Jake Wildman pushed his way through dense corn stalks that tower over his head, carrying what looks like a pogo stick with two prongs sticking out of the end.
He stopped in a clearing and pushed the prongs down into the soil. Thanks to recent rains, it’s much wetter than it was earlier this summer.
“It’s saying about 29 percent of this soil — that's how much water is in it right now,” he said. “So that's good."
Wildman relies on the hand-held soil moisture sensor, along with a stationary one planted in the middle of the field, to provide accurate information about how much water he needs to apply to his corn.
"I swear by them,” he said. “I gotta have something to give me a measurement, just so I can have an idea of what's going on underneath us."
It's been a tough year to be a Minnesota farmer trying to keep crops alive during the worst drought in decades. Growers who irrigate their fields had to use a lot of water this summer.
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In some cases, they likely will meet or exceed the amount they’re allowed under water use permits issued by the state Department of Natural Resources.
But Wildman, 33, who serves as president of the Irrigators Association of Minnesota, is among a growing number of farmers using technology and data to be more efficient about how much water they use, and when.
Wildman grew up near Glenwood, in central Minnesota’s Pope County. After college, he returned to farm with his father and uncle. They grow corn, soybeans, wheat, canola and vegetables.
"My dad's still old school,” Wildman said. “He's got a shovel in the back of his pickup. And he goes, ‘What's your sensor saying?’ I'm like, ‘Well, you got your shovel. You tell me what you think.’”
Their farm is on the northwestern side of the Bonanza Valley, which stretches from Paynesville northwest almost to Alexandria. The region is known for coarse, sandy soil that water quickly drains through.
“It's tough to beat these irrigated sands for production,” Wildman said. “If you treat them right, they'll treat you right. They can be extremely productive. But we need Mother Nature's help, too.”
This year, Minnesota farmers didn't get much help from Mother Nature. Much of the state was in severe or extreme drought for most of the summer, and even the recent rains haven't replenished the dry soil.
"We never want to pump this hard as irrigators,” Wildman said. “This was not an enjoyable summer at all."
There are about 600,000 acres of irrigated cropland in Minnesota, much of it growing corn, soybeans and potatoes in the central part of the state. More than 81 billion gallons of water — the vast majority from groundwater — are applied to those lands every year.
Nearly a decade ago, a sharp increase in irrigation permits in the Bonanza Valley raised concerns that groundwater was being depleted faster than it was being replenished. There were also a number of unpermitted irrigation wells in the region.
The Minnesota Department of Natural Resources requires a permit to withdraw more than 10,000 gallons of water a day, or a million gallons a year.
The Bonanza Valley was one of several places in the state where the DNR created a groundwater management area, to monitor water use to see whether it's having negative impacts, rein in unpermitted wells and work with local growers on sustainable irrigation practices.
The DNR also launched a statewide online permitting system where farmers can self-report their water use annually.
This year's data won’t be available until after the reporting deadline in February. But it will provide valuable insight into how much water farmers actually used compared to what they’re allocated.
It can be difficult for farmers to calculate how much water they'll need in such an abnormally dry year, said Randall Doneen, who manages conservation assistance and regulation for the DNR. Climatologists anticipate that such extreme droughts could be more common in the future.
“We do permit it to account for dry years,” Doneen said. “Now, if those dry years get longer and more of them, then that might be something to reassess, if that’s a suitable amount.”
The DNR suspended about 230 permits for irrigation this summer due to the drought conditions, but all of those were for use of surface water from lakes or rivers, not groundwater, Doneen said.
Wildman is done irrigating for the season. But he said many farmers — including himself — likely will exceed their permitted allocations this year. They’re willing to pay additional fees, he said, but are worried that it might affect their future allocations.
“I'm more concerned about, how's our aquifer going to hold up?” Wildman said. “That's my biggest fear, is where are we going to sit for aquifer levels? What's our recharge going to be over winter?”
Carrie Jennings is research and policy director at the nonprofit advocacy group Freshwater. She praised the irrigators association’s leadership on promoting smarter irrigation, using schedules based on climate models and weather station data.
“So farmers know exactly how much is going on to their field, how much is evaporating in any given time and when the crop actually needs it,” she said. “Those are all great approaches.”
But Jennings said unchecked irrigation in some parts of the state could have long-term impacts on groundwater aquifers and surface waters like trout streams. So far, the DNR has mostly provided data and equipment to farmers and relied on their voluntary cooperation, she said.
“At some point, I think there will have to be a heavy hand that says, ‘This can't keep going on,’” Jennings said.
Researching better methods
Over-irrigation can cause other problems besides wasting water. It can also can cause nutrients such as nitrate to leach into the groundwater, which supplies drinking water for three-fourths of Minnesotans.
Vasudha Sharma, an irrigation specialist in the University of Minnesota’s soil, water and climate department, is studying the optimum rates to apply water and nitrogen to improve crop production and reduce nitrate leaching. She’s conducting her research at two sites, near Becker and in the Bonanza Valley.
“If you apply only the amount that your soil can hold, and at the same time your crop can use, all that water and nutrients will stay in that soil profile in that root zone of the crop,” she said.
Sharma is also evaluating different types of sensors, comparing low-cost varieties with newer electronic models that do a better job of measuring water in the soil.
“Many growers are using it now, and they are interested at least in learning how to incorporate these new technologies into their farming system,” she said.
Irrigation systems themselves also have gotten more efficient, Sharma said, with low-pressure sprinklers that use less water. They can apply different amounts of water to different parts of a single field based on how much they need — a practice called precision irrigation.
Sharma said if this year’s dry conditions continue for several years and farmers face additional restrictions on their water use, the research would be even more valuable.
“We know that if we reduce this much water, what is the impact on yield?” she said. “That would be really, really helpful for the growers in making decisions on their farm.”
‘We’re not wasting’
Wildman is aware of criticism of farmers for their water use that's sometimes seen as wasteful. The statewide association advocates for farmers' rights to irrigate, but also supports science-based research.
"I just want to tell people we're not wasting,” Wildman said. “We have science. We have technology to incorporate to help us out.”
In another field, where kidney beans were recently harvested and a cover crop of wheat was planted, a center pivot irrigation system stretches along one edge. A black bucket-like device mounted on the top collects and measures rainfall.
Wildman opened a control panel to reveal a computer screen. He can adjust the irrigators from his home miles away, using his smart phone.
"We can change how much we're putting on just by a click of a button — our speed, monitor our pressure, direction, anything you want,” he said.
But Wildman said there's also value in getting out in the field, kicking the dirt and checking the crops firsthand.
And while irrigation keeps the region’s farms productive, he said, some help from Mother Nature would be nice, too.
"We just hope it rains,” he said.