Effect of chemical and bio-fertilizers on the life table attributes of Eisenia fetida

Earthworms are important soil invertebrates and play an important role in improving soil quality. Indiscrete use of chemical fertilizers poses a threat to soil quality. Alteration in the soil chemistry is known to negatively impact the macrofauna of soil, especially, epigeic earthworms. The study aimed to understand the effect of chemical and biological fertilizers on the life table attributes of earthworm, Eisenia fetida. Laboratory adapted E. fetida were reared on artificial soil supplemented with chemical fertilizers, Urea and DAP, and biofertilizers, vermicompost and Rutoz®.It was observed that the presence of urea in soil proved to be detrimental to the biomass accumulation, life span, as well as reproductive potential of the earthworms. Application of urea to the soil harbouring earthworms reduced the weight of individual earthworms from 286±14.24 mg in the control group to 242±12.047 mg as soon as 15 days of the application, while the DAP diminished the earthworm weight to 272±13.54 mg. The effect was more pronounced on the total biomass of the culture owing to the high toxicity of urea. The total mass diminished to one-third,i.e., 1.02±0.05 g on Day 60 as compared to the corresponding control (3.46±0.172 g). The urea and DAP treatment decreased the percent survival of the earthworms by 70% and 40%, respectively.On the other hand, the bio-fertilizers had a positive effect on the earthworms and the biology is comparable to that of the control group. To the best of our knowledge, this is the first attempt to understand the effect of chemical fertilizers on the survival and reproductive fitness of the worms.