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WSU Turfgrass Science Characterization of Leaching at the Coeur d’Alene Golf Course Floating Green
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Characterization of Leaching at the Coeur d’Alene Golf Course Floating Green

Bill Johnston, Chris Kleene, Bill Pan, and Eric Miltner


The project sampling equipment was received during the middle of March and installed on March 30, 1998. During this period, the back green-side bunker was excavated and the leachate storage tank below the bunker was re-examined for drain pipe layout into, and within, the storage tank to determine the best method for installation of the equipment. A reducer was installed in the main drain line of the green and a small 60 degree trapezoid flume was installed into the system for accurate leachate flow level analysis. Two sampling lines were routed through the vent line and attached to the ISCO model 6700 refrigerated sampler, which is located underneath the floating green in a storage room. The system was then programmed and calibrated to the appropriate flow conditions. Currently, the sampler is monitoring flow from the green and sampling leachate every 24 hours. As the research continues, the sampler will be programmed to sample during a flow event for more accurate leachate representation.

Six Timco micro-lysimeters will be tested off-site in late May. Once the preliminary testing phase has been completed at the WSU Turfgrass Research area in Pullman, WA the lysimeters will be installed on the floating green. The addition of micro-lysimeters will aid in the determination of variation within the green due to spatial variability factors (i.e. slope, traffic, etc.). The addition of micro-lysimeters will also provide a check for the primary ISCO sampler.

John Anderson, the golf course superintendent, is currently taking clipping samples from the green and freezing them for later tissue analysis at WSU. In addition, fertilizer and irrigation schedules are being monitored for their impact on the clipping and leachate samples. Discussion is currently taking place on altering fertilizer form and application rate and their effect on leachate and clipping weight. The application of a bromide tracer is also being currently investigated.

Preliminary leachate data indicates very low levels of both ammonia and nitrate. Nitrate levels range from 0.11 to 1.79 ppm, well below the EPA limit of 10 ppm. Ammonia levels were even lower than the nitrate, ranging from 0.18 to 0.47 ppm. Leachate volumes are increasing with irrigation, and hand watering. No data is currently available on tissue N levels.

A weather station has been located at the back of the green to provide environmental data, which will assist in constructing a water balance for the floating green. A flow meter was installed on the main irrigation intake pipe during the construction of the floating green. By monitoring this flow meter and current irrigation practices, a water balance can be constructed for the green. Irrigation application, precipitation, drainage and evapotranspiration are being measured, creating an opportunity to monitor all water inputs and outputs. By better understanding the water balance of the green, the nitrate study is more accurate and later modeling will be possible.

Proposed Research Schedule and Anticipated Results

May to June 1998 – Finalize materials and methods for leachate study. Continue to monitor leachate, clippings, and weather data. Conclusion of preliminary data analysis and calibration.

July to Aug. 1998 – Site visits as needed. Data and sample collection and analysis. Poster presentation at Puyallup, WA field day. USGA site visit July 9, 1998.

Sept. to Dec. 1998 – Site visits as needed. Sample collection and analysis. Data analysis and summarized for the year. Research presentation at Northwest Turfgrass Conf. annual meeting at Coeur d’Alene, ID. November 1998 progress report to USGA.

Publications and Presentations

  • Kleene, C. M., and W. J. Johnston. 1997. Pesticide and nutrient leaching through turf soil profiles. IEGCSA Trade Show, Spokane, WA. 6 Nov. 97.
  • Johnston, W. J. 1998. Pesticide and nutrient leaching through turf soil profiles. Peaks & Prairies GCSA, Missoula, MT. 2 March 98.