Growth of Gynura procumbens and oreochromis spp. by using cocopeat media in aquaponics system

Abstract

Lightweight expanded clay aggregate (LECA) and gravel are common growing media that are used to support plants in hydroponic system. However, LECA is quite expensive and gravel causes the presence of algae. Therefore, alternative media from local source are required. The study evaluates the growth rate of Gynura procumbens plants by using four different growing media (LECA, cocopeat, rice husk and mixture of cocopeat with rice husk) in an aquaponic system. The media were analysed based on the physical and chemical properties before being used as growing media in the aquaponics system for water quality, nutrients level and growth of Gynura procumbens plants and Hybrid red Nile Tilapia fish. Results attained signified the suitability of utilizing rice husk and cocopeat as alternative media compared to commercial media such as LECA because there was a significant difference (P< 0.05) between all analytical tests. Commercial media such as LECA did not require water treatment unit but the usage of cocopeat is not guaranteed by its effectiveness in treated water in the aquaponics system. Therefore, extra filtration system (single or combined) filter was required and the study of four different water treatment units (mechanical, biological, combination and media) by using cocopeat as media in the aquaponics system. The water treatment unit was being compared based on water quality, nutrients level and growth of plants and fish. All the aquaponics systems were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level measured to be within the range of 6.4-6.9 (± 0.07), 27.7-29.0°C, and 5.5-7.0mg/L (± 0.09), respectively. Satisfactory reduction (50-70%) was achieved for total suspended solids (TSS) and the nitrogen compounds within the systems. The results revealed that cocopeat was insufficient to act as a water treatment unit in the aquaponics system studied. The aquaponics system required at least a biological or mechanical filter for effectiveness in treating water of the system.