Stuart Z. Cohen, Ph.D., CGWP
Poster presented at 10th IUPAC International Congress on the Chemistry of Crop Protection, Basel, Switzerland. (2002)
There are approximately 17,100 golf courses in the USA (NGF, 2002), and 5,900 courses in Europe (EGA, 2002). The closely mown, heavily traveled turf makes it susceptible to insect, weed, and disease pests that can require intensive chemical management. Golf courses are also often located close to wetlands, surface water features, and/or over shallow ground water, raising environmental risk concerns during the land use approval process. The results of computer simulation modeling can be used to aid pesticide registration decisions and approval decisions on specific sites/watersheds, as well as inspire the design of risk mitigation measures (Best Management Practices). Standard risk assessment/modeling methods focus on row crop agriculture, but the turf system is unique and requires special considerations. Golf courses consist of natural areas, roughs, fairways, tees, and greens, in order from less intensive to more intensive management. Thus a typical U.S. golf course site is approximately 56 ha, but the percent turfgrass area (PTA) for greens, tees, and fairways is typically only 31% and 3.4%, as a function of the whole golf course and the watershed, respectively. More fungicides are applied more often to greens than other areas, but more herbicides are applied to fairways. Turf is a unique system in that it contains a dense canopy (verdure), a dense bioactive root system, and a surficial organic mat called thatch. The thickness of thatch typically varies between 0.3 cm and 2.0 cm, depending on the area of the course and its age. Its organic carbon content is very high (20%-40%), which slows pesticide migration, but its pesticide sorption capability is not as efficient as soil organic matter due to the aging and higher surface area to volume ratio of the latter. The key hydrologic parameters field capacity, wilting point, and bulk density are also different for thatch than most other cropping systems. Dissipation half lives in turf are usually shorter than in bare ground studies. Greens and tees are generally well drained, which influences the runoff curve numbers chosen for these turf surfaces. Fairways are usually not built on runoff-prone soils. A two-tier modeling system is suggested, using rules-of-thumb, the runoff curve number method, TurfPQ, PRZM, and SWAT.