Annual Bluegrass and Creeping Bentgrass Evapotranspiration Rates

Potential evapotranspiration (ET) (i.e., ET when soil water is not limiting) rates of creeping bentgrass ( Agrostis palustris Huds.) and annual bluegrass ( Poa annua L.) were determined during two consecutive summers using weighing lysimeters in the field. When evaluated under putting green conditions, significant species differences in ET were observed during several weeks in 1985 and 1986. Differences were small, however, and irrigation requirements should not vary much between these species. Both species exhibited lower water use rates in 1986 when cut at 6 mm (4.6 mm·day -1 ) than at 12 mm (4.9 mm·day -1 ). These small differences should not greatly affect water requirements of putting green turf maintained at variable cutting heights. Variability of ET throughout the study periods suggests that water savings could result if ET is monitored, and irrigation adjusted accordingly.