Environmental Science & Technology
Permanent URI for this communityhttp://hdl.handle.net/1903/2216
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Item Release, Survival, And Removal of Bovine Manure-Borne Indicator Bacteria Under Simulated Rainfall(2017) Stocker, Matthew Daniel; Hill, Robert L; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The effects of simulated rainfall intensities and its interactions with manure consistency and weathering on the release, survival, and removal of fecal indicator bacteria, Escherichia coli and enterococci, from land-applied dairy manure were evaluated. Rainfall intensity had significant effects on the number of bacteria in the soil following rainfall. Bacteria concentrations in soil decreased with increased soil depths and the topmost centimeter of soil accounted for the greatest proportion of bacteria. Escherichia coli persisted longer than enterococci once removed from manure. Manure consistency was not a significant factor in the removal of bacteria when manure was fresh, but as manure weathering progressed, consistency became a significant factor. The Vadas-Kleinman-Sharpley model was preferred over the exponential model for simulating the removal of manure-borne bacteria. Results of this work will be useful for improving predictions of the human health risks associated with manure-borne pathogenic microorganisms.Item Impact of Surface Application of Flue Gas Desulfurization Gypusum on Infiltration, Phophorus Behavior, and Total Sulfur in a Previously Manured Coastal Plain Soil(2014) Collins, Loretta; Felton, Gary K; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Flue gas desulfurization (FGD) gypsum was surface-applied on a poorly drained cultivated Coastal Plain soil in Maryland containing excessive amounts of plant-available phosphorus (P). Using a constant head double-ring infiltrometer, a field experiment indicated a slight increase in final infiltration rate (FIR) at 10 and 15 Mg ha-1 application rates, however a laboratory rainfall simulation showed no significant effect of FGD gypsum on FIR. Water extractable phosphorus (WEP) decreased by 13-47% one year after application of FGD gypsum. Linear relationships were established between Mehlich 3 (M3) and ammonium oxalate extractions of P and aluminum (Al) (r2 = 0.83, 0.56, respectively), supporting previous research on the reliability of M3 in place of ammonium oxalate to predict P loss. One year after FGD gypsum application total S was 3-150% higher at 15 cm and 44-74% higher at 30 cm depths. No significant difference in total S was apparent at deeper depths.