Center pivot checks

Make time to maintain center pivots to get the most out of them during the season.
By Xin Qiao, PhD
Photos: Xin Qiao

In the 1950s, the landscape of agriculture underwent a significant transformation with Frank Zybach’s introduction of the center pivot sprinkler irrigation system. With its commercialization, led by figures like Robert Daugherty, vast stretches of the Great Plains in the U.S. became arable powerhouses. These once rain-dependent lands now had the capability to support consistently high-yielding crops. However, as with any potent innovation, understanding its nuances and ensuring its optimal operation is crucial.

Start off strong

Before the planting season begins, preventive maintenance becomes paramount. Check the tire condition, make sure the lug nuts are tight and tires are at the proper pressure. Drain moisture buildup at the gearbox by loosening the plug. Ensure the gearbox oil levels are optimal. If needed, grease the pivot point bearings. Test the sprinkler pressure at the pivot, and make sure you have the correct numbers for the pressure and flow rate that the system was designed for. It’s also the time to make sure you have your irrigation schedule prepared appropriately for the crop that water is being applied to. If you’re operating with water allocations or permits, make sure you remember what you have available.

Equally crucial is verifying the system’s proper grounding to ensure its safe operation throughout the season. If conditions permit, a brief pivot test run can reveal issues such as misalignments, water leaks, clogged nozzles or even missing components. Modern center pivots often come with telemetry and associated apps, facilitating real-time monitoring. This is also a good time to confirm the system’s communication and its responsiveness to commands such as starting and stopping.


Remember that your center pivots are just a part of a larger set of factors in your crop’s development, including weather and crop management.


Remember that your center pivots are just a part of a larger set of factors in your crop’s development, including weather and crop management. Keeping your center pivots working correctly will ensure that this part of the equation is supporting crop health as much as possible.

Check in

As the growing season unfolds, periodic drive-by checks become invaluable, especially when crops are still in the early stages. When doing a drive-by check, there are a few different types of indicators that can be helpful in making a quick decision about how well a center pivot is working. That is, in a drive-by, you can directly see if a system is operating and moving correctly or in need of repair.


It’s always a priority to monitor the pressure and flow rate at the pivot point, ensuring they match the design specifications.


Start by making sure the sprinklers are operating and there aren’t any plugged nozzles. It’s always a priority to monitor the pressure and flow rate at the pivot point, ensuring they match the design specifications. As crops develop, the crops’ health, such as visible water stress, can be a tell-tale sign of the system’s performance. Certain patterns such as rings or wheel spokes are likely indicators of nozzle or pressure issues, respectively. Look for runoff and ponding as well, as those might be indicators that the pivot is dealing with a leak or should be sped up and applying less water per pass.

At the start of the season, do preventive maintenance like checking the tire condition and pressure as well as the tightness of the lug nuts.

If your center pivots have telemetry or remote operation available, a quick daily check-in can supplement those regular drive-by assessments.

In a lot of ways, a daily remote check mirrors many of the same ideas you’d use for a physical check-in. Note if the pivot is where it’s meant to be at that time and whether the end gun and aux ports are operating as you expect.

Depending on what information is being collected, if a soil water sensor is installed, check the data to ensure that the correct water depth is being reached and staying within the desired threshold to meet crop water requirements and prevent deep percolation.

As the season draws to a close, recording water usage, tracking operational hours and preparing the system for its off-season are pivotal. Ensuring compliance with water permit limits and allocations underpins both legal and sustainable operations. This is also a good time to clear out sand traps and drain water from the pivot while getting it ready for winter. Moreover, yield maps can be helpful to pinpoint if any low-yield zones are a result of center pivot inefficiencies.

Every handful of years, a more thorough inspection is helpful. Regular audits, perhaps every five years or sooner if issues arise, offer a holistic system assessment. This time is ideal for reevaluating the sprinkler package design, conducting pumping plant performance reviews, examining system components and making necessary replacements or updates. A catch can test can be beneficial to gauge the center pivot’s application uniformity.

By following these steps and properly maintaining center pivot sprinkler systems, growers can ensure optimal performance of their pivots, leading to successful crop production.

Following through

Center pivot maintenance goes beyond daily checks. Look through these additional checklists for ideas of what to keep in mind on a weekly or annual basis.

▶ WEEKLY ITEMS:

  1. If the irrigation resource is surface water and a filter is used, check the filters to make sure pressure loss is in an acceptable range.
  2. If there is a flow meter: Is the weekly flow rate close to the expected value?
  3. If the flow rate or well drawdown changes during the season, update the percent timer on the panel based on the current well flow rate. Does the flow rate require a change in sprinkler nozzles?
  4. If using aerial imagery to assess uniformity issues, look for indicators such as a pattern of rings that could represent nozzle or leak issues or of wheel spokes where low pressure or surging could be a problem.

▶ ANNUAL ITEMS:

Start of season

  1. Locate the current sprinkler chart.
  2. If there is a flow meter: Does the flow rate match the sprinkler chart?
  3. If it is a part-circle or wiper pivot: Are the bumper bars in place and functional?
  4. Has the pivot point bearing been greased?
  5. With the power off (be sure it’s really off), have an electrician check for loose connections (terminal screws) or loose cord grips in the control panel and tower boxes. Do contactors show signs of arcing?
  6. Are the electrical grounding conductors solidly connected (both to the ground leads/terminals and the power supply ground wire)? Clean or tighten as required.
  7. Check all tire condition and pressure. Check wheel lug nut torque and wheel alignment if the pivot is newly installed.
  8. Check for water leaks at tower joints, goosenecks, and at sprinkler and hose couplings.
  9. Does the operating pressure match the design pressure (from the sprinkler chart)?
  10. Check the oil level in the gear boxes (you will need a wrench to open fill plug). Is there water in the oil? If so, drain the old oil into a collector and fill with new oil.
  11. Are the drive shaft safety shields in place?
  12. During center pivot operation, check for gearbox noise indicating wear or problems?
  13. Is the filter for the hydraulic tubes for hydro-valve actuators clean?
  14. Does the pivot alignment look straight when it is operating?
  15. Check for rodent damage to wiring by checking if there are visual marks on the wires and if all electrical communications/commands are working as expected.
  16. Walk the entire system while it is operating and check wheel track depth.
  17. Is it time to replace the sprinkler nozzles, sprinklers or regulators?

End of season

  1. Prepare water use report.
  2. Record hours of operation for the season. Do they seem reasonable based on the weather conditions?
  3. Will you need to budget for winter maintenance?
  4. Was the system flushed? Are the sand traps clean?
  5. Are  the pivot and connections to the well completely drained of water?
  6. Is the power off?
Xin Qiao, PhD, is an associate professor in the Panhandle Research, Extension and Education Center at the University of Nebraska-Lincoln in Lincoln, Nebraska.
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