Which method is commonly used to calculate irrigation requirements?

The use of evapotranspiration data is fundamental in calculating irrigation requirements because it combines the effects of evaporation and plant transpiration, providing a comprehensive measure of water loss from a crop. Evapotranspiration reflects not only the amount of water needed to maintain plant health but also accounts for environmental factors such as temperature, humidity, and wind that can affect the rate at which water is lost.

Understanding the amount of water that is lost from the soil and plants allows irrigation managers to determine how much supplemental water is necessary to achieve optimal crop growth. By using data on evapotranspiration, irrigation systems can be designed and managed more efficiently, ensuring that crops receive the right amount of water while minimizing waste and promoting sustainability in water use.

The other methods mentioned, such as measuring wind velocity, assessing soil pH, and measuring plant height, do not directly provide the necessary information about water loss and requirements for irrigation. While they can be useful for other aspects of agronomy or plant health, they are not effective for determining irrigation needs.