COMPARATIVE EVAPOTRANSPIRATION RATES OF TALL FESCUE CULTIVARS

Comparative evapotranspiration (ET) rates of 20 cultivars of tall fescue (Festuca arundinacea Schreb.) were measured over 7 days in a greenhouse study. Small but significant differences in ET rates existed between the cultivars grown under nonlimiting water and nutrient conditions on day 1 following mowing. Greater differences had developed after 7 days of growth, with ET ranging from a low of 10.0 mm.day-1 for 'Shortstop' to a high of 13.5 mm.day-1 for 'Alta'. Day 7 ET was positively correlated (r = 0.82) with clipping dry weight. Six of the tall fescue cultivars were selected for a subsequent experiment to determine the stability of relative rankings for ET over time. Although average ET varied by up to a factor of two among five dates, the rankings were nearly identical for the five dates and were consistent with the rankings in the first experiment.