Technology Proofing: Aquaponics transforming the future of agriculture

Washington

It can’t fly but, if the founders of the startup Phood Farm have their way, their business will soon take off. They hope the future of agriculture will be birthed here. The method used by the five young founders to grow up to 200 kilograms of lettuce per week on an area smaller than a tennis court is called aquaponics a combination of aquaculture, or fish farming, and hydroponics, which is growing vegetables in water without soil.

The two systems together create a highly resource-efficient water and nutrient cycle. Monoculture food production and excessive use of fertilisers and pesticides are harming our soils and biodiversity and threaten entire ecosystems. Global food cultivation is responsible for about one-fifth of all greenhouse gas emissions  not including transportation.Meanwhile, 70% of the world’s drinking water is used for agriculture, despite half the world’s population facing serious water shortages for at least a month of the year. Phood Farm believes that aquaponics can be an important part of the solution. For one, its food production system uses 90% less water than conventional farming. In a greenhouse, water is only lost when it evaporates or is absorbed by the plants, explains Tim Elfring, a Phood Farm co-founder.

How does a recirculating agricultural system work? It’s a relatively simple process: After the seedlings are grown, the lettuces are placed with their roots on a floating Styrofoam plate and spend five to six weeks ripening before they are harvested. In front of the plant basins are two large pools in which 180 koi carp swim. Their excrement is pumped into a pool where natural bacteria from the air, soil and water convert potentially toxic ammonia from the fish manure into nitrate — which plants need to grow.

As the plants feed on the nitrate, they also purify the water, which is pumped back clean into the fish pond. Plants need little or no extra fertiliser to grow in an aquaponics system. “We have the fish, they deliver all the nutritional value,” said Elfring. Because the system is closed to the outside and extremely controlled, it also doesn’t need pesticides.

The yields are also significantly higher compared to conventional aquaculture, said Werner Kloas, a scientist at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB). “If you have 10 litres of water, you can usually produce 2.5 grams of fish in a closed recirculation system,” he said. “With a fully equipped aquaponics system, you can now get up to 100 grams of fish, and you can produce 500 grams of tomatoes at the same time.” Tomatoes, eggplants, lettuce, various herbs and vegetables can be grown in this way. Theoretically, it would even be possible to plant grain and corn, but the infrastructure investment would be too high to make it economically viable. Perennial plants and fruits such as apples or oranges are not suitable.

Unlike other aquaponics systems, Phood Farm raises koi carp for fish collectors. Elfring and his partners are considering switching to fish for consumption soon, partly as a means of combating overfishing, which is one of the biggest threats to marine ecosystems. Though aquaculture has been touted as a solution to overfishing in the ocean, the resulting fish excrement is an enormous burden on surrounding ecosystems.

This article was provided by Deutsche Welle