THE EFFECT OF THE CONCENTRATION OF UREA FERTILIZER ON ROTIFER (Brachionus plicatilis) POPULATION GROWTH
This study aims to determine the effect of the best concentration of urea fertilizer on population growth of rofiter (Brachionus plicatilis). The method used in this study is an experimental method using a Completely Randomized Design (CRD), with 4 treatments namely giving KW21 1ml / L as a control, urea 50 mg / L, 100 mg / L urea, 150 mg / L which is repeated as many as 3 time. Observation of density was carried out for 24 hours. Parameters observed include population growth rate, relative growth, specific growth and self-doubling time. The results showed that the highest rotiter population growth rate was 4.34 ind / mL achieved on the 6th day (exponential phase), the highest relative growth of 76.33%, the highest specific growth of 1.88%, and the shortest self-doubling time of 1.31 per hour. Based on this study, for growth it is recommended to use urea fertilizer at a dose of 150 mg / L.