Submitted to: Animal Production Systems and the Environment
Publication Type: Proceedings
Publication Acceptance Date: 7/22/1998
Publication Date: N/A
Interpretive Summary: Many agricultural lands receive nutrients from more than one source. Pastures in the Ozark Highlands, for instance, may receive nutrients from both applied poultry litter and from grazing animal depositions. Too many nutrients, especially phosphorus, in runoff water may cause excessive algal blooms and weed growth in lakes and reservoirs. This study compared the amount of nutrients contained in runoff water from small grass plots receiving poultry litter and dairy animal feces and urine. Simulated rainfall was used to generate runoff from small plots with tall fescue sod. The rainfall was applied 1 and 14 days after the waste materials were applied. Significantly more nutrients were contained in the runoff water from plots receiving poultry litter as compared to the dairy waste. After two weeks, however, these differences and the total amount of nutrients in the runoff were much smaller. Further studies under field conditions are needed to confirm the relative importance of poultry litter versus grazing animal depositions on surface water quality.
Technical Abstract: Many agricultural lands have multiple inputs of nutrients making differentiation between sources essential for optimal nutrient management. The objective of this study was to compare nutrient runoff from ungrazed tall fescue plots receiving poultry litter with and without feces and urine from dairy animals fed fresh-cut tall fescue. Simulated rainfall was applied 1 and 14 days after waste application to replicated 1.5 by 6.1 m runoff plots with established tall fescue (Festuca arundinacea Schreb.) cover. Treatments included control (C), dairy feces and urine (D), poultry litter (L), and dairy feces and urine with poultry litter (D+L). Runoff samples were analyzed for soluble reactive phosphorus (SRP), total nitrogen (TN), ammonium (NH4-N), nitrate (NO3-N), and several other macro and micronutrients. Significantly higher loads of SRP, TN, NH4-N, and micronutrients from the L and D+L plots were observed for the first simulation run. Total losses and differences between treatments were much smaller for the second simulation but the trends were similar (D+L=L>D=C). There were no significant differences between treatments with respect to total micronutrient load for the second simulation. Under the conditions of this study, poultry litter had a greater impact than grazing animal excretions on nutrient transport during runoff events occurring shortly after waste application.