilters]], and deliver nutrients. As plants and [[Microbiota|micro-flora]] absorb these nutrients, they purify the water, which is recirculated back to the fish tanks.


The system often includes an [[aeration]] device, such as an aerating cascade, to [[oxygenate]] the water before it returns to the fish tanks. This multi-functional use of sand beds contributes to the relative simplicity of the iAVs design compared to other aquaponic systems.<ref name=":1" />
IAVS is also informally referred to as 'Sandponics'{{Citation needed|date=July 2024}} which is actually a trademark for Agricultural cultivating equipment that is unlike IAVS.<ref>{{Cite web |title=SANDPONICS Trademark of Sumitomo Electric Industries, Ltd. - Registration Number 5409239 - Serial Number 87279671 :: Justia Trademarks |url=http://trademarks.justia.com/872/79/sandponics-87279671.html |access-date=2024-05-06 |website=trademarks.justia.com |language=en}}</ref>

IAVS is also informally referred to as 'Sandponics'<ref name=":5" /> which is actually a trademark for Agricultural cultivating equipment that is unlike IAVS.<ref>{{Cite web |title=SANDPONICS Trademark of Sumitomo Electric Industries, Ltd. - Registration Number 5409239 - Serial Number 87279671 :: Justia Trademarks |url=http://trademarks.justia.com/872/79/sandponics-87279671.html |access-date=2024-05-06 |website=trademarks.justia.com |language=en}}</ref>


== History ==
== History ==


=== Development and Early Research ===
=== Development and Early Research ===
Dr. Mark McMurtry, along with Professor Doug Sanders, Paul V. Nelson, and Merle Jensen, pioneered the iAVs at North Carolina State University. The system was designed to address issues such as soil infertility, pollution, and water scarcity, which Dr. McMurtry observed during his time in Africa. The initial research aimed to create a sustainable and efficient method for producing nutrient-rich food while conserving water.{{Citation needed|date=July 2024}}
Dr. Mark McMurtry, along with Professor Doug Sanders, Paul V. Nelson, and Merle Jensen, pioneered the iAVs at North Carolina State University. The system was designed to address issues such as soil infertility, pollution, and water scarcity,<ref name=":0" /> which Dr. McMurtry observed during his time in Africa. The initial research aimed to create a sustainable and efficient method for producing nutrient-rich food while conserving water.{{Citation needed|date=July 2024}}
[[File:Iavs research week 1.png|thumb|View of the research greenhouse approximately one week after transplant of tomato crop. The tanks are below the wood-grate walkway]]
[[File:Iavs research week 1.png|thumb|View of the research greenhouse approximately one week after transplant of tomato crop. The tanks are below the wood-grate walkway]]


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* Dr. Edward A. Estes, an expert in Agricultural and Aquacultural Economics, provided insights into the economic viability and sustainability of the system.
* Dr. Edward A. Estes, an expert in Agricultural and Aquacultural Economics, provided insights into the economic viability and sustainability of the system.
* Dr. Blanche C. Haning specialized in Integrated Pest Management and Plant Pathology, ensuring the health and productivity of the plants within the system.
* Dr. Blanche C. Haning specialized in [[Integrated pest management|Integrated Pest Management]] and Plant Pathology, ensuring the health and productivity of the plants within the system.
*Dr. Ronald G. Hodson brought expertise in Aquatic Ecosystems, Fisheries Management, and Genetics, which was crucial for the aquaculture component of iAVs.
*Dr. Ronald G. Hodson brought expertise in Aquatic Ecosystems, Fisheries Management, and Genetics, which was crucial for the aquaculture component of iAVs.
* Dr. Paul V. Nelson, a Fellow of the American Society for Horticultural Science (FASHS), focused on Botanical Mineral Nutrition and Greenhouse Management, optimizing plant growth conditions.<ref>{{Cite web |title=Paul Nelson |url=https://cals.ncsu.edu/horticultural-science/people/pvnelson/ |access-date=2024-07-03 |website=Horticultural Science |language=en-US}}</ref>
* Dr. Paul V. Nelson, a Fellow of the [[American Society for Horticultural Science]] (FASHS), focused on Botanical Mineral Nutrition and Greenhouse Management, optimizing plant growth conditions.<ref>{{Cite web |title=Paul Nelson |url=https://cals.ncsu.edu/horticultural-science/people/pvnelson/ |access-date=2024-07-03 |website=Horticultural Science |language=en-US}}</ref>
* Dr. Robert P. Patterson, a Fellow of the Crop Science Society of America (FCSSA), contributed his knowledge in Agronomy, Soil Fertility, and Plant Physiology.<ref>{{Cite web |date=2017-03-19 |title=Bob Patterson {{!}} Crop and Soil Sciences {{!}} NC State University |url=https://cals.ncsu.edu/crop-and-soil-sciences/people/rpatters/ |access-date=2024-07-03 |language=en}}</ref>
* Dr. Robert P. Patterson, a Fellow of the [[Crop Science Society of America]] (FCSSA), contributed his knowledge in [[Agronomy]], Soil Fertility, and Plant Physiology.<ref>{{Cite web |date=2017-03-19 |title=Bob Patterson {{!}} Crop and Soil Sciences {{!}} NC State University |url=https://cals.ncsu.edu/crop-and-soil-sciences/people/rpatters/ |access-date=2024-07-03 |language=en}}</ref>
*Dr. Douglas C. Sanders, also a FASHS Fellow, provided expertise in Horticultural Science and Plant Physiology.
*Dr. Douglas C. Sanders, also a FASHS Fellow, provided expertise in Horticultural Science and [[Plant physiology|Plant Physiology]].


Additionally, several principal consultants offered their specialized knowledge to enhance the system:
Additionally, several principal consultants offered their specialized knowledge to enhance the system:


* Dr. J. Lawrence Apple in International Development and Plant Pathology.
* Dr. J. Lawrence Apple in International Development and Plant Pathology.
* Dr. Marc A. Buchanan in Agricultural Ecology and Soil Science.
* Dr. Marc A. Buchanan in Agricultural [[Ecology]] and [[Soil science|Soil Science]].
* Dr. Stanley W. Buol in Geomorphology, Mineralogy, and Soil Genesis.
* Dr. Stanley W. Buol in [[Geomorphology]], [[Mineralogy]], and Soil Genesis.
* Dr. JoAnn Burkholder, a Fellow of the American Association for the Advancement of Science (FAAAS), in Phycology and Aquatic Ecology.
* Dr. JoAnn Burkholder, a Fellow of the [[American Association for the Advancement of Science]] (FAAAS), in [[Phycology]] and [[Aquatic ecosystem|Aquatic Ecology]].
* Dr. James E. Easley in Aquacultural Economics and Business.
* Dr. James E. Easley in Aquacultural Economics and Business.
* Dr. Donald Huisingh in Ecology and Environmental Resource Recovery.
* Dr. Donald Huisingh in Ecology and Environmental Resource Recovery.
* Dr. Merle H. Jensen in Agricultural Program Development at the University of Arizona's Environmental Research Laboratory (UAZ ERL).<ref>{{Cite web |title=Merle Jensen {{!}} Controlled Environment Agriculture Center |url=https://ceac.arizona.edu/person/merle-jensen |access-date=2024-07-03 |website=ceac.arizona.edu |language=en}}</ref>
* Dr. Merle H. Jensen in Agricultural Program Development at the [[University of Arizona]]'s Environmental Research Laboratory (UAZ ERL).<ref>{{Cite web |title=Merle Jensen {{!}} Controlled Environment Agriculture Center |url=https://ceac.arizona.edu/person/merle-jensen |access-date=2024-07-03 |website=ceac.arizona.edu |language=en}}</ref>
* Dr. Thomas Losordo in Recirculatory Aquaculture.<ref>{{Cite web |date=2017-01-17 |title=Thomas Losordo |url=https://bae.ncsu.edu/people/tlosordo/ |access-date=2024-07-03 |website=Department of Biological and Agricultural Engineering |language=en-US}}</ref>
* Dr. Thomas Losordo in Recirculatory Aquaculture.<ref>{{Cite web |date=2017-01-17 |title=Thomas Losordo |url=https://bae.ncsu.edu/people/tlosordo/ |access-date=2024-07-03 |website=Department of Biological and Agricultural Engineering |language=en-US}}</ref>
* Dr. L. George Wilson, a FASHS Fellow, in Horticultural Science and Extension.<ref>{{Cite web |title=George Wilson |url=https://cals.ncsu.edu/horticultural-science/people/lgw/ |access-date=2024-07-03 |website=Horticultural Science |language=en-US}}</ref>
* Dr. L. George Wilson, a FASHS Fellow, in Horticultural Science and Extension.<ref>{{Cite web |title=George Wilson |url=https://cals.ncsu.edu/horticultural-science/people/lgw/ |access-date=2024-07-03 |website=Horticultural Science |language=en-US}}</ref>


=== Commercial Application and Modern Developments ===
=== Commercial Application and Modern Developments ===
Further research on aquaponics at North Carolina State University was discontinued once the system was deemed ready for commercial application.{{Citation needed|date=July 2018}}
Further research on aquaponics at North Carolina State University was discontinued once the system was deemed ready for commercial application.<ref name=":3">{{Cite journal |last=Diver |first=Steve |date=2006 |title=Aquaponics—Integration of Hydroponics with Aquaculture |url=https://d1wqtxts1xzle7.cloudfront.net/54584884/aquaponic-libre.pdf?1506790891=&response-content-disposition=inline%3B+filename%3DA_Publication_of_ATTRA_National_Sustaina.pdf&Expires=1719991861&Signature=YbVYaH7sKDnxRSYWZmdKK~czpzEkzGBsEEjMxyVYWFgd~V0lDKujIjU4RjuLNYg~-nSZFM3e72cQ~tQgIrab9l8g5EffdCAlFWU0wFjDcm5KCjhCCVqt0NOARUpIXhFWLZnqdKWWTh8UgLj1RyEONqARU0jKQ00l8b2qZhOve5GSN4KMVgEi~HTxvJjPbXKdYQbvtUxlN4CQPq8Qm3EzZqJmyeC2JUsqFL60IK9ljdZgwvJCQ2QIjFgVdYHCQNUV7V8sJVo1sgHBXJutDZvmZ4NrmxQpjcyJxzu8008UkhBOaD8kMPo-cYr~R0C94A5pVze8bUuD6jPQ9jKiLKL4tQ__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA |journal=National Sustainable Agriculture Information Service}}</ref>

[[File:Iavs research 4 weeks.png|thumb|Tomato crop after 4 weeks of growth in the biofilter. Flowering has started.]]
=== Open Source ===
Dr. McMurtry is the Inventor of Record of iAVs,<ref>{{Cite web |title=Profile |url=https://www.researchgate.net/profile/Mark-Mcmurtry |website=Research-Gate}}</ref> and made it open source in 1985.<ref name=":1" />

=== Global Outreach ===
Following the completion of his PhD, Dr. McMurtry assumed the position of Research Associate with the International Programs at North Carolina State University. Between 1989 and 1994, he undertook extensive travel across sub-Saharan Africa and the Middle East, collaborating with local universities, international aid organizations, and agricultural professionals to showcase the advantages of integrated agricultural practices.<ref name=":2">{{Cite web |title=Aquaponics' Biggest Mistake – iAVs (Sandponics) |url=https://iavs.info/aquaponics-biggest-mistake/ |access-date=2024-07-27 |language=en-AU}}</ref>

=== Modification and Commercialization ===
Following the completion of his PhD dissertation at North Carolina State University in December 1989, Mark R. McMurtry embarked on a series of trips to demonstrate the benefits of the Integrated Aqua-Vegeculture System (iAVs) to faculty, students, and aquaculture industry professionals. One notable event was a 3-day interactive workshop at the Meadowcreek Project in Fox, Arkansas, attended by Tom and Paula Speraneo.

In the early 1990s, Tom and Paula Speraneo, owners of S & S AquaFarm in Missouri, adapted the iAVs design by replacing sand with gravel and using above-ground tanks for fish. This modified system, known as "Speraneo Systems," employed bell siphons to facilitate an ebb-and-flow irrigation cycle, popularizing what is commonly termed flood and drain aquaponics.In 2005, Joel Malcolm purchased the Speraneo’s information kit and adapted it for use in Australia. The [[Australian Broadcasting Corporation]]'s Gardening TV program featured Malcolm's home-based system, leading to a renewed interest in the basic flood and drain system.

The introduction of gravel in aquaponics brought about several significant changes. It reduced mechanical filtration capability, decreased populations and activity of soil organisms, and lowered aeration in the media bacteria and plant root zone. Additionally, it diminished nutrient utilization and system stability, leading to reduced fish survival, feed rate, and growth. These changes also resulted in increased capital costs with lower fish and plant yields, as well as higher operating costs per unit of production.<ref name=":2" />

== Operation ==
Operating an Integrated Aqua-Vegeculture System (iAVs) requires managerial skills developed through experience. The system is user-friendly and resilient to changes in water chemistry, allowing for minor errors. Prior experience in gardening or husbandry is advantageous.

First-time operators should receive minimal training in aquaculture management, pest prevention, and water quality monitoring. While experienced operators may make occasional errors, regular monitoring facilitates correction.

The startup phase is the most sensitive for balancing the iAVs, but once stabilized, the system becomes easier to maintain at optimal production levels.

Throughout the day, a portion of the water from the fish tank, along with the accumulated residues from the tank's bottom, is either scooped or pumped onto the surface of the filter and plant bed. This nutrient-rich water percolates through the sand of the filter bed, where larger waste particles are filtered out at the surface. Meanwhile, smaller particles and dissolved nutrients are absorbed by the roots of the plants and by the various microorganisms present in the filter bed.

This filtration and irrigation process occurs at regular intervals during daylight hours, potentially as many as eight times each day. The primary operational objective is to ensure that the total volume of the fish tank is incrementally and cumulatively circulated through the filter bed at least once each day.

Once an iAVs is established, the primary inputs required are fingerlings, seeds or transplants, fish feed, and an energy source to facilitate water movement.<ref name=":1" />

=== Aeration ===
The fish tank and filter bed are positioned vertically to ensure adequate elevation change between the drainage outlet of the filter bed and the water surface level in the fish tank, facilitating the installation of a cascade aerator.

The cascade, consisting of a series of small waterfalls, is intentionally designed to disperse the water flow into smaller droplets, promoting efficient mixing of air (oxygen) with the water as it descends back into the tank by gravity.<ref name=":1" />

=== Intermittent Irrigation ===
Irrigation water is pumped from the bottom of the fish tanks eight times daily and delivered to the biofilter (growbed) surfaces, with no irrigation at night.<ref name=":3" /> The water floods the biofilter surfaces, percolates through the medium, and drains back to the fish tank. The tank water level drops approximately 25 cm during each irrigation event. Therefore, the returning water provided additional aeration resulting from the effect of the cascade.{{Citation needed|date=July 2024}}

=== Energy usage ===
IAVs only requires 2 hours of water pumping per day and is suitable for off grid applications.{{Citation needed|date=July 2024}}

=== pH stabilization ===
In traditional recirculatory aquaculture, carbonate inputs are typically used to neutralize the acidification caused by [[nitrification]]. However, research has shown that [[Soil conditioner|alkaline amendments]] are unnecessary when the nitrogen input rate closely matches the nitrogen assimilation rates of plants. In the Integrated AquaVegeculture System (iAVs) research, water [[pH]] remained stable at approximately 6.0 when fish feed rates were balanced with plant nitrogen assimilation rates, avoiding excessive feed inputs.{{Citation needed|date=July 2024}}

The plant availability of both ammonium and nitrate ions helps to buffer the pH of the nutrient solution.{{Citation needed|date=July 2024}}

To see if plants help keep the water pH stable in the iAVs system, an experiment was done. For 42 days, they continued watering the system and feeding the fish, but no plants were grown in the biofilters. This was to check if plants were helping to keep the water pH stable. Without the plants, the water pH quickly dropped below 4.0.<ref name=":3" />

=== Nutrients ===
Plant growth in the Integrated Aqua-Vegeculture System (iAVs) is sustained despite minimal nutrient levels in the recirculating water and the absence of supplemental fertilization, due to the system's constant replenishment characteristics.{{Citation needed|date=July 2024}}

=== Water Use ===
Research from iAVs published in 1990 showed that the amount of water used was about 1% of what is needed in a similar pond culture system.<ref name=":6">{{Citation |last=Lennard |first=Wilson |title=Aquaponics: The Basics |date=2019 |work=Aquaponics Food Production Systems: Combined Aquaculture and Hydroponic Production Technologies for the Future |pages=113–143 |editor-last=Goddek |editor-first=Simon |url=https://link.springer.com/chapter/10.1007/978-3-030-15943-6_5 |access-date=2024-09-03 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-15943-6_5 |isbn=978-3-030-15943-6 |last2=Goddek |first2=Simon |editor2-last=Joyce |editor2-first=Alyssa |editor3-last=Kotzen |editor3-first=Benz |editor4-last=Burnell |editor4-first=Gavin M.}}</ref>[[File:Iavs research 4 weeks.png|thumb|Tomato crop after 4 weeks of growth in the biofilter. Flowering has started.]]


== System Components ==
== System Components ==
The Integrated Aquaculture System (iAVs) consists of a sealed containment structure designed to house the fish and to prevent the leakage of water, along with a sand filter bed designated for the growth of vegetable crops, and a water distribution system.
The primary components of an iAVs include the fish tank, water distribution system, and the plant growing area which doubles as a sand biofilter. The three live components are plants, fish and bacteria.

The three live components are plants, fish and bacteria.


=== Fish tanks ===
=== Fish tanks ===
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* Nutrient delivery to plants
* Nutrient delivery to plants
=== Water circulation device ===
=== Water circulation device ===
Fish tank water and sediment are regularly removed and applied to the plant bed. The tank has a sloped base for easy waste extraction using a bucket or calabash. Enhanced circulation is possible with mechanical pumps powered by human or animal effort, or electric pumps with automated timers.<ref name=":1" />
Either a pump or manual method is required to circulate the water.
[[File:Iavs research greenhouse photo at 18 weeks.png|thumb|Tomato vines after 18 weeks (note: all fruit has been harvested)]]
[[File:Iavs research greenhouse photo at 18 weeks.png|thumb|Tomato vines after 18 weeks (note: all fruit has been harvested)]]


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The sand used in the Integrated Aqua-Vegeculture System (iAVs) is critical to avoiding clogging and ensuring efficient filtration and rapid drainage. The ideal sand composition is 99.25% quartz sand, 0.75% clay, and 0.0% silt.{{Citation needed|date=July 2024}}
The sand used in the Integrated Aqua-Vegeculture System (iAVs) is critical to avoiding clogging and ensuring efficient filtration and rapid drainage. The ideal sand composition is 99.25% quartz sand, 0.75% clay, and 0.0% silt.{{Citation needed|date=July 2024}}


The criteria for selecting sand involved evaluating its water retention capacity through percolation tests, assessing its turbidity, and examining its drainage capabilities. The sand must be free of carbonates, heavy metals, and salts, and it should be inert.<ref name=":5" />
The sand should be free from carbonates, heavy metals, and salts. The sand should be inert.<ref name=":5">{{Cite journal |last1=Sewilam |first1=Hani |last2=Kimera |first2=Fahad |last3=Nasr |first3=Peter |last4=Dawood |first4=Mahmoud |date=2022-06-30 |title=A sandponics comparative study investigating different sand media based integrated aqua vegeculture systems using desalinated water |journal=Scientific Reports |language=en |volume=12 |issue=1 |pages=11093 |bibcode=2022NatSR..1211093S |doi=10.1038/s41598-022-15291-7 |issn=2045-2322 |pmc=9247079 |pmid=35773314}}</ref>


The primary functional requirement for sand in a sand bio-filter is that the entire filter or plant bed must drain completely and efficiently. This requirement is crucial to prevent over-saturation of plants. Therefore, the sand should have a relatively coarse texture with minimal fines content, specifically no particles smaller than 200 microns in diameter.
== Horticultural subsystem ==
In the Integrated AquaVegeculture System (iAVs), plants are grown in a [[horticulture]] subsystem where their roots are embedded in sand. This sand acts as a filtration medium, allowing the plants to absorb the nutrient-rich effluent water from the aquaculture subsystem. The plants effectively filter out [[ammonia]] and its metabolites, which are toxic to the aquatic animals. After the water has passed through the horticulture subsystem, it is cleaned and oxygenated, making it suitable to return to the aquaculture vessels. It uses a method of intermittent irrigation, flooding the furrows of the beds every 2 hours, during the day, until the sand is saturated. There is no irrigation at night,{{Citation needed|date=July 2024}}


The optimal filter sand should have a consistency similar to that of common table salt or granulated sugar, without any powdery constituents. Larger particles can be screened out if necessary. Generally, it is relatively straightforward to source an appropriate grade of sand.<ref name=":1" />
The sand is shaped into [[furrows]] and ridges. [[Surface irrigation]], or furrow irrigation, is used to evenly distribute water throughout the grow beds. The plants are grown in raised sections of the sand which ensures the crown of the plants are kept dry.{{Citation needed|date=July 2024}}


== Operation ==
== Live Components ==
The five main inputs to the system are water, oxygen, light, feed given to the aquatic animals, and electricity (or alternative or manual energy) to pump and oxygenate the water.


=== Intermittent Irrigation ===
=== Plants ===
A broad array of vegetable crops may be cultivated in various combinations, which include tomatoes, cucumbers, melons, eggplants, peppers, beans, lettuce, assorted greens, and herbs; additionally, tree seedlings for reforestation projects may also be included.<ref name=":1">{{Cite web |title=THE AQUA-VEGECULTURE SYSTEM – iAVs (Sandponics) |url=https://iavs.info/the-aqua-vegeculture-system/ |access-date=2024-07-26 |language=en-AU}}</ref>
Irrigation water is pumped from the bottom of the fish tanks eight times daily and delivered to the biofilter (growbed) surfaces. The water floods the biofilter surfaces, percolates through the medium, and drains back to the fish tank. The tank water level drops approximately 25 cm during each irrigation event. Therefore, the returning water provided additional aeration resulting from the effect of the cascade.{{Citation needed|date=July 2024}}


=== Energy usage ===
=== Algae ===
Before the establishment and rapid growth of vegetable crops, the filter surface frequently becomes completely covered in algae.
IAVs only requires 2 hours of water pumping per day and is suitable for off grid applications.{{Citation needed|date=July 2024}}


Together, the bacteria and algae (collectively referred to as micro-flora) play a crucial role in the chemical transformation of fish waste products into nutrients that are available for plant uptake. During the initial start-up phase, they also serve as a nutrient sink or buffer until the vegetable plants reach growth rates that allow them to effectively purify the water themselves. As the plants grow larger, they increasingly absorb a greater percentage of the available nutrients from the water and begin to shade the surface of the plant bed.
=== pH stabilization ===
In traditional recirculatory aquaculture, carbonate inputs are typically used to neutralize the acidification caused by [[nitrification]]. However, research has shown that [[Soil conditioner|alkaline amendments]] are unnecessary when the nitrogen input rate closely matches the nitrogen assimilation rates of plants. In the Integrated AquaVegeculture System (iAVs) research, water [[pH]] remained stable at approximately 6.0 when fish feed rates were balanced with plant nitrogen assimilation rates, avoiding excessive feed inputs.{{Citation needed|date=July 2024}}


This shading effect leads to a noticeable decline in algal populations, which subsequently releases the accumulated nutrients for absorption by the vegetable crops.<ref name=":1" />
The plant availability of both ammonium and nitrate ions helps to buffer the pH of the nutrient solution.{{Citation needed|date=July 2024}}


In the iAVs research, tilapia ate the algae that grew in the water and on the sides of the tank.<ref name=":3" />
=== Nutrients ===

Plant growth in the Integrated Aqua-Vegeculture System (iAVs) is sustained despite minimal nutrient levels in the recirculating water and the absence of supplemental fertilization, due to the system's constant replenishment characteristics.{{Citation needed|date=July 2024}}
== Horticultural subsystem ==
The upper surface of the plant/filter bed is prepared to a level grade and designed to accommodate the specific vegetable crops or species to be cultivated. Irrigation furrows are created between the rows of plants to promote the uniform distribution of irrigation water across the surface and through the volume of the filter bed.<ref name=":1" /> The plants are grown in raised sections of the sand which ensures the crown of the plants are kept dry.{{Citation needed|date=July 2024}}

In the Integrated Aqua Vegeculture System (iAVs), plants are grown in a [[horticulture]] subsystem where their roots are embedded in sand. This sand acts as a filtration medium, allowing the plants to absorb the nutrient-rich effluent water from the aquaculture subsystem. The plants effectively filter out [[ammonia]] and its metabolites, which are toxic to the aquatic animals. After the water has passed through the horticulture subsystem, it is cleaned and oxygenated, making it suitable to return to the aquaculture vessels. It uses a method of intermittent irrigation, flooding the furrows of the beds every 2 hours, during the day, until the sand is saturated. There is no irrigation at night,{{Citation needed|date=July 2024}}


== Comparison with other systems ==
== Comparison with other systems ==
Previous integrated fish-vegetable systems removed suspended solids from the water by [[sedimentation]] in clarifiers prior to plant application..{{Citation needed|date=July 2024}} Removal of the solid wastes resulted in insufficient residual nutrients for good plant growth; acceptable fruit yields had previously only been achieved with substantial supplementation of plant nutrients.<ref name=":3" />
Previous integrated fish-vegetable systems removed suspended solids from the water by [[sedimentation]] in clarifiers prior to plant application..{{Citation needed|date=July 2024}} Removal of the solid wastes resulted in insufficient residual nutrients for good plant growth; acceptable fruit yields had previously only been achieved with substantial supplementation of plant nutrients.{{Citation needed|date=July 2018}}


In contrast, iAVs extracts fish effluent, including solids, from the bottom of the fish tanks at regular intervals, up to eight times daily, from dawn to sunset..{{Citation needed|date=July 2024}} The effluent is pumped directly from the bottom of the fish tank onto the surface of the sand bed, which serve as both biological and mechanical filtration and the locus for oxidation of organic solids.{{Citation needed|date=July 2024}}
In contrast, iAVs extracts fish effluent, including solids, from the bottom of the fish tanks at regular intervals, up to eight times daily, from dawn to sunset..{{Citation needed|date=July 2024}} The effluent is pumped directly from the bottom of the fish tank onto the surface of the sand bed, which serve as both biological and mechanical filtration and the locus for oxidation of organic solids.{{Citation needed|date=July 2024}}

Traditional aquaponics systems are often complex, requiring expertise in multiple disciplines such as environmental, mechanical, and civil engineering, as well as aquatic and plant biology, biochemistry, and biotechnology. Additionally, managing these systems involves understanding computer science for automatic control technologies, and expertise in economics, finance, and marketing for commercial viability. This complexity demands a high level of theoretical and practical knowledge, which can pose significant challenges to efficiency.<ref name=":4">{{Cite journal |last1=Goddek |first1=Simon |last2=Delaide |first2=Boris |last3=Mankasingh |first3=Utra |last4=Ragnarsdottir |first4=Kristin Vala |last5=Jijakli |first5=Haissam |last6=Thorarinsdottir |first6=Ragnheidur |date=April 2015 |title=Challenges of Sustainable and Commercial Aquaponics |journal=Sustainability |language=en |volume=7 |issue=4 |pages=4199–4224 |doi=10.3390/su7044199 |doi-access=free |issn=2071-1050}}</ref> In contrast, the Integrated Aqua-Vegeculture System (iAVs) is intentionally designed to simplify the process. iAVs minimizes the technical complexities, making it easier to construct and operate. This approach significantly reduces the level of technical knowledge needed, thereby alleviating many of the perceived challenges associated with traditional aquaponics.


=== DWC ===
=== DWC ===
In a comparative trial with [[Deep water culture|Deep Water Culture]] (DWC), the economic feasibility analysis indicated that the Integrated Aqua-Vegeculture System (iAVs) produced more crops with a wider variety at almost 20% less capital expenditure and operational expenditure costs. Sand beds are able to grow a greater variety of plants than the DWC system.<ref name=":6">{{Cite journal |last1=El-Essawy |first1=Hisham |last2=Nasr |first2=Peter |last3=Sewilam |first3=Hani |date=2019-06-01 |title=Aquaponics: a sustainable alternative to conventional agriculture in Egypt – a pilot scale investigation |url=https://doi.org/10.1007/s11356-019-04970-0 |journal=Environmental Science and Pollution Research |language=en |volume=26 |issue=16 |pages=15872–15883 |bibcode=2019ESPR...2615872E |doi=10.1007/s11356-019-04970-0 |issn=1614-7499 |pmid=30955197}}</ref>
In a comparative trial with [[Deep water culture|Deep Water Culture]] (DWC), the economic feasibility analysis indicated that the Integrated Aqua-Vegeculture System (iAVs) produced more crops with a wider variety at almost 20% less capital expenditure and operational expenditure costs. Sand beds are able to grow a greater variety of plants than the DWC system.{{Citation needed|date=July 2024}}


In Deep Water Culture (DWC) systems, iron supplementation is typically required. In contrast, the Integrated AquaVegeculture System (iAVs) exhibits a significant increase in iron levels within the system and the crops without the need for external supplementation. This characteristic is considered one of the primary advantages of iAVs, as it eliminates the necessity for additional nutrient supplements.<ref name=":6" />
In Deep Water Culture (DWC) systems, iron supplementation is typically required. In contrast, the Integrated AquaVegeculture System (iAVs) exhibits a significant increase in iron levels within the system and the crops without the need for external supplementation. This characteristic is considered one of the primary advantages of iAVs, as it eliminates the necessity for additional nutrient supplements.{{Citation needed|date=July 2024}}


=== Innovations in Filtration ===
=== Innovations in Filtration ===
IAVS does not need any mechanical filters as the filtration is performed by the sand.<ref name=":6" />
IAVS does not need any mechanical filters as the filtration is performed by the sand.{{Citation needed|date=July 2024}}


In earlier aquaponic systems, the media often became clogged or resulted in uneven fertigation, which hindered their efficiency and effectiveness.<ref name=":1">{{Cite journal |last1=Yep |first1=Brandon |last2=Zheng |first2=Youbin |date=2019-08-10 |title=Aquaponic trends and challenges – A review |url=https://www.sciencedirect.com/science/article/pii/S0959652619313812 |journal=Journal of Cleaner Production |volume=228 |pages=1586–1599 |doi=10.1016/j.jclepro.2019.04.290 |bibcode=2019JCPro.228.1586Y |issn=0959-6526}}</ref> The development of the reciprocating biofilter, where filter beds are alternately flooded and drained, has significantly mitigated issues such as clogging, channelization, and low oxygen levels. This innovation has enabled the retention of solids as a nutrient resource for plant growth, enhancing the overall productivity of the system.{{Citation needed|date=July 2024}}
In earlier aquaponic systems, the media often became clogged or resulted in uneven fertigation, which hindered their efficiency and effectiveness.{{Citation needed|date=July 2024}} The development of the reciprocating biofilter, where filter beds are alternately flooded and drained, has significantly mitigated issues such as clogging, channelization, and low oxygen levels. This innovation has enabled the retention of solids as a nutrient resource for plant growth, enhancing the overall productivity of the system.{{Citation needed|date=July 2024}}


=== Nutrient Availability ===
=== Nutrient Availability ===
In other aquaponic systems, nutrients can become unavailable for plant uptake due to non-optimal system water pH.<ref name=":1" />
In other aquaponic systems, nutrients can become unavailable for plant uptake due to non-optimal system water pH.{{Citation needed|date=July 2024}}


In North Carolina, research by McMurtry et al. (1993) demonstrated that wastewater from recirculating aquaculture systems used for tilapia can effectively irrigate greenhouse tomatoes. The study found that the concentrations of essential nutrients such as nitrogen, phosphorus, potassium, and magnesium in the tomato tissues were adequate, indicating that fish wastewater can supply the necessary nutrients for tomato cultivation.<ref>{{Cite journal |last1=Palada |first1=Manuel C. |last2=Cole |first2=William M. |last3=Crossman |first3=Stafford M. A. |date=1999-10-21 |title=Influence of Effluents from Intensive Aquaculture and Sludge on Growth and Yield of Bell Peppers |url=http://www.tandfonline.com/doi/abs/10.1300/J064v14n04_08 |journal=Journal of Sustainable Agriculture |language=en |volume=14 |issue=4 |pages=85–103 |doi=10.1300/J064v14n04_08 |bibcode=1999JSusA..14d..85P |issn=1044-0046}}</ref>
In North Carolina, research by McMurtry et al. (1993) demonstrated that wastewater from recirculating aquaculture systems used for tilapia can effectively irrigate greenhouse tomatoes. The study found that the concentrations of essential nutrients such as nitrogen, phosphorus, potassium, and magnesium in the tomato tissues were adequate, indicating that fish wastewater can supply the necessary nutrients for tomato cultivation.{{Citation needed|date=July 2024}}


Fish production can be effectively achieved without the need for exchanging large quantities of water or utilizing complex biofiltration devices. The solid waste produced by the fish is retained in sand beds, facilitating good crop growth without the necessity for supplemental fertilizers.{{Citation needed|date=July 2024}}
Fish production can be effectively achieved without the need for exchanging large quantities of water or utilizing complex biofiltration devices. The solid waste produced by the fish is retained in sand beds, facilitating good crop growth without the necessity for supplemental fertilizers.{{Citation needed|date=July 2024}}

=== pH Stability ===
In traditional aquaponics systems, a major challenge is finding the right pH levels for plants, fish, and bacteria. Each of these elements needs different pH conditions to stay healthy and perform well. Over time, the pH in these systems usually drops, which means it requires regular checking and adjusting to keep everything balanced. On the other hand, the Integrated Aqua-Vegeculture System (iAVs), when used as recommended, provides a stable pH that doesn't need constant monitoring or adjustments. This stability is a major benefit, making it easier to manage the system and ensuring the best conditions for all living components. <ref name=":4" />

=== Zero Discharge ===
It has been recognized in academic literature that aquaponics aims for a low environmental footprint; therefore, it is preferable to implement a zero-discharge system <ref name=":4" />, however, iAVs already achieved this by utilizing 100% of the waste.

== Terminology ==
Historically, aquaponics, which combines aquaculture (fish farming) and hydroponics (growing plants in water), was only seen as relating to these two practices, making current connections to traditional soil-based farming seem out of place.<ref name=":6" />

The Integrated Aqua-Vegeculture System (iAVs), developed by Dr. Mark McMurtry prior to the popularization of the term "aquaponics," represents a specialized methodology within the broader domain of aquaponics.

Hydroponics is traditionally understood as a soil-less cultivation method utilizing nutrient solutions, which can create confusion when discussing systems like iAVs that incorporate soil. This distinction emphasizes the unique methodology of iAVs as compared to other aquaponic systems, which generally do not utilize sand.

The ongoing dialogues surrounding the definitions of aquaponics and hydroponics highlight the necessity for standardized terminology in this field. Without clear definitions, the scientific advancement of aquaponics, including iAVs, may be impeded, as researchers and practitioners might struggle to communicate their findings and innovations effectively.

Additionally, this semantic challenge can influence public perception and the adoption of these systems, leading to potential confusion regarding the functionalities and requirements of various aquaponic setups. Establishing standardized terminology for describing aquaponic systems, including iAVs, will facilitate clearer communication, promote scientific progress, and enhance public understanding and support for these agricultural technologies.<ref name=":2" />


== References ==
== References ==

Revision as of 22:20, 3 September 2024

iAVs Schematic Diagram

The Integrated Aqua-Vegeculture System (iAVs),also informally known as Sandponics,[1] is a food production method that combines aquaculture and horticulture (olericulture).[2] It was developed in the 1980s by Dr. Mark McMurtry and colleagues at North Carolina State University including Professor Doug Sanders, Paul V. Nelson and Dr. Merle Jensen. This system is one of the earliest instances of a closed-loop aquaponic system.[3]

Many of the modern developments and discoveries of aquaponics are generally attributed to the New Alchemy Institute and North Carolina State University.[3] Further research on aquaponics at North Carolina State University was discontinued due to the fact that the system was ready for commercial application.[4] Today's flood-and-drain systems, as favoured by backyard practitioners, are derived from this model.[5]

Before the Integrated AquaVegeculture System, other systems that combined fish and vegetable farming used special tanks called clarifiers to remove solid waste from the water before it was given to the plants. While this process cleaned the water, it also took away important nutrients that plants need to grow well. As a result, these systems often had to add extra supplements to make up for the missing nutrients. iAVs is different because it uses sand to filter the water, which keeps the essential nutrients in the system. This means the plants get all the natural nutrients they need without needing extra supplements.[2]

Tomato transplants in a biofilter (composed of sand, bacteria and plants) shown being irrigated with aquacultural water for the first time.

One benefit is the production of high quality food products in close proximity to center of need, and reduction of operating costs.[citation needed]

In an iAVs, fish are raised in tanks, and their nutrient-rich water irrigates and fertilizes sand-based grow beds that support plant growth, act as biofilters, and deliver nutrients. As plants and micro-flora absorb these nutrients, they purify the water, which is recirculated back to the fish tanks.

The system often includes an aeration device, such as an aerating cascade, to oxygenate the water before it returns to the fish tanks. This multi-functional use of sand beds contributes to the relative simplicity of the iAVs design compared to other aquaponic systems.[6]

IAVS is also informally referred to as 'Sandponics'[1] which is actually a trademark for Agricultural cultivating equipment that is unlike IAVS.[7]

History

Development and Early Research

Dr. Mark McMurtry, along with Professor Doug Sanders, Paul V. Nelson, and Merle Jensen, pioneered the iAVs at North Carolina State University. The system was designed to address issues such as soil infertility, pollution, and water scarcity,[3] which Dr. McMurtry observed during his time in Africa. The initial research aimed to create a sustainable and efficient method for producing nutrient-rich food while conserving water.[citation needed]

View of the research greenhouse approximately one week after transplant of tomato crop. The tanks are below the wood-grate walkway

IAVS Research Group

The Integrated AquaVegeculture System (iAVs) was developed through the collaborative efforts of several key researchers and experts in various disciplines. The principal investigator, Dr. Mark R. McMurtry, played a pivotal role in the system's inception and development. Dr. McMurtry, who holds a PhD in Horticultural Science and Integrated Bio-production Systems, focused on addressing issues like soil infertility, pollution, and water scarcity through the innovative use of sand as a filtration medium.[citation needed]

Several co-investigators contributed significantly to the iAVs project:

  • Dr. Edward A. Estes, an expert in Agricultural and Aquacultural Economics, provided insights into the economic viability and sustainability of the system.
  • Dr. Blanche C. Haning specialized in Integrated Pest Management and Plant Pathology, ensuring the health and productivity of the plants within the system.
  • Dr. Ronald G. Hodson brought expertise in Aquatic Ecosystems, Fisheries Management, and Genetics, which was crucial for the aquaculture component of iAVs.
  • Dr. Paul V. Nelson, a Fellow of the American Society for Horticultural Science (FASHS), focused on Botanical Mineral Nutrition and Greenhouse Management, optimizing plant growth conditions.[8]
  • Dr. Robert P. Patterson, a Fellow of the Crop Science Society of America (FCSSA), contributed his knowledge in Agronomy, Soil Fertility, and Plant Physiology.[9]
  • Dr. Douglas C. Sanders, also a FASHS Fellow, provided expertise in Horticultural Science and Plant Physiology.

Additionally, several principal consultants offered their specialized knowledge to enhance the system:

Commercial Application and Modern Developments

Further research on aquaponics at North Carolina State University was discontinued once the system was deemed ready for commercial application.[citation needed]

Open Source

Dr. McMurtry is the Inventor of Record of iAVs,[13] and made it open source in 1985.[6]

Global Outreach

Following the completion of his PhD, Dr. McMurtry assumed the position of Research Associate with the International Programs at North Carolina State University. Between 1989 and 1994, he undertook extensive travel across sub-Saharan Africa and the Middle East, collaborating with local universities, international aid organizations, and agricultural professionals to showcase the advantages of integrated agricultural practices.[14]

Modification and Commercialization

Following the completion of his PhD dissertation at North Carolina State University in December 1989, Mark R. McMurtry embarked on a series of trips to demonstrate the benefits of the Integrated Aqua-Vegeculture System (iAVs) to faculty, students, and aquaculture industry professionals. One notable event was a 3-day interactive workshop at the Meadowcreek Project in Fox, Arkansas, attended by Tom and Paula Speraneo.

In the early 1990s, Tom and Paula Speraneo, owners of S & S AquaFarm in Missouri, adapted the iAVs design by replacing sand with gravel and using above-ground tanks for fish. This modified system, known as "Speraneo Systems," employed bell siphons to facilitate an ebb-and-flow irrigation cycle, popularizing what is commonly termed flood and drain aquaponics.In 2005, Joel Malcolm purchased the Speraneo’s information kit and adapted it for use in Australia. The Australian Broadcasting Corporation's Gardening TV program featured Malcolm's home-based system, leading to a renewed interest in the basic flood and drain system.

The introduction of gravel in aquaponics brought about several significant changes. It reduced mechanical filtration capability, decreased populations and activity of soil organisms, and lowered aeration in the media bacteria and plant root zone. Additionally, it diminished nutrient utilization and system stability, leading to reduced fish survival, feed rate, and growth. These changes also resulted in increased capital costs with lower fish and plant yields, as well as higher operating costs per unit of production.[14]

Operation

Operating an Integrated Aqua-Vegeculture System (iAVs) requires managerial skills developed through experience. The system is user-friendly and resilient to changes in water chemistry, allowing for minor errors. Prior experience in gardening or husbandry is advantageous.

First-time operators should receive minimal training in aquaculture management, pest prevention, and water quality monitoring. While experienced operators may make occasional errors, regular monitoring facilitates correction.

The startup phase is the most sensitive for balancing the iAVs, but once stabilized, the system becomes easier to maintain at optimal production levels.

Throughout the day, a portion of the water from the fish tank, along with the accumulated residues from the tank's bottom, is either scooped or pumped onto the surface of the filter and plant bed. This nutrient-rich water percolates through the sand of the filter bed, where larger waste particles are filtered out at the surface. Meanwhile, smaller particles and dissolved nutrients are absorbed by the roots of the plants and by the various microorganisms present in the filter bed.

This filtration and irrigation process occurs at regular intervals during daylight hours, potentially as many as eight times each day. The primary operational objective is to ensure that the total volume of the fish tank is incrementally and cumulatively circulated through the filter bed at least once each day.

Once an iAVs is established, the primary inputs required are fingerlings, seeds or transplants, fish feed, and an energy source to facilitate water movement.[6]

Aeration

The fish tank and filter bed are positioned vertically to ensure adequate elevation change between the drainage outlet of the filter bed and the water surface level in the fish tank, facilitating the installation of a cascade aerator.

The cascade, consisting of a series of small waterfalls, is intentionally designed to disperse the water flow into smaller droplets, promoting efficient mixing of air (oxygen) with the water as it descends back into the tank by gravity.[6]

Intermittent Irrigation

Irrigation water is pumped from the bottom of the fish tanks eight times daily and delivered to the biofilter (growbed) surfaces, with no irrigation at night.[2] The water floods the biofilter surfaces, percolates through the medium, and drains back to the fish tank. The tank water level drops approximately 25 cm during each irrigation event. Therefore, the returning water provided additional aeration resulting from the effect of the cascade.[citation needed]

Energy usage

IAVs only requires 2 hours of water pumping per day and is suitable for off grid applications.[citation needed]

pH stabilization

In traditional recirculatory aquaculture, carbonate inputs are typically used to neutralize the acidification caused by nitrification. However, research has shown that alkaline amendments are unnecessary when the nitrogen input rate closely matches the nitrogen assimilation rates of plants. In the Integrated AquaVegeculture System (iAVs) research, water pH remained stable at approximately 6.0 when fish feed rates were balanced with plant nitrogen assimilation rates, avoiding excessive feed inputs.[citation needed]

The plant availability of both ammonium and nitrate ions helps to buffer the pH of the nutrient solution.[citation needed]

To see if plants help keep the water pH stable in the iAVs system, an experiment was done. For 42 days, they continued watering the system and feeding the fish, but no plants were grown in the biofilters. This was to check if plants were helping to keep the water pH stable. Without the plants, the water pH quickly dropped below 4.0.[2]

Nutrients

Plant growth in the Integrated Aqua-Vegeculture System (iAVs) is sustained despite minimal nutrient levels in the recirculating water and the absence of supplemental fertilization, due to the system's constant replenishment characteristics.[citation needed]

Water Use

Research from iAVs published in 1990 showed that the amount of water used was about 1% of what is needed in a similar pond culture system.[15]

Tomato crop after 4 weeks of growth in the biofilter. Flowering has started.

System Components

The Integrated Aquaculture System (iAVs) consists of a sealed containment structure designed to house the fish and to prevent the leakage of water, along with a sand filter bed designated for the growth of vegetable crops, and a water distribution system.

The three live components are plants, fish and bacteria.

Fish tanks

Fish are raised in tanks, producing nutrient-rich water.

Sand-based grow beds

These beds serve multiple functions:

  • Plant support
  • Biofiltration
  • Particulate removal
  • Nutrient delivery to plants

Water circulation device

Fish tank water and sediment are regularly removed and applied to the plant bed. The tank has a sloped base for easy waste extraction using a bucket or calabash. Enhanced circulation is possible with mechanical pumps powered by human or animal effort, or electric pumps with automated timers.[6]

Tomato vines after 18 weeks (note: all fruit has been harvested)

Sand Composition

The sand used in the Integrated Aqua-Vegeculture System (iAVs) is critical to avoiding clogging and ensuring efficient filtration and rapid drainage. The ideal sand composition is 99.25% quartz sand, 0.75% clay, and 0.0% silt.[citation needed]

The criteria for selecting sand involved evaluating its water retention capacity through percolation tests, assessing its turbidity, and examining its drainage capabilities. The sand must be free of carbonates, heavy metals, and salts, and it should be inert.[1]

The primary functional requirement for sand in a sand bio-filter is that the entire filter or plant bed must drain completely and efficiently. This requirement is crucial to prevent over-saturation of plants. Therefore, the sand should have a relatively coarse texture with minimal fines content, specifically no particles smaller than 200 microns in diameter.

The optimal filter sand should have a consistency similar to that of common table salt or granulated sugar, without any powdery constituents. Larger particles can be screened out if necessary. Generally, it is relatively straightforward to source an appropriate grade of sand.[6]

Live Components

Plants

A broad array of vegetable crops may be cultivated in various combinations, which include tomatoes, cucumbers, melons, eggplants, peppers, beans, lettuce, assorted greens, and herbs; additionally, tree seedlings for reforestation projects may also be included.[6]

Algae

Before the establishment and rapid growth of vegetable crops, the filter surface frequently becomes completely covered in algae.

Together, the bacteria and algae (collectively referred to as micro-flora) play a crucial role in the chemical transformation of fish waste products into nutrients that are available for plant uptake. During the initial start-up phase, they also serve as a nutrient sink or buffer until the vegetable plants reach growth rates that allow them to effectively purify the water themselves. As the plants grow larger, they increasingly absorb a greater percentage of the available nutrients from the water and begin to shade the surface of the plant bed.

This shading effect leads to a noticeable decline in algal populations, which subsequently releases the accumulated nutrients for absorption by the vegetable crops.[6]

In the iAVs research, tilapia ate the algae that grew in the water and on the sides of the tank.[2]

Horticultural subsystem

The upper surface of the plant/filter bed is prepared to a level grade and designed to accommodate the specific vegetable crops or species to be cultivated. Irrigation furrows are created between the rows of plants to promote the uniform distribution of irrigation water across the surface and through the volume of the filter bed.[6] The plants are grown in raised sections of the sand which ensures the crown of the plants are kept dry.[citation needed]

In the Integrated Aqua Vegeculture System (iAVs), plants are grown in a horticulture subsystem where their roots are embedded in sand. This sand acts as a filtration medium, allowing the plants to absorb the nutrient-rich effluent water from the aquaculture subsystem. The plants effectively filter out ammonia and its metabolites, which are toxic to the aquatic animals. After the water has passed through the horticulture subsystem, it is cleaned and oxygenated, making it suitable to return to the aquaculture vessels. It uses a method of intermittent irrigation, flooding the furrows of the beds every 2 hours, during the day, until the sand is saturated. There is no irrigation at night,[citation needed]

Comparison with other systems

Previous integrated fish-vegetable systems removed suspended solids from the water by sedimentation in clarifiers prior to plant application..[citation needed] Removal of the solid wastes resulted in insufficient residual nutrients for good plant growth; acceptable fruit yields had previously only been achieved with substantial supplementation of plant nutrients.[citation needed]

In contrast, iAVs extracts fish effluent, including solids, from the bottom of the fish tanks at regular intervals, up to eight times daily, from dawn to sunset..[citation needed] The effluent is pumped directly from the bottom of the fish tank onto the surface of the sand bed, which serve as both biological and mechanical filtration and the locus for oxidation of organic solids.[citation needed]

Traditional aquaponics systems are often complex, requiring expertise in multiple disciplines such as environmental, mechanical, and civil engineering, as well as aquatic and plant biology, biochemistry, and biotechnology. Additionally, managing these systems involves understanding computer science for automatic control technologies, and expertise in economics, finance, and marketing for commercial viability. This complexity demands a high level of theoretical and practical knowledge, which can pose significant challenges to efficiency.[16] In contrast, the Integrated Aqua-Vegeculture System (iAVs) is intentionally designed to simplify the process. iAVs minimizes the technical complexities, making it easier to construct and operate. This approach significantly reduces the level of technical knowledge needed, thereby alleviating many of the perceived challenges associated with traditional aquaponics.

DWC

In a comparative trial with Deep Water Culture (DWC), the economic feasibility analysis indicated that the Integrated Aqua-Vegeculture System (iAVs) produced more crops with a wider variety at almost 20% less capital expenditure and operational expenditure costs. Sand beds are able to grow a greater variety of plants than the DWC system.[citation needed]

In Deep Water Culture (DWC) systems, iron supplementation is typically required. In contrast, the Integrated AquaVegeculture System (iAVs) exhibits a significant increase in iron levels within the system and the crops without the need for external supplementation. This characteristic is considered one of the primary advantages of iAVs, as it eliminates the necessity for additional nutrient supplements.[citation needed]

Innovations in Filtration

IAVS does not need any mechanical filters as the filtration is performed by the sand.[citation needed]

In earlier aquaponic systems, the media often became clogged or resulted in uneven fertigation, which hindered their efficiency and effectiveness.[citation needed] The development of the reciprocating biofilter, where filter beds are alternately flooded and drained, has significantly mitigated issues such as clogging, channelization, and low oxygen levels. This innovation has enabled the retention of solids as a nutrient resource for plant growth, enhancing the overall productivity of the system.[citation needed]

Nutrient Availability

In other aquaponic systems, nutrients can become unavailable for plant uptake due to non-optimal system water pH.[citation needed]

In North Carolina, research by McMurtry et al. (1993) demonstrated that wastewater from recirculating aquaculture systems used for tilapia can effectively irrigate greenhouse tomatoes. The study found that the concentrations of essential nutrients such as nitrogen, phosphorus, potassium, and magnesium in the tomato tissues were adequate, indicating that fish wastewater can supply the necessary nutrients for tomato cultivation.[citation needed]

Fish production can be effectively achieved without the need for exchanging large quantities of water or utilizing complex biofiltration devices. The solid waste produced by the fish is retained in sand beds, facilitating good crop growth without the necessity for supplemental fertilizers.[citation needed]

pH Stability

In traditional aquaponics systems, a major challenge is finding the right pH levels for plants, fish, and bacteria. Each of these elements needs different pH conditions to stay healthy and perform well. Over time, the pH in these systems usually drops, which means it requires regular checking and adjusting to keep everything balanced. On the other hand, the Integrated Aqua-Vegeculture System (iAVs), when used as recommended, provides a stable pH that doesn't need constant monitoring or adjustments. This stability is a major benefit, making it easier to manage the system and ensuring the best conditions for all living components. [16]

Zero Discharge

It has been recognized in academic literature that aquaponics aims for a low environmental footprint; therefore, it is preferable to implement a zero-discharge system [16], however, iAVs already achieved this by utilizing 100% of the waste.

Terminology

Historically, aquaponics, which combines aquaculture (fish farming) and hydroponics (growing plants in water), was only seen as relating to these two practices, making current connections to traditional soil-based farming seem out of place.[15]

The Integrated Aqua-Vegeculture System (iAVs), developed by Dr. Mark McMurtry prior to the popularization of the term "aquaponics," represents a specialized methodology within the broader domain of aquaponics.

Hydroponics is traditionally understood as a soil-less cultivation method utilizing nutrient solutions, which can create confusion when discussing systems like iAVs that incorporate soil. This distinction emphasizes the unique methodology of iAVs as compared to other aquaponic systems, which generally do not utilize sand.

The ongoing dialogues surrounding the definitions of aquaponics and hydroponics highlight the necessity for standardized terminology in this field. Without clear definitions, the scientific advancement of aquaponics, including iAVs, may be impeded, as researchers and practitioners might struggle to communicate their findings and innovations effectively.

Additionally, this semantic challenge can influence public perception and the adoption of these systems, leading to potential confusion regarding the functionalities and requirements of various aquaponic setups. Establishing standardized terminology for describing aquaponic systems, including iAVs, will facilitate clearer communication, promote scientific progress, and enhance public understanding and support for these agricultural technologies.[14]

References

  1. ^ a b c Sewilam, Hani; Kimera, Fahad; Nasr, Peter; Dawood, Mahmoud (2022-06-30). "A sandponics comparative study investigating different sand media based integrated aqua vegeculture systems using desalinated water". Scientific Reports. 12 (1): 11093. Bibcode:2022NatSR..1211093S. doi:10.1038/s41598-022-15291-7. ISSN 2045-2322. PMC 9247079. PMID 35773314.
  2. ^ a b c d e "Food Value, Water Use Efficiency, and Economic Productivity of an Integrated Aquaculture-Olericulture System as Influenced by Tank to Biofilter Ratio – iAVs (Sandponics)". Retrieved 2024-07-27.
  3. ^ a b c Okomoda, Victor Tosin; Oladimeji, Sunday Abraham; Solomon, Shola Gabriel; Olufeagba, Samuel Olabode; Ogah, Samuel Ijabo; Ikhwanuddin, Mhd (2022-12-18). "Aquaponics production system: A review of historical perspective, opportunities, and challenges of its adoption". Food Science & Nutrition. 11 (3): 1157–1165. doi:10.1002/fsn3.3154. ISSN 2048-7177. PMC 10002891. PMID 36911833.
  4. ^ Goodman, Elisha R. (Elisha Renee) (2011). Aquaponics : community and economic development (Thesis thesis). Massachusetts Institute of Technology. hdl:1721.1/67227.
  5. ^ Aqu@teach (2020-09-03). "History of aquaponics". learn.farmhub.ag. Retrieved 2024-05-05.
  6. ^ a b c d e f g h i "THE AQUA-VEGECULTURE SYSTEM – iAVs (Sandponics)". Retrieved 2024-07-26.
  7. ^ "SANDPONICS Trademark of Sumitomo Electric Industries, Ltd. - Registration Number 5409239 - Serial Number 87279671 :: Justia Trademarks". trademarks.justia.com. Retrieved 2024-05-06.
  8. ^ "Paul Nelson". Horticultural Science. Retrieved 2024-07-03.
  9. ^ "Bob Patterson | Crop and Soil Sciences | NC State University". 2017-03-19. Retrieved 2024-07-03.
  10. ^ "Merle Jensen | Controlled Environment Agriculture Center". ceac.arizona.edu. Retrieved 2024-07-03.
  11. ^ "Thomas Losordo". Department of Biological and Agricultural Engineering. 2017-01-17. Retrieved 2024-07-03.
  12. ^ "George Wilson". Horticultural Science. Retrieved 2024-07-03.
  13. ^ "Profile". Research-Gate.
  14. ^ a b c "Aquaponics' Biggest Mistake – iAVs (Sandponics)". Retrieved 2024-07-27.
  15. ^ a b Lennard, Wilson; Goddek, Simon (2019), Goddek, Simon; Joyce, Alyssa; Kotzen, Benz; Burnell, Gavin M. (eds.), "Aquaponics: The Basics", Aquaponics Food Production Systems: Combined Aquaculture and Hydroponic Production Technologies for the Future, Cham: Springer International Publishing, pp. 113–143, doi:10.1007/978-3-030-15943-6_5, ISBN 978-3-030-15943-6, retrieved 2024-09-03
  16. ^ a b c Goddek, Simon; Delaide, Boris; Mankasingh, Utra; Ragnarsdottir, Kristin Vala; Jijakli, Haissam; Thorarinsdottir, Ragnheidur (April 2015). "Challenges of Sustainable and Commercial Aquaponics". Sustainability. 7 (4): 4199–4224. doi:10.3390/su7044199. ISSN 2071-1050.