The Senate rejected two attempts to limit annual payments to American farmers, frustrating lawmakers who had hoped that this year's multibillion-dollar farm bill would scale back the government's massive subsidy programs.

Senators voted 78-12 late Thursday to cut off debate on the bill and drop some amendments that were not farm-related. The margin comfortably exceeded the 60 votes Democrats needed on the procedural move and set the stage for a final vote as early as Friday.

"The time has come that we stop this," Senate Majority Leader Harry Reid, a Democrat, said on the floor. "We need a farm bill."

Earlier in the day, the chamber rejected a bipartisan amendment to the $286 billion bill that would have limited overall farm payments to $250,000 yearly per married couple, down from the current limit of $360,000. The amendment, rejected 56-43 — short of the 60 needed, also was meant to close loopholes that allow some farmers to collect higher payments and required that farmers be "actively engaged" to receive subsidies.

"We have a federal farm program to help family farmers make it through tough times," said Sen. Byron Dorgan, a Democrat who sponsored the amendment with Sen. Charles Grassley, a Republican. "It was not created to send multimillion-dollar payments to giant corporate farms, or payments to people who haven't been near a farm in decades."

Later in the day, senators rejected an amendment by Sen. Amy Klobuchar, a Democrat, that would have banned payments to farmers who make more than $750,000 a year, after expenses. The vote was 48-47, again short of the 60 votes required.

Senate Agriculture Chairman Tom Harkin, a Democrat from the Midwestern state of Iowa, had hoped to take significant steps to reduce subsidies in the five-year farm legislation this year but was stymied by Southern lawmakers who favor current law. Southern crops such as rice and cotton are more expensive to produce than most other crops grown around the country.

Harkin voted for both amendments, arguing that they would make his bill better.

"Today's vote is a missed opportunity," he said after the Dorgan amendment was defeated.

The amendments were the latest attempt to reduce subsidies to wealthy farmers. The Senate also rejected an amendment Tuesday by Sens. Richard Lugar, a Republican, and Frank Lautenberg, a Democrat, that would have phased out most farm subsidies and replaced them with stronger crop insurance for all farmers.

The overall bill would extend and expand crop and dairy subsidies along with popular nutrition aid programs, including food stamps. Most of those programs have been operating under a temporary extension since the last five-year farm law expired Sept. 30.

The legislation would attempt to limit subsidies by eventually banning payments to "nonfarmers" whose income averages more than $750,000 a year. The bill defines farmers as those who earn more than two-thirds of their income from agriculture. There would be no new income-based limits on what a farmer could collect, though the bill would prohibit some farmers from collecting payments for multiple farm businesses.

A House measure passed in July would bar payments to all who earn an average $1 million a year or more.

The Bush administration has threatened to veto both bills, arguing they do not go far enough to reduce subsidies. An administration farm proposal suggested reducing payments to individuals who make more than an average of $200,000 yearly. The current cap is $2.5 million.

A coalition of environmental, religious and hunger groups has also been pushing lawmakers to reduce subsidies. Several of those groups expressed disappointment Thursday.

"Family farmers in the United States, impoverished families abroad who are dependent upon agriculture to survive, and American taxpayers who foot the bill for unnecessary United States farm subsidies will ultimately pay the price," said Raymond Offenheiser, president of Oxfam America.