Water Use and Drought Responses of Cool-Season Turfgrasses

Evapotranspiration (ET) rates of four turf grass species were compared in Rhode Island to aid in the selection of grasses with lower water requirements. ET was measured under well-watered conditions using weighing lysimeters placed into field plots of mature turf. Measurements were obtained regularly from July to September in 1984 and 1985. Average daily ET ranged from 0.23 to 0.41 cm of water/day for: Paa pratensis L. cvs. \u27Baron\u27 and \u27Enmundi\u27, Lolium perenne L. cv. \u27Yorktown II\u27, Festuca rubra var. commutata Gaud. cv. \u27Jamestown\u27, and Festuca ovina var. duriuscula L. Koch cv. \u27Tournament\u27. Significant differences in ET rates were found between species. Kentucky bluegrass and perennial ryegrass transpired more than the fescues. Potential ET was computed using the modified Penman equation and the pan evaporation methods. Crop coefficients (KCs) were calculated to determine the predictive consistency of the methods. Seasonal KCs based on the Penman equation ranged from 0.88 to 1.09. KCs based on pan evaporation showed more variability, ranging from 0.86 to 1.35