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Web URL(s): | http://archive.lib.msu.edu/tic/rpr/1997/54856,%20U%20Georgia,%20Smith.PDF Last checked: 10/30/2013 Requires: PDF Reader |
Publication Type:
| Report |
Material Type: | Manuscript |
Monographic Author(s): | Smith, Albert E.; Bridges, D. C. |
Author Affiliation: | Department of Crop and Soil Sciences, College of Agric. Exp. Stn., University of Georgia, Griffin, GA |
Monograph Title: | Evaluation of the Potential Movement of Pesticides Following Application to Golf Courses: [1997 Annual Research Report], 1997. |
Publishing Information: | Griffin, Georgia: University of Georgia |
# of Pages: | 42 |
Collation: | 42 pp. |
Abstract/Contents: | "The objectives of our research program over the past 6 years has been to evaluate the potential movement of pesticides and fertilizer components following application to golf courses and to develop Best Management Practices to reduce the potential for pesticide transport to potable water systems. The initial steps for evaluating the potential movement of pesticides has been accomplished using pesticides registered for use on golf course greens and fairways on simulated greens and fairways at the Georgia Experiment Station. The facilities were constructed at the Georgia Station and analytical procedures were developed in our laboratories for this research program. Our simulation facilities were developed for the control of the environmental parameters in order to determine the potential transport of pesticides through the soil and in surface water runoff. Experimental control was necessary for defining and controlling the variable parameters that influence pesticide transport into the environment. Although, some of the recommended Best Management Practices resulting from our research program may already be in practice, there are no real data to support those practices. Additionally, there may be a concern for the choice of pesticides included in our research. Initially, we realized that the actual molecule used was not as important as to establish the characteristics of an expanse of molecular structures in the simulated greens and fairways (i.e. 2,4-D, dicamba, and mecoprop are not used on a lot of golf course greens but there is more research information available on these molecules than any other analytes). Therefore, we included 2,4-D, dicamba, and mecoprop in many of our simulated greens treatments. From these data we are developing models for predicting the potential movement of many molecules through golf course greens and from golf course fairways. In 1995 high school student conducted research to determine the potential risk from kneeling on a green that had been treated 2,4 d, mecoprop and dicamba (included in 1995 annual report). Additionally, in 1997 a senior from Mercer University conducted research to determine the potential risk from licking a golf ball that had been rolled across a treated green and from chewing a tee that had been placed in the treated tee-box. The construction of golf course greens according to USGA specifications results in the rapid infiltration and percolation of water through the rooting media and out the drain system into surface drainage areas. At first inspection these characteristics could allow for the movement of large quantities of pesticides onto the surface drainage areas. Our data indicate that the quantities of pesticides transported through the simulated greens are very low. The more water soluble pesticides (i.e. 2,4-D; dicamba; and mecoprop) were found to have short residence time under the sod due to the rapid microbial degradation of the molecules. The pesticides with lower water solubilities (i.e. benefin, pendimethalin, dithiopyr, chrolothalonil, and chlorpyrifos) had higher soil sorption capacities increasing their residence time in the rooting medium (because of the sphagnum peat moss component) allowing for degradation even if the half-lives were much longer. This concept is best demonstrated by dithiopyr and the specific results are included in published reports and in previous annual reports. Assuming that the simulated greens mixture is a worst case scenario, it can be concluded that pesticide transport in soil water probably is not a major problem if the pesticides are applied according to the label and massive amounts of water are not applied after application. Certainly, the desired management practice would be to restrict incoming water to an amount slightly above the quantity lost by evaporation/transpiration. Loss of surface water from fairways is not uncommon and in some areas of the United States as much as 70% of the incoming water can be lost as surface runoff. Our simulated fairways were developed with a 5% slope which is considered average for the southeastern U.S. Also, the simulated rainfall intensities of 2.3 cm hr-1 are not uncommon for summer rain events in the Piedmont Region. Results of our research indicate that the water solubility of the pesticide and sequence of rain events influenced the quantity of pesticides transported from the fairways. The more water soluble pesticides (i.e. 2,4-D; mecoprop, and dicamba) readily dissolve in the water during runoff and are transported from the treated fairway. The less water soluble pesticides (i.e. benefin, pendimethalin, chlorpyrifos, chlorothalonil, and dithiopyr) are resistant to transport in surface runoff (see 1995 and 1996 annual reports). We also present data to support the hypothesis that the soil moisture content at the time of applying pesticides influences the quantity of water and ultimately pesticide to be transported from application site. A soil moisture content near the field capacity at the time of applying the pesticide results in as much as 5 times more pesticide to be transported from the fairway than a soil moisture content near the wilting point. The data indicate that sequencing irrigation prior to and following pesticide application could help reduce the quantity of water soluble analyte to be transported in surface water runoff. Additionally, more pesticide was transported from dormant sod than green sod. Some pesticides (the insecticide trichlorphon) can be pressure injected into the thatch and rooting medium reducing the potential for transport of the pesticide in surface water. We found that pressure injection significantly reduced the quantity of the water soluble pesticides transported in surface water runoff from the fairway. Additionally, our data indicate that a buffer zone between the point of application and the exit point does not reduce the fraction of the applied water soluble pesticide transported from the site. The buffer zone not only dilutes the solution concentration due to a reduced area of treatment. Certainly, this does not imply that pesticide applications should be made up to the water's edge. It only substantiates that the transported water soluble analytes are in solution and buffer zones will not screen out the molecules. Buffer zones to screen out soil and foliage particles that have pesticides adsorbed to them and for this reason should be part of the Best Management Practices. Our data indicate that pesticides having a low water solubility generally have a high soil sorption capacity (Koc) and will have a higher residence time on the foliage of the grass. These pesticides will have a higher probability of being removed with the clippings and could result in a nonpoint source of pollution as compared to water soluble pesticides that will be washed from the foliage surface. We found that as much as 20% of the dithiopyr was removed over a 10 week period on leaf clippings (See manuscripts in 1996 annual report specific data). The water solubility of dithiopyr would not allow for the analyte to be readily washed from the waxy surface of the leaf during simulated rain and irrigation events. These data indicate the importance of the management of the clippings following mowing the treated greens. Distribution of these clippings over the fairway or rough areas would be much better than accumulating the leaves for disposal. The data on potential risk from kneeling on the treated green, licking a ball rolled across a treated green, and chewing on a tee placed in a treated tee-box indicate the exposure in minimal especially at 24 HAT. However, 2,4-D, mecoprop, and dicamba were recovered from the simulated skin, ball, and tee indicating that although the potential risk may be low it isn't wise to lick the golf ball or chew on the tee following use. Data collected from lysimeters in the practice putting greens located at the Cherokee Town and Country Club indicate that very little of the chlorothalonil and chlorpyrifos were transported through the greens. However, nitrates and phosphates were found in the leachate from the greens and pointing out the need for additional research to determine the mode of phosphate transport. In summary, our data indicate that golf course management should include environmental impact as a quality measure for a pest management strategy and the academy must recognize the importance for developing Best Management Practices based on reliable data. We commonly restrict the quality measure of a pest management strategy to its degree of control of the pest and the safety to the sod." |
Language: | English |
References: | 0 |
See Also: | See also related summary article "Potential movement of certain pesticides following application to golf courses" 1997 Turfgrass and Environmental Research Summary [USGA], 1997, p. 74-75, R=54856. R=54856 |
Note: | Also appears as pp. 781-823 in the USGA Turfgrass Research Committee Reporting Binders for 1997. Includes Potential Pesticide Dose from Licking a Golf Ball and Placing a Tee in the Mouth, by Jennifer Starr and Al Smith, starting on p. 23. "1997 Annual Report and Project Summary Report Submitted to the United States Golf Association" Tables Graphs |
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