Growing Diverse Healthy Food For A Neighborhood

At Nanniode, a remote village in the district of Palakkad in Kerala, India, a radical experiment in food and agriculture is taking place. Twenty-five kilometers south of the Palakkad town, The Venus Project Integrated Aquaponics System (#TVPIAS) is a small-scale project on less than a quarter acre, including a fish tank, plant beds and a surrounding orchard. This unique food growing system is partially within a rain shelter protected greenhouse structure.

Every week, this system provides a variety of vegetables, fruits and greens (and soon fish) of very high quality to households from the surrounding community. The immediate physical proximity makes it possible for the produce to be harvested and delivered within a few hours, completely fresh. People value that the food is completely free from any spraying with toxic chemicals, and they are glad to subscribe to receive weekly produce as part of our Community Supported Agriculture (CSA) model. We are currently supplying 10 households weekly with some 2 kg (4.4 lbs) produce each. One of our primary goals is to increase the number of people we are able to feed using this piece of land.

This is not a fixed system but one that is rapidly evolving, as we overcome challenges and continuously innovate. Read below for technical details and how you can get involved.

Technical Details

Imagine gardening year-round, with no weeds to pull, no mudding to plant or harvest, no worries about watering or fertilization. Picture you working in a green, vital, healthy environment – doing what you love to do. This hybrid growing system integrates recirculatory aquaculture system (RAS), organic hydroponics and regenerative natural farming methods in a simple to operate way to produce premium fish, fresh vegetables, greens and herbs, fruits and other plants.

In brief, you feed the fish; the fish feed the soil microbes; the microbes feed the plants. Microbes and plants help the fish by filtering fish excreta from the water. You harvest the vegetables, fruits and fish. The more we can emulate natural processes, the better it works. In its closed cycle, self-balancing system, mineral salts as plant food are replaced by bioremediated natural nutrients from a biological source: fish effluent. This practical, original growing system needs no expensive equipment or patented parts, and uses easily available materials to grow safe, high analysis chemical-free, superior quality food. And, it is adaptable enough to provide family food supply, or expand to commercial scale.

Fish

The heart of the Integrated Aquaponics System is the fish culture tank (60 m³). What we have is a longitudinal canal tank lined with geomembrane liners. The shape is a parabolic cross-section (lateral) canal with each end a semi-circle in the plan view. This shape provides highly effective concentration of wastes along a central/longitudinal axis for ease of extraction with multiple spaced-out small submersible pumps and also eliminates ‘dead-spots’ and sludge accumulation in the corners. Canal length can be whatever length suits/fits. A fish culture tank can be larger or smaller, to comfortably house any number of fish or fit any space.

TVPIAS fish culture tank is stocked with 5967 Nile Tilapia, the world’s most popular fish for aquaculture, a hardy, disease-resistant, warm-water fish native to Africa and the Middle East, and raised for food by ancient Egyptians. It is delicious with white flesh and few bones. Tilapia tolerate low oxygen and poor water conditions that will kill most fish. Tilapia are vegetation eaters. They devour algae in addition to their regular feed. Any excess on-farm plant cuttings such as Spinach tossed in the tank, they feast on happily. Cuttings are broken down by bacteria into algae, then fish filter the algae out. Their gill rakers take out anything over 3 microns, which is red blood cell size. This helps keep water really clear. Extremely simple, but very efficient.

In a commercial production system, maximum growth is achieved by assuring high protein intake, so TVPIAS fish are fed a daily ration of 32% protein fish feed, the most chemical-free fish feed we could find. It doesn’t have copper sulfate, tetracycline, actinomycin, and additives, like many commercial fish foods do. The quantity and number of antibiotics and chemicals is so high in fish feeds. As an organic fish feed supplement, we have begun trialing on-farm inputs such as the plant leaves of colocasia, water hyacinth, moringa, etc. Black soldier fly larval rearing for fish feed is undergoing an R&D trial.

The feed conversion rate for Nile Tilapia is excellent: roughly one-and-a-half kilogram of feed yields a kilogram of fish. Nile Tilapia fish has grown from starter 1.5 grams to 170 grams in 137 days. Fish would be harvested as per CSA requirement staggered by size using nets that only catch larger fish. We looked up the feed input data (first 137 days).
Summary,
Initial feed input rate at 15% of biomass/day tapering off to 1% per day.
Initial mean weight of the fish = 1.5 g
Total feed (mean) per individual = 123 g
Mean weight of the fish after 137 days = 170 g
Feed conversion ratio = 1.38

Animals excrete wastes. Fish dump excess nitrogen (urea, nitrite, ammonia) and other wastes into water. Crowding fish together in a closed container, and feeding them a high protein diet to force rapid growth, generates a lot of wastes. If these fish metabolites aren’t removed from the water, they will quickly build up and poison the fish. Toxic waste – a key limiting factor in aquaculture – restricts a system’s production capacity. So fish farmers invest a lot of money, time and technology in waste disposal problems. Pumps, filters, aerators, sedimentation tanks, and more equipment clutter and confound most fish farms. In the Integrated Aquaponics System, fish wastes become food for the soil microbes which then becomes plant food, and expensive machinery and complex technology are replaced by biology. Plants grown in biofilter beds use nutrients in fish water bioremediated by soil microbes, and purify the water to benefit the fish. An Integrated Aquaponics System is simple and revolutionary for the very reason it doesn’t use technology normally necessary for aquaculture and hydroponics.

Plants

Plants grow in permanent biofilter beds (250 m²) which contain Quartz Silica sand as growing media. Periodically, pumps flush these biofilter beds with water from the fish tank. Plants get all the nutrients they need from this irrigation water with no cost or fuss to mix chemicals. Thus, animal wastes become plant food, and the Integrated Aquaponics System removes the need to add chemical fertilizers to water to feed plants. Fish water effluent is pumped from the fish culture tank through 1-inch PVC pipe straight to growing beds to trickle on the beginning. Water is then moved through the biofilter beds by gravity and drained back to the fish culture tank. Effluent isn’t filtered or purified before reaching growing beds. Water is aerated as it flows out of holes in the pipe and trickles over sand.

In the stable, moist greenhouse atmosphere, plants grow in denser spacings than conventional garden beds. TVPIAS biofilter beds are so nutrient-rich and fertile, plants grow in less time than by conventional methods – and larger, too. Tomatoes and cucumbers are tied up in tall vines, and peppers and eggplants become baby bushes. Gourds are climbing up on hanging garden trellises above the fish culture tank. And, cuttings from almost any plant (even trees) will root and grow if stuck in a bed, with no rooting hormones or chemicals. Yields of the edible portions of vegetables such as spinach, okra, cowpea, cucumber, green chillies, eggplants, tomatoes are currently being assessed and distributed to the neighborhood Community Supported Agriculture (CSA) subscribers. Several gourds, banana, colocasia, sweet potatoes, papaya and moringa trees are in growth stages. Some potential crop yield was lost due to the development of pest and disease attacks in the okra, cucumber and eggplants.

In return for bioremediated fish effluent feedings, plants through their roots purify and recharge the water for fish. Well water is used to replace the water lost through evaporation, transpiration and development of the fish and plants biomass. The Integrated Aquaponics System approach to system integration not only knocks out nitrogen troubles, but carbon dioxide too. Plants need CO2 to grow. In winter, this scarce gas is a growth limiting resource. We have no CO2 generators but have a fish culture tank full of CO2 generators. They’re alive and have fins. Fish are CO2 generators for the system, just a natural side effect. That’s a lot simpler than hydroponics.

Microbes

Unseen by naked eye, a few kilograms of microorganisms thrive on sand in each biofilter bed. Plant roots only take up nutrients after the microbes consume and convert them. It is these teeming tiny creatures that filter, convert fish wastes to plant food and recharge the water. Growing biofilter beds aren’t just sand-filled trenches, but fluidized bioreactors – living biofilters. In a mechanical filtration system, this key component must be backflushed to get solid wastes out. But with the Integrated Aquaponics System, microbes dissolve solid wastes, so we don’t have any buildup. This mineral-to-microbe-to-plant, nitrogen-fixing, amino acid building food chain is a foundation to all agriculture. No supplemental fertilization was added to fertilize the soil medium. The mineral composition and nutrient content of the crops are to be assessed and studied. Legumes are a key in all crop rotation and companion planting, but the real work is done by a microbe with a trace element. In the Integrated Aquaponics System, similar microbial links turn animal wastes (nitrogen) into plant food (nitrates). Hidden in the sand, billions of soil microbes filter the fish water and feed the fish wastes to the root hairs of the plants. But we really know little else about this unseen universe, and the myriad lifeforms of this microbial dimension. Yet, ample evidence indicates microbes also synthesize many essential nutrients such as B vitamins, and primary protoplasm. For one, vitamin B12 is only made by a group of bacteria that grow in alkaline environments rich in amino acids. Many other microbes function as specialized partners in immune systems. Who are these bacteria? What is their active biomass? How do they digest minerals into streaming liquid protoplasm? How do they digest and disarm toxins? What nutrients do they make available to plants? What other specialized functions do microbes perform? What do they require for happiness?

Get Involved

Several questions like these ones need to be answered. We need help from experts on topics such as soil/plant/animal microbiology, olericulture, integrated pest management, and more, to join our team.

We also welcome your comments and feedback below.

Post written by:

Vijayakumar Narayanan (VKN)

VKN runs a private limited company (named startup of the year) in India backed by over 9 years of hands-on experience as an early adopter of Integrated Aquaponics System (IAS) methods. His focus areas include but are not limited to commercial farming, training, consulting and/or franchising IAS technology. For the last couple of years, he has been working with various teams in planning and designing the agricultural belt of an entire social complex of The Venus Project. His work on that included scalable IAS solutions for the execution of various agricultural methods and practices of cultivating the soil, producing crops and raising livestock and in varying degrees the preparation and marketing of the resulting products. Those efforts led to this current #TVPIAS project and VKN is now in charge of its implementation.

Borislav Zlatanov

Borislav’s background includes neuroscience, teaching and IT engineering. He is interested in both design for radical effectiveness and a wider systems perspective across space and time. His work with The Venus Project over the years has been in diverse roles, often supporting the creation or automation of procedures and workflows in various teams. He has created a couple of web platforms which were inspired from integrating insights from disparate areas. For this project, one main purpose for him will be to support the integration of knowledge from a variety of fields into a single whole, out of which completely new insights can be born, as well as to support the spreading of this knowledge to people around the world.

Frixos Proedrou

Frixos is a nutritionist/dietitian specialized in both health and disease. He has done a Bachelor’s and a Master’s degree in this area, collaborated with several hospitals and universities, and worked professionally and conducted research with patients on nutrition and quality of life. He has also co-created simple nutrition analysis and menu creation tools. For the past decade he has shifted his focus on a more holistic approach towards nutrition, including botany, natural remedies and traditional medicine. He has experience in natural building, hydraulic engineering, composting, soil creation, companion planting, landscaping, water management, heating systems, geopolymer techniques and is interested in anything related to the land, food production and energy conversion.