Most of the water entering a plant's root will exit
the leaves by transpiration. Transpiration in plants is the
passage of watery vapor through the stomata of plant tissue.
By knowing the amount of water
exiting each plant trough the process of transpiration we can
estimate the amount of water the plant needs. We can also compare
different plants based on their need to water and select the best
plants for different locations based on the availability of water.
The rate of transpiration may also
change in different hours of the day, so while using automated
irrigation systems, we can increase or decrease the amount of water
supplied to the plant based on the time of the day.