Variability of Reference Evapotranspiration Across Nebraska

Reference evapotranspiration is a critical variable used to determine actual crop water use. It is used to make irrigation management decisions and has many other applications in water resource management. Since reference ET is not limited by water availability or plant function, it depends on the ability of the environment to extract water from the surface. As such, it varies significantly throughout the year and growing season as a function of climate. It also varies significantly from the eastern to the western edge of Nebraska.