What does an ET sensor determine to adjust in a controller?

• A. Root Zone Temperature
• B. Rainfall Amount
• C. ETo and local weather
• D. Soil pH Levels

Answer: (C)

An ET (Evapotranspiration) sensor is designed to measure the amount of water that is lost through evaporation from the soil and transpiration from plants. By utilizing local weather data and Actual Evapotranspiration (ETo) calculations, the ET sensor can determine the water needs of a landscape. This information allows for real-time adjustment of irrigation schedules based on current environmental conditions, ensuring that plants receive the appropriate amount of water.

This capability of adjusting irrigation based on ETo and local weather is crucial for water conservation and maintaining the health of landscapes, particularly in areas prone to drought or water scarcity. It optimizes water use by preventing overwatering when rainfall is sufficient or reducing irrigation during hot or windy conditions when evaporation rates increase. Thus, the correct answer highlights the sensor's role in integrating weather data and plant water use, which is essential for efficient landscape irrigation management.