Runoff water monitoring at Dove Canyon Country Club
Summary: Irrigation water and runoff water was monitored for three years at Dove Canyon Country Club to evaluate the impact of the golf course on down-stream water quality. When compared to the reclaimed irrigation water used throughout the development and the golf course, the runoff water was significantly lower in nitrates, total phosphorus, and total organic halogens. Oil and grease, total organic carbon, pH, and electrical conductivity of the runoff water were significantly higher than the irrigation water. There was no significant difference in the concentration of ammonia, nitrites, total Kjeldahl nitrogen in the irrigation and runoff waters. These results support the value of turfgrasses in capturing nitrogen and phosphorus, two key nutrients that can lead to eutrophication of waterways. The origin of the oil and grease, organic carbon, elevated pH and inceased salinity may be the golf course or the surrounding community that also drains into the same streams.
Printable version of full report
Principal Investigator: Larry Stowell, Ph.D.
Cooperator: Eric Lover, Dove Canyon Country Club
Sponsor: Dove Canyon Country Club
Evaluation of Proxy as a Growth Regulator and Seedhead Inhibitor on Overseeded Fairways
Summary: In replicated field trials conducted at two locations (The Country Club of Rancho Bernardo, and Admiral Baker Golf Course), the effect of the experimental product ethephon (Proxy) on turf quality, turf growth regulation and Poa annua seedhead inhibition was evaluated on bermudagrass fairways that had been overseeded with perennial ryegrass. Key results include:
- The use of Proxy at rates of either 5 oz or 10 oz/1000 square feet resulted in a significant decrease in the density of Poa annua seedheads. This effect was observed for as long as seven weeks after a single application of Proxy.
- Primo L (0.5 oz/1000 square feet) also resulted in decreased poa seedhead densities, but this effect was neither as strong nor as consistent as that for Proxy.
- Overall, Proxy applications performed inconsistently in the regulation of cool season turf growth on overseeded bermudagrass fairways. While the 5-oz rate produced significant clipping weight reductions at one location, it took several weeks for the effect to appear. The 10-oz rate of Proxy resulted in significant increases in turf growth on several evaluation dates. This unexpected result was observed at both test locations.
- No phytotoxicity was caused by any of the products tested, although Primo L (0.5 oz/1000 square feet) caused a dark colored cast to appear on treated plots due to growth inhibition and stress caused on senescing bermudagrass. The lack of any damage to bermudagrass or ryegrass caused by Proxy, in combination with its ability to reduce poa seedhead densities, may make it a valuable tool in golf course poa management on fairways and greens,despite its disappointing performance as a cool-season turf growth regulator.
Printable version of full report
Principal Investigators: Wendy Gelernter, Ph.D. and Larry J. Stowell, Ph.D., CPPP, CPAg
Cooperators: Alan Andreasen and Mike Magnani, Admiral Baker Golf Course; Sandy Clark, The Country Club of Rancho Bernardo
Sponsor: Chris Olsen, Rhone-Poulenc
Evaluation of Chipco Proxy and EXP 310309 for Use as a Turf Growth Regulator on Kikuyugrass Fairways
Summary: In replicated field trials conducted on a kikuyugrass nursery that was mowed at fairway height, the effect of the experimental product ethephon (Proxy) or a combination of ethephon plus cyclanilide (EXP 310309) on turf quality, turf growth regulation and scalping was evaluated. Key results include:
- A single application of Proxy at either 5 oz or 10 oz/1000 square feet had little or no effect on growth regulation of kikuyugrass, with significant clipping reductions observed on only one (5 oz rate) or two (10 oz rate) out of a total of six sampling dates. The addition of cyclanilide to ethephon, in the form of EXP 310309, had a small but positive effect on performance, with significant clipping reductions observed on two sampling dates (2.5 oz rate) or three sampling dates (5.0 ozrate). However, in contrast, Primo L (0.5 oz/1000 square feet) resulted in significantly reduced clipping rates on all six sampling dates.
- Turf quality was not improved through application of Proxy or EXP310309 at any of the rates tested. In contrast, Primo L (0.5 oz/1000 square feet) produced turf with significantly improved quality (when compared to the non-treated check) on all six sampling dates.
- The degree of scalping (appearance of brownish, stubbly, unisghtly areas, as a result of mowing) of kikuyugrass was not consistently reduced through application of either Proxy or EXP310309. In contrast, application of Primo L resulted in signficant reductions in scalping on all sampling dates.
- In general, EXP310309 performed slightly better than Proxy in terms of growth regulation, turf quality and reduced scalping, suggesting that the addition of cyclanilide to ethephon has a beneficial effect. However, the improvement in performance was small, and still did not result in commercially acceptable performance. For these reasons, neither product was judged to demonstrate commercial viability for use as a growth regulator on kikuyugrass fairways.
Printable version of full report
Principal Investigators: Wendy Gelernter, Ph.D. and Larry J. Stowell, Ph.D., CPPP, CPAg
Cooperator: Bruce Duenow, La Jolla Country Club, La Jolla, CA.
Sponsor: Chris Olsen, Rhone-Poulenc
