|HORGAN, BRIAN - UNIVERSITY OF MINNESOTA
Submitted to: International Turfgrass Society Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2009
Publication Date: 5/29/2009
Citation: Rice, P.J., Horgan, B.P. 2009. Fungicide and Nutrient Transport with Runoff from Creeping Bentgrass Turf. International Turfgrass Society Research Journal. 11(1):61-76.
Interpretive Summary: The detection of pesticides and excess nutrients in surface waters of urban watersheds has lead to increased environmental concern and suspect of contaminant contributions from residential, urban, and recreational sources. Highly managed biotic systems such as golf courses and commercial landscapes often require multiple applications of pesticides and nutrients that may be transported with runoff to surrounding surface waters. The objective of this study was to evaluate the off-site transport and impact of flutolanil, soluble phosphorus, ammonium nitrogen, and nitrate nitrogen with runoff from creeping bentgrass turf managed as a golf course fairway. Runoff from plots aerated with hollow tines and pre-wetted to field capacity 48 h prior to fertilizer and fungicide application contained the chemicals of interest in the initial runoff and throughout the runoff events. Edge-of-plot runoff contained phosphorus concentrations that were greater than USEPA water quality criteria to limit eutrophication, nitrate nitrogen levels below the drinking water standard to prevent blue baby syndrome and flutolanil concentrations below the median lethal concentration for 6 of 7 aquatic organisms assessed. Extrapolation of measured runoff loads to estimated environmental concentrations in a receiving surface water (runoff from 10-ha area into a 1-ha surface area x 2-m depth) resulted in phosphorus concentrations remaining above levels associated with increased algal growth and eutrophication. Quantitative data collected from this study provides information on the transport of chemicals with runoff from turf that can be used in model simulations to predict non-point source pollution potentials and assess ecological and human health risks.
Technical Abstract: Runoff from managed turf may contain pesticides and nutrients that contribute to contamination of receiving surface waters. In this study we observed that NH4-N, NO3-N, sol-P, and flutolanil were measured in edge-of-plot runoff when fertilizer and a fungicide were applied at label rates to creeping bentgrass fairway turf, 26 ± 13 h prior to simulated precipitation (45 to 75 mm). All chemicals of interest were detected in the initial runoff samples and throughout the runoff events. The edge-of-plot runoff contained concentrations of NO3-N that were less than the drinking water standard, levels of flutolanil that were below the LC50 for 6 of 7 aquatic organisms assessed, and phosphorus concentrations above the USEPA water quality criteria to limit eutrophication. Estimated environmental concentrations of the chemicals of interest were calculated based on the dilution of runoff when entering a receiving body of water (runoff from 10-ha area into a 1-ha surface area x 2-m depth). Concentrations of flutolanil, NH4-N, and NO3-N were below the evaluated levels of concern while sol-P remained above concentrations associated with increased algal growth and eutrophication. Quantitative data collected from this study provides information on the transport of chemicals with runoff from turf that can be used in model simulations to predict non-point source pollution potentials and assess ecological and human health risks.