1. Download irrigation calculators in individual Microsoft Excel 2003 files.
Use this calculator to determine the length of time that an irrigation system must run to apply enough water to replace the water lost to evapotranspiration. This depends on the irrigation frequency, the water use rate of the crop, the irrigation application rate (precipitation rate), and the irrigation efficiency.
The results are not applicable to self-propelled irrigation systems such as center pivots, linear moves, or hose-reel systems.