Bermudagrass Response to Deficit Irrigation and Traffic Stress.

Golf course water use in Texas has become increasingly regulated in recent years due to persistent drought conditions, diminishing water supplies, and rapidly growing population. Golf course superintendents are being asked to prepare for considerable cutbacks in the amount of irrigation water used, but information is limited regarding critical levels needed for maintaining adequate quality, persistence, and recovery from drought.  The objectives of this research are to 1) Characterize the response of 'Tifway 419' bermudagrass fairway and rough plots to season-long irrigation programs of 100, 60, 45, 30, and 0% of reference evapotranspiration (ET_o), 2) Determine the impacts of simulated traffic stress on irrigation requirements, and 3) Quantify divot recovery time as a function of irrigation amount and traffic.  Digital analysis software is being used to quantify changes in turf canopy and root architecture dynamics.  Soil moisture and electrical conductivity (EC) are also being tracked in plots. In the initial season, traffic stress has failed to significantly impact irrigation requirements.  Irrigation levels of ³45% ET_o have been necessary for consistently achieving acceptable levels of green cover (>80%) in plots.  Soil EC measurements reveal greatest concern of salt accumulation within the upper 2.5 cm profile of 60 and 45% ET_o treatments, although to date, this has not reached damaging thresholds (< 1 dS m^-1).  Canopy temperatures increase considerably as irrigation is reduced; with a 16°C increase detected between irrigated and non-irrigated plots.  During the fall months, irrigation will be returned to full levels across plots for evaluating recovery and survival.