Effect of Three Different Seaweed Liquid Fertilizers and a Chemical Liquid Fertilizer on the Growth and Histopathological Parameters of Eudrilus Eugeniae (haplotaxida: Eudrilidae)

The present study has a strong focus on the practical aspects of the effect of Seaweed liquid fertilizers (SLF) and Chemical liquid fertilizer (CLF) on the earthworms. The three different types of seaweeds such as Caulerpa scalpelliformis (Chlorophyta), Cheilosporum spectabile(Rhodophyta), Sargassum wightii (Phaeophyta) were taken. The earthworm Eudrilus eugeniae was reared in a cowdung based medium which was amended with a chemical liquid fertilizer and seaweed liquid fertilizer in two different concentrations such as 0.5% and 1% respectively. During the experiment, the growth rate of the earthworm, pH of the amended medium was analysed. The CLF sprayed earthworms showed decreased growth rate from 0 to 60 day but the SLF sprayed earthworms recorded increased growth rate. Among the three SLF, Sargassum wightii indicated highest growth rate 9.88±0.104 in 1% concentration on the 60 day. The pH value in the CLF amended medium was 8±0.1 in 0.5% concentration and 8.06±0.15 in 1% concentration on 0 day and it went down to 6.4±0.4 and 5.8±0.2 respectively in 0.5% and 1% concentration on 60 day. In SLF amended medium, the pH value slowly moved to neutral level. The histopathological studies were carried out in the gut region of Eudrilus eugeniae. In 0.5% concentration of CLF, the epithelial linings were fused and a chloragogen tissue layer was observed to be granulated whereas in 1% concentration of CLF, extravillous growth in the epithelial layer, pyknotic nuclei were found in many epithelial cells and the size of the chloragogen tissue layer was reduced with the nerve cord affected severely. But in SLF incorporated earthworm, the nerve cord was seen clearly and the chloragogen tissue was well developed and it appeared similar to the control.