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This study investigated the potential for controlled tile drainage (CD) to reduce bacteria and nutrient loading to surface water and groundwater from fall season liquid manure application (LMA) on four macroporous clay loam plots, of which two had CD and two had free draining (FD) tiles. Rhodamine WT (RWT) was mixed into the manure and monitored in tile water and groundwater following LMA. Tile water and groundwater quality were influenced by drainage management. Following LMA on the FD plots, RWT, nutrients and bacteria moved rapidly via tiles to surface water; however, at the CD plots, tiles did not flow until the first post LMA rainfall, so immediate risk of LMA induced contamination of surface water was abated. Over the 36 d monitoring period, flow weighted average specific conductance, redox potential, and turbidity, as well as Kjeldahl N (TKN), total P (TP), NH4-N, reactive P and RWT concentrations, were higher in the CD tile effluent; as a result, there was no significant (P ≤0.05) difference in surface water nutrient and RWT loading between the CD and FD plots. TKN, TP, and RWT concentrations in groundwater also tended to be higher at the CD plots. Bacteria behaved differently than nutrients and RWT, with no significant difference in total coliform, E. coli, fecal coliform, fecal streptococcus, and C. perfringens concentrations between the CD and FD tile effluent; however, for all but C. perfringens, hourly loading was higher from the FD plots. Results indicate that CD has potential for mitigating bacteria movement to surface water.
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