Limited water resources in the arid southwestern USA have created greater interest on the part of municipalities to utilize nonpotable waters in urban areas. Research was conducted to assess the feasibility of using a perched saline aquifer as an alternative irrigation source for turfgrass. Two line‐source irrigation gradients, one using municipal water with an EC of ≈ 1.1 dS m−1 and the other using saline aquifer water blended with municipal water to an EC of 6.0 dS m−1, were established to impose a salinity and/or water deficit gradient on tall fescue (Festuca arundinacea Schreb. ‘Monarch’) and an improved common bermudagrass (Cynodon dactylon L. ‘Numex Sahara’). Yield was found to be highly correlated with actual evapotranspiration (ETa) (r = 0.92, P < 0.001 for bermudagrass; r = 0.83, P < 0.001 for tall fescue), regardless of how the stress was imposed. Relative ETa (ratio of ETa to maximum ETa under municipal irrigation) values as a function of the summation of the leaf‐to‐air temperature differences also indicated no distinguishable change in stress response based on water quality (r = 0.94, P < 0.001 for tall fescue; r = 0.86, P <0.001 for bermudagrass). Relative turf color and percent cover remained unchanged if the ratio of irrigation volume to potential evapotranspiration (I/ETo) remained above species‐specific threshold values of 0.80 for tall fescue and 0.65 for bermudagrass. Below these thresholds, cover and color declined linearly, with differences due to water quality treatment in tall fescue but with no differences due to water quality treatment in bermudagrass.

The use of poor quality water for irrigation purposes in the urban landscape has the potential to save significant quantities of good quality water for higher priority uses. Research was conducted to determine the impact leaching fractions (LF = drainage volume/irrigation volume) and irrigation-uniformity distributions have on the spatial distribution of water and salts and plant response when irrigating with saline water. Tall fescue (Festuca arundinacea Schreb. 'Monarch') was grown in 18 plots, each with a centrally located lysimeter that enabled estimates of evapotranspiration and irrigation requirements. Imposed treatments included setting LF at 0.05, 0.15, or 0.25 and manipulating plot irrigation systems such that the Christiansen uniformity coefficient (CUC) was set at 0.65, 0.75, or 0.85. Saline irrigation water (2.5 dS m-1 ) was applied for an 18-mo period. Significant LF X CUC interactions were observed for depth-weighted soil salinity, yield, evapotranspiration (ET), tissue moisture content, and canopy temperatures. Although the coefficient of variation increased with each measured parameter as the CUC decreased, only the depthweighted electrical conductivity (EC,) showed a coefficient of variation >20%. A 14% savings in irrigation water was obtained when the high CUC, low LF treatment was compared with the high LF, low CUC treatment. Ninety-one percent of the variability in the average plot EC, could be accounted for if the actual LF, lysimeter ET, and average plot canopy temperatures at the end of the experiment were taken into consideration. Under the conditions of this experiment, irrigating tall fescue with 2.5 dS m-1 water would be an acceptable practice even at LFs as low as 0.05 if the CUC is optimized.

Plants grown under saline conditions can experience elevated matric and osmotic stress between irrigation events. Research was conducted to assess the physiological response of tall rescue (Festuca arundinacea Schreber 'Monarch') and common bermudagrass (Cynodon dactylon L. 'Numex Sahara') to varying combinations of soil matric (~M) and osmotic potentials (0n). Two line-source gradient experiments were conducted, using municipal water with an electrical conductivity (EC) of 1.1 dS-~ or s aline a quifer water blended w ith municipal water (EC of 6.0 dS m-t). Turf temperature, leaf xylem water potential (0L), tissue osmolality (0U-TISS), yield, evapotranspiration (ETa), percent cover, turf color, and tissue ion concentrations were monitored during a 68-d drydown period during the summer of the second year of experimentation. The total soil water potential (t~T) was highly linear with distance from the line source with no significant difference between fresh and saline treatments within each species (bermudagrass, Adj r 2 = 0.867**; tall rescue, Adj r~ = 0.810"). Significantly lower soil osmotic potentials were recorded under the saline treatment, while lower soil matric potentials were recorded under the fresh treatment for both species. Turf temperature, yield, ETa, turf color, and canopy cover responded to ~M and t~u in an additive fashion. The ~L, ~n-TISS and tissue ion concentrations in bermudagrass and 0~ T~SS and tissue ion concentrations in tall rescue responded in a nonadditive fashion, however. Our results suggest that water with a salinity level of 6.0 dS m-t could be used as a supplemental irrigation source for both tall fescue and bermudagrass if irrigation practices were designed to minimize water deficit.