The Alfalfa Club, whose stock in trade for most of this century has been rib-poking, boozy humor, has canceled its 78th annual stag dinner Saturday night because of what a spokesman called "unhumorous times."

"We felt that if ground troops went into Iraq or Kuwait just before the dinner, it would be in particularly bad taste to have a humorous dinner," club Secretary Richard E. Pearson said yesterday. "You can't really have a humorous dinner in what I call unhumorous times."

Compounding the situation brought on by war in the Persian Gulf was the problem of security posed by a head table composed of the president of the United States, the vice president, Supreme Court justices, the Senate and House leadership, Cabinet members and top military brass.

Pearson said he doubted that President Bush, who was scheduled to deliver closing remarks, Secretary of State James A. Baker III or anyone else at the 49-person head table would have come if a ground war were underway in the gulf.

"And that would have been devastating to the dinner," Pearson said.

He said there was no directive from "up high" to cancel but that Baker, slated to become the club's next president, telephoned him Thursday to discuss the dinner.

"He said we could do several things, one of which was to wait until this week to see how things were going, but if we did that it might be a problem toward the end of the week. He gave no indication of what the problem might be," Pearson said, "but we were smart enough to figure out that there might be ground action."

In a subsequent telephone poll of the club's 15 directors, Pearson said, the feeling was "unanimous" that the dinner be canceled. Besides the obvious concern over security for the 500 political and corporate leaders who were expected, he said, "We did not want to change the dinner format and have it somber."

Sen. Lloyd Bentsen (D-Tex.), scheduled to be this year's Alfalfa Club candidate for president of the United States, said it was "generally agreed that it wouldn't be appropriate to go ahead with the dinner. Let's face it, a lot of those jokes aren't all that funny under the best of circumstances."

Sen. David Boren (D-Okla.), outgoing club president, said, "Many of us simply felt that it would not be appropriate to proceed with an occasion devoted to humorous speeches at a time when the lives of young Americans are at risk in the Persian Gulf."

As it now stands, the club's outgoing and incoming officers will be "frozen" for a year, with Boren passing the torch to Baker at next year's dinner. Sen. Charles Robb (D-Va.) will become vice president, and in the following year, 1993, president.

Also frozen as new members-designate are Sen. Richard Lugar (R-Ind.); Sen. Dale Bumpers (D-Ark.); Bell Atlantic CEO Raymond Smith, of Arlington; Helmerich & Payne CEO Walter Helmerich III, of Tulsa; American International Group Chairman Maurice Greenberg, of New York City; and FBI Director William Sessions.

On Friday, Pearson and two helpers telephoned 164 of the club's 200 members holding reservations for the event at the Capital Hilton hotel. Many had guests coming, some from abroad, including Conrad Black, chairman of the Daily Telegraph in London, guest of U.S. Ambassador to Canada Edward Ney; and Hyundai Chairman Se Yung Chung of Korea, guest of former senator Howard Baker.

Two other wars have forced cancellation of Alfalfa's "meetings," held only once a year. None was held throughout World War II. When the club "reconvened" in January 1946, Gen. Dwight D. Eisenhower was the evening's hero. And seven months after the June 1950 outbreak of the Korean War, club directors decided to scale back their January 1951 get-together to a members-only dinner.

Founded in 1913, the club, which has consistently excluded women from its ranks, was called the Alfalfa because that plant has the deepest roots looking for liquid refreshment. In keeping with that theme, members are referred to by the year in which they were inducted. President Bush, for example, is a "vintage 1970."

Capital Hilton manager Kevin Deverich said he wouldn't want to put "a loss value" on the club's decision to cancel the dinner because of the ongoing relationship spanning some 40 years. "We certainly understood and are genuinely empathetic," he said.

Meanwhile, a spokesman for the Washington Press Club Foundation said its Jan. 30 dinner at the Grand Hyatt will go on as scheduled, as it did in 1986, the night after the space shuttle Challenger exploded.

"Many administration guests are not directly involved in the war effort and there's nothing to keep them from attending," said foundation President Benjamin Shore of Copley News Service.

As for humor in unhumorous times, Shore said many dinner subjects are not war-related.

"We have four freshman members of Congress speaking, and there are many things they can talk about that have nothing to do with the gulf. At the same time, there is no requirement or tradition that their remarks be entirely humorous."