Powerful interests in Washington have swayed a new farm bill toward big business, Democrat Barack Obama said Monday, campaigning in the most rural region of this crucial early voting state and promising to do better as president.

"Once again the lobbyists stepped in to make sure that big agribusinesses got the multimillion-dollar giveaways that they've come to count on," said Obama.

The issue is crucial in rural sections of the country because the new farm bill will set food and farm policy for the next five years, including subsidy levels farmers will receive. There's a home-state tie as well because Iowa Sen. Tom Harkin heads the Senate Agriculture Committee which crafted a farm bill.

"Tom Harkin fought hard to pass a farm bill that stressed support for conservation and support for specialty growers," Obama said, contending the effort was deflected by the power of the agribusiness lobby.

Obama missed the final vote in the Senate on the farm bill — as did several of his presidential rivals — but Harkin said on the floor at the time that Obama had assured him he would support the measure and would alter his schedule to be in Washington if his vote were needed.

Questioned about the issue during a stop in Cherokee, aides pointed to a statement Obama issued at the time of the vote saying there were strengths in the measure as well as weaknesses.

"While the farm bill is a step in the right direction, I am disappointed that those who blocked payment limitations chose to put big agribusiness ahead of family farmers," Obama said. He said he "will continue to fight for meaningful payment limitations."

Obama's crowds remained strong throughout the day, though he was stumping in heavily Republican territory.

He ended with a noisy rally before more than 1,000 people in an ornate restored theater in Sioux City, urging backers to throw caution to the wind and not be afraid to be bold.

"If we're serious about winning this election, we can't be afraid to lose it," Obama said, as his staff busily collected names and telephone numbers from the crowd.

He returned to the theme of lobbyist influence on a chilly day in northwest Iowa, speaking to more than 400 gathered at Storm Lake High School.

"The corporate lobbyists are going to have to understand that a new day has dawned," said Obama. "No child should grow up in a community that is devastated by teacher shortages or nursing shortages."

Driving into Storm Lake, Obama's motorcade passed by towers at wind farms similar to those sprouting throughout the region, and he said alternative energy could help rejuvenate rural America.

"We've got wind farms that are being built, entirely new industries are being developed," said Obama. "There are some competitive advantages in our rural economy, not only for wind but for biodiesel and ethanol."

Last summer, Obama held more than 30 hearings around the state getting grass-roots input before issuing a package of farm and rural development policies last fall. He was touting that package of proposals as he swept through northwest Iowa.

From tougher regulation of animal feeding operations to a shift in attention to family farms, Obama said he would change the focus away from big businesses and their interests.

"We need to set priorities that reflect our values," said Obama. "Well it's time to stand up to these lobbyists and tell them we're putting family farms first, we're putting conservation of our land and water first, we're putting tough choices for CAFOs first and if there's going to be a hog lot in your community then the community gets a say about where it goes."

Obama said his plans were designed "to make sure the child in Spencer can dream as big as the child in Des Moines or the child in Chicago."

Heading into the final days of the campaign for Iowa's Jan. 3 leadoff precinct caucuses, Obama is in a tight race with rivals John Edwards and Hillary Rodham Clinton.

While rural sections of the state are traditionally Republican, smaller farmers are increasingly under economic pressure and open to an argument from Democrats. That's where Obama was aiming his pitch.

Like his rivals, Obama is making a special focus on the relatively large number of voters yet to make up their minds or who are willing to switch at the last minute. He asks who's undecided in his audiences, and in Spencer that was about a third of the 300 or so who showed up on a chilly morning.

"Those are the folks we're going after," said Obama, giving his backers directions. "We're going after them. Take their picture."