Larry Stowell and Wendy Gelernter. PACE Turfgrass Research Institute (PTRI), 1267 Diamond St., San Diego, CA 92109
Irrigation design problems frequently result in turfgrass stress and damage in the arid southwest. Although catch-can evaluations to determine irrigation distribution uniformity are the standard practice, they are cumbersome to conduct and are not practical for diagnostic purposes in real-time. Soil moisture uniformity can be evaluated using hand-held soil moisture meters but they do not help identify the cause of a soil moisture uniformity problem. To improve the efficiency of visualizing and diagnosing irrigation design problems, a Trimble AgGPS 132 sub-meter GPS receiver, HGIS software from StarPal, and a TDS Recon hand held computer were used to perform virtual irrigation audits in real-time. Golf course green and fairway perimeters, irrigation sprinkler location, and the theoretical throw of each irrigation head were easily mapped. Turfgrass problem can be mapped and overlaid onto the virtual irrigation audit to help identify the interaction between irrigation design and turfgrass performance. The virtual irrigation audit aids in diagnosing the cause of turfgrass excess or deficit soil moisture stress and weaknesses in irrigation designs. The image below illustrates a virtual irrigation audit of a golf course green where the heads throw 18 m (60 ft) and the green design prevents head to head coverage because some heads are separated by 32 m (108 ft).