Center Pivot Irrigation

• Water is supplied under pressure to the pivot point from a well or surface source
• The overhead pipeline distributes water to sprinkler heads or drop nozzles along its length
• Motorised, wheeled towers move the pipeline slowly around the pivot point
• The speed of rotation controls the depth of water applied per pass
• A full rotation irrigates the circular area the machine’s length reaches

Center pivots suit large, relatively flat to gently sloping fields where a fixed pivot point and long structural span are practical, and they are widely used for maize, wheat, potato, soybean, and other field crops on large-scale farms. Adaptations exist for rougher terrain, but very steep or highly irregular fields are generally less suited to this method.

Center pivots can achieve relatively high and uniform application efficiency compared with surface irrigation, particularly with drop nozzles that release water closer to the canopy or soil surface rather than high overhead, which reduces evaporative and wind-drift losses.

As with other pressurized systems, matching application depth and timing to crop water need — using evapotranspiration estimates and soil moisture data — is central to achieving efficient water use rather than simply running the system on a fixed schedule.

Corner system

An articulated extension arm that swings out to irrigate part of the field corners a standard pivot would otherwise miss

Linear-move system

A related straight-span machine that travels across a rectangular field rather than pivoting, covering corners a circular pivot cannot reach

Drop nozzles (low-energy precision application)

Nozzles hung close to the crop canopy rather than mounted high on the pipeline, reducing evaporation and wind drift

Center pivots require a substantial capital investment and a source capable of supplying continuous pressurised flow, along with ongoing energy costs for pumping. Uneven application can occur near the pivot point (where ground speed is slowest) versus the outer end (where it is fastest) if nozzle output is not correctly matched along the span.