Back to the Future

Back to the Future

To fully appreciate what Sandgardening is about, it’s necessary to understand how it came into being.

For that we need to talk about the Integrated Aqua-Vegeculture System (iAVs) and its inventor Dr Mark R McMurtry.

Mark – an avid angler and aquarist – lamented the time and effort involved in maintaining about a dozen three-stage external canister filtration systems fitted to his home aquariums and so, in 1983, he began experimenting with different filtration substrates.

He had formed an association with Merle Jensen who had designed the Land Pavilion at the EPCOT Center at Walt Disney World in Orlando Florida.  

Through Jensen, Mark learned that water quality in the large (57 million gallons) aquariums at the Center was managed through fluidized-bed sand filters – and substantial daily water replacement.

It occurred to him that, if the filtration needs of large fish tanks like those at the EPCOT Center (and most other commercial aquariums) could be met with sand filters, then he should be able scale them down to suit his own home-based fish tanks.

“My first sand filter trials consisted of a 3-gallon dishpan sitting on top of a 30-gallon aquarium that held up to 100 fathead minnows which were fed to a mated pair of African reticulate knifefish (Papyrocranus Afer).”  

Sand proved to be a highly effective mechanical filter of particulate and suspended (even microscopic) solids.  As the filter surface eventually became clogged with accruing particulate matter, Mark simply scraped the surface to remove the detritus layer.  When he added plants to the biofilter, he first created furrows to distribute the fish water evenly and ridges to keep the plant crowns dry (from molds and rot). Subsequently, he discovered that there were multiple positive consequences of the ridge and furrow design.

The other important outcome was that sand was an excellent medium for bio-filtration providing significantly greater surface area for colonisation by beneficial bacteria than his previous bio-filters.  

Each de-watering (drain) cycle recharged the filter with oxygen.  This “recharging” (analogous to the scavenge effect in internal combustion engines) benefited the nitrifying bacteria and facilitated mineral nutrient assimilation by vascular plants.

Mark found that not only was he able to reduce the filter maintenance frequency from an hour per week to just a few minutes per month, he was also able to dispense with the expensive three-stage cannister filters that he’d been using.

Amateur fish-keepers manage nitrate levels in their fish tanks by regular replacement of water.  Mark (also a keen gardener) was aware that ammonium nitrate was plant food so he got to thinking that he may be able to capture the nitrates (and other nutrients) in his aquarium water using plants.

To test this idea, he planted some lettuce seeds in the filter bed.  The rapid growth of the lettuce was such that Mark then tried chives, basil and bush beans with similarly satisfying results.

Mark’s interest in Africa was not limited to Reticulate Knifefish. 

He loved all things African, but he was dismayed at the nutritional deficiencies and hunger that plagued so many of the continent’s impoverished villagers…and at the devastation that their food gathering wreaked on the local environment.

He sought to demonstrate that there were ways for humans to live on this planet without destroying it through the integration of fish and plants.  

He pondered whether the integration of fish and plants that worked so well with his might not have a broader application.  So, in 1983, he sold up his successful architectural woodworking business and headed off to school to pursue his idea.

In the autumn of 1984, Mark began to study with Paul V. Nelson (Professor Emeritus), a greenhouse operations management and plant nutrition expert based at North Carolina State University (NCSU).

In the winter of 1984-85, his studies led him to establish two 375-litre tanks each equipped with grow beds filled with sand.  

One tank contained Hoagland solution (a standard nutrient mix well known to hydroponicists and horticultural researchers) and the other contained fish – tilapia niloticus.  

Each bed had five furrows, and along each furrow a different plant species was grown …lettuce, spinach, carrots, beets and bush beans.  

Irrigation frequency and volume, pH, temperature and relative humidity – and insolation – were held constant (identical) across both trial units.

The principal outcome of Mark’s trial was that plant growth in the system containing the tilapia outperformed that of the inorganic hydroponics system by a margin of 200% to 300%.

In the summer of 1986, Mark set up a much larger (approx. 500m2) demonstration system off campus – effectively a proof-of-concept exercise for his evolving integrated aquaculture system.

In the winter of 1986-87, he commenced tracking all the plant nutrients to determine where they went. He spent several months, in a laboratory, engaged in elemental analysis of plant tissues and changes within the filter volume.

In May 1987, the late Dr. Douglas C. Sanders (NCSU) persuaded Mark to commence a PhD in Horticultural Science – with a unique interdisciplinary committee comprising 6 senior faculties representing 4 life-science disciplines.

His dissertation required that he build yet another IAVS system – this one comprising 16 tanks in total – to test tank to filter volume ratios.  These ratio trials were based on four crops – one after the other.

The eventual outcome of his work was the Integrated Aqua-Vegeculture System (iAVs) – the first successful ‘closed loop’ attempt to grow fruit and vegetables using the metabolic wastes of fish.

It was also a means by which impoverished villagers could source their nutrition without harming their environment.

That he achieved his goal was one thing, but it was the sheer performance of iAVs that excited the seasoned horticultural and aquacultural researchers at NCSU and other universities.

Encouraged by the reaction to his discovery – and its possibilities – Mark took to the road to demonstrate the method at other US universities and institutions.

A Fateful Meeting

In December 1989, one such trip to Arkansas put Mark in contact with Arkansas farmers Tom and Paula Speraneo – at the University of Arkansas in Little Rock.

A week later, Mark facilitated a 3-day interactive discussion/workshop at the Meadowcreek Project in Fox Arizona attended by faculty, students and representatives of the aquaculture industry – and the Speraneos.

The Speraneos returned home and began to construct an integrated aquaculture system based on what they’d seen.   They couldn’t afford the sand that was central to IAVS’ effectiveness, so they dug up their pea gravel driveway for use in their system bio-filter.

Mark recalls counselling them at length about their decision to use gravel.  But, despite his efforts to persuade them otherwise, they persisted.  

This “mistake” (subsequently wilful ignorance) was what best-selling author Malcolm Gladwell would come to describe as a tipping point – one that would later turn out to have devastating implications for iAVs.

Meanwhile, Mark completed his dissertation at NCSU.  He submitted several articles that were peer-reviewed and published in various professional aquaculture and horticulture journals.  

Then, oblivious to the fact that his work was about to be usurped, he took his work off to sub-Saharan Africa and the Middle East.

During the period, 1989 – 1994, Mark travelled to over a dozen countries – funding most of the travel costs himself – spreading the word about IAVS. 

The United States Department of Agriculture funded a successful commercial trial of the method and NCSU declared it ready for implementation.  

USAID committed $7.5 million to the implementation of iAVs across the then newly formed nation of Namibia.

It was clear that iAVs was a game-changer with a very bright future.

At this point, it would be entirely reasonable to ask why – given the excitement that iAVs generated within the scientific community at NCSU – iAVs is not better known today.

The answer, quite simply, is that Fate took a hand…and the day that she stumbled across Mark McMurtry she was in a foul mood.

No Good Deed Goes Unpunished

Bureaucratic and intergovernmental malfeasance killed the plan to implement iAVs across Namibia….and Mark returned from Africa to discover that the university had terminated his tenure because he’d thwarted its plans to sell iAVs off to large food production conglomerates.

It took some tense legal proceedings for Mark to assert his ownership of the iAVs method – which he then gifted to humanity.  iAVs effectively become ‘open source’ before the term gained popular use.

The Israeli Likud government – and the powerful Israeli lobby in the US – thwarted World Bank (IBRD) and UN/FAO intentions to “feed a million Palestinians” with 100 hectares of iAVs polyculture at Jericho by sourcing fossil water from deep below the Dead Sea.

After six frustrating years spent trying to navigate the overseas agricultural and aid agencies – and the United Nations bureaucracy – Mark returned to the US – disillusioned and disgusted.  

In 1996, he established an off-grid residence on a mountaintop northwest of Yellowstone National Park.

But that wasn’t to be the end of Mark’s woes.

Tom and Paula Speraneo, who you’ll recall initially set out to build an iAVs, claimed their utilization of gravel as a point of sufficient (in their minds) difference to assume ownership of the concept. They referred to their “discovery” as “Bio-culture” and promoted it widely using the new digital discovery called the Internet.

Bankrupt and in declining health – and lacking both institutional support and an income – Mark was no longer able to support the dissemination of iAVs.

In the ultimate irony, as iAVs began to slide inexorably into obscurity, the Speraneo aberration triggered a wave of popular interest – and it took the ascendancy over its forebear.

In the ensuing years, this inferior mutation was popularized as the flood and drain aquaponics system.

Quite by Chance

But for his decision to attach to a conversation on the Aquaponics Nation discussion forum (of which I was a member) in 2014, his work may well have remained buried in time.

I saw the potential of iAVs almost immediately and we commenced a day-by-day collaboration that has spanned six years and has seen me – with Mark’s support – teach and support the implementation of the method to hundreds of farmers and gardening enthusiasts throughout the world.

As of 2022, we had an expanding cadre of iAVs farmers in places like Egypt, India and the United Arab Emirates… and a much larger number of home gardeners spread right across the world.

What’s in a Name?

Notwithstanding our modest success in spreading the iAVs word, however, we still had a problem.

The name “Integrated Aqua-Vegeculture System” gave little hint as to what it was and the acronym “iAVs” meant even less to the audience that we sought to attract.

We needed a name that conveyed greater meaning as a brand.

We flirted briefly with ‘Sandponics’ until we discovered that the name had been used in connection with a hydroponics method that had been developed by the giant Sumitomo Electrical Corporation…to whom we were keen to avoid giving offense – for obvious reasons.

In any case, given the way aquaponics had usurped his work, Mark (quite understandably) had little taste for anything ‘ponics.  

He had always asserted that iAVs was principally about growing fruit and vegetables and that the fish (while a significant aspect of the method) was simply a means to that end.

By contrast, the approach of most aquaponicists was ‘fish-centric’…to the point where most of them have to ‘un-learn’ much of what they thought they knew about using fish to grow plants once they graduate to the iAVs method.

Ironically, while we have had to work hard for every small gain in advancing the iAVs method, the name ‘Sandponics’ caught on very quickly…to the point where our efforts to persuade our adopters to use another name quickly became a matter of closing the gate after the horse had bolted.  

Suffice to say, it doesn’t matter whether you call it the integrated aqua-vegeculture system…or iAVs…or…Sandgardening…or Sandponics…so long as it all means the same thing.

Sand + gardening = Sandgardening

When we sat down to describe the iAVs method, we established that what most distinguished it was its use of sand as a growing media and its focus (for production purposes) on horticulture – or gardening.

It’s useful to understand that, in iAVs, Sandgardening has a noble lineage and knowing about the circumstances of its development helps us to understand why it’s taken over 30 years for it to begin to gain traction. 

To summarise…iAVs is, in a horticultural context, a very big deal.  It’s not a wannabe startup that’s conjured up to separate you from your money…it’s the real deal.  It has the power to save the lives of millions…and to change the lives of many of millions of others.

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