Cyclic Irrigation of Turfgrass Using a Shallow Saline Aquifer

Abstract

water as a supplemental irrigation source on landscapes would free up potable water for higher priority uses, A 2-yr cyclic irrigation study using shallow saline groundwater lower water tables in contact with structural foundawas conducted on a sports field in southern Nevada [bermudagrass (Cynodon dactylon L. 'Tifway') overseeded with perennial ryegrass tions, reduce the potential of contaminating the primary (Lolium perenne L. 'Champion')]. Shallow groundwater with a salinity aquifer, and reduce the flow of shallow groundwater to of 3.3 dS m Ϫ1 was substituted for municipal water (0.9 dS m Ϫ1) at a the Las Vegas Wash and the Colorado River system. rate of one, two, three, or four times per seven irrigation events during However, such water does contain a significant salt load. the peak water demand periods of 15 May to 15 October. Salinity Salinity in the shallow system varies from 1.8 dS m Ϫ1 in sensors and tensiometers were installed at depths of 10, 25, and 40 cm the central part of the valley to Ͼ10.0 dS m Ϫ1 in the and recorded weekly. Midday leaf xylem water potential, canopy southeastern part of the valley (Dean 1996; Schaan temperature, and turfgrass color and cover ratings were taken on a 2001). bimonthly basis. Soil salinity cycled up (as high as 24 dS m Ϫ1) and Many studies have demonstrated the feasibility of down (baseline values of 4.0-10.0 dS m Ϫ1) in response to substitution using saline water for irrigating agricultural and hortiperiods. However, the duration in which soil salinity exceeded salt tolerance threshold values for bermudagrass were short in all treat-cultural crops (Ayers and Wescot, 1985; Rhoades et al., ments (Ͻ21 d during the 2-yr period at the 10-cm depth). These 1989; Grattan, 1994; Dean et al., 1996; Leskys et al., short durations of threshold values being exceeded combined with 1999). Results from previous investigations into the pothe successful return to baseline soil salinity values during the cyclic tential use of the shallow saline aquifer in the Las Vegas off periods (freshwater only) led to little change in turfgrass color, Valley indicated that bermudagrass is well suited for cover, and plant water status. Freshwater savings as high as 50 cm irrigation with such water if threshold irrigation/potenyr Ϫ1 and a reduction in as many as 62 municipal irrigation days (days tial evapotranspiration (ET o) ratios are not exceeded irrigations took place) during the peak water demand periods oc-(where ET o is generated with an empirical-based equacurred. Results of this experiment indicate that the cyclic irrigation tion such as the Penman Combination equation and strategy is feasible in the urban setting with large turfgrass areas. threshold values relate to a well-defined point where turfgrass color and cover ratings decrease with declining irrigation/ET o ratios) (

Pertinent Water-Saving Management Strategies for Sustainable Turfgrass in the Desert U.S. Southwest

“…To meet emerging demands for water in the U. S. southwest, desalinization brackish water can be considered as an option. Responsible utilization of this resource through addition of leaching fraction, blending with potable water, sub-surface drip irrigation, or alternating sources of irrigation water have been suggested as strategies to manage salinity accumulation in landscapes [123][124][125]. Depending on treatment, wastewater can contain significant amounts of nutrients, including N, phosphorus (P), and potassium (K).…”

Tolerance of Tall Fescue (Festuca arundinacea Schreb.) Growing in Extensive Green Roof Systems to Saline Water Irrigation with Varying Leaching Fractions

“…The ability to utilize low-quality water for turfgrass irrigation has been evaluated by several researchers, particularly upon natural soil or sand-based artificial substrates [23][24][25]. However, it is worth considering that green roofs offer a more suitable environment for saline water irrigation.…”

Performance of Two Seashore Paspalum (Paspalum vaginatum Sw.) Varieties Growing in Shallow Green Roof Substrate Depths and Irrigated with Seawater

“…The use of poor quality water for turfgrass irrigation has been reported to be successful by several researchers [16][17][18][19]. Saline irrigation water sources include saline groundwater, which may either be naturally saline or a result of salt leaching or due to seawater intrusion into the aquifer, brackish surface water, saline sewage effluent, and reclaimed or recycled water [20].…”