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Optimization of Fly Ash Incorporation into Cow Dung–Waste Paper Mixtures for Enhanced Vermidegradation and Nutrient Release
Author(s) -
Mupambwa Hupenyu A.,
Mnkeni Pearson N. S.
Publication year - 2015
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2014.10.0446
Subject(s) - vermicompost , cow dung , humus , fly ash , eisenia andrei , compost , earthworm , chemistry , nutrient , biomass (ecology) , zoology , wood ash , agronomy , biology , soil water , ecology , organic chemistry , fertilizer
This study was conducted to establish an appropriate mixture ratio of fly ash (F) to optimized cow dung–waste paper mixtures (CP) to develop a high‐quality vermicompost using earthworms ( Eisenia fetida ). Fly ash was mixed with cow dung–waste paper mixtures at ratios of (F:CP) 1:1, 1:2, 1:3, 2:1, and 3:1 or CP alone and composted for 14 wk. Olsen P, inorganic N (NO 3 , NO 2 , and NH 4 ), C:N ratio, ash content, microbial biomass C, and humification parameters were measured together with scanning electron micrograph images to determine compost maturity. Based on C:N ratio, the extent of vermidegradation of the waste mixtures followed the decreasing order (F:CP) of 1:3 > 1:2 > 1:1 > CP alone > 2:1 > 3:1. Similarly, Olsen P was significantly higher ( P < 0.05) where earthworms were added. The mean percentage increase in extractable P was in the order CP alone > 1:2 > 1:3 > 1:1 > 2:1 > 3:1, with earthworm addition almost doubling P release across the 1:1, 1:2, and CP alone treatments. Fly ash incorporation enhanced conversion of organic N to the plant‐available inorganic forms, with the 1:3 treatment resulting in the highest conversion. Scanning electron micrograph images confirmed the extent of vermidegradation reflected by the various humification parameters determined. Fly ash incorporation at the 1:2 ratio proved to be the most appropriate because it allows processing of more fly ash while giving a vermicompost with desirable maturity and nutritional properties.