Importance of Evapotranspiration in Drip Irrigation

Importance of Evapotranspiration in Drip Irrigation

Date: 01-11-2023

Definition: The loss of water from soil is called Evaporation & the loss of water from plant leaves is called transpiration. Both the Evaporation & transpiration are combine called Evapotranspiration. The main factor deciding the evapotranspiration in the plant is temperature, humidity, Wind Speed & Radiation.

Water Requirement of Crop at any time

Water Requirement of Crop= Evapotranspiration of the earlier day (ETc) The water lost by plant earlier day by Evapotranspiration is its next day’s water requirement.

The factors deciding the water requirement of any plant are

• Crop factor
• Evapotranspiration (ETc)

Here ETc= ETo X Crop Factor

ETo is the reference Evapotranspiration which is the Evapotranspiration from the well watered Grass surface in 24 hours. The data of ETo is usually available with Weather stations. It is calculated in mm/Day.

Crop Factor is the crop growth stages can be divided into four main growth stages: initial, crop development, mid-season, and late season. The length of each of these stages depends on the climate, latitude, elevation, planting date, crop type, and cultural practices. The crop factor varies accordingly those growth stages.

Here today’s ETc is the next day water requirement of the Plant in mm/Day & finally the drip Irrigation timing is calculated as per the designed application rate of drip Irrigation which is calculated as

Drip Application Rate= Dripper Discharge/ (Inline Spacing X Dripper Spacing) The unit for drip application rate is mm/Hr.

Operating hours for today= ETc of the earlier day/ Drip Application Rate