What is ET-based weather-based irrigation control and its benefit?

• A. It uses rainfall data alone to decide irrigation schedules.
• B. ET-based irrigation control uses ET data to estimate plant water use, enabling more precise watering and water savings.
• C. It uses only soil pH to determine watering.
• D. It irrigates on a fixed schedule regardless of weather.

Answer: (B)

ET-based weather-based irrigation control uses evapotranspiration data to gauge how much water a crop is actually using, then adjusts irrigation accordingly. Evapotranspiration combines water loss from soil evaporation with plant transpiration, and it changes with weather factors like temperature, humidity, wind, and solar radiation. By feeding this weather-driven ET information into the controller, the system estimates daily crop water demand and applies just enough water to meet that need. The main benefit is precise, responsive watering that matches plant demand, which saves water, reduces runoff and leaching, and supports healthier plant growth. This approach differs from relying on rainfall data alone, soil pH, or a fixed irrigation schedule, which don’t adapt to actual plant water use.