Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2010
Publication Date: 3/22/2011
Citation: Johnson, K.N., Allen, A.L., Kleinman, P.J.A., Sharpley, A.N., Stout, W.L. 2011. Effect of coal combustion by-products on phosphorus runoff from a coastal plain soil. Communications in Soil Science and Plant Analysis. 42:778-789. DOI: 10.1080/00103624.2011.552660. Interpretive Summary: The development of phosphorus-based management strategies has focused attention on soils with excessive phosphorus content that are prone to dissolved phosphorus losses in runoff. One novel approach has been to amend such soils with materials that reduce the solubility of phosphorus in the soil, hence the availability of that phosphorus to runoff water. This study represents a comprehensive evaluation of the use of coal combustion byproducts, often referred to as “coal fly ash,” in agricultural soils on the Delmarva Peninsula. While some of the coal combustion byproducts were quite effective in reducing soil phosphorus solubility, their effects on runoff phosphorus losses were mixed, as were their effects on nutrient and trace metal concentrations in soils and plant tissue. As such, this study provides a tempered endorsement for the use of coal combustion byproducts in agricultural soils.
Technical Abstract: The use of coal combustion by-products (CCPs) to decrease soil phosphorus (P) solubility, hence runoff P losses, has received considerable attention, but most studies have not directly assessed runoff. Trials were conducted to evaluate the effect of applying different CCPs to an Othello silt loam (Mehlich-3 P = 338 milligrams per kilogram) under continuous, no-till corn (Zea mays L.). Forty-eight, 60 by 120 centimeters runoff plots were amended with either fluidized bed combustion ash (FBC), flue gas desulfurization gypsum (FGD) or anthracite refuse ash (ARA) at rates from 0-40 grams per kg soil. In the first year, dissolved P (DP) in runoff was significantly lower (up to 47%) from CCP treatments than from the control, but differences did not persist into the second and third years. However, total P (TP) losses in runoff were not significantly affected by CCPs, likely due to elevated particulate P losses (DP accounted for only 29% of runoff TP). Water extractable P (WEP) was up to 40% lower in CCP-treated soils than in the unamended control across the study period, suggesting that better erosion control could have improved CCP effectiveness over time and effectively reduced total P in runoff. Corn yields were not affected by CCPs and plant-available soil nutrients remained sufficient for crop production. However, significant increases in boron were consistently observed in plant tissue. Better understanding of CCP properties and interactions with soil constituents is required before they can be recommended for mitigation of P runoff from agricultural soils.