The Senate, in a fitting epilogue to a tongue-tied week, emerged from an extraordinary Sunday session yesterday unable to reach agreement on emergency farm legislation or a nuclear waste-disposal bill. All hands had agreed that both items were urgent.

The farm bill, which would give the secretary of agriculture authority to carry out a payment-in-kind program, was given up for dead after John Melcher (D-Mont.) objected to its consideration under expedited procedures.

Agriculture Committee leaders had hoped to push their hastily written bill to passage during a break in the inaction between an early afternoon vote on the continuing resolution and a 6 p.m. cloture vote to shut off debate on the highway bill.

But Melcher, a member of the committee, threw up a roadblock and refused to allow the bill to come to debate. For almost two hours, one senator after another stood to announce support for the emergency measure and plead with Melcher to permit a vote on the proposal.

Before the Senate tied itself into another of its rhetorical knots, final approval was quickly given to a conference report on the $7.5 billion Interior Department appropriation, clearing it for the president's signature. It was only the seventh of 13 appropriations bills for fiscal 1983 adopted so far.

The long, drawn-out discussion about the farm legislation virtually precluded Senate consideration this year of a controversial nuclear waste-disposal bill that James A. McClure (R-Idaho), Energy and Natural Resources chairman, tried to call up for debate. McClure gave up the ghost when it became clear that his request would draw an objection from someone among the weary legislative troop, which had worked overtime all last week in an exasperating exercise in wheel-spinning over a continuing resolution and the highway bill.

Russell B. Long (D-La.) and Howard M. Metzenbaum (D-Ohio) said it best. "There are some real dogs around here that ought not to be passed," Long said. And Metzenbaum said, "No member of this body at 3 p.m. on a Sunday should be forced to debate anything but the two bills the continuing resolution and the road bill ."

All was not solemnity, however. At one point, Minority Leader Robert C. Byrd (D-W.Va.) snapped at his West Virginia colleague, Jennings Randolph (D), about a remark he had made on the gasoline tax portion of the highway measure.

Paul Laxalt (R-Nev.), attired in turtleneck sweater and leather coat, appeared to be in violation of the Senate dress code when he rushed in from a pro football game.

And a simultaneous roar of approval from television viewers in the GOP cloakroom and the upstairs press gallery, booming through the chamber in stereophonic effect, interrupted events when the Redskins' Mark Moseley kicked a game-winning field goal.

Melcher's triumph on the farm bill was sealed when Majority Leader Howard H. Baker Jr. (R-Tenn.) reclaimed his floor time and announced he would move ahead on other noncontroversial bills that required passage. Melcher broke into a broad grin, and the payment-in-kind (PIK) proposal was virtually dead.

Agriculture Secretary John R. Block, who made a brief and unusual appearance on the Senate floor in an effort to push the bill forward, said afterward that he is "still hopeful" that Congress can give him the authority he seeks before it adjourns. He said he remains uncertain how far he can move with a PIK program without the new authority.

"I think it's incredible that one senator could obstruct the will of most senators, of the House of Representatives and most of the farm community," Block said.

Most of Melcher's colleagues agreed but, under Senate rules, there was nothing they could say to undo his obstruction of the authorizing bill. Senators pleaded, cajoled and stroked, hovering at his elbow most of the afternoon. Melcher would not budge.

On Saturday, the House had passed without dissent a measure giving Block authority to go ahead with PIK, under which the administration would give farmers surplus grain, rice and cotton in return for not planting crops next year. The aim is to reduce supplies and drive up prices in the deeply troubled farm economy.

That put extra pressure on the Senate to act. Melcher, however, complained that he feared the program actually would drive prices lower and give the secretary too much of a "blank check" to administer farm programs.

"This is a bad bill," he said. "The fine tuning you promise will not happen very readily . . . The secretary wants a bill giving him broader authority without some price protection in the marketplace . . . There's no chance we're going to do this."