Potential Use of FGD Gypsum for Overcoming Environmental Problems in Southeast.

Agricultural productivity is constrained by unfavorable soil, climate and management factors in the southeastern USA. Flue gas desulfurization gypsum (FGDG) has the potential for alleviating some of these problems but its effectiveness in southeastern environments needs to be established by additional field studies. We conducted rainfall simulations two years apart (June 2009 & May 2011)on a randomized block design experiment with three replications setup on a Costal bermudagrass (Cynodon dactylon L.) hay field on Cecil (Typic kanhapludult) soil near Watkinsville, GA, consisting of four rates of FGDG (0, 2.2, 4.5, 9.0 Mg ha-1) with 13.5 Mg ha-1 each of broiler litter (BL) and two control (0-0) and (9.0-0.0) Mg ha-1 (FGDG-BL) treatments. After 3 amendments in two years runoff showed a significantly quadratic response to increased FGDG rate but with no statistical difference among treatments due to variability within and among replications. Addition of BL increased soluble P concentration and load several fold compared to (0-0), but these levels reduced significantly (up to 80%) by addition of FGDG to BL. Increasing FGDG rates caused significant linear reduction in concentration and load for nitrate-nitrogen in 2011 and ammonium-nitrogen in 2009. Concentration and load of Ca and Mg increased linearly due to increasing FGDG rates. Over 90% of applied nutrients stayed in the soil. Results indicate that an optimal FGDG-BL rate would maximize benefits seen in this study.