WASHINGTON-- The Senate opened debate on Attorney General-designate Edwin Meese Ill's nomination yesterday after Majority Leader Robert Dole (R-Kan.) told colleagues they should not "hold the Meese nomination to hostage" to demands for farm credit legislation.

Senators from agricultural states allowed the debate on the controversial appointment to proceed, but held out the possibility of a filibuster to prevent a vote on Meese until their demands are met

"The Justice Department seems to be operating quite well," said Sen. Tom Harkin, (D-Iowa) "Why is it more important for us to take the time to act on the Meese nomination than it is to take up important farm legislation?"

"Ed Meese has been waiting a year now," Dole replied. "We have been trying to solve the farm crisis for the last 40 years. There are a lot of ideas. They haven't jelled.

"We've started the process to go over a number of suggestions (on the farm problem), and we hope that progress can be made," the Kansas Republican said. "And I would hope we would not hold the Meese nomination hostage."

Earlier, Dole predicted that Meese would be confirmed by a comfortable two-to-one margin to become the nation's 75th attorney general, despite lingering questions among some Democrats about the presidential counselor's fitness to serve.

"Ed Meese will be confirmed by the full Senate I expect about 65-70 votes for him" in the 100-member Senate, Dole had said in a statement released in advance of the debate. "He's been scrutinized about as much as anybody has been in a long time. But that will be behind him after this week."

Sen. Strom Thurmond (R-S.C.), chairman of the Judiciary Committee, said the Meese nominations "has been subjected to some of the most intense and exhaustive scrutiny I have witnessed in my Senate career. In every case, the facts have clearly shown the Mr. Meese has violated no criminal laws and has violated no in his business and personal dealings."

Thurmond, too, predicted that Messe would be confirmed by more than two-thirds of the 100 senators.

The Senate was taking up the nomination two weeks after the Judiciary Committee recommended Meese's confirmation by a 12-6 vote and 13 months after Reagan first sought approval of Meese for the nation's top law enforcement job.

The timing of the debate and vote was uncertain:

Sen. David L. Boren (D-Okla.) threatened yesterday to filibuster against any matter the Senate tries to consider unless an agreement can be reached with the Senate leadership to address "a widespread farm credit crisis."