What is an aquaponics pond?
Aquaponics pond is a cultivation method that combines hydroponics (the cultivation of plants without soil, in pure water, rich in nutrients and minerals) and aquaculture (the breeding of aquatic animals such as fish, crayfish, snails, or shrimp) to reproduce the natural cycle of ponds, lakes, and streams.
Opinions differ on the historical origins of aquaponics, but it is considered that it was already used before the 16th century, in pre-Columbian America, and in China!
What is an aquaponics pond?
An aquaponics pond (also called an aquaponics garden ) is simply the place where aquaponics is practiced to produce food. The environment of plants and aquatic animals is directly linked to it in order to create a virtuous and ecological circle in a closed circuit.
The waste produced by fish thus provides plants with the nutrients and minerals they eat, and the plants filter the water in which the animals live, which maintains a healthy environment for both fish and plants.
So, how does the aquaponics pond work?
In an aquaponics system, animals eat and produce organic waste. These wastes are taken to be digested by bacteria naturally present in the water. Through the nitrification cycle, bacteria convert these wastes into nutrients and minerals. This water is then sent to the plants, which, by feeding on these nutrients and minerals, filter and purify the water. This pure water is then returned to the animals, ensuring them a healthy environment.
At the Echo-village, waste that cannot be returned to the aquaponics production cycle is recycled into other crops and livestock, ensuring zero-waste production.
A crop without fertilizers or pesticides
With aquaponics, fish directly supply the natural minerals and nutrients that plants require, without the need for fertilizers. In addition, pesticides, herbicides, and other chemicals are not used because they could harm the animals, helping to protect the environment as well as the quality of production.
Healthy, pure, and organic food
By producing in a closed, rigorously controlled, and protected system, the food produced by aquaponics is indeed 100% organic, protected from pollution, soil, and water diseases. This exceptional quality, superior to the requirements of the Organic Label, is one of the motivations behind the creation of a label dedicated to aquaponics.
At the Echo-village, we have also chosen to go further in this approach: where the farming of Label Bio fish requires a maximum of 35 kg of fish per cubic meter of water, the Echo- trout village are produced with a maximum of 25kg / m 3 and their feed is devoid of drugs. It is the guarantee for them of a healthier life, and for you, of a pure diet with fresh, healthy fish raised in the best conditions.
Very low water consumption
Although aquaponics is based on water, it circulates efficiently in a closed circuit, which means that very little is consumed. Thus, an aquaponic garden consumes only 1 / 10th of the water that would be used in a vegetable garden or crops on the ground, which represents a saving of 90% of drinking water!
Optimal crop efficiency
Because fish suckers are particularly nutritious, plants grown by aquaponics grow quickly. Thanks to indoor cultivation and temperature control, the production of plants and fish can be done continuously, in a small space, with partial harvests all year round and respecting the seasons.
In addition, the supports require little maintenance, and their harvest is easy and without losses.
Practical and intelligent production
An aquaponics system can be of any size and can be installed almost anywhere: indoors, outdoors, in the city, in an arid environment, etc. Because feeding the fish is enough for the fish to feed your plants, each aquaponics farm produces both plants and fish, offering both good protein and fresh vegetables.
A preserved natural heritage
By promoting the culture of farmed fish, preserving water and soil, aquaponics offers a 100% responsible production method, more efficient, more sustainable, and more ecological than conventional agriculture. Being able to be installed in the city and offer its products for sale directly from the farm to gourmets, aquaponics responds directly to consumer demand for healthy, local, and environmentally friendly food.
To guarantee good results and reproduce the natural cycle of water and nutrients, however, this technique requires installations and, of course, an appropriate set-up.
What can be produced with an aquaponics pond?
Aquaponics pond is a particularly versatile system. Fruits, vegetables, aromatic plants, trout, crayfish, and even flowers: the possibilities are numerous!
What fish and aquatic animals can we breed in an aquaponics pond?
While there is a branch of aquaponics called “saltwater aquaponics” because it employs saltwater fish, the most commonly used aquatic animals in aquaponics farms are generally freshwater fish, as they are more common. resistant and flourish easily in ponds.
Many species of hot and cold water fish adapt very well to aquaponics systems, as do freshwater crayfish and shrimp which also have the advantage of feeding on organic waste from the sea. processing of fish following their harvest, further optimizing the ecological impact of this mode of production.
Depending on the nature of the aquaponics project (domestic, commercial, etc.) and the production conditions (temperature, availability of resources, etc.), certain fish are particularly popular: for example, tilapia tolerates reduced living space and changes very well. water, catfish, or bluegill are used in domestic systems in temperate climates that cannot permanently maintain a specific temperature, and goldfish and koi carp can be used if the fish in the system does not need to be bred for their flesh.
Other fish often used are barramundi, silver perch, catfish, jade perch, or even Murray cod, rainbow trout, perch, common carp, arctic char, bass in big mouth, and striped bass
What vegetables and plants can you grow with an aquaponics pond?
The choice of plants that can be grown by aquaponics directly depends on the volume of fish that can be reared and stored in the ponds.
Indeed, the volume of fish directly influences the quantity and concentration of minerals and nutrients that they produce, and on which the plants will be able to feed. Plants with low or medium nutritional requirements, such as herbs and green leafy vegetables (cabbage, lettuce, basil, spinach, chives, herbs, watercress, etc.), are thus particularly suited to aquaponic systems.
Plants with higher nutritional requirements, such as tomatoes, cucumbers, and peppers, can only be grown in aquaponics systems capable of storing high densities of fish. This is the case for the Écho-village, for example, which allows our farm to offer a wide range of vegetables and herbs that are delicious in terms of flavor as well as nutrients.
Other fruits, vegetables, and plants have known to thrive in an aquaponics system include roses, cilantro, lemongrass, parsley, beans, peas, strawberries, melons, onions, sweet potato, eggplant. …
So, what does an aquaponics pond installation look like?
Aquaponics is based on hydroponics and aquaculture, aquaponics installations very precisely form a harmonious mixture of these two systems. Thus, an aquaponics installation looks like a hydroponic installation to which we would have added fish in the tanks.
Aquaponics typically consists of two main parts and sub-systems to preserve their quality: the aquaculture part, for raising aquatic animals, and the hydroponics part, for growing plants.
In the aquaculture section, waste from animal husbandry (droppings, uneaten food, etc.) accumulates in the water and forms aquatic effluents. This effluent-rich water, which becomes toxic to animals, contains nutrients essential for plant growth. It is therefore sent to the hydroponic part to be filtered thereby the plants whose roots are immersed in this nutrient-rich water, while mechanical and biological subsystems ensure that a quality environment for the fish is preserved by eliminating naturally solid waste, by re-oxygenating the water, and neutralizing its acidity.
How do you generate a healthy environment in an aquaponics pond system? We will distinguish four main parts:
Nitrification by bacteria
Ammonia is a substance that is naturally released into the water from the feces and gills of fish and is particularly toxic to them. Although plants can absorb ammonia, nitrates are absorbed more easily and are less toxic to fish.
To clean fish water while producing the substances that plants feed on, aquaponics, therefore, depends on bacteria to convert ammonia into nitrates. This process, called nitrification, is essential to any aquaponics system. The nitrification bacteria make it possible to purify water while transforming ammonia into nutrients easily assimilated to the plants of the hydroponic system.
Nitrification takes place in two stages: Nitrosomonas bacteria convert ammonia to nitrites, and Nitrobacter bacteria then convert nitrites to nitrates. In order for these bacteria to grow and flourish, they need sufficient space and a favorable environment. The choice of materials for the culture bed, therefore, requires careful analysis and maintenance.
The pH (hydrogen potential of water, or, more simply, its level of acidity) is the other essential element to take into account in aquaculture because every organism living in water needs a Different pH: plants, fish, and bacteria.
The pH is a scale that goes from alkaline (<7) to acid (> 7). Typically, the ideal water for an aquaponics pond should have a neutral pH, between 6.8 to 7.2. With a pH that is too alkaline or too acidic, plants will not be able to absorb nutrients optimally, bacteria will not be able to convert ammonia to purify the water, and the fish will eventually die.
Since this imbalance or too sudden change in the pH of the water is one of the main reasons for the death of fish or plants in an aquaponics system, it is very important to monitor the pH level every day to maintain it. as neutral as possible. This process is facilitated by pH adjusters, devices that must be specially designed for aquaponics pond, or risk injuring the fish.
Many organisms are present in an aquaponics system. As with the pH, it is, therefore, necessary to take into account the needs and requirements of each.
Typically, the water temperature is always above 15 ° C, and can even reach up to 25-28 ° C for plants and fish in hot climates. Depending on whether one is in a covered system in a closed greenhouse, or outdoors, the choice of fish and plants must therefore be made wisely in order to ensure the possibility of cultivating them!
At the Echo-village, we have chosen to use geothermal energy while cultivating rainbow trout, whose temperature requirements are among the lowest of the species used in aquaponics. By optimizing the energy present in the earth thanks to a geothermal heat exchanger, we thus guarantee our trout an ideal temperature all year round, at a very low energy cost, in collaboration with the local ecosystem.
Oxygen in water is a major issue in aquaculture and crop production. Its content is expressed either as a concentration (mg / l or ppm) in the water or as a “saturation percentage”, which makes it possible to know the balance between air and water. When% S <100%, the water is undersaturated with oxygen, and when% S> 100%, the water is supersaturated with oxygen.
The oxygen requirements in aquaculture depend on many factors:
- The cultivated species: the needs of trout are greater than those of a crustacean, for example;
- The strain of the animal: those with a high metabolism can consume more oxygen to grow better;
- Temperature: the higher the temperature, the more oxygen needs to increase;
- Age: young animals consume more oxygen than adults at equal weight;
- The availability of oxygen in water: when oxygen becomes scarcer in water, its consumption decreases;
- Activity: an active fish that moves a lot consumes a lot more oxygen;
- Digestion: after a meal, a fish consumes more oxygen;
- Sex and the state of sexual maturation;
- Stress: resulting from unsuitable breeding conditions, noise, vibrations, diseases …
- Aeration of ambient air
Note that fish breathe in water by picking up oxygen through their gills, like lungs separating water and gas to send oxygen into the blood. While breathing, fish also emit CO2. By dissolving in water, the CO2 released by fish can become toxic in high concentrations (> 20 mg / l). The quantity of CO2 must therefore be constantly adjusted, and in the event of a fish stocking density greater than 50 kg / m3, an oxygenation system is generally employed to saturate the water with oxygen.
At the Écho-village, we have chosen to only cultivate 25 kg of trout per m3 of water, in order to be able to produce a healthy and responsible diet while consuming fewer resources.
History and origins of aquaponics pond
Aquaponics pond until today
Although it is impossible to date the appearance of an aquaponics pond, it is nevertheless an ancient practice. 1000 years ago, before he developed greater mastery thanks to technological advances, humans had already been able to observe the wonders of this natural phenomenon to reproduce and optimize it in a closed circuit. !
In particular, traces of these aquaponic systems are found in pre-Columbian Mesoamerica (present-day Central America), as well as in China.
Thus, the Aztecs already cultivated many vegetable and flower plants on chinampas (literally “places of the reed fence”, cultivation plots or floating gardens), agricultural islands arranged in shallow lakes, which dredged natural waste. through canals from the surrounding towns. This nutrient-rich product then made it possible to irrigate and feed the vegetables, in symbiosis with the aquatic animals living in the lake. Although this technique disappeared with the insertion of domesticated animals and new cultivation techniques by the conquistadors, chinampas then made it possible to produce more than half of the food requirements. of Mexico-Tenochtitlán, the capital of Mexico between 1300 and 1521, whose population is still estimated today between 500,000 and 1 million inhabitants!
In China and South Asia, rice and fish already coexisted in rice paddies, allowing rice production at the same time as the rearing of fish such as oriental loach, marsh eel, common carp, and cruciferous carp, or pond snails. A 13th-century Chinese agricultural manual, Wang Zhen’s Agricultural Book, also describes floating planters in the form of wooden rafts covered with mud and earth, used for the cultivation of fodder rice. Called jiatian or Fengtian (literally “framed rice field”). These floating planters allowed the roots to draw nutrients from the water and were mainly used from the 6th to the 8th century, from the Tang Dynasty (6th century) to that of the Northern Song.
These examples are among the first aquaponics systems recreated and managed by man.
Modern aquaponics pond
Modern aquaponics has seen its development primarily through the work of Dr. Mark McMurtry, North Carolina, who sought to develop alternative aquaponics techniques. This renewed interest in the good results obtained by McMurtry quickly inspired other institutes to develop their own research. Dr. James Rakocy and his colleagues at the University of the Virgin Islands were able to develop a large-scale, deep-water aquaponics pond system through the use of hydroponic growing beds.
In the East, the technique is also experiencing a resurgence of interest that had been lost with socio-political unrest and experiences: China is still a good example, and, to feed an ever-growing population, floating aquaponic pond systems have been installed there. en masse in recent years to produce all types of crops, including rice, wheat, and lilies. Wang Zhen is not far away!
Today, aquaponics is spreading again in the West as an innovative technique to feed isolated populations who cannot benefit from conventional methods of cultivation on the ground, as well as to develop new concepts of urban agriculture and vertical cultivation directly in towns.
It is these centuries of experimentation, research, and practice that today allow aquaponics breeders and growers to reproduce with optimal efficiency closed cycles in a controlled environment, for exceptional feeding and responsible production, ecological, which offers the best of nature.