Farmer Ken Betzold has planted 50-foot-wide buffer strips on more than 1½ miles of riverland he owns in Dakota County.

And not entirely for charitable reasons. A state law requires such buffers along some lakes, rivers and streams in agricultural areas. And unlike some Minnesota counties, Dakota County strictly enforces it.

Though the requirement means taking some cropland out of production, Betzold, 72, of Castle Rock Township, sees the benefit of the buffer strips.

"It stops dirt from running into the river, and cleans the water,'' he said. "There's a cost, but you have to weigh that with the benefits to the environment."

A side perk: Those buffer strips also provide wildlife habitat.

"Any time you have permanent vegetation that isn't monoculture, there's a wildlife benefit,'' said Tom Berry, Dakota County water resources supervisor.

While the state's buffer law seems to work in Dakota County, enforcement in some other counties is lax. In 2013, 32 of the state's 87 counties enforced the buffer law, according to the Department of Natural Resources. Another 29 counties told the DNR they had engaged in "non-enforcement" activity to support buffers.

"The short answer is we don't have a good sense of how counties are doing [with buffers],'' DNR Commissioner Tom Landwehr said. "We do know some counties are doing a bang-up job, like Dakota, Olmsted, Otter Tail and others."

But the Environmental Working Group, a national nonprofit that conducts environmental research, reported last year that vast amounts of stream and river shoreland in southern Minnesota were missing required buffers. Nearly half were along small streams that form the headwaters of major rivers.

The issue of buffer law noncompliance also arose at a Pheasant Summit in December called by Gov. Mark Dayton. The top priority that participants suggested to boost pheasant habitat was to enforce the existing buffer requirements. Dayton took that idea another big step last month when he proposed a law that would require all waterways — possibly including ditches — to have grass buffers. That could create about 200 square miles of habitat, he said.

And Dayton suggested the DNR enforce the law instead of counties. State officials are working on the details and plan to offer a bill to the Legislature this session, Landwehr said.

Meanwhile, local governments are charged with enforcing the existing buffer law, and, as Dayton said, enforcement has been inconsistent.

"Dakota County is on one end of the spectrum; other counties are on the other end," said Dan Petrik, Department of Natural Resources land use specialist.

Though the law has been on the books for years, Dakota County started enforcing it in 2010, Berry said. The county board and county attorney's office has supported enforcement, which isn't always the case in other counties. But even in Dakota County, enforcement is uneven. The county doesn't have countywide land-use authority, as do most counties, so it only enforces the buffer law in 13 unincorporated townships, which encompass about two-thirds of the county, Berry said.

Berry said his office used aerial photography to determine whether shoreland had or needed buffers. Landowners were contacted and educated about the requirement. The vast majority complied. Those who didn't received a notice of violation from the county attorney's office. Only a few landowners ended up in court, where stipulation agreements were negotiated.

"The county isn't interested in fining people. We just want compliance," Berry said.

The county succeeded in getting about 89 miles of buffers on some 1,600 parcels, and today has about a 99 percent compliance with the law, Berry said.

But the existing buffer law only applies to agricultural land. So in Dakota County, the Vermillion River has buffers where it runs through agricultural land but not where it courses through residential land.

And the law doesn't apply to all streams and rivers.

"There are thousands of miles of rivers and streams that aren't designated shoreland because they are too small or the watershed isn't large enough,'' said Berry.

Said the DNR's Landwehr: "I don't think people understand that a relatively small percentage of waterways actually require a buffer."

Ditches are covered under a different law, Landwehr said. Currently, buffers are required only when ditches are improved, and a lot of them haven't been improved over the years, meaning they have no buffers.

Which leads to erosion. And a landscape sometimes barren of wildlife habitat.

"And as the governor said, the land belongs to the landowner, but the water belongs to all of us,'' Landwehr said.