MORGAN, Minn. -- Scott VanderWal came across the South Dakota border to southwest Minnesota's Farmfest to scare farmers.

The American Farm Bureau vice president wasted no time doing that as keynote speaker Wednesday before a panel launched into a water issues discussion.

"Right this minute, a California farmer is in the legal battle of his life over Waters of the U.S.," the Volga, S.D., farmer said about rules federal authorities have released, but courts have put on hold until court cases can be decided.

The California farmer used a chisel plow to dig less than a foot into his soil, something he has done many times. The Obama administration wants to fine him up to $8 million for what federal lawyers said in court papers looked like "small mountain ranges."

"There aren't many farmers who can put up with that kind of fine," VanderWal said.

He and others on the Farmfest panel said that may be one of the worst examples, but they are hearing of court cases across the country as the federal government seeks to extend its authority over American land.

The Waters of the U.S. issue has farmers up in arms because federal authorities now are doing what farmers say is overstepping their authority. It is one of the most-discussed issues in farm circles.

VanderWal said that farmers feel they are in "a farm at your own risk situation."

The issue has brought together sometimes-rival organizations, the Farm Bureau and Farmers Union.

President Roger Johnson of the National Farmers Union, a former North Dakota agriculture commissioner, said the new rules come from a clean water law passed in the early 1970s. The law's words have not changed, he said, but new rules and court decisions have changed how it is enforced.

The law was passed, Johnson said, because "we had rivers that literally were on fire." That industrial water pollution has eased, and now federal authorizes are looking at cleaning up farmland runoff.

However, experts on the Farmfest panel said proof is lacking that farm-caused pollution is getting worse, and there are indication it actually is getting better.

Don Parrish of the Farm Bureau said farmers are producing more products, from crops to livestock, with less pollution than in the past.

Because of the need to save money in a time when farm commodity prices are low, he said, farmers meter out feed, chemicals and other input "almost on a teaspoon by teaspoon basis" to save costs. That cuts pollution, he said, because there is so little waste.

"What you ultimately have is ... the public wanting to get clean water, but wanting to get someone else to pay for it," Parrish said.

The public can believe farmers are to blame, VanderWal said, because most Americans understand little about farming. "Public perception ... is going to determine whether we are allowed to keep farming."

The Farm Bureau vice president and others said farmers must do a better job of explaining what they do and why they do it.

At his eastern South Dakota farm, VanderWal said, he encourages tours to increase agriculture education.

"I would encourage each and every one of you to do that," he told a couple hundred farmers and other in the ag industry.

He also suggested talking to politicians. "Influence the influencers."

"We can say we care, but until we show we are caring, it is going to be hard for the public to understand us," Parrish said. "We got to get better at showing our work."