THE APTNESS OF NILE TILAPIA POND SLUDGE AS A BEDDING MEDIA FOR EARTHWORM GROWTH AND VERMICOMPOST PRODUCTION

THE APTNESS OF NILE TILAPIA POND SLUDGE AS A BEDDING MEDIA FOR EARTHWORM GROWTH AND VERMICOMPOST PRODUCTION

Safwat A.A. Gomah¹; Yasser Thabet A. Moustafa^2*;

Ahmed Abdel Fattah¹; Ahmed Moustafa M. Batran²

¹Aquaculture Department, Central Laboratory for Aquaculture Research (CLAR), Agricultural Research Centre (ARC).

²Limnology Department, Central Laboratory for Aquaculture Research (CLAR), Agricultural Research Centre (ARC).

* corresponding author: [email protected]

ABSTRACT

The disposal of aquaculture sludge (AS) from freshwater aquaculture system is causing serious pollution in waterways or in agriculture as organic fertilizer. Therefore, the present study investigated the potentiality of AS for vermicomposting and the influence of different types of AS on the vermicompost bio-chemical composition and earthworm growth performance. Ten treatments with five mixing ratios (40, 50, 60, 70 and 100%) were applied using sludge of either broodstock or fry Nile tilapia with peat moss, harnessing three species of earthworm (Eisenia fetida; Perionyx excavaus; Lumbricus rubellus) for 60 days.

The results showed that the concentration and type of AS had significant influence on earthworm weight gain % as well as on the chemical composition of the resulted vermicompost. The maximum weight gain % (111,4%) was recorded at 100% broodstock AS. The maximum phosphorus content in the produced vermicompost (VC) was determined in 40% broodstock AS. The maximum nitrogen content was recorded in 40% fry AS. The results elucidated that there was significant influence of the type of AS on both the Indole acetic acid and amino acids content of the resulted VC. However, their impact was insignificant on the abscisic acid and gibberellic acid contents of VC.

This study is an attempt for finding effective way to treat AS and produce biofertilizer that can improve the soil properties of aquaculture ponds and leads to improved water quality and hence fish productivity. Further studies are needed to manipulate the biochemical composition of vermicompost and its influence on aquaculture as biofertilizer.

Key Words:
Aquaculture sludge, Vermicomposting; fish sludge treatment; earthworms; vermicompost; Nile tilapia broodstock sludge, Nile tilapia fry sludge.