Comparative Evaluation of Media Types in Aquaponic Systems for Tomato Growth and Yield

Aims: To evaluate the performance of tomato crops grown in four different media in a bell siphon arranged aquaponics system. Study Design:  completely randomized design. Place and Duration of Study: Hi-tech Research and Training Unit (HTR&TU), Instructional Farm (IF), Kerala Agricultural University, Vellanikkara from 03-08-2021 to 03-01-2022 and 01-02-2023 to 30-06-2023. Methodology: An aquaponic system was equipped with twenty-four media beds with bell siphons, three filter tanks (sedimentation tank, mechanical filter, and biofilter), three fish tanks having 1000L capacity each, a submersible pump, and two aerators. Two hundred genetically improved farmed tilapia (GIFT) fingerlings were grown in the fish tanks. Four types of media, viz., 20mm gravel (M1), 8-20mm broken tiles (M2), 8-15mm hydroton (M3), and 8-10mm gravel (M4), were filled in the media beds. The two varieties of tomato, Manulakshmi and Yakamoz RZ, were raised. Plant height, plant spread, days to first flowering, days to first harvest, total yield, and average fruit weight were observed to compare the crop performance in each media and identify the best-performing media in an aquaponics system. Results: During the first and second seasons of Manulakshmi in the aquaponics system, plants grown in 8-10mm gravel exhibited significantly superior results than all other media. The maximum plant spread (66.833cm), plant height (140.556cm), total yield (1.730Kg), and average weight of fruit (38.433g) were observed in 8-10mm gravel during the first season. In the second season of Manulakshmi, the observed plant spread, plant height, total yield, and average weight of fruit were 140.778cm, 66.556cm, 1.729Kg and 38.611g, respectively. In the first season of Yakamoz RZ in the aquaponics system, maximum plant height (145.222cm) and total yield (3.871Kg) were observed in 8-10mm gravel, whereas maximum plant spread (50.500cm) was observed in 20mm gravel. The days to first flowering and days to first harvest were comparatively shorter in 8-10mm gravel in both varieties. Conclusion: Plants grown in 8-10mm gravel exhibited superior results than all other media. Variations of plant characteristics among different media in the aquaponics system reveal that 8-10mm gravel is more favorable for the growth and yield of tomato plants than other media.