Effects of foliar application of Fermented Fish Waste Solution from yellowfin tuna (Thunnus albacares) on growth and yield of MI-2 chilli (Capsicum annuum)

Yellowfin tuna is the most popular fish species consumed by Sri Lankans, and the majority of waste generated during processing is not utilized properly. The waste of this species has been identified as a rich source of amino acids and micro-nutrients which are essential for plant growth, but they are dumped into the ocean, or disposed in landfills leading to pollution. The study was conducted to prepare a fermented fish waste solution (FFWS) from yellowfin tuna and evaluate its efficiency on the growth and yield of MI-2 chilli crops. The FFWS solution was prepared by using fish waste from yellowfin tuna and jaggery in a 1:1 ratio and kept for about 21 days for fermentation in a cool and well-ventilated location. The filtrate of FFWS was applied separately as a foliar spray in different concentrations (2.5%, 5% and 7.5%) on chilli plants (n = 10 per treatment) once in a week with a negative control. The height of the plants, number of leaves and number of branches were measured, and the number of flowers and fruits were counted weekly until the first harvest. According to the findings, crops subjected to FFWS started flowering earlier and showed better growth and yield than control crops. Overall, plants treated with 5% and 7.5% of FFWS promoted growth and yield similarly, without significant differences. According to the research results, the application of the 5% FFWS is a more cost-effective and affordable choice than the application of the 7.5% FFWS. Further study and commercialization of FFWS foliar fertilizer may promote environmentally-friendly agriculture and the effective use of fish waste, as well as provide better solutions for the current scenario in Sri Lanka to reduce the usage of synthetic fertilizer.