OSAGE, Ia. — U.S. Sen. Bernie Sanders on Sunday called for "radical" changes to the American agricultural economy that would transition the nation's food system away from the big agribusinesses that dominate much of the sector today toward a model built upon small, family farms.

During a 50-minute speech at the Mitchell County Fairgrounds in Osage, Sanders introduced new policy approaches to farm subsidies, supply management programs and rural investments. While his speech and the simultaneously released policy proposals focused largely on agriculture, Sanders called for a rejuvenation of rural America with new investments in long-declining communities.

"Those of us that come from rural America have nothing to be ashamed about," Sanders said in an open-air swine barn, "and the time is long overdue for us to stand up and fight for our way of life."

Invoking the trust-busting legacy of President Teddy Roosevelt, the Vermont senator said new anti-trust measures were needed to combat the "growing monopolization of agriculture."

"If he were alive today, I think I know what he would be saying to these huge agribusiness corporations," Sanders said. "He would say we are going to break them up. And working together, that is exactly what we are going to do."

To do that, Sanders pledged to appoint an attorney general who would not only regulate future mergers and acquisitions but also seek to undo recent ones.

Sanders' rhetoric on agriculture fits into the overall framework of his campaign, which is largely driven by the idea that the nation's economy is rigged in favor of the ultra-rich to the detriment of everyday Americans. On Sunday, he said small farmers were being squeezed out by huge multinational corporations that dominate ag markets.

He noted that farmers today receive the lowest share of the consumer food dollar since the measure was first calculated.

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The senator blamed consolidation in the ag economy for harming family farmers. That consolidation has played out in Iowa and across the country: According to data for the U.S. Agriculture Census, Iowa lost 32,600 farms during a 30-year period that ended in 2012. And research from Iowa State University shows about one-quarter of Iowa's 88,000 farms controlled nearly 70 percent of the state's cropland and drove 80 percent of agricultural sales.

"We need a radical change in policy if we are going to save what we all hold dear," Sanders said. "And that is rural America and the kind of way of life that we love."

His newly released ag policy calls for redistributing federal farm subsidies to target small- and mid-sized family farms, rather than that the largest farm operations. He also wants to move back to a parity farm system that would set price floors on commodities and ensure farmers earn enough to cover the costs of production and living expenses.

He said supply management programs like the re-establishment of a grain reserve program — in which the government subsidizes the stockpiling of grain for future demand — would provide more stability in pricing.

"It goes without saying that farmers should not be forced to sell their crops below the cost of production," Sanders said. "That’s another no-brainer.

"Farmers deserve a fair price for the very, very hard work they do."

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Sanders lost the 2016 Iowa caucuses by less than half a percentage point. While much of his 2016 bid focused on breaking up big banks, raising taxes on the ultra-wealthy and providing free college and health care for all, he has expanded his aim this year, focusing more on agriculture and rural decline on the stump.

"I come from a rural state," Sanders said Friday in an interview with the Des Moines Register. "It's an issue we probably should have talked about more last time. We will do that this time."

During his first Iowa trip in early March, he targeted "factory farming" and derided the concentration of players from the corn seed market to pork production.

Massachusetts Sen. Elizabeth Warren, often seen as competing for the same slice of liberal voters as Sanders, released her own agricultural policy in late March. She specifically called for federal regulators to break up Tyson, Dow-DuPont and Bayer-Monsanto — some of the key players in Iowa's ag economy.

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On Sunday, Sanders again targeted large-scale farming, blaming so-called factory farms for "destroying the social fabric of rural America."

He said industrial farming threatens the safety of air and water as well as the quality of life in rural areas.

"Who wants to live in a community where you're smelling manure all day?" he said.

Asked whether the nation could realistically move back to a system of smaller, family farms in the Friday interview, Sanders said: "I don't think we're going to go back to the 1880s."

But, he said, Americans must push for major changes across the food production system.

During his speech Sunday, Sanders identified the food production system as a matter of national security, and he pledged to restrict foreign ownership of American farmland. Since the 1970s, Iowa law has prohibited foreign ownership of farmland.

Aside from agriculture, Sanders called for a new approach to rural communities, which have been declining for decades. He proposed investing more in rural public education programs and increasing rural teacher pay.

His plan calls for universal broadband and doubles down on his recently introduced legislation that would increase funding for community health centers.

Collectively, he pledged his policy proposals would help revive small towns across the country while simultaneously boosting smaller farming operations. But, he said, agribusiness remains a powerful political force in states like Iowa.

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"Here in Iowa, a third of the entire state’s economy is tied directly to agriculture," he said. "More and more of the state’s agriculture is being dominated by just a handful of large corporations, who, it seems to me from a distance, own the Iowa state Legislature and legislatures throughout this country."

In introducing Sanders on Sunday, retired Marshall County farmer Larry Ginter told the crowd how he had worked and lived through the massive transformation of agriculture. What once was a stable business — thanks to government intervention — is now dominated by market-driven cycles of boom and bust, he said.

"It's time to say 'Hell, no' to boom and bust and market instability and monopolization," Ginter said. "It's time to raise less corn and more hell."