Which of the following best describes the adjustment feature of a conventional irrigation controller?

• A. Local weather conditions only
• B. Global percentage adjustment for all programs
• C. Specific adjustments for each zone independently
• D. Adjustment based solely on soil type

Answer: (B)

The adjustment feature of a conventional irrigation controller is best described by a global percentage adjustment for all programs. This means that when an adjustment is made—such as increasing or decreasing the irrigation duration or frequency—it applies uniformly across all the zones managed by the controller.

This type of adjustment is useful for instances when there is a need to modify the watering schedule in response to general conditions, like a seasonal change or a prolonged period of rain or drought. By applying a uniform change across the board, the user can save time and ensure that all sections of the landscape receive the same relative amount of water, rather than having to adjust each zone individually.

Other approaches, such as local weather conditions or specific adjustments for each zone, offer more precision but are not characteristic of conventional controllers, which typically do not have the capability for zone-specific adjustments without manual intervention. Furthermore, soil type influences irrigation needs but does not specifically guide the adjustment feature of conventional controllers in the same straightforward manner as a global percentage adjustment does.