What is iAVs?

What is iAVs?

Put simply, iAVs is a food production system in which plants derive nutrients from the metabolic wastes of fish.

Its most tangible outcome is clean fresh fruit and vegetables – and freshwater fish.

In essence, we feed the fish – the fish supply the nutrients for the plants – and the plants clean the water for the fish.

iAVs is an intentional ecosystem – one that ‘mimics’ the Earth’s natural biological processes – and it is the symbiotic integration of all three of the primary ecological niches:

• The aquatic environment
• The soil ecosystem
• Terrestrial plants – including the rhizosphere

OK…so how did iAVs come into being?

iAVs was the brainchild of Dr. Mark R McMurtry.

He looked at the issues that impacted the world’s future ability to feed itself…

• Aquifer depletion
• Drought
• Climate change
• Pollution
• Soil salinity
• Erosion
• Desertification

…and realized that humanity needed a means by which to derive sustenance – without harming the planet.

It was developed and investigated in the Department of Horticulture Science at North Carolina State University in the mid 1980’s.  Co-investigators included Professors Emeritus Paul V Nelson, Douglas C Sanders, Merle H Jensen – and many other notable contributors.

iAVs was experimentally proven, and described – and the results were published in peer-reviewed scientific journals.

Following completion of the iAVs research program, NCSU determined that it was ready for commercialization.  USDA subsequently funded a successful commercial demonstration trial in 1991-92. 

Sounds a bit like Aquaponics?

iAVs was the first successful ‘closed loop’ integration of fish and edible plants.  The name ‘aquaponics’ was not even in use at the time that iAVs was developed.  The basic flood and drain model popularised by Tom and Paula Speraneo was spawned by iAVs.  While the UVI raft model was developed independently by James Rakocy PhD, it occurred after iAVs .

What iAVs – and its various aquaponics’ descendants – have in common is that they all source plant nutrients from fish wastes – and uneaten fish food.

How does iAVs differ from Aquaponics?

iAVs utilizes sand as the growing media…while the basic flood and drain system (sometimes known as the Speraneo model) uses gravel or clay pebbles.

Another method, known as deep water culture (DWC), utilizes Styrofoam rafts to support plants growing in long water tanks.

So, what distinguishes iAVs from other so-called Aquaponics systems?

It’s the sand…and the things that sand will do…that gravel or water can’t do.  

Note:  When we refer to ‘sand’, we mean Silicon dioxide (quartz).

1. Sand is a vastly superior mechanical filtration media compared to gravel – indeed it is among the best of all filtration substrates in terms of its efficacy and the cost-effectiveness of its use.  The use of sand as a filtration medium pre-dates recorded history – and it is still widely used today.  By contrast, using gravel or clay pebbles to filter fish wastes is like using a fishing net to catch mosquitoes.
2. Sand is also a far more effective biological filtration media – with a far higher specific surface area than gravel – or any other commonly used media.  But there’s an even more compelling difference….
3. Sand is the only commonly available natural filtration media that will facilitate the soil biology that is the foundation of all successful organic gardening.  Which means that iAVs is the only closed integration of fish and plants that does not require supplementation.  Everything that the plants need comes from the fish food…assuming the use of a properly formulated diet.

This focus on soil biology acknowledges that iAVs is essentially a horticulture system in which the fish are simply a means to an end.  This contrasts with aquaponics where – given the focus on nitrification and the technology used to achieve it – there is a greater emphasis on aquaculture…even where the plants are acknowledged to be the more valuable harvest.

Suffice to say, for now, what occurs between plants and sand in an iAVs is consistent with the interactions much admired by organic gardeners.  

However, it wasn’t organic gardeners for whom iAVs was developed but rather impoverished villagers in places like Namibia, the Sahel and the Middle East.

Many of the challenges that confronted these villagers are emerging as issues in other places (like China, India, the US, Australia and large chunks of Europe)…to the point where future food security is increasingly at threat.

To summarise… iAVs seeks to maintain a balanced symbiotic ecosystem… …the outcome of which is nutritious fresh fruit and vegetables…and some fish, too.

But that’s just the beginning of the story.

iAVs is possibly the most productive, resilient and sustainable food production systems ever devised.

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