time clock systems (Beeson, personal communication). Most irrigation managers are unaware of day-to-day changes in reference evapotranspiration (ETo), a value that quantifies evaporation potential of the immediate microclimate, and corresponding changes
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Jason E. Stout, Joan R. Davenport, and R. Troy Peters
.22″) located less than 5 km from the research site. Total precipitation was measured, and growing degree days (base of 10 °C, 1 Apr. to 31 Oct.) and grass reference evapotranspiration (ET o ) were calculated. The accumulated growing degree days (GDD) increased
Tej P. Acharya, Gregory E. Welbaum, and Ramón A. Arancibia
.08 mm, respectively (54% ET reduction). Overall, average ET reduction under LT in all three trials was 60%. Fig. 1. Daily evapotranspiration at canopy levels in brussels sprouts grown under low tunnel (LT) and open field (Open). Air temperatures, solar
Kuan Qin and Daniel I. Leskovar
flowering stage): deficit irrigated based on 50% evapotranspiration (ET) and fully irrigated based on 100% ET. The required irrigation was determined following the potential ET (ET 0 ) and crop coefficient of watermelon (K c initial = 0.4, K c mid = 1
Richard C. Beeson Jr
explain observations noted decades earlier in rhododendron nursery production. The objectives of this research were to verify theoretical reductions in plant evapotranspiration with increases in canopy closure and to begin defining the depth of the upper
Luke Miller, George Vellidis, and Timothy Coolong
evapotranspiration (ET c ) from weather data collected by the University of Georgia Weather Network weather station in Tifton. These data were used to calculate ET o from air temperature, solar radiation, wind speed, and relative humidity using the Penman
Luke Miller, George Vellidis, Osama Mohawesh, and Timothy Coolong
and Florida are based on variations of the WB method ( Harrison, 2009 ). The WB method estimates daily crop water use based on historic evapotranspiration (ET o ) values for a region adjusted with a crop coefficient (K c ) ( Allen et al., 1998
Amanda Bayer, John Ruter, and Marc W. van Iersel
) mounted on steel platforms with an acrylic platform on top of each load cell. Plant mass was measured every minute and averages were recorded by the data logger (CR1000; Campbell Scientific, Logan, UT) every 10 min. Hourly evapotranspiration was determined
Esmaeil Fallahi, Bahar Fallahi, and Bahman Shafii
calculated based on ETc where ETc = ETr × Kc with ETr (Penman-Monteith reference evapotranspiration) ( Allen et al., 1998 ) being calculated from the Agri-Met Parma Weather Station data and Kc being the crop coefficient. Each year starting 2002, the crop
Tamara Wynne and Dale Devitt
, enabling estimates of reference evapotranspiration (ET ref ) using the Penman-Monteith equation ( Allen et al., 1998 ). Each of the irrigation basins surrounding the 30 trees and all of the lysimeters selected for this study had a single access tube placed