Concerned about growing nitrate contamination in Minnesota’s drinking water, state regulators have ordered a farmer in the Pineland Sands area to complete a major environmental study before granting him a permit to dig an irrigation well.

The move could signal how state officials plan to respond to a decadeslong wave of deforestation in central Minnesota, where farmers and landowners have cleared thousands of acres of timberland to plant potatoes and row crops on land with vulnerable soil and groundwater.

An environmental study is essential because the state simply doesn’t know the cumulative impact of irrigation and fertilizer use on water quality — and when it might reach a tipping point, said Randall Doneen, a conservation manager for the Minnesota Department of Natural Resources (DNR).

“There are a bunch of tiny straws right now on the camel’s back, and it’s not like we’ve determined that this will be the one that breaks it,” Doneen said. “But at some point we will have crossed that threshold.”

Last year, the DNR told cattle farmer Tim Nolte of Sebeka to complete a study known as an environmental assessment worksheet, which the agency will use to try to pinpoint what the impact his irrigation would have on the region. Nolte is seeking three permits to irrigate a total of about 300 acres in Wadena County.

While those 300 acres are just a sliver of the timberland that has been converted to row crops in central Minnesota, the DNR must determine if the watershed can handle more irrigation and fertilizer and where to draw the line, Doneen said.

The DNR’s move has caught the attention of lawmakers in both parties. Nolte was asked to speak before a legislative subcommittee in December, where he said he felt he was caught in the middle of larger battle that had little to do with him or his farming practices.

“We got caught in [the] cross hairs of people to the north of us 40 to 50 miles,” Nolte told lawmakers.

The fight over water use and the clearing of woods in central Minnesota has been simmering for several years. The groundwater throughout the Pineland Sands region, which covers parts of Hubbard, Wadena, Cass and Becker counties, has a worsening nitrate problem.

Recent tests by the Minnesota Department of Agriculture show that, in Wing River Township just south of the Nolte land, about 10% of the tested private wells exceed the state’s nitrate safety standard, 10 milligrams per liter. About 15% of wells in Hubbard Township to the north are past that limit; and nearly 20% exceed the standard in Pine Point, in the northwest corner of the region.

The fight came to a head in 2015, when R.D. Offutt Co., a Fargo-based potato company that’s become one of the largest irrigators in Minnesota, applied for more than 50 well assessments and permits as part of a plan to clear thousands of acres of forest to create potato fields. The DNR held off approving the permits, ordering the company to first complete the same environmental worksheet it has now asked of Nolte.

Offutt instead withdrew all but five of its permit applications, and the DNR agreed not to require the environmental study. The agency said at the time that it planned to conduct its own, more comprehensive study on the entire region to determine how much water could be pumped and how much fertilizer could reasonably be used without endangering the region’s drinking water. Lawmakers, however, have not funded the estimated $1.5 million study, and the DNR has not started it.

Why them?

As it happens, the land that Nolte hopes to irrigate is a parcel he’s buying from Offutt. His original well proposal said he planned to rotate crops — growing hay for his cattle some years, then corn or soybeans, and potentially leasing the land back to Offutt to grow potatoes for a year. It’s unclear if that’s still Nolte’s plan.

A group of citizens and environmental groups led by Mike Tauber of Backus, Minn., circulated a petition that raised the issue of nitrate contamination, along with concerns about deforestation and pollution from Nolte’s proposal.

Tauber said he saw Nolte’s well application as a backdoor way for Offutt to grow potatoes on the same land it hoped to irrigate back in 2015.

The DNR ordered the environmental study in August. It could be completed in weeks.

State Rep. John Poston, who represents the area, says concern over the aquifer is understandable but that the DNR couldn’t have chosen a worse family in the area to single out over environmental issues.

“They’re role models for doing things the right way,” said Poston, R-Lake Shore.

Nolte is a Wadena County Soil and Water Conservation District conservationist of the year. He’s received water-quality certifications from the Department of Agriculture. Wadena County recently named the Noltes its farm family of the year.

Poston said he’s upset that the citizens petition that first sparked the environmental assessment didn’t seek to understand how this family farms, and he has called for reviewing the petition process.

Tests, then still uncertainty

The problem with the Pineland Sands area is this: The same sandy soil that makes the land ideal for growing potatoes and edible beans also makes it terrible for holding nitrates, said Keith Olander, an irrigation expert who leads the Agriculture and Energy Center at Central Lakes College. Fertilizers quickly seep through the soil and into the groundwater.

But in recent years, Olander said, farmers have become much better at limiting their use of nitrogen fertilizers — applying them several times throughout the year, as needed, rather than in one large dose.

“In this specific case, [Nolte] is doing stellar job of protecting water quality,” Olander said. “He’s someone who doesn’t just want to farm today but for generations.”

The question is whether a farmer such as Nolte can mitigate it enough.

The state has no set criteria for where to draw the nitrate line in the region. “The challenge is this costs a lot of money to go through this worksheet, and in the end you still don’t know if you’re going to get approved,” Olander said.

Yet simply ignoring the cumulative effect of fertilizers and irrigation wells is unacceptable, said state Rep. Peter Fischer, DFL-Maplewood.

“It’s unfortunate that people who seem to be doing the right thing can get caught up in that,” he said. “But we need to make sure we’re protecting water sustainability.”