Impacts of FGD Gypsum Application, Nitrogen Rates and Tillage on Corn Grain Production.

Flue Gas Desulfurization (FGD) gypsum is a by product of the process that removes sulfur from the gas emissions of coal fired electric power plants. FGD gypsum has a similar composition to mined gypsum; however, as much as half the FGD gypsum produced in recent years has not been utilized. This gypsum source can be used for wallboard production and as an agricultural soil amendment. The use of mined gypsum in agriculture has a long history since it is a good source of calcium and sulfur, but FGD has a finer particle size and reacts faster with soil than mined gypsum.  The goal of this study is to determine the interaction between nitrogen fertilizer application and FGD gypsum application on agronomic production of two tillage systems. A split-split plot design was implemented in three different locations in Wisconsin, covering common soil types and conditions. Ear leaf samples were collected to assess the N and S status of corn during the growing season at a critical physiological stage. At harvest, above ground biomass and grain yield were measured. Sub samples of grain and biomass were collected to determine total N uptake and Nitrogen Use Efficiency (NUE). Preliminary yield data indicates that the impact of treatments varies greatly by site.