Flue gas desulfurization by-products additions to acid soil: alfalfa productivity and environmental quality

Flue gas desulfurization (FGD) by-products are created when coal is burned and SO2 is removed from the flue gases. These FGD by-products are often alk aline and contain many plant nutrients. Land application or FGD by-products is encouraged but little information is available related to plant respons es and environmental impacts concerning such use. Agricultural lime (ag-lim e) and several new types of FGD by-products which contain either vermiculit e or perlite were applied at 0, 0.5, 1.0, and 2.0 times the soil's lime req uirement (LR) rate to an acidic soil (Wooster silt loam). The highest FGD b y-products application rate was equivalent to 75.2 Mg ha(-1). Growth of alf alfa (Medicago sativa L.) was significantly increased compared to the untre ated control in the second year after treatment with yields for the 1 x LR rate of FGD approximately 7-8 times greater compared to the untreated contr ol and 30% greater than for the commercial ag-lime. Concentrations of Mo in alfalfa were significantly increased by FGD by-products application, compa red to the untreated control, while compared to the ag-lime treatment, conc entrations of B increased and Ba decreased. No soil contamination problems were observed, even at the 2xLR rate, indicating these materials can be saf ely applied to agricultural soils. (C) 2001 Elsevier Science Ltd. All right s reserved.