The Senate is poised to approve a package of three spending bills after lawmakers last night worked through many of the remaining amendments on the legislation and agreed to limit debate.

Senators voted until the wee hours of the morning on amendments, approving new limits on farm subsidies for wealthy farmers and a bump-up for watershed conservation programs.

A vote on final passage on the bill is scheduled for the week of Oct. 31, after senators return from their weeklong recess. It is expected to pass. Lawmakers agreed to cut off debate on the measure in an 83-16 cloture vote early this morning.

The overall bill, known as the "minibus" spending package, would set the fiscal 2012 budgets for the Agriculture Department; Commerce, Justice and Science; and Transportation, Housing and Urban Development.

The bills squeeze federal spending in an attempt to meet budget targets: The measure would cut funding for farmland conservation programs below the levels set in the farm bill and reduce some marine accounts for the National Oceanic and Atmospheric Administration.

Senators approved an amendment last night that would cut off some subsidies for farmers making more than $1 million a year. Sen. Tom Coburn's (R-Okla.) amendment to block "direct payments" for millionaires passed handily 84-15.

The amendment could be more symbolic than substantive. It would apply to few farmers, but the resounding support for the change could reflect a tougher political environment for farm subsidies, which have previously survived attacks. Critics of the farm subsidies will press for their overhaul as part of the deficit debate and in the next farm bill.

Senate Agriculture Chairwoman Debbie Stabenow (D-Mich.) asked senators last night to reject Coburn's amendment because she and other agriculture leaders are working on their own farm bill proposals. Stabenow said she would release the committee leaders' plan within 10 days.

In past years, Agriculture Committee leaders have been able to stave off many of the efforts to alter farm subsidies in spending bills, usually by arguing the changes should only be taken up during a farm bill debate.

Stabenow's proposal is expected to eliminate direct payments for all farmers, not just those making $1 million or more. Direct payments, which go to farmers regardless of crop prices or weather, have been a frequent target of the Obama administration and of groups opposed to farm subsidies, including environmental groups and hunger advocates.

Lawmakers also approved, 58-41, a proposal to boost funding for the emergency conservation and watershed protection programs. The amendment from Sen. Kirsten Gillibrand (D-N.Y.) would allot an extra $49 million for the emergency conservation program and just over $61 million more for the emergency watershed protection program.

The programs offer assistance to help landowners respond to floods, fires and other natural disasters. Gillibrand said extra money is needed for the program to help landowners clean up debris and restore bridges hit by hurricane-related floods in August.

The Senate also approved an amendment from Sen. Jerry Moran (R-Kan.) that would transfer $8 million from the administrative account of USDA's Natural Resources Conservation Service into the Watershed Rehabilitation Program, which provides funding for water infrastructure maintenance and rehabilitation.

Citing benefits that dams and other water infrastructure provide, such as erosion control, irrigation and recreation, Moran said it is crucial to ensure those structures are sound. Many of the country's more than 1,000 structures are aging, he said.

"In the absence of maintaining these structures, we run the risk that the investment we made over decades begins to disappear," he said on the Senate floor, "and not only do we lose the value of the asset but also potentially life."

Senators also included an amendment from Sen. Thad Cochran (R-Miss.) that would expand eligibility for a USDA program offering loans to renewable energy plants or power plants using carbon sequestration systems.

The Cochran language would change the designation for the program, already written into the president's budget request, to allow for baseload generation plants in rural areas to compete for the loans. The measure was agreed to by unanimous consent.

As a part of the late-night negotiations, senators also tacked onto the bill a new salmon research program to respond to a deadly virus that has devastated fish farms in Chile and recently been detected in wild Pacific salmon.

The amendment from Sen. Maria Cantwell (D-Wash.) directs a national task force to coordinate research on the infectious salmon anemia. It was accepted by unanimous consent.

The group would establish research objectives to assess potential transmission pathways, any role foreign salmon farms may have in spreading the disease to wild populations and susceptibility of various salmon populations to the disease.

A transportation amendment from Sen. Rand Paul (R-Ky.) is still on the docket.

Senate leaders jettisoned dozens of other amendments proposed for the bill. A measure that would have put limits on the Obama administration's push for marine spatial planning did not make the amendment list.

And an amendment from Sen. Patty Murray (D-Wash.) regarding environmental requirements for road reconstruction after natural disasters was withdrawn yesterday. The amendment would have removed language from the bill that eliminated some environmental reviews for projects rebuilding highways damaged in natural disasters and emergencies.

That language in the appropriations bill received a rebuke from the administration in its official policy statement.

Reporter Jason Plautz contributed.