Author(s): T N RAVIKUMAR, N A YELEDHALLI, M V RAVI, K NARAYANA RAO
In view of the environmental problems generated by large-scale production of fly ash, increasing attention is now being paid to the recycling of fly ash as a good source of nutrients. Because availability of many nutrients is very low in fly ash, available ranges of such nutrients must be improved to increase the effectiveness of fly ash as a soil amendment and possibility of increasing total nutrient content in fly ash through vermicomposting. Fly ash was mixed with different organic residues in 1: 0, 1:1, 1:1.5, 1:2.0 and 1:3 ratios and incubated with Eudrilus eugeniae for 75 days. The concentration of above said macro and micronutrient was found to increase in the earthworm-treated series of fly ash and organic residue combinations compared with the fly ash alone. This helped to transform considerable amounts of total nitrogen, phosphorus, potassium and micronutrients from fly ash into more soluble forms and thus resulted in increased bioavailability of the nutrients in the VERMIASH compost. Among different combinations of organic residues and fly ash, nutrient availability was significantly higher in the 1:1 and 1:1.5 ratio treatment compared with the other treatments. The dehydrogenese, urease and phosphate activity of VERMIASH compost increased significantly due to earthworm activity .The source of organic residues also had significant influence on the soil enzyme activity.