Aquaponics and the hydroponics it requires are umbrella terms for the cultivation of fish and plants outside their natural environment, i.e. without soil.
In hydroponics, the fertilisation of the plants is carried out via a parallel fish farming operation.
More details here.
Purpose of the Concepts
In addition to the environmentally friendly use of water resources, the aim is to avoid pesticides, herbicides and medicines (according to regulations in force as of 2021 in Germany) while making optimal use of fertilisers and feed.
The systems are separated from nature and operate in a closed cycle. Contamination of groundwater as well as the use of machinery — as is common in conventional agriculture and fish farming — is avoided here as a matter of principle. The cultivation of plants (hydroponics) is carried out in combination with fish farming (aquaponics) in a closed system. The excretions of the fish are used as fertiliser.
Difference from Hydroponics
The difference from hydroponics lies in the additional fish farming component. Fish waste consists of a large variety of organic substances, most of which are not directly available to plants. Worms and bacteria (decomposers) are used to convert the waste into nutrients. Without this approach, plants do not receive enough nutrients and the fish become poisoned. When living conditions are kept optimal, they together produce a nutrient-rich growing bed.
Advantages of Natural Fertilisation
This natural fertilisation is more productive than adding artificial fertiliser, as the worms release growth-promoting substances for plants. This means no hydroponic fertiliser needs to be introduced into the system. Since hydroponic fertiliser is expensive and must be added in a controlled (precisely dosed) manner, this is the main reason why aquaponics is preferred over hydroponics. It saves both time and money.
Complexity of the Systems
Aquaponics consists of complex biological systems. These biological systems require expert knowledge, as they represent complex units. Aquaponics is more technically and scientifically complex than hydroponics. These are highly dynamic systems that can change without external influence.
However, since they involve living organisms (fish, worms, bacteria, plants), they self-regulate within a certain framework. Once the material balance between fish, worms, bacteria and plants is in equilibrium, the system barely needs to be readjusted. This fine-tuning can take one or even up to two years. The fish need to be fed, dead plant matter must be removed, and the system must be monitored for pest infestation.
Schematic Diagram of an Aquaponics System
This consists of a fish farming unit connected to a hydroponics installation, which uses the residual matter from fish farming to meet its nutrient requirements.
Pro
For all existing businesses that already have a customer base or even a farm shop, aquaponics is ideal. Operations can be gradually converted to aquaponics without having to worry about losing existing customers.
Contra
A significant obstacle, in addition to legal requirements, is the high initial cost. Before the system can be operated commercially, a capacity of approximately 20 to 30 tonnes of fish per year must be planned for. Furthermore, considerable persuasion of customers is required, as conventionally farmed fish is significantly cheaper.
Historical Background
Aquaponics has ancient roots, although its first appearance is a matter of debate:
Aztec Chinampas
The Aztecs cultivated agricultural islands known as chinampas in a system regarded by some as an early form of aquaponics for agricultural purposes, in which plants were grown on stationary (or sometimes movable) islands in the shallows of lakes, and waste materials dredged from the chinampa canals and surrounding towns were used to manually irrigate the plants.
Asian Rice Paddy Systems
Southern China and Southeast Asia, where rice was grown in paddies in combination with fish, are cited as examples of early aquaponics systems, although the technology was brought by Chinese settlers who had migrated from Yunnan around 5 AD. These polyculture farming systems existed in many Far Eastern countries and raised fish such as the oriental loach, swamp eel, carp and crucian carp, as well as pond snails in the rice paddies.
Chinese Floating Planting Machines
The Chinese agricultural handbook Wang Zhen's Book on Farming from the 13th century describes floating wooden rafts piled with mud and soil, used for growing rice, wild rice and fodder crops. Such floating planting machines were used in regions that now form the provinces of Jiangsu, Zhejiang and Fujian.
Sources
Image: Sennedjem and his wife in the fields sowing and tilling, from the tomb of Sennedjem, The Workers' Village, New Kingdom (wall painting). The work of art depicted in this image and the reproduction thereof are in the public domain worldwide.
4) Boutwelluc, Juanita (December 15, 2007). "Aztecs' aquaponics revamped". Napa Valley Register.
5) Rogosa, Eli. "How does aquaponics work?".
6) Crossley, Phil L. (2004). "Sub-irrigation in wetland agriculture" (PDF). Agriculture and Human Values.
7) Integrated Agriculture-aquaculture: A Primer, Issue 407. FAO. 2001.
8) Tomita-Yokotani, K. et al. (2009). "Space agriculture for habitation on mars and sustainable civilization on earth". Recent Advances in Space Technologies.
9) "Carassius carassius". Food and Agriculture Organization of the United Nations.
10) McMurtry, M. R. et al. (1988). "Aqua-Vegeculture Systems". International Ag-Sieve.
11) Bocek, Alex. "Introduction to Fish Culture in Rice Paddies". Water Harvesting and Aquaculture for Rural Development.
12) "王禎農書::卷十一::架田 - 维基文库，自由的图书馆" (in Chinese).
References and Glossary
| Further articles (internal): | Planting Methods |
| Video feature BR, Unser Land (external): | Aquaponics Basics |
| Glossary (external): |
Wiki: Hydroponics / Hydroculture Wiki: Aquaponics / Aquaculture |
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