Irrigation scheduling using evapotranspiration (ET): example schedule
Rogers, Danny H., author
Irrigation scheduling can be accomplished by keeping an account of crop water use relative to the amount of water available for withdrawal from the soil profile. Measurement of crop water use or evapotranspiration (ET) can be indirectly measured by monitoring soil water levels or calculated using weather information and specific crop growth characteristics. Calculating crop water use, although an estimate, is a reliable and accurate method that is finding favor with many irrigators since the information can be gathered and delivered electronically to the office and eliminates much of the labor involved in indirectly measuring water through soil sampling. Some soil monitoring is still necessary to confirm scheduling accuracy and account for rainfall and other variations. KSU bulletins, Scheduling Using Evapotranspiration Reports for Center Pivots, L-915, and Furrow Irrigation, L-914 are available from the county extension office. This example will follow the procedures discussed in those bulletins and will assume use of a center pivot system.
Presented at the Central Plains irrigation short course and exposition on February 4, 1997 at the Colby Community Building in Colby, Kansas.