A central Minnesota family’s application to dig three irrigation wells will face another challenge in a case that could have ramifications for how state regulators study and permit potato and row-crop irrigation in areas where groundwater is increasingly polluted by fertilizers and nitrates.

The Environmental Working Group said it will appeal a June decision by the Minnesota Department of Natural Resources (DNR) to allow a cattle rancher in the Pineland Sands area to apply for the irrigation wells without completing an environmental impact study. The DNR, which studied the application for months, ignored clear evidence about potential health, groundwater and environmental impacts, said Jamie Konopacky, Midwest director of the nonprofit.

Konopacky said the agency didn’t adequately address concerns raised by water quality experts that the proposed irrigation wells could cause nitrates to contaminate the groundwater near the site at double to quadruple the state’s health limits.

“DNR has failed in its duty to protect human health and the environment,” Konopacky said.

The challenge, which will go before the Minnesota Court of Appeals, could tie up the family’s permit application for months.

The DNR did not immediately respond to a request for comment.

The case centers on rancher Tim Nolte of Sebeka, who plans to convert 300 acres of former timberland and forest in Wadena County into potato fields and row crops. The acreage is just a sliver of the timberland that has been converted in recent years to heavily irrigated agriculture in central Minnesota, raising concerns about the cumulative impacts of the loss of woods and the increased use of water and fertilizer. Recent tests by the Minnesota Department of Agriculture show that up to 20% of private wells in some parts of the Pineland Sands area exceeded the state’s nitrate safety standard.

Nolte bought the land from potato farming giant R.D. Offutt. His original land deed included a provision to lease the land back to Offutt every few years to grow potatoes as part of a crop rotation once it was irrigated. That provision was later removed. Before selling the land, the Offutt company applied for its own irrigation permits on the site, but withdrew once state regulators ordered the company to complete an environmental study.

Environmental groups argued to the DNR that by selling the land to a small farmer and renting it back, R.D. Offutt has found a back-door way to expand its potato operations while avoiding costly environmental studies.

The DNR, which reached its decision after months of reviews, extensions and delays, said that it remained concerned about the cumulative impacts of the growing farms, but found that any impacts from Nolte’s proposed wells would be “minimal in nature.”