Water Quality and Growth Regulator Effects on Bermudagrass Managed Under Irrigation Stress

Reagan Hejl, Benjamin Wherley, and Richard White

As the need for landscape and golf course water conservation increases, use of poor-quality irrigation water combined with deficit irrigation practices become commonplace.  Information is lacking concerning the relationship between water quality and minimal irrigation requirements, as well as the extent to which plant growth regulators may aid in ameliorating warm-season turfgrass quality under irrigation stress.  The objectives of this 10-week greenhouse lysimeter study were to 1) characterize growth and quality response of 'Tifway' bermudagrass (Cynodon dactylon x C. traansvalensis Burt Davy) to irrigation replacement of 100, 50, and 30% of actual turfgrass evapotranspiration (ET_a), 2) determine whether application of trinexapac-ethyl (TE) aids turf quality under water stress, and 3) determine whether minimal irrigation requirements are impacted by water quality (reverse osmosis, sodic, and saline). During the initial study, there was not a strong relationship between water source and turf quality, however plants receiving sodic irrigation exhibited somewhat greater consumptive water use rates.  Untreated turf receiving 30% x ET_a gradually declined to unacceptable quality levels; however, decreased leaf firing and improved turf quality resulted from TE application.