Effect of Chemical Fertilizers on Growth Dynamics and Survival of Eisenia fetida: An Ecotoxicological Assessment

Aims: Soil biota, particularly the earthworms that are essential to soil ecosystem health and functioning, are suffering from the intensive use of chemical fertilizers in modern agriculture. In the present study, effects of four fertilizers, namely urea, NPK (15:15:15), NPK (10:26:26) and superphosphates, on the growth and survival of Eisenia fetida were evaluated. Study Design: Specimens of Eisenia fetida collected from a vermiculture unit in Ahmednagar district, Maharashtra, India, were acclimatized under laboratory conditions before experimentation. The effects of selected fertilizers were evaluated over 11 weeks for the parameters such as biomass reduction and mortality. Methodology: To study the effects of treatment and periodic growth trends, statistical techniques such as one-way ANOVA, linear regression, and descriptive statistics were used. Results: The findings showed that the treatments vary significantly (F = 5.77, p < 0.01). With a high negative growth trend (R2 = 0.922), a loss in biomass of 72.10% and mortality of 48%, urea demonstrated significant toxicity. A slight decrease in biomass without significant mortality was indicative of the moderate sublethal stress caused by NPK fertilizers. Superphosphate, on the other hand, supported biomass gain (19.15%) that was either equal to or greater than control conditions and had no harmful consequences. Conclusion: The results emphasize the ecological risks associated with excessive use of nitrogenous fertilizers and show a clear gradient of toxicity (urea > NPK > superphosphate ≈ control). In order to maintain soil biodiversity and functionality, this study highlights the necessity of careful fertilizer management and encourages the use of environmentally friendly substitutes.