FGD Gypsum Effects On Soil Water Use and Yield of Cotton.

Flue Gas Desulfurized (FGD) gypsum is a by-product of energy production from burning coal.  This material is currently being land filled but offers an opportunity as a soil amendment in agricultural practices.  In 2009 and 2010, FGD Gypsum was applied on a cotton field across both no-till and tilled systems at rates of 0, 2.24, 4.48, 6.72, and 11.2 Mg ha^-1 to determine if gypsum rate affected cotton yield.  In 2009, neither tillage nor gypsum rate significantly affect yield.  However, in 2010 both tillage and gypsum rate significantly affect yield, with greater yields in the no-till system and 0 Mg gypsum ha^-1 with an irregular yield decline across the other gypsum rates.  Yields across years were not significantly different amongst tillage systems, but yield was significantly affected by gypsum rate.  In 2010 soil water content in the 0, 2.24, and 4.48 Mg gypsum ha^-1 was monitored using time domain reflectrometry (TDR) at 15, 30, and 45 cm.  There were no significant differences in water content across tillage systems or gypsum rates.