Document Type

Article

Abstract

Increasing fiscal, human, and environmental costs of coal fly ash (FA) management are leading to advocacy for greater beneficial uses of the by-products as soil amendments in agriculture. Greenhouse experiments were conducted in Armour silt loam (ASL) soil that was amended with FA (10%, wt/wt) with and without poultry litter (PL 5 75 mg N/kg). Biomass productivity of eastern gamagrass (GG), a warm-season perennial grass, was measured to serve as complementary biofuel feedstock to switchgrass (SG). FA was obtained from a site at the 2008 ash spill in Kingston, TN. GG and SG were grown individually in 15-cm-wide 3 41-cm-high tree pots, each containing 6 kg of oven-dry soil equivalent (ods) and treated with the following combinations: 0FA/0PL, 10FA/0PL, 0FA/PL, and 10FA/PL. Each treatment was replicated eight times. The tree pots were randomly arranged on greenhouse benches and watered as needed. Biomass production was assessed in soil adjusted to initial pH 5 4.5 or 6.5. After 12 weeks at initial pH 5 4.5, GG produced significantly higher biomass (p , 0.05) in acidic ASL soil that was amended with a combination of 10FA/PL (21.8 g/tree pot) than in unamended ASL soil (13.3 g/tree pot). At initial pH 5 6.5, total biomass productivity of GG ranged from 13.2 to 15.7 g/tree pot, and the differences were not significant. Biomass productivity of SG trended similarly, with the highest biomass productivity (18.2 g/tree pot) observed in ASL soil amended with the 10FA/PL combination, which was significantly higher than the control (14.3 g/tree pot). The treatment combinations did not have a significant effect on biomass productivity of SG at pH 5 6.5. X-ray imaging and analysis of selected washed roots grown at pH 5 4.5 confirmed significant enhancements of root system architecture traits, including root length and area, in the 10FA/PL treatments compared with other treatments. We conclude that FA and PL can be beneficially used to produce biofuel feedstock in acid-impacted soil.

First Page

33

Last Page

39

DOI

https://doi.org/10.4177/ccgp-d-15-00002.1b

Volume

7

Publication Date

1-1-2015

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