BELGRADE, MINN. – While Republicans in the Legislature again take aim at the state's new stream-and-ditch buffer law, John Mages rests easy.

Mages, a past president of the Minnesota Corn Growers Association, farms 850 acres of good soil in Stearns County, planting corn and soybeans in spring and harvesting the crops in fall. To save topsoil and reduce overhead costs, he practices minimum tillage. And if the weather cooperates, his yields are superb: The past two years he's averaged more than 200 bushels an acre of corn, without irrigating.

But one day last week, as Mages showed a visitor around his well-kept operation, the issue wasn't crops but buffers. In all, he has about 30 acres of grasslands bordering waterways that either abut his croplands or run through them.

"The buffers are in CRP," Mages said, referring to the federal Conservation Reserve Program that pays an annual fee to participating landowners. "On 10-year contracts."

Planting grassland borders, or buffers, along ditches, streams and rivers is important if Minnesota is going to clean up its waterways, conservation professionals say. About 40 percent of tested state waters are polluted, and significant portions of chemicals and soil runoff that infiltrate the state's ditches and rivers can be traced to farms.

Which is why Gov. Mark Dayton pressed the issue two years ago, arguing that farmers — as well as their non-farm neighbors in the Twin Cities and other towns — must reduce runoff if Minnesota is going to clean up its maze of subprime waters.

Mages held a sign signifying that his property is a “Minnesota Water Quality Certified Farm,” which he notes as a source of pride. Mages, who came into Stearns County roughly 35 years ago, farms 850 acres, planting corn and soybeans.

Now with a fall deadline to at least begin installation of buffers where they will be required along public ditches, streams and other waters, Republicans in the House are attempting to postpone the law's implementation, if not overturn it altogether. They say the law is too burdensome on farmers and that its buffer requirements amount to a taking of private property without compensation.

But here in Stearns County, where about 94 percent of waters that require buffers under the new law already are protected with grassland borders, implementation is seen, generally, as a good thing.

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Tom Gregory runs a 500-cow dairy operation not far from Cold Spring and is one of five Stearns County Soil and Water Conservation District (SWCD) citizen supervisors.

"My opinion is that buffers are necessary," Gregory said. "Actually, the law has been on the books for 15 or 20 years. It just hasn't been enforced. And buffers definitely filter out runoff, including manure runoff."

When Gregory began his dairy operation in the early 1980s, it was commonplace, he said, for livestock owners to allow cows and pigs to wallow in streams and rivers.

"I moved all that back and fenced it off," he said. "We got a grant to build a manure pit if we kept the animals out of the creek, and we did that."

Not all Stearns County farmers have complied with the new law, and recently SWCD employees here mailed about 300 letters containing detailed aerial maps of waters requiring attention before the fall deadline.

"We've heard back from about a quarter of the people we mailed the maps to," said Ben Ruley, a Stearns County SWCD conservationist. "Some of these producers intend to put in buffers on their own, because they have a need for hay, and can mow the buffers a couple times a year.

"But of those who don't need hay, some are upset about the crop acreage they would lose putting in buffers. Some say it's an illegal taking of their land and they're not going to do it."

Dustin Frieler, his dad, Tom Frieler, and partner Dave Schoenborn farm 4,000 acres in Stearns County. About 2,000 acres are in corn, another 1,600 in soybeans, and the rest in wheat and oats. A lot of water runs through their land.

"We started planting buffers 15 years ago, mostly through the CRP program," Dustin Frieler said. "It was a win-win for us. We were protecting the water while taking ground out of production that wasn't that good."

Most buffers in the Frieler operation are 30 feet wide. But the new law might require some of them to be widened to 50 feet, depending on a parcel's slope and other considerations.

Wider buffers in some cases will mean more lost revenue.

Example: If a landowner is required to plant 50-foot buffers on each side of a stream that runs a half-mile through a farm, 6 acres would be lost in production. At 200 bushels an acre of corn, multiplied by, say, $4 a bushel, the cost to the farmer in lost revenue would be $4,800.

In some cases, or perhaps most, much of that income could be made up by government payments through CRP or similar programs. And cost sharing to establish buffers is generally available.

Still, Frieler said, property taxes on the buffered acres would be the same as if they were planted in corn.

"That's why the reaction by some farmers is so negative to the buffer law," he said. "If they would cut you some slack on property taxes, it would be different. Our property tax bill now is $120,000 a year."

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Mages came into the country near Belgrade some 35 years ago. He and his wife, Cindy, a nurse, had been farm kids near Sleepy Eye in the southern part of the state, and they came north to make their mark.

They did that, raising four kids on the home place, while running a profitable operation.

A believer in buffers, Mages nonetheless is sympathetic to farmers who might struggle with compliance with the law by this fall.

"Each farm is individual, and one size won't fit all with buffers," he said.

As he spoke, Mages held a sign he displays prominently in the window of his farm shop.

"Minnesota Water Quality Certified Farm," the sign reads.

Like the neatly kept tractors and other equipment housed in nearby outbuildings, and the hundreds of fertile acres that surrounded him, the sign, for Mages, was a source of pride.

Dennis Anderson • danderson@startribune.com