The Senate began consideration Tuesday of a farm and food bill that would bring fundamental changes to how the government protects food growers during hard times, including putting an end to paying farmers regardless of whether they plant a crop.

The Senate is expected to spend several weeks on the five-year bill as lawmakers thrash out differences between Northern and Southern farmers over safety net programs and address the costs of the federal food stamp program, which makes up about 80 percent of the $100 billion in annual spending under the legislation.

The current farm act expires at the end of September, and getting a new plan in place by then will likely require tough negotiations between the Senate and the House, which is taking a different approach to farm protection programs and seeks deeper cuts than the $23 billion over 10 years envisioned in the Senate bill. The House Agriculture Committee is expected to take up its version later this month.

Senate Agriculture Committee chairman Debbie Stabenow, D-Mich., who crafted the bill with the panel's ranking Republican Pat Roberts of Kansas, said it represented "the most significant reform in agriculture policy in decades."

She said she was confident she had the 60 votes to formally begin debate on the bill if opponents tried to block it.

The measure ends direct payments to farmers who may or may not actually plant crops, saving some $5 billion a year. That's replaced with a greater emphasis on federally subsidized crop insurance and a new program that compensates farmers for "shallow losses" in revenues as measured over a five-year average.

"We're not going to be paying farmers for crops they don't grow. We're not going to be paying farmers when they are already doing very well," Stabenow said.

The new Agriculture Risk Coverage program has the backing of most major farm groups, but faces resistance from Southern rice and peanut growers who say it hurts their bottom lines. They are seeking the retention of some kind of target pricing to protect their crops.

The Congressional Budget Office estimates that the Senate bill would save about $8.5 billion over five years by ending direct payments as well as other commodity support payments, and moving to the new ARC program and save another $1.8 billion by streamlining conservation programs. It says $1.7 billion over five years and $4.5 billion over 10 years will be saved through changes to the Supplemental Nutrition Assistance Program, or food stamps, mainly by ending an automatic qualification for food stamps for households receiving less than $10 a year in the federal low-income heating assistance program. Some 46 million Americans are now receiving food stamps.

House Republicans are seeking far greater cuts to food stamps, while Sen. Kirsten Gillibrand, D-N.Y., says she will offer an amendment to restore that $4.5 billion, paying for it by reducing federal subsidies for crop insurance companies. The crop insurance program, costing about $9 billion a year, provides farmers with an average subsidy of 62 percent on their insurance premiums.