Kentucky Bluegrass Cultivar Evapotranspiration Rates

Abstract

Abstract Twenty well-watered Kentucky bluegrass ( Poa pratensis L.) cultivars were evaluated for evapotranspiration (ET) under controlled environment, using the water-balance method. ET ranged from a low of 3.86 mm·day −1 for ‘Enoble’ to a high of 6.43 mm·day −1 for ‘Merton’, ‘Birka’, and ‘Sydsport’. Cultivars differed in shoot density, verdure, root density, stomatal density, and stomatal index. Only verdure was significantly correlated ( r = 0.60) to ET for the 20 cultivars. Five cultivars were selected using cluster analysis to represent categories of high, medium, and low ET rates. ET for these cultivars increased from 1.1- to 1.7-fold when temperature was increased from 25° to 35°C, depending on cultivar. ET at 35° was positively correlated to vertical elongation rate ( r = 0.96), and negatively correlated to shoot density ( r = − 0.87) and verdure ( r = − 0.83) under well-watered conditions.