Assessing Benefits and Risk of Using Flue Gas Desulfurized Gypsum (FGDG) As Soil Amendment in a Coastal Plain Soil.

The influence of FGDG and grass buffers on runoff water quality and corn production following poultry litter (PL) application is being evaluated as part of a regional USDA-ARS project (Auburn-AL, Oxford-MS, and Tifton-GA).  Treatments at Tifton were laid out in a randomized complete block design with three replications. Gypsum and PL rates were 0 and 6 tons/acre (13.5 kg/ha) each. Non-amended plots received inorganic fertilizer equivalent to the PL (N, P, K). N availability from PL in mineralized form was assumed to be 70% of the total PL N content. Additional check areas between plots received inorganic fertilization with and without additional FGDG. Irrigation was applied only to avoid crop failure. Year one (2014) corn grain yield at Tifton in bushels per acre was 134 (±8) from inorganic, 124 (±7) from PL, and 129 (±4) from PL + FGDG treatments. The trend to lower yields with PL was likely due to less N availability from PL than assumed. Mean yield from check areas with inorganic fertilization was 114 and 102 (± 6) bushels per acre with and without FGDG, respectively. The trend to greater yield from FGDG, in these preliminary results, suggests that it may be possible to enhance corn yields on Southeastern Coastal Plain soils with FGDG. The study will continue for another 3 years.