Center-Pivot systems and lateral move irrigation machines

Center pivots are a form of sprinkler irrigation consisting of several spans joined together and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length. The machine is fed with water that comes from the Pivot pad.

Center-Pivots are typically less than 500 metres in length (circle radius). To achieve uniform application, center Pivot systems require a continuously variable emitter flow rate across the radius of the machine. Nozzle sizes are smallest at the inner spans to achieve low flow rates and increase with distance from the pivot point.

Most center pivot systems now have drops hanging from goosenecks attached at the top of the pipe with sprinkler heads that are positioned a few feet above the crop, thus limiting evaporative losses and wind drift. Pressure regulators are typically installed upstream of each nozzle to ensure each is operating at the correct design pressure.

Crops may be planted in straight rows or are sometimes planted in circles to conform to the travel of the center pivot.

Originally, most center pivots were water-powered. These were replaced by hydraulic systems and electric motor-driven systems. Most systems today are driven by an electric motor mounted at each tower.

For center pivot to be used, the terrain needs to be reasonably flat; but one major advantage of center pivots over alternative systems is the ability to function in undulating country. This advantage has resulted in increased irrigated acreage and water use in some areas.

Linear/Lateral Move Irrigation Machines

The above mentioned equipment can also be configured to move in a straight line where it is termed a linear move or lateral move irrigation system. In this case the water is supplied by an irrigation channel running the length of the field and positioned either at one side or midway across the field width.

The motor and pump equipment is mounted on a cart adjacent to the supply channel that travels with the machine. Farmers may opt for linear moves to conform to existing rectangular field designs such as those converting from furrow irrigation.

Lateral moves are far less common, rely on more complex guidance systems and require additional management than compared to centre pivot systems.

Center pivot irrigation

Center-pivot Irrigation, is a method of crop irrigation in which equipment rotates around a pivot. A circular area centered on the pivot is irrigated, often creating a circular pattern in crops when viewed from above. The system is fed with water from the pivot point at the center of the circle.
Central pivot irrigation is a form of sprinkler irrigation consisting of several segments of pipe galvanized steel or aluminium, joined together and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length. The inner sets of wheels are mounted at hubs between two segments and use angle sensors to detect when the bend at the joint exceeds a certain threshold, and thus, the wheels should be rotated to keep the segments aligned.
Centre pivots are typically less than 500m in length (circle radius) with the most common size being the standard 1/4 mile machine (400 m). Most center pivot systems now have drops hanging from a u-shaped pipe called a gooseneck attached at the top of the pipe with sprinkler heads that are positioned a few feet (at most) above the crop, thus limiting evaporative losses and wind drift. Drops can also be used with drag hoses or bubblers that deposit the water directly on the ground between crops. This type of system is known as Low Energy Precision Application. Crops may be planted in straight rows or are sometimes planted in circles to conform to the travel of the center pivot.
Most systems today are driven by an electric motor mounted at each tower. The equipment can also be configured to move in a straight line, where the water is pulled from a central ditch. In this scenario, the system is called a linear move irrigation system. Terrain needs to be reasonably flat, but one major advantage of centre pivots over alternative systems is the ability to function in undulating country.