Submitted to: American Society for Microbiology General Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/22/2012
Publication Date: 6/18/2012
Citation: Jenkins, M., Schomberg, H.H., Endale, D.M., Franklin, D.H., Fisher, D. 2012. Hydrologic transport of fecal bacteria attenuated by flu gas desulfurized (FGD) gypsum. American Society for Microbiology General Meeting. Interpretive Summary:
Technical Abstract: Background Flue gas desulfurized (FGD) gypsum is a byproduct of coal-fired power plants. As a soil amendment for crop production it has the potential of improving soil water infiltration, soil conservation, and decreasing nutrient losses from broiler litter applications. Because broiler litter is a source of fecal bacteria with the potential of contaminating surface waters we tested the hypothesis that FGD gypsum applications would decrease the hydrologic load of fecal bacteria. Method Two rainfall simulation experiments were undertaken in the spring of 2009 and 2011 on an established bermudagrass pasture. Six treatments (including two controls) consisted of four rates of FGD gypsum (0, 2.24, 4.48, and 8.87 Mg ha-1) and two rates of broiler litter (0, and 13.45 Mg ha-1) in a completely randomized block design with three blocks. Experimental plots, 1 by 2 m, were delineated by metal plates pounded 10 cm into the soil and a flume that captured total runoff. E. coli was assayed for in litter, soil and runoff samples. Rainfall was applied at ~64 mm h-1. Sampling began at initiation of runoff and continued for 60 min. Runoff volumes were measured. Flow-weighted concentrations, total loads, and soil concentrations of E. coli were determined. In 2011, before each rainfall simulation an inoculum of E. coli in oven dried and sieved poultry litter (1011 cells per plot) was spread on each plot that had received litter at the time of the gypsum application. Results No significant differences between treatments were observed for the 2009 rainfall simulation. In 2011 a significant (P < 0.05) decrease in flow-weighted concentration, total load, and percent of E. coli inoculum spread on the plots associated with the highest rate of FGD gypsum application was observed. Conclusion By the third year of FGD gypsum applications at 8.97 Mg ha-1, increased water infiltration and reduced runoff loads of fecal bacteria were observed.