Wednesday, November 15, 2006 - 3:45 PM
264-7

The Impact on Turf Quality of Reduced Irrigation Plus Surfactants Compared to ETp Replacement Irrigation in Soils Prone to Exhibit Water Repellency.

Dara Park, University Of Florida, 3205 College Ave, Fort Lauderdale, FL 33314 and John Cisar, 3205 College Ave., University of Florida, University of Florida, REC, Ft. Lauderdale, FL 33314.

Water restrictions for irrigating turfgrass are routinely implemented by regulatory agencies. In order to optimize irrigation reduction, plant responses to water stress needs to be identified to avoid reductions in turfgrass performance. This experiment was conducted to determine if monitoring reflectance in the near-infrared and red wavelengths can (i) be used to indicate turf quality, (ii) detect early water stress in bermudagrass before it is visually perceptible, and (iii) whether frequent surfactant application reduces the need for irrigation while maintaining turfgrass quality. Trials were conducted in which Tifdwarf bermudagrass (Cynodon dactylon X Cynodon transvaalensis) was subjected to either (i) no irrigation (non-irrigated control), (ii) irrigated daily (irrigated control) or, (iii) initially treated with a non-ionic surfactant (surfactant) over a dry-down period. Visual turfgrass quality and localized dry spot symptoms were monitored by an experimental active infrared/red sensor. Absolute correlation values of sensor measurements with visual observations increased over each trial period. On some dates, the sensor determined water stress before stress was visually apparent. Furthermore, turfgrass quality and localized dry spot symptoms from surfactant-treated turfgrass was similar or better than irrigated turfgrass, with both showing greater quality and less LDS symptoms than observed from the non-irrigated turfgrass. Results indicate that applying a surfactant decreased irrigation requirements up to 71% while maintaining similar quality as bermudagrass that is not water stressed. This may be important for maintenance of sports turf subjected to watering restrictions.