Influence of Seaweed Liquid Fertilizer on the Growth of Red Algae Gracillaria verrucosa under controlled conditions

Abstract

The use of pesticides in agriculture has a negative effect on environment. Thus, environmentfriendly fertilizers are needed to minimize the use of pesticides. The present study used seaweed liquid fertilizer (SLF) extracted from Sargassum sp., Gelidum sp., and Padina sp. to support the coastal agricultural activity, especially in the production of red algae (Gracilaria verrucosa). SLF extracted from Gelidium sp. exhibited a higher nutrient content in Ca, K, and P than other seaweeds. SLF extracted from Gelidium sp. also demonstrated a higher absolute growth and daily growth rate of G. verrucosa than other treatment. The highest growth of G. verrucosa was observed on the SLF fromGelidium sp. with the optimum concentration of 2.0 -2.5 ml/L. The results suggested that Gelidium sp. might provide a prospective future in developing seaweed SLF for Gracilaria verrucosa production.