The water from the ground to the atmosphere passes from the liquid to the gaseous state through the process of evapotranspiration, that is, by direct evaporation from the soil and by transpiration of the plants. The water both in the soil and in the plant is held back by a set of forces that oppose the process of evapotranspiration itself.
Figure 1 – Evapotranspiration
In the plant, transpiration occurs through the leaf apparatus with the stomatal openings, so if we want to measure the force with which the plant retains water we can refer to the so-calledpotenziale fogliare .
