FLY ASH-ORGANIC BYPRODUCT MIXTURE AS SOIL AMENDMENT

Greenhouse studies were conducted to assess the potential of fly ash-organic waste co-disposal to enhance crop production. Two pot experiments, one using sorghum sudangrass (Sorghum vulgaris) and other using collard greens ( Brassica olreraceae) were conducted under greenhouse conditions. In addition, a leaching experiment was also conducted to assess the leaching potential of selected heavy metals from fly ash (FA)-sewage sludge (SS) amended soils. The results indicated that biomass production of sorghum sudangrass was significantly increased up to 250 Mg/ha FA: SS mixture amendment, regardless of various ratios of FA: SS mixed amendment. Similarly, the collard greens biomass significantly increased up to 50 Mg/ha. The elemental uptake showed a similar pattern for both sorghum sudangrass and collard greens. The leaching study indicated that increased application rates of amendments ( either alone or as mixtures) resulted in increa(sed leaching of metals. Therefore, low to moderate rates of FA: SS mixture (1:1 ratio) could be successfully used as soil amendments.