Soil Salinity and Quality of Sprinkler and Drip Irrigated Warm-Season Turfgrasses

A study was conducted in New Mexico from 2005 to 2007 to investigate the effects of two potable water-saving strategies, irrigating with saline water and using subsurface systems, on changes in rootzone salinity and quality of nine warm-season turfgrasses. Plots were irrigated using either sprinklers or subsurface drip with water of 1 of 3 salinity levels (0.6, 2.0, and 3.5 dS m(-1)). Plots were rated monthly for quality during the growing seasons and bi-annually for spring and fall color. Soil samples were collected bi-annually (June and November) and analyzed for electrical conductivity (EC), Na, and sodium adsorption ratio (SAR) at depths of 0 to 20 and 50 to 60 cm. Electrical conductivity and Na values in 0 to 20 cm peaked in June of 2005 and 2006 and dropped to lower levels aft er the summer rainy season. With the exception of moderately saline irrigated plots in 2005, summer EC did not differ between drip and sprinkler irrigated plots for any of the three water qualities. Electrical conductivity, Na, and SAR at a rootzone depth of 0 to 20 cm were highest in June 2006 reaching 4.7 dS m(-1), 1024 mg L-1, and 16.1, respectively. For most of the grasses tested, EC, Na, or SAR values showed no significant relationship with turf quality. Drip irrigation resulted in earlier green-up than sprinkler irrigation but had no effect on summer quality or fall color retention. Most of the warm season grasses included in this study maintained an acceptable quality level when drip-irrigated with saline water.