The term evapotranspiration is used to describe the entire field evaporation (e.g. within a crop), i.e. the sum of evaporation from the plants resulting from their life processes (transpiration) and evaporation from the soil surface (evaporation).
A distinction is made between:
- current (actual) evapotranspiration,
- potential evapotranspiration – a climatic indicator of how fast evaporation could take place if water availability was sufficient.
Both of these values can theoretically be calculated on an ongoing basis for each day, e.g. in the irrigation calculator provided by the Institute of Horticulture in Skierniewice.