Induced growth of phytoplankton using two fertilizers (NPK and agrolyser) under laboratory conditions

Abstract

An investigation was carried out on the ability of two types of fertilizer; agrolyser micronutrient and NPK (nitrogen, phosphorus, potassium)-macronutrient in inducing phytoplankton growth for sixteen days under laboratory conditions. The parameters studied were abundance, species diversity and occurrence of the phytoplankton. Twelve 14 L plastics tanks labeled A, B, C and D was used. Each letter represented a fertilizer treatment (three replicates): A, 0.27 g agrolyser; B, 200 g NPK; C, 200 g agrolyser + 0.27 g NPK; and D which is the control. Before the application of these fertilizers, water samples were taken for phytoplankton analyses using 250 ml wide mouth plastic containers. All the tanks were allowed to be naturally inoculated for 3 days. Samples were collected for phytoplankton and physicochemical parameters at an interval of 3 days except temperature which was measured twice daily (morning and evening). A total of 1244 phytoplankton made up of 20 species, belonging to three families: Bacillariophyceae (diatoms), Cyanophyceae (blue-green algae) and Euglenophyceae (euglenophytes) were observed. Out of these algae, tanks C had 51.7%, B 33.2%, A 10.6% and D 4.5% phytoplankters. In the various groups of tanks, the orders of abundance, species diversity and percentage distribution of species of algae were C>B>A>D, C>B>A=D and C>B>D>A, respectively. This paper intends to provide preliminary information to fish farmers that agrolyser should be combined with a macronutrient fertilizer for better fertilization of pond.

Keywords: Induced growth, phytoplankton, fertilizer, NPK, agrolyser