Bacterial Population Dynamics in Fly Ash Amended Soil With and Without Amelioration by Earthworms

摘要

The experiment was conducted to study the bacterial population in fly ash amended soil with and withoutearthworm inoculation in laboratory by dilution plate method. It was found that in presence of Drawida willsiat 5% fly ash (FA) amendment showed maximum population of 43.2 ± 1.15 × 10 9 cfu/ g soil from initialpopulation. At 10% and 15% FA amendment gradual decline to 14.3 ± 0.4 × 10 9 and 7.63 ± 0.6 × 10 9 cfu/gsoil from 21.7 ± 0.36 × 10 9 and 15.33 ± 1.1 × 10 9 cfu/g soil over 90 days of experiment at an interval of 15days was observed. In absence of earthworms gradual decline in population was seen in the threeconcentrations of fly ash amendment to 22.7 ± 0.5 × 10 9 , 11.6 ± 0.7 × 10 9 and 3.43 ± 0.7 × 10 9 cfu/g soilrespectively. ANOVA test showed that with earthworms the effect of concentration of FA on the bacterialpopulation was significant (F = 69.9, df = 6, 2, p≤ 0.05) and in the absence of earthworm both concentrationand time interval played a significant role (F = 155.1, df = 6, 2, p≤ 0.1; F= 10.5, df = 6, 2, p ≤ 0.001). Lowerdose of 5% fly ash in soil proved to be optimum for the bacterial activity in the presence of earthworms.Morphological details of different bacterial colonies were assessed and found to be of punctiform, irregular,circular and filamentous shapes with punctiform dominating the culture.