How center pivots and Growsmart® by Lindsay Precision VRI are giving researchers more flexibility and more data
The Washington State University (WSU) Potato Group conducts about 40 research trials a year. Graduate students and faculty plant early to late harvest potatoes for a wide variety of agronomy and physiology research trials, including some designed to identify water-efficient and stress-tolerant potato varieties.
This research is helping define the 4.3 billion-dollar potato business in the U.S., where America’s love of all-things-potato drives our annual 128-pound per person (47.77 kg) potato consumption.
“Precision VRI has enabled us to efficiently grow different maturing varieties and trials, with different harvest dates under the same pivot,” says Associate Professor and Potato Agronomist Mark Pavek, who conducts research alongside students and fellow Professor and Potato Physiologist Rick Knowles.
“We are also able to conduct water-efficiency and irrigation-rate research amongst the other research trials without rigging up a convoluted mess of irrigation equipment and planting between large, irrigation-transition borders. Instead, we use GPS, a computer, and Precision VRI. Precision VRI expanded our research options exponentially.” It’s also helping produce exacting data and preventing test plots from becoming damaged by foot traffic in the field.
“Before Precision VRI, we would have to put research trials into pie- shaped irrigation zones when grown under a pivot. These zones required large, wasteful transition borders for switching from one irrigation rate to the next. We also used different nozzle configurations and various attachments in combination with solid set or lateral-move irrigation systems.
Without Precision VRI, one option we utilized was manual shut-off nozzles on the pivots and lateral-move systems. Someone would have to run out there and shut them off. Occasionally you would have to do it when the water was running. That person gets wet,” Pavek says.
“Now if we need to adjust irrigation during the season, we can go into the Precision VRI program that is just for that research trial. It gives us a lot of flexibility.”
VARIABLE RATE IRRIGATION PUTS THE WATER WHERE IT’S NEEDED
“When you plant potato rows, which we do, your research trials tend to be square or rectangular,” says Pavek.
"Because of this, we have to leave some places under a center pivot unplanted and, quite often, we’ll plant peas or a cover crop in that area. With Precision VRI, we are able to adjust irrigation inside of the research trials as well as on the non-crop or cover crop areas to whatever we need. For a cover crop like peas, we adjust our water output to match pea growth, typically less than what we would use on the potatoes.
If we plant a cover crop, we can actually shut the water off in the non-crop areas, or keep it lightly watered to prevent wind erosion. Some of our circles have roads going through them and we prefer not to soak the roads as it is wasteful and can create a muddy mess.
Instead, we’ll apply a light amount of water just to keep the dust down. It’s keeping weeds at bay, too, in those areas where you don’t have anything planted. You’re using less water and it’s going where it needs to go.”
CHOOSING CENTER PIVOT IRRIGATION WITH VRI
So, why not use a rectangular lateral move system instead of a center pivot?
The university had been using a lateral move system until it was damaged and became inoperable in 2012. The university approached the Washington State Potato Commission to request funding of a new lateral move system.
“We liked using the lateral move system because it irrigated square and rectangle research plots well, and we were used to that type of system. The Potato Commission actually convinced us that center pivots were the way to go,” says Pavek.
"Many Commissioners farm and they said ‘why don’t you consider a center pivot? You can irrigate a larger area more efficiently with the same span of equipment, and it requires less hands-on management and maintenance.’”
The Commission explained that for the price of one long lateral system, it could fund two or three shorter pivots, irrigating more land. Moreover, by adding the latest VRI technology to the pivots, researchers would have the greatest flexibility to customize watering patterns. “The farmers on the commission have good insight when it comes to purchasing equipment. They go through this process often,” says Pavek.
Pavek and the university are thrilled with the new equipment. And so is the Commission, which serves an estimated 250 Washington State potato growers that can benefit from the research data collected, as well as potato growers around the world.
Pavek says that Precision VRI is the key to agricultural research and has become a vocal proponent for growers and other researchers to invest in the technology after experiencing the benefits first hand.
PRECISION VRI MAXIMIZES THE VALUE OF A LIMITED WATER SUPPLY
“Variable rate irrigation has changed what we do,” says Pavek. “As our world grows, water is going to be a limiting factor. I think at some point water is going to be so valuable that everybody will have to have some kind of variable rate system. Growers are going to have to tussle it out and see where the savings are. It’s probably a little expensive at first, but it makes sense over time. It’s going to be a huge deal. Common sense just says that.”
NOTE: The Washington State Commission has since merged some of its research funding with Idaho and Oregon Commissions to form the Northwest Potato Research Consortium, which continues to fund research, share information, and support the potato industry.