|Horgan, Brian - UNIV. OF MINNESOTA|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 18, 2005
Publication Date: July 28, 2005
Citation: Rice, P.J., Horgan, B. 2005. Transport of pesticides and nutrients with surface runoff from fairway turf [abstract]. 2005 University of Minnesota Turf and Grounds Field Day. p. 8-9. Technical Abstract: The overall objective of this research is to improve the current understanding of pesticide and nutrient runoff from turf, and to evaluate the ability of management practices to mitigate pesticide and nutrient loss with rainfall and snowmelt runoff. This project is also part of a multi-state cooperative initiative with researchers from universities in Maryland, Mississippi and Oklahoma to evaluate the influence of regional, turf species and plot size variability on pesticide transport with surface runoff. A standardized protocol was used for the construction and maintenance of fairway turf plots at each location. Pesticide applications, rainfall simulation, runoff collection, and chemical analysis are similar for all locations, while plots size (small: 12’ x 30’, medium: 20’ x 80’, large: 40’ x 125’) and turf species (bentgrass, Bermuda grass) vary according to location. We selected 20’ x 80’ plots planted with creeping bentgrass. The construction and instrumentation of each plot and the assembly of a rainfall simulator was completed in the summer of 2004, followed by the initiation of three studies to evaluate the impact of location of chemical application, pesticide transport with rainfall runoff, and the mobility of snow-mold fungicides and late-fall fertilizer with rainfall and snow melt runoff. Beginning in 2005, an additional management practice was implemented to assess the ability of management practices to mitigate pesticide and nutrient loss with runoff. Impact of location of chemical application: Potassium bromide and fluorobenzoic acids, traditional and alternative conservative-tracers, have been utilized as valuable hydrologic tools for characterizing water movement through soil. In this study, three fluorobenzoic acids (2,6-difluorobenzoic acid, o-trifluoromethylbenzoic acid, pentafluorobenzoic acid) and potassium bromide were applied to selected areas of each turf plot to evaluate water movement and the influence of location of chemical application to transport with surface runoff. Use of conservative water-soluble tracers represents a worst-case scenario for off-site movement of pesticides and fertilizers with runoff, and can identify areas of high impact that contribute the most to chemical transport. Preliminary results will be discussed. Pesticide transport with rainfall runoff: A commonly utilized herbicide (2,4-D), insecticide (chlorpyrifos), and fungicide (flutolanil) were applied to each plot to evaluate the tranport of these chemically different compounds with runoff. Forty-eight hours prior to pesticide application each plot was pre-wet to saturation to ensure uniform water distribution. Rainfall simulation was initiated 24 hours after pesticide application, according to the standardized protocol. Replicate samples of surface runoff water and turf/soil cores were collected for analysis to determine levels of pesticides and nutrients removed from the site of application with runoff water or leaching to the underlying soil. Mobility of snow-mold fungicides and late-fall fertilizer with rainfall and snow melt runoff: Chlorothalonil, iprodione and urea were applied to the fairway turf plots in October 2004. Natural rainfall runoff, occuring before snowfall, and snow melt runoff were collected along with weather data and soil temperatures. A second study will be repeated this fall to provide replication between field seasons and additional within-season replication. Ability of management practices to mitigate pesticide and nutrient loss with runoff: Despite the widespread use of turf management practices, their impact on runoff and potential to mitigate pesticide loss with runoff is not well studied. Our goal is to identify management practices that maximize pesticide and nutrient retention at the site of application, thereby improving desired results of pest control and turf maintenance while minimizing environmental contamination and adverse impacts associated with the off-site tranpsort of these compounds. For the 2005 season, plots will be maintained according to the standardized protocol with the exception that hollow-tine aerfication will replace solid-tine aerification for half of the plots. Replicate samples of surface runoff water and turf/soil cores will be collected for analysis to determine levels of pesticides and nutrients removed from the site of application with runoff water or leaching to the underlying soil. The off-site transport of pesticides and nutrients is both an agronomic and environmental concern. Data collected from the describe research projects will provide quantitative-information to turf managers on cultural practices or application strategies that will provide quality turf while reducing off-site transport of applied chemicals. This data can also be utilized in model simulations to assess potential environmental impacts. Maintaining pesticides and fertilizers at their intended sites of application will increase their efficacy and minimize adverse impacts to surrounding sensitive non-target areas.