Effect of Coal Combustion By-products on Phosphorus Runoff from a Coastal Plain Soil

Abstract

Coal combustion by-products can lower soil phosphorus (P) solubility, but few studies have assessed their effect on runoff P. A soil with elevated P content was amended with fluidized bed combustion ash, flue gas desulfurization gypsum, and anthracite refuse ash at rates of 0–40 g kg⁻¹ soil, and runoff from small plots was monitored over 3 years. In the first year, by-products lowered dissolved P in runoff by up to 47% below the untreated control; however, effects did not persist into the remaining years of the study. Total P losses were not significantly affected by coal combustion by-products, likely because of elevated particulate P losses. Water-extractable P was up to 40% less in treated soils than in untreated soils across the 3 years. Results demonstrate that although coal combustion by-products readily lower P solubility in soils, their impact on P losses in runoff can be undermined by erosional processes.

Keywords:

• Fly ash
• phosphorus
• water quality

Acknowledgments

The authors are grateful to the staff of the University of Maryland Eastern Shore Nutrient Management Laboratory and USDA-ARS Pasture Systems and Watershed Management Laboratory for their contributions to the study. Don Mahan oversaw field work at UMES. Jaime Davis, Mary Kay Krazinski, and Joan Weaver oversaw laboratory analyses at ARS.

Notes

This paper is dedicated to the memory of William (Bill) Stout, mentor, friend, and passionate conservationist.