Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 9, 2000
Publication Date: November 9, 2000
Citation: Dinnes, D.L., Jaynes, D.B., Meek, D.W., Cambardella, C.A., Colvin, T.S., Hatfield, J.L., Karlen, D.L. 2000. Reducing n contamination of surface waters from tile-drained soils at the watershed scale [CD-ROM]. ASA-CSSA-SSSA Annual Meeting Abstracts. Madison, Wisconsin.
Field drainage systems can have a significant impact on water quality because they behave like shallow, direct pipelines or conduits to surface waters. Nitrogen (N) is often transported with agricultural drainage water and has been implicated as contributing to hypoxia in the Gulf of Mexico. Beginning in 1997, we implemented a N fertilizer best management practice (BMP) on all corn production fields in a Midwesten, tile-drained agricultural watershed to determine its impact on water quality. Although plot-scale studies had previously been conducted, with mixed results, this is the first project to examine a N fertilizer BMP at the watershed scale. Beginning in early 1998, the treatment watershed's nitrate-N concentrations began to decrease compared to the control watershed. From mid-October 1998 to date, the treatment watershed has maintained a significantly lower nitrate-N concentration (30% reduction) than the control subbasin at the 95% confidence level. These results suggest that by implementing N BMPs on tile-drained agricultural landscapes with similar climatic and soil conditions, we should expect lower tile flow nitrate-N concentrations and improved water quality.