Assessing the Effect of Flow Rate on the Growth of Lettuce in Three Aquaponics Systems

Abstract

Today’s agricultural industry threatens natural resources through their extensive land, water, and fossil fuel usage in order to meet the food demands of the growing population. Out of the various sustainable agricultural practices used, aquaponics allows for minimal effects on the environment by growing plants and raising fish at the same time, either indoors or outdoors. However, because aquaponic systems can be constructed differently, the most efficient system for production is still unknown. This experiment was conducted to determine how the flow rate within three different aquaponics systems would affect the growth and efficiency of the production of lettuce. The three aquaponics systems being compared included an AquaDuo Filter system (116 gal/h), an integrated system (0 gal/h), and a separated system (60 gal/h). It was hypothesized that an increase in flow rate would allow for more readily available nutrients to the plant roots; thus, allowing for maximum growth. The first trial of the experiment found that both the separated system (60 gal/h) and integrated system (0 gal/h) performed the best with statistically the same average change in lettuce volume and average surface area of the largest leaf while, the second trial showed that the average change in plant volume, average change in plant length, and the average surface area of the largest leaf was greatest within the integrated system (0 gal/h). The hypothesis was not supported and it was concluded that the lettuce reached maximum yields within a system containing a slower flow rate. By using the most efficient aquaponics system, faster sustainable food production can be achieved.