Inside pivots Pivot irrigation offers options for farmersWritten by Natasha Wheeler
Low labor and maintenance, convenience, flexibility and easy operation are potential advantages of a pivot system over flood or furrow irrigation, according to Jeremiah Vardiman, UW Extension educator.
“The biggest thing that jumps out at me is reduced irrigation time – only six to seven hours per acre,” he comments. “This isn’t about man hours. It is the hours of water going across our field.”
Different power supply options, drive systems, nozzles, tires and control panels make pivot systems customizable for producers’ various needs.
“Power supply is going to pertain to where we are located with our pivot,” notes Vardiman.
Systems can run from electricity, gas or diesel engines – or even renewable energy, such as hydroelectric sources, in some cases.
“There may be a huge upfront cost to install a renewable resource, but over the long term, it is going to pay for itself,” he comments.
Diesel, propane or natural gas motors incur expenses through fuel costs, and electricity expenses depend on the system’s distance from a power pole.
“Electric also has peak load times,” adds Vardiman. “When we are running a pivot at those peak times, we can be charged three times the normal amount.”
If the pivot is located at a power pole and producers can shut the systems down during peak hours, electricity is likely more cost effective than a fuel-powered source.
“Also, for producers close to a methane well, this energy source is another option,” he adds.
Producers can also consider different drive systems, such as electric or hydraulic oil systems.
“With electrical, we will have an electric motor on each tower and a gearbox on every tire,” he explains.
A hydraulic system involves a hydraulic oil reserve that is pumped down the entire pivot with a flow regulator and a hydraulic motor and gear at each wheel.
“The biggest difference is how the pivot moves in the field,” comments Vardiman.
An electric pivot moves tower by tower as trigger plates are initiated while hydraulic systems move in one continuous motion.
“One is not necessarily better than the other, but we should be aware that there is a difference in how they drive,” he continues.
Nozzles are another component for producers to consider when looking into pivot systems.
“What we are growing dictates our nozzles, and there are all kinds of functions out there,” says Vardiman.
One example is called a double-ended sock or hose.
“It drags along the ground and basically does flood irrigation in the field,” he explains.
Different kinds of sprinkler heads shoot a steady stream of water or break the flow into small droplets.
“We can also have an in-canopy sprinkler or an above-canopy sprinkler,” he adds.
In Wyoming, a bubbler may be an appropriate nozzle, since it produces large water drops that have a better chance of making it the ground before they evaporate or blow away.
“It depends on what we are managing for, what crop we are growing and what our soil conditions are,” Vardiman describes.
Tires are also a key piece of equipment to consider.
“Just like anything else that has tires, there are many different options,” comments Vardiman.
Rubber tires come in different tread patterns and different sizes, but poly-solid and steel wheels are available as well.
“There is a huge difference in cost,” he notes. “It depends on the size and the grade.”
Control panels are another variable in pivot systems, from very simple to much more complicated set-ups.
“Don’t be intimidated. Technology does have a learning curve, but like our cellphone or computer, the more we use it, the more we get accustomed to it and the easier it is to function,” Vardiman says.
GPS is one example of pivot technology that can be incorporated into the controls.
“GPS can keep our pivot straight as it moves around, and it can turn the pivot on and off when it gets specifically where we want it,” he notes.
This can be used to avoid fines for spraying county roads or highways.
“The other benefit of GPS is that it ties into chemigation and fertigation,” Vardiman says.
Herbicide, pesticide or fungicide solutions can be mixed into a nurse tank and pumped through the pivot, spreading over the field.
Bells and whistles
“The other thing for bells and whistles is our computer, tablet or smartphone,” adds Vardiman.
With a high-grade system, pivots can be controlled remotely, straight from a smartphone.
“This is totally different than when we are out changing parts for flood irrigation and opening and closing gates,” he explains.
Depending on the field and producer, systems can be designed for many different needs.
“It is site-specific. All of these center pivots, all of the options and all of the technology depend on our site, our location and what we are trying to accomplish,” he says.
Maintenance of pivots
When considering pivot installation, Jeremiah Vardiman with UW Extension notes that there are several management concerns to address.
“If we don’t have strong enough streams in our ditch or if we have a very mossy irrigation ditch, we can plug a sprinkler in a hurry,” he says.
He encourages producers to inspect their systems on a regular basis for leaks, blown gaskets or other problems, even if the system is being controlled remotely with a smartphone or computer.
“We need to keep our screens in good condition,” he comments.
Using algaecides at certain times of the year may also reduce blockages.
“One of the biggest concerns is digging trenches,” notes Vardiman. “Center pivots are really not that heavy until we load the system up with water.”
Tracks, polymer spray, boom-back attachments or mechanical gravel fill options are some of Vardiman’s suggestions to minimize tire ruts.
“We should do our due diligence and try to help ourselves out where you can,” he adds.
Initial installation costs can also be a concern for producers.
“The Natural Resources Conservation Service (NRCS) has an agricultural management assistant program that offers assistance for up to 75 percent of the cost of installing conservation practices to those who qualify,” he explains.
Loans may also be available through Farm Service Agency and used equipment can often be found at a discount.
“Talk to equipment dealers,” says Vardiman. “Remember that this is a piece of equipment, and we need to do our upkeep on it.”
Jeremiah Vardiman spoke at Fremont County Farm and Ranch Days in Riverton on February 12.
Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at wylr.net.