Project Number: 6408-13660-007-08
Project Type: Trust

Start Date: May 26, 2009
End Date: Mar 31, 2014

Objective:
Evaluate FGD gypsum influences soil physical properties and losses of P from poultry litter on pastures (Watkinsville and Auburn) and crop land (Oxford). The research would help establish proper combinations of rates of FGD gypsum and poultry litter to reduce losses of P in runoff and improve soil productivity and provide documentation of water quality improvements associated with FGD gypsum needed to help qualify practices for use as a BMP and water quality improvement credits.

Approach:
Watkinsville and Auburn FGD gypsum and poultry litter will be applied at four rates (0, 2, 4, 6 Mg ha-1) to bermudagrass pasture to evaluate changes in available soil P over three years. Use of similar treatments at Auburn and Watkinsville is to evaluate differences in treatment effects associated with differences in soil and climate at the two locations. FGD gypsum and poultry litter would be applied annually and measurements of soil P fractions (Total P, water soluble P, Mehlich P, and organic P) would be made at 6 month intervals. Soil aggregate stability would be measured yearly to evaluate impacts of FGD gypsum on soil structural stability. In addition we would evaluate FGD gypsum and poultry litter effects on forage production and quality along with the potential for nutrient removal by grazing and haying which is important for management of high P soils. Forage would be harvested at regular intervals to simulate haying and evaluated for P content (P removal) and forage quality. Results would establish potential for using FGD gypsum as an amendment to increase poultry litter application rates and improve water use efficiency on pasture and hay land. Oxford - Two studies will be conducted; one at the Northeast Mississippi Experiment Station at Verona will evaluate the effects of FGD gypsum on an existing set of no-till cotton plots. FGD gypsum application rates of 0, 1, 1.5, 2, and 3 tons/acre would be applied on a replicated plot experiment. A Study at Milan, TN will evaluate the effects of tillage-gypsum interactions on cotton yields. Crop yields will be measured by the experiment station personnel responsible for all agronomic practices. Following harvest each growing season, soil cores will be collected to a depth of 36 inches from each plot and characterized for water dispersible clay as a measure of erodibility, particle size distribution, organic carbon content, pH, exchangeable Al, exchangeable bases, total calcium, sulfur, nitrogen, and phosphorus.