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United States Department of Agriculture

Agricultural Research Service

Title: Effectiveness and Safety Coal Combustion by-Products in Controlling Phosphorus Export from Cropland

Authors
item Stout, William
item Sharpley, Andrew

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 20, 1999
Publication Date: June 13, 2000
Citation: Stout, W.L., Sharpley, A.N. 2000. Effectiveness of coal combustion by-products in controlling phosphorus export from soils. Journal of Environmental Quality. 29:1239-1244.

Interpretive Summary: Because of heavy applications of manure and fertilizer, many soils in the northeast U.S. contain excessive levels of phosphorus. When rain falls on these soils, the runoff carries dissolved and sediment-associated phosphorus into streams and lakes causing pollution. One way to reduce the amount of P in the runoff is to reduce dissolved P concentrations by tying it up in the soil using different types of combustion by-products. We tested some of these coal burning by-products to see how well they would prevent phosphorus loss in runoff and if they would affect plants growing on the treated soils. We found that the by-products substantially reduced the dissolved P in runoff, but did not detrimentally effect plants growing in the treated soil.

Technical Abstract: Phosphorus (P) export from high P soils is a major cause of eutrophication in fresh waters of the northeast U.S. Recent work has shown that the solubility of P in high P soils can be reduced with coal combustion by- products (CCBs), decreasing the potential for dissolved P (DP) export from these soils. However, the effect of such treatments on plant available P and P export has not been quantified. We measured P uptake by canola (Brassica napus L.) from three high P (130 370 mg kg-1 Mehlich-3 P) soils treated with two CCBs, fluidized bed combustion (FBC) flyash, flue gas desulfurization (FGD) CaSO4 anhydride, and agricultural gypsum (GYP). We measured DP, particulate P (PP) and total P (TP) concentrations in runoff from grassed and bare soils treated with these materials and subjected to simulated runoff. Phosphorus, As, Cd, and Pb uptake by canola were unaffected by CCB treatment, and dry-matter yields were unrelated to treatment. On grassed soils FBC, FGD, and GYP reduced DP concentration in runoff by 20, 43, and 33%, respectively, but did not affect As, Cd, or Pb concentrations in runoff. Also on grassed soils, the high application rate of FGD reduced TP in runoff by 35%. On bare soils where erosion of PP controlled P loss, CCBs and GYP had no effect on DP concentration in runoff. Application of CCBs to high P soils in zones of high surface runoff potential, where there is little erosion, has the potential to reduce P export, without affecting crop production.

Last Modified: 9/2/2014
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