Lyndon Kelley, Michigan State University Extension - June 3, 2020

Running through a checklist of inspections and repairs for each irrigation system greatly improves the chance of being able to start irrigating the day the crop needs it.

As planting nears the end, crop producers need to start preparing for irrigation season. If you ignore irrigation equipment until the day you need to water, it leads to cutting corners and taking risks that can lead to damage and downtime. Here are a few suggestions of system inspection and repair areas to concentrate on.

With all power off, open each electric box and blow it out with compressed air. Avoid leaving any dust or debris in the box or connections. Seal holes that rodents, snakes or insects may use to gain access to the box. A small application of a long residual action insecticide to the bottom of the box can reduce ant and spider problems in the future. Inspect disconnects function and repair or replace faulty equipment. Make sure all connections are tight and all connection surfaces are free of corrosion. Many electrical disconnects or pivot control boxes meet an early demise from an electrified mouse nest explosion in the box.

If you generate your own power, start the engine and bring it up to proper RPMs for the generator. Check the voltage at each pump and pivot in the system. Inspect the grounding wire from terminal to rods. Some irrigated crop contracts have requirements for testing of the grounding system and maximum resistance. Make a list of needed repairs for your electrician to follow-up on and get them started before the traditional over-committed first days of irrigation season.

Pumps run for hours without operator presence, and even small oil or coolant leaks can result in damage. Inspect belts, batteries and recharge system. Look carefully for rodent damage and insect nests that may result in a malfunction later. Inspect pump murphy or safety shut-down systems, or install them if you do not have them. Low oil and high temperature shutdowns can avoid burning up your engine.

Many of your neighbors may be concerned that irrigation water use is permanently lowering the water table. Documenting the static water level in your well and surrounding wells before you start pumping each year allows a comparison from beginning to end of pumping season. A late fall reading will show the recovery levels. If you do not have the equipment to measure the static water level of your well, consider an annual well maintenance company inspection or a single visit from a well driller to inspect equipment and measure water levels.

Slowly fill water supply lines allowing air to escape from ends of lines. With the distribution system running furthest from the water source, inspect all the remaining outlets for freeze damage, missing frost plugs and leaks. Compare last year’s records with your start-up reading for pressure and flow.

Remove debris, sand and small stones from rock traps. Clean screens and filters often used in conjunction with end guns and cornering arms. Rock traps are often removed for the winter to prevent freeze damage from water condensation in pipe and accumulating in trap. If rock traps were removed for the winter and bird guards are not put in place, inspect openings for nests.

Start the system up and pressurize it. Look for leaks and bad sprinklers, create a list of units in need of attention. Remember to check risers and other irrigation pipe areas that may need attention. Small leaks can saturate the soil and weaken force blocks used to hold underground pipe end plugs in place. Create a list of pressure and flow meter readings (if available) for each pumping station and pivot point. Knowing the starting pressure can help diagnose in-season irrigation problems later.

With water up to pressure, check sprinkler patterns. This can be easily done on bare earth or when crops are small. Look for sprinklers that have smaller wetted patterns than others. Plugs, no-turns and watering patterns would indicate damage. Check pressure at the pivot point and the last sprinkler and compare to the sprinkler chart; pressure that varies from the chart by more than 10% indicates the need for attention.

Hydro valves are the most common method to turn off the irrigation water on cornering arm and Z-arms that are in their folded back position. If valves are stuck open, you are grossly overwatering end-rows or other field edges where the arm is not deployed. Valves that are stuck closed will result in under watering corners of the field. While the machine is running, inspect sprinklers in a corner area with the arm fully deployed to make sure all sprinklers come on and in an area with the arm fully folded to see if all valves shut off.

Make sure you are covering every foot of planted ground possible and are not watering areas that are not cropped. Fine adjustments now can improve coverage area or keep you out of trouble if irrigation water ends up where it should not be. Avoid going overboard—higher surface and ground water levels in the spring can give a little bigger coverage area now than they will late summer.

Check air pressure in each pivot tire. Refill to 20 pounds or the recommended level. Note tires less than 5 pounds and return a week later to see if they leaked. Expect tires to lose 2 or 3 pounds pressure each year if not re-aired annually.

Gearboxes should be checked annually. First, drain condensation water from the bottom of the box and then refill with recommended gear lube.

Check fence row height compared to pivot overhangs and cut or spray to eliminate damage to the center pivot. Ohio State University Extension’s bulletin, “Relative Effectiveness of Herbicides Commonly Used to Control Woody Vegetation” is an excellent resource.

Wheel tracks will only deepen as the season progresses. Identify potential problem areas now to allow time to build-up, fill, level and permanently seed problem areas. In some situations, larger tires or track systems may need to be added to allow the pivot to float over wet spots.

Many producers are investigating chemigation/fertigation as an option. Adding the equipment now makes it a far more viable option in the future. Make sure there is a functional chemigation valve on each water supply feeding into the system. Install an interlocked injection pump power source. This will operate only when the irrigation water pump is on, avoiding undiluted fertilizer from ever going into the irrigation system. For a diesel engine, this may be as simple as running the injection pump from a v-belt off of the engine shaft.

Pivots that make partial circles often use stop barricades at the edge of the water area. Check stops for integrity, making sure the height is still appropriate for the machine’s turnoff mechanism. Manually operate the turn off arms on the pivot to make sure they are functioning. Newer style stop barricades are designed to catch and spin the tire against the barricade, allowing the safety system to shut the pivot down as a backup safety system.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).

Did you find this article useful?

Haul manure? Check out the Michigan Manure Hauler Certification Program!

MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential.

Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Quentin Tyler, Director, MSU Extension, East Lansing, MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

The 4-H Name and Emblem have special protections from Congress, protected by code 18 USC 707.

We comply with the Federal Trade Commission 1998 Children’s Online Privacy Protection Act (COPPA).