The ratio of AET to PET lies between

Concept:

Actual Evapotranspiration:

It is the quantity of water that is actually removed from a surface due to the processes of evaporation and transpiration.

Potential Evapotranspiration:

It is a measure of the ability of the atmosphere to remove water from the surface through the processes of evaporation and transpiration assuming no control on water supply.

The relation between actual evapotranspiration and potential evapotranspiration with different soil moisture conditions is as follows:

1. If the water supply to the plant is adequate, soil moisture will be at field capacity then, the ratio of AET to PET = 1.
2. If the water supply to the plant is inadequate, then the ratio of AET to PET is less than 1.
3. In clayey soils, AET/PET is almost equal to 1.
4. When the soil moisture approaches the permanent wilting point, AET tends to 0.

Hence, If the moisture content in soil is at the field capacity of the soil, the ratio of Actual Evapotranspiration (AET) to the potential Evapotranspiration (PET) is equal to 1.

Additional InformationField Capacity (FC):

The field capacity is the amount of water held in soil after excess water has been gravity drained.

Permanent Wilting point (PWT):

A permanent wilting point is the moisture content of a soil at which the moisture is no longer available in sufficient quantity to sustain the plants.