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Impact of Swine Manure Application on Phosphorus, NO3-N, Bacteria, and Antibiotics Concentrations in Surface Runoff and Subsurface Drainage Water
YEAR: 2006
INVESTIGATORS: Ramesh Kanwar, Allah Bakhsh, Matthew Helmers Antonio P. Mallarino, John Sawyer

Animal production systems are becoming larger, and the public is concerned about the impacts of large animal facilities on water quality. Of particular concern are losses of nitrogen (N) in the forms of NH4-N, NO3-N, phosphorus (P) as PO4-P, pathogens, and antibiotics with surface runoff and subsurface drainage water. The proposed study deals with assessing the effect of land application of swine manure on NO3-N, PO4-P, bacteria, and antibiotic losses in surface runoff and subsurface drainage water. In 2000, with funding from the Leopold Center, a six-year (20002006) field study was initiated at the Iowa State University Northeast Research Center near Nashua to investigate the impact of land application of swine manure on water quality. The specific objectives of this study are: i) to determine the impact of recommended rates of swine manure, based on N and P uptake requirements of crops, on water quality; ii) to study long-term effects of over-application of swine manure on NO3-N, PO4-P, and bacteria leaching to shallow groundwater; and iii) to study the effects of spring and fall injection methods of swine manure on crop yields and NO3-N, PO4-P, and bacteria concentrations in surface runoff and shallow groundwater. From 2000 to 2003, we did not monitor the concentration of antibiotics in surface runoff and subsurface drain water. In 2004, a renewal grant proposal was submitted to the Leopold Center to continue this study for three more years as we needed to collect six years of water quality data for corn-soybean production system. In this renewal grant we proposed that we should collect data on antibiotics in the surface runoff and subsurface drainage water. The Leopold Center decided not to fund this project as the Leopold Center priorities changed to other areas. This was the first time since 1988 that the water quality research project for the Nashua site was not funded by the Leopold Center. Therefore, we requested the National Manure Management Center (NMMC) at North Carolina State University to fund this proposal and include the monitoring of antibiotics in surface and subsurface drainage water in addition to N, P, and bacteria. The NMMC funded this project for 18 months until December 2005 to analyze drainage water samples for antibiotics in objective (ii) in addition to NO3-N, PO4-P, and bacteria. The NMMC was funded with a USDA grant and this USDA grant will end on Dec. 31, 2005, thus, closing the NMMC permanently. With this proposal, we are requesting the ISWRRI to fund this project for the remaining 18 months (January 2006 to June 2007) so that this ongoing study can be completed and final conclusions of various treatments can be drawn to benefit the producers. This study site has 36 one-acre plots, with complete surface and subsurface drain monitoring system (Kanwar et al, 1999). The state-of-the-art surface runoff water and tile water monitoring facilities were installed at this site in 1988 on each of these 36 plots for sampling tile water for various water quality parameters. In 2000, nutrient management treatments were established on these plots (Table 1). These treatments include the application of swine manure to meet N and P uptake needs of corn and soybeans. Also, a new treatment was introduced in this study to apply swine manure at double the P uptake needs of corn to determine the effect of excessive application of swine manure on water quality. In addition to rate effects, manure was applied in the spring and fall to study the effect of timing of manure application on N and P leaching. Surface and subsurface drain water samples are analyzed on a weekly basis for various water quality parameters when tile drains are flowing. Five years of water quality data have been collected and we need one more years data to make final conclusions of this study. Therefore, funding from the ISWRRI for the next 18 months would be critical to the success of this project. At present, we do not have any other source of funds to complete this study.