COMPARISON OF SUBSURFACE DRIP IRRIGATION AND SPRINKLER IRRIGATION FOR BERMUDA GRASS TURF IN ARIZONA

A subsurface drip irrigation (SDI) system is potentially efficient because it provides water directly to the rootzone, minimizing evaporative loss, especially in arid lands. In this study, subsurface drip irrigation was compared tostandard overhead sprinkler irrigation of Bermuda grass turf using reclaimed water. Research focused on the response ofBermuda grass to two irrigation treatments, subsurface drip irrigation and overhead sprinkler irrigation. Soil moisturecontent was calculated via time domain reflectometry (TDR) and neutron probe data. The remotely sensed crop waterstress index (CWSI) could not be used to schedule irrigation. When the average soil moisture of all eight plots wasdepleted to 50% of readily available water, they were irrigated until the soil moisture content reached field capacity. Nosignificant differences were observed between the two irrigation systems in total irrigation depth, relative root weight, dryclipping mass per unit area, or visual quality. The electrical conductivity (EC) of a soil water extract measured at thebeginning and end of the season indicated salt accumulation near the ground surface in the subsurface plots, but therewas not sufficient accumulation to affect the appearance of turf. Visual inspection of emitters after one irrigation seasonshowed signs of root intrusion because of water stress in certain plots with high surface sand content.