Refinement and performace evaluation of media bed aquaponic system

Abstract

In Kerala, the production of fish and vegetables is much less than that of the daily requirement. In this study, an attempt was made to design and develop an aquaponics system to achieve an efficient, less energy-consuming, problem-free operational system working in a sustainable manner at the Hi-tech Research and Training Unit (HTR&TU), Instructional Farm (IF), KAU, Vellanikkara. The study was also made for selection of suitable media (20 mm gravel/ 8-20 mm broken tiles/ 8-15 mm hydroton/ 8-10 mm gravel), performance evaluation of the two aquaponics systems (S1- Aquaponic system fitted with a conventional siphon system and S2- Aquaponic system fitted with feeder cum operation regulation system) with fruiting plant (Tomato) and leafy vegetable (Lettuce) and developing and evaluating a system for automatic recording of temperature and dissolved oxygen level of water in the fish pond. At all stages, the growth and yield of tomato, lettuce and fish in the S2 system were comparatively higher than that of S1 system. Lettuce crop (Cherokee RZ and Starfighter RZ) have given maximum yield in broken tile and minimum yield in hydroton in both S1 and S2 systems during the first and second seasons. 8-10mm gravel was found to be more favorable for the growth and yield of tomato (Yakamoz RZ and Manulakshmi) than all other media selected for the study. In all the cases, the plants grown in the dutch buckets filled with 75 % portion of gravel and wick inserted buckets filled with 75 % portion of gravel showed better performance than the buckets filled with 50 % portion of gravel. The performance of the plants grown in dutch buckets and wick-inserted buckets of S2 system was superior to S1 system. The overall result showed that tomato grown in 8- 10mm gravel and lettuce grown in broken tiles of S2 system showed better performance than all other media of S1 and S2 systems. The macro and micro nutrient level in the water of S2 system was found to be higher than that of S1 system during the study period. The benefit cost ratio obtained while cultivating tomato and lettuce in S2 system was more than that of S1 system. Considering the economic benefits, trouble free and easy operation, S2 system can be recommended for the aquaponics farmers of Kerala.