Irrigation Scheduling & Evapotranspiration Flashcards

Which term describes the combined process of water evaporation from soil and transpiration from plants?

Answer: Evapotranspiration

Evapotranspiration (ET) is the combined water loss through evaporation from soil surfaces and transpiration from plant leaves.

Reference evapotranspiration (ETo) is most commonly calculated using which method recognized by the FAO?

Answer: Penman-Monteith method

The FAO-56 Penman-Monteith equation is the globally recognized standard for calculating reference evapotranspiration.

A crop coefficient (Kc) is used to adjust ETo for a specific crop. What does a Kc value of 1.2 indicate?

Answer: The crop uses 20% more water than the reference crop

A Kc of 1.2 means the actual crop evapotranspiration (ETc) is 20% greater than the reference ETo.

Which irrigation scheduling method uses soil moisture sensors to determine when to irrigate?

Answer: Soil water depletion method

The soil water depletion method uses sensors such as tensiometers or capacitance probes to monitor soil moisture and trigger irrigation at a set threshold.

What is the Management Allowable Depletion (MAD) typically set at for most turf and landscape irrigation?

Answer: 25–40%

MAD for turf and landscape is typically set between 25–40% of plant available water to avoid plant stress.

An irrigation controller that automatically adjusts run times based on local ET data is called a:

Answer: Smart or ET-based controller

Smart or ET-based controllers use weather data or on-site sensors to continuously adjust irrigation schedules to match actual plant water needs.