Overview
The Big Picture
The world population is an estimated 7.7 billion and is expected to reach 10 billion by 2050. To feed this expanding global populace, food production must increase by 30-50%. This increase would require that land used to raise crops expand by almost 1.5 billion acres; that is about ¾ the size of the continental United States. In 2020, agriculture utilized almost 50% of the world’s vegetated land. The ongoing increase in atmospheric CO~2~ levels, leading to increased global warming, would be exacerbated by the large-scale conversion of forested lands to crop land necessary for food production.
· Kentucky State University1.4 System Types
There are two main types of AP systems, coupled and decoupled. The coupled approach is widely used and is based on feeding the system known nutrient-input amounts/values. The support for plant growth and bacterial consumption (in the biofilter) typically come from commercial fish food and must be factored into system input requirements. These ratios are used to ensure that toxic waste products from fish effluent do not build up (due to an insufficient biofilter), excess nitrates do not occur (from not enough plants), and nitrate deficiencies do not develop (from an excess of plants).
· Kentucky State University1.3 Importance
Hydroponics and intensive RAS each have ecological and economical drawbacks when considered individually. Hydroponic crops rely on chemical fertilizers that are expensive, hard to source, and in some cases are derived from rapidly disappearing natural resources. In intensive fish production, concentrated wastes are generated (i.e. effluent) that require expensive treatment methods, leading to poor consumer perception regarding environmental impacts. The high initial investment may be prohibitive to potential producers, as well.
· Kentucky State University1.2 Context
Development of aquaponic systems resulted from the need to reduce costs associated with high-nutrient effluent discharged from recirculating aquaculture systems (RAS). Known for intensive aquaculture, RAS can produce large quantities of fish in a small volume of water. Some water is discharged and replaced in the system over time, as solid waste and toxic nitrogen by-products (ammonia (NH~3~-N), nitrite (NO~2~-N), and nitrate (NO~3~-N)) build up. Concentrated discharge from intensive aquaculture is a barrier to positive consumer perception of aquaculture.
· Kentucky State University1.1 Definition
Aquaponics (AP) is a self-supporting food production system that combines recirculating aquaculture with plant culture in the absence of soil (hydroponics). High-volume fish production results in nutrient- rich water that can be used to provide nutrients for plant cultivation. Source: Janelle Hager, Leigh Ann Bright, Josh Dusci, James Tidwell. 2021. Kentucky State University. Aquaponics Production Manual: A Practical Handbook for Growers.
· Kentucky State University