Combining Coal Fly Ash and Poultry Litter Amendments for environmental clean up and enhancing Biofuel Feedstock Production in Indian grass

Abstract:

Coal is a major resource for generating electricity worldwide. Burning of coal not only produces electricity but also generates coal combustion wastes (CCW). In 2011, in U.S alone, 130 million tons of CCW were produced annually during generation of 4 trillion kilowatt energy per hour. The incessant increase in the generation of CCW, especially the Fly ash which is a serious pollutant necessitates its prompt disposal. Currently, the disposal methods of FA are limited to environmentally undesirable options of either storage in large, wet impoundments or disposal in landfills. Increasingly high costs of management and disposal of FA has prompted growing advocacy for beneficial uses for the product, including its utilization in agriculture. Despite its hazardous contents, FA possesses excellent physical and chemical characteristics that are required for crop production. An emerging emphasis on bioenergy production using warm season perennial grasses, (WSPGs), presents opportunities to use two waste products, namely FA and poultry litter (PL) as soil amendments to enhance biofuel feedstock production, especially on marginal and/or degraded lands.

Greenhouse pot experiments were conducted with indiangrass, (Sorghastrum nutans) IG, to evaluate its suitability as a feedstock that can complement model bioenergy crop, switchgrass, (Panicum virgatum) SG, for diversifying biofuel biomass production. The evaluations were carried out in Amour silt loam soil collected from Tennessee State University Agricultural Research and Education Center in Nashville TN, USA. Treatments evaluated biomass productivities by IG with or without FA (5%) and PL (75 mg/kg N) soil amendments at neutral (6.5) and acidic (4.5) pHs.

Results of these preliminary investigations suggest that soils amendment with FA with or without PL at the specified levels at best only marginally enhanced in biomass productivities by IG. Furthermore, soil pH did not appear to influence biomass productivity by IG, an important consideration for biomass production by WSPGs in acid-impacted soils. The results also showed overall lower biomass productivities by IG than by SG; however, the trends of biomass productivities were similar. Further experiments would be carried out with vermicompost to enhance biomass.