Upper Profile Changes Over Time in an Appalachian Hayfield Soil Amended with Coal Combustion By-products

Large amounts of flue gas desulfurization (FGD) and fluidized bed combustion (FBC) by-products from burning coal, consisting primarily of gypsum, are available for potential use as a soil amendment. However, information is limited on longer-term changes in chemical and physical properties induced over time and over small depth increments of the upper soil profile after applying these amendments. This study examined longer-term effects in an abandoned Appalachian pasture soil amended with various liming materials and coal combustion by-products (CCBPs). Soil chemical and physical properties were investigated over time and depths. Received 10 January 2005, Accepted 8 September 2005 Address correspondence to X. Zhou, Department of Crop and Soil Sciences, 116 ASI Building, Pennsylvania State University, University Park, PA 16802, USA. E-mail: [email protected] Communications in Soil Science and Plant Analysis, 37: 1247–1267, 2006 Copyright # Taylor & Francis Group, LLC ISSN 0010-3624 print/1532-2416 online DOI: 10.1080/00103620600623574 1247 D o w n l o a d e d B y : [ U S D A N a t l A g r i c u l t u l L i b ] A t : 2 2 : 5 1 1 2 A u g u s t 2 0 0 9 The results indicated limited dissolution and movement of the calcium (Ca) and magnesium (Mg) applied with the chemical amendments, except for Ca and Mg associated with sulfate. However, sufficient dissolution occurred to cause significant increases in exchangeable Ca and Mg and decreases in exchangeable Al that were reflected in corresponding increases in soil pH. These beneficial effects persisted over time and were confined to the upper 0to 15-cm depth of the profile. The greatest benefits appeared to be in the upper 0to 5-cm surface layer. Both Ca and Mg applied as calcitic dolomitic limestone tended to be immobilized in the upper 0to 5-cm layer of the soil profile; Ca more so than Mg. The presence of S applied in the FGD and FBC amendments appeared to enhance the mobility of Ca and Mg. The ratio of Ca/Mg in HCI extracts from the calcitic dolomitic treatment was close to that of applied calcitic dolomite, implying that the inactive component in soil might be the original calcitic dolomite particles. Soil physical properties measured over small depth increments showed that application of the amendments improved the saturated hydraulic conductivity only in the upper 0to 5-cm depth and had little or no significant effect on the dry bulk density and plant-available water.