Center pivot irrigation is a form of overhead (sprinkler) irrigation consisting of several segments of pipe (usually galvanized steel or aluminum) joined together and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length.
The major components include:
- Pivot
- Pivot tower
- Control Panel
- Spans of pipe between towers
- Trusses to support the spans
- Tower drive wheels
Most center pivot systems now have drops3 hanging from a U-shaped pipe called a goose neck attached at the top of the pipe with sprinkler heads positioned a few feet (at most) above the crop, thus limiting evaporative losses and wind drift.
Irrigators typically install pressure regulators upstream of each nozzle to ensure each is operating at the correct design pressure. They can also use drops with drag hoses that deposit the water directly on the ground between crops or with spray-type sprinklers less than two feet (0.6 meters) off the ground. These types of systems are respectively known as Low Energy Precision Application (LEPA) or Low Elevation Spray Application (LESA).
Most center pivots originally operated with high water pressure, a practice later replaced by hydraulic systems and electric motor-driven systems. Most systems today are driven by an electric motor mounted at each tower.