Cyclic Irrigation of Turfgrass Using a Shallow Saline Aquifer

Abstract

A 2-yr cyclic irrigation study using shallow saline groundwater was conducted on a sports field in southern Nevada [bermudagrass (Cynodon dactylon L. ‘Tifway’) overseeded with perennial ryegrass (Lolium perenne L. ‘Champion’)]. Shallow groundwater with a salinity of 3.3 dS m−1 was substituted for municipal water (0.9 dS m−1) at a rate of one, two, three, or four times per seven irrigation events during the peak water demand periods of 15 May to 15 October. Salinity sensors and tensiometers were installed at depths of 10, 25, and 40 cm and recorded weekly. Midday leaf xylem water potential, canopy temperature, and turfgrass color and cover ratings were taken on a bimonthly basis. Soil salinity cycled up (as high as 24 dS m−1) and down (baseline values of 4.0–10.0 dS m−1) in response to substitution periods. However, the duration in which soil salinity exceeded salt tolerance threshold values for bermudagrass were short in all treatments (<21 d during the 2-yr period at the 10-cm depth). These short durations of threshold values being exceeded combined with the successful return to baseline soil salinity values during the cyclic off periods (freshwater only) led to little change in turfgrass color, cover, and plant water status. Freshwater savings as high as 50 cm yr−1 and a reduction in as many as 62 municipal irrigation days (days irrigations took place) during the peak water demand periods occurred. Results of this experiment indicate that the cyclic irrigation strategy is feasible in the urban setting with large turfgrass areas.