Evapotranspiration Rate ($ET$):

For Vegetative Stage:

$$ET = 0.8 E + 0.3$$

For Reproductive Stage:

$$ET = 0.9 E + 0.2$$

Where:

• $ET$ is the evapotranspiration rate, in millimeters per day (mm/day).
• $E$ is the pan evaporation, in millimeters per day (mm/day).