What does Distribution Uniformity (DU) measure in irrigation performance?

• A. It measures how evenly water is applied across a field or area.
• B. It determines the total depth of water applied.
• C. It sets the maximum allowable pressure in lines.
• D. It is unrelated to irrigation performance.

Answer: (D)

Distribution Uniformity is about how evenly water is applied across every part of a field. It measures spatial consistency—how close the depth of water received in the driest areas is to the average depth across the whole area. A high DU means most of the field gets about the same amount of water, while a low DU means there are dry spots and wet spots. This helps you judge irrigation system performance, calibrate sprinklers, and protect crops from under- or over-watering. It’s not about the total amount of water applied, the pressure in the lines, or something unrelated—those are separate aspects of irrigation performance.