Beneficial Utilization of Coal Fly Ash with Organic Amendments to Enhance Biofuel Feedstock Production of Indiangrass (Sorgastrum nutans) in Armour Silt Loam Soils

Vanaja Kankarla, Tennessee State University


Waste to energy conversions are emerging as one of the creative strategies with the current focus on energy security and environmental sustainability. With the increasing costs of effective management of coal fly ash (CFA) and the emerging focus on bioenergy crops for biofuel feedstock production, the current thesis project investigated biofuel feedstock production of indiangrass (IG), a warm season perennial grass (WSPG) grown in Armour silt loam soils (ASL) that was amended with CFA and organic amendments such as poultry litter (PL) and vermicompost (VC). Two experiments were conducted in the greenhouse; preliminary and the main experiment, to assess biomass productivity of IG in ASL soils whose pH was adjusted to initial levels of 4.5 representing acid impacted soils that account for 30% of the world's arable cropland and 6.5 representing soil `agronomic' conditions. In the first experiment, addition of CFA alone at 5% caused a reduction of shoot biomass production by IG. However, there were no significant differences in total biomass production between ASL control, treatments with PL alone or with combination of CFA+PL. Similarly, there were no significant differences between any of the treatments at pH=6.5 In addition to CFA and PL amendments, the second experiment also evaluated biomass productivities of ASL together with vermicompost (VC) alone or in combination with other treatments. At pH=4.5 in this experiment, only treatments with CFA alone or combination CFA+PL+VC showed lower biomass production. At pH=6.5, all treatments consisting of CFA, PL or VC alone, or in combinations showed significant total biomass enhancement compared to unamended ASL soils. Biomass productivities of switchgrass (SG), the model bioenergy feedstock showed no influence of pH or soil amendment on biomass productivity. In the preliminary experiment, biomass production by SG was practically identical at both pHs. In the final experiment, only selected SG treatments were evaluated (ASL control and 10% CFA+PL+VC) with similar results. These assessments support further investigation of IG as biofuel feedstock that could be grown on CFA-amended soils in the presence of appropriate organic amendment at least in "agronomic" soils.

Subject Area

Alternative Energy|Environmental management|Agricultural engineering

Recommended Citation

Vanaja Kankarla, "Beneficial Utilization of Coal Fly Ash with Organic Amendments to Enhance Biofuel Feedstock Production of Indiangrass (Sorgastrum nutans) in Armour Silt Loam Soils" (2014). ETD Collection for Tennessee State University. Paper AAI1584247.