Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 19, 1997
Publication Date: N/A
Technical Abstract: Evapotranspiration (ET) from a mowed, well-watered grass is often used as the reference ET for irrigation scheduling models. The purpose of this study was to measure ET from fescue grass [Fescuea arundinaca (Shregb.), cv. Emerald Green] in a semi-arid environment and compare that data with reference ET computed using standard measured meterological data and the ASCE and FAO versions of the Penman-Monteith equation. Grass ET was measured using a 1.5 m by 1.5 m surface area weighing lysimeter that was 2.3 m deep containing an undisturbed soil monolith of Pullman clay loam (Torrertic Paleustoll) at Bushland, TX. The grass was irrigated with a subsurface drip system and mowed regularly. Measurements were made in 1996 and 1997. Daily grass ET rates ranged from below 1 mm/d to just over 12 mm/d. Both reference ET methods under-predicted daily grass ET. Results will be presented to show agreement between measured and computed net radiation and soil heat flux, and the application of these reference ET equations in a semi-arid environment will be discussed.