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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #310782

Title: Flue gas desulfurization gypsum agricultural network alabama (bermudagrass)

item Watts, Dexter
item Torbert, Henry - Allen

Submitted to: Technical Report
Publication Type: Research Technical Update
Publication Acceptance Date: 10/5/2014
Publication Date: 10/5/2014
Citation: Watts, D.B., Torbert III, H.A. 2014. Flue gas desulfurization gypsum agricultural network alabama (bermudagrass). Electric Power Research Institute Grant Final Report. Available:

Interpretive Summary: Power company gypsum is being produced at utility plants when sulfur is removed from the exhaust of burning coal. This power company gypsum is believed to be similar (or better for) soil/plant improvement capabilities than mined gypsum. Thus, a study was conducted in the Southeastern Region to compare two power company gypsum sources to a commercially available mined source. The gypsum sources were applied to pasture after poultry litter application. All gypsum sources increased soil Calcium and Sulfur content in soil. The addition of power company gypsum did not increase significantly increase the accumulation of toxic metals in soil. No negative effects on plant growth were observed. None of the gypsum additions beneficially improved forage production.

Technical Abstract: Synthetic gypsum is being produced in large quantities each year as a byproduct of SO2 removal from flue gas stream at coal-fired utility plants. This synthetic gypsum which is believed to be comparable or better than mined gypsum may enhance crop production. However, there is a paucity of information on the agricultural and environmental impacts that this gypsum source may have on soils and plant nutrient uptake. Thus, flue gas desulfurization (FGD) and mined gypsum sources were evaluated to determine their potential beneficial and detrimental effects on soil and forage productivity. The study was located at the Sand Mountain Research and Extension Center in Northeast Alabama, USA, on an Appalachian Plateau soil; Hartselle fine sandy loam (fine-loamy, siliceous, subactive, thermic Typic Hapludults). Poultry litter was applied at a rate of 4 tons acre-1 in an established bermudagrass pasture (Cynodon dactylon L.) as the fertility source. Treatments consisted of commercial gypsum (1, 5, and 10 tons acre-1), flue-gas desulfurization (FGD) gypsum (1, 5, and 10 tons acre-1), FGD gypsum + fly ash (1, 5, and 10 tons acre-1), lime (5 tons acre-1), gypsum + lime (5 ton acre-1 gypsum and lime at an equivalent Ca content), and a control. Gypsum application rates generally did not result in any significant yield difference compared to control regardless of source. All gypsum sources clearly increased the soil CEC and EC with increasing application rates. Calcium and S concentrations in soil and plant tissues also consistently increased with increasing rates. Concentrations of K and Mg decreased in soil, while only Mg was lower in plant tissues. Evaluation of water leaching through the profile showed that gypsum additions can promote the displacement of soil solution Mg, K, and Mn; thus, with long-term use may require supplemental amendments to replenish these nutrients. Accumulation of trace elements in the soil/plant system was minimal regardless of gypsum source; most values were below detection limits or similar to controls. Results from this study suggest that gypsum additions may not beneficially improve forage production when applied in conjunction with poultry litter or other organic sources. However, if used to reduce P loss from agriculture fields there appears to be no negative environmental effects.