The Senate began debate yesterday on a new four-year farm bill, and it turned into sparky work with a threat of filibuster and suggestions of White House treachery and unsavory deal-cutting.

Last minute compromising by the Senate Agriculture Committee, bowing to administration pressures to cut spending even more than it already had, helped to inflame farm-state passions.

The proffered committee compromise, however, wasn't enough for the White House. Administration officials continued pressuring yesterday for further cutbacks in the bill, which is designed to maintain commodity price levels and foster rural development.

The committee backed away from its original bill and agreed to reduce target price levels for major commodities, but it remained snarled over dairy price support provisions.

Even with the compromise, Sen. Richard G. Lugar (R-Ind.), a member of the committee and occasional farmer, said that his colleagues had lost touch with reality.

He plans amendments that could shave as much as $3 billion from the five-year cost of the bill, by eliminating target price payments, and get the measure back to where the White House wanted it earlier this year.

"The only compromise is among the members of the committee sitting around a table trying to protect separate commodities," Lugar said. "There still are uncontrollable expenditures in every direction in this package."

Lugar's principle objection was to the target system that provides direct payments to farmers when production costs exceed market prices. This year's record wheat crop is expected to cost the government an estimated $500 million in unanticipated outlays.

Without its dairy component, the committee compromise for fiscal 1982 would bring farm programs within about $100 million of the administration's demands. With dairy, it would be more than $1 billion over the White House limit.

Kansas Republican Robert J. Dole, urging acceptance of the compromise, warned that an over-budget bill will invite a veto and that dairy interests should yield or face the possibility of separate legislation at a later time.

Dole and Agriculture Committee Chairman Jesse Helms (R-N.C.) noted that existing farm programs expire at the end of this month--making quick congressional resolution of the debate urgent. Dole said one way out of the dilemma would be quick passage of the compromise so that the House can begin its deliberations. He suggested that Congress could deal with a dairy program in the future if no agreement is reached now.

Dole said that the current atmosphere of budget restraint means that all farm commodity groups must yield. "It used to be a cafeteria approach--everyone could take what they wanted, and they did," he said.

But not everyone, not even all Republicans, were heeding Dole's warning. Rudy Boschwitz (R-Minn.) threatened to filibuster unless he got his way on the dairy language--the same language adopted by the committee earlier this year with administration approval.

Boschwitz complained that the prospect of heavy outlays for wheat target price payments had caused the administration to break its earlier commitment to support his committee-approved dairy language.

"Especially irritating is that the administration's opposition to sugar and peanuts was traded away for the votes of southern Democrats in the tax and budget bills. . . farmers of the Midwest who had supported the administration at the ballot box watched their crop support situation erode away," Boschwitz said.

And Republican Larry Pressler of South Dakota took exception to the administration's push to end the target price system, saying that U.S. export prices would be seriously jeopardized without the psychological support the system provides.