President Carter swept four more primaries last night with landslide wins over Sen. Edward M. Kennedy, moving him ever closer to the Democratic nomination.

In contests that attracted little attention from either candidate, Carter won by nearly 3 to 1 in Kentucky, Arkansas and Idaho, and held a comfortable lead in Nevada.

But a sizable number of voters in the four states voiced displeasure with both Democrats. In Kentucky and Idaho, 8 percent of the voters cast ballots for "uncommitted," in Arkansas 18 percent. In Nevada, almost a third of the voters picked "none of the above," about the same number that voted for Kennedy.

The wins gave Carter 66 more delegates, but not enough to lock up the Democratic nomination. They set up a final Carter-Kennedy face-off next week on the last day of the presidential primary season, June 3.

Ronald Reagan, who was endorsed yesterday by former president Gerald R. Ford, rolled to even more lopsided wins in Kentucky, Nevada and Idaho. But they were little more than frosting on the cake, for his nomination was assured Monday when George Bush ended his two-year quest for the nomination.

At a news conference in Niagara Falls, N.Y. Ford congratulated Reagan, whom he defeated for the GOP nomination four years ago, and pledged his support this fall. "I have always supported the Republican nominee and will do so in 1980," Ford said.

He also put new pressure on Republican John B. Anderson, who is running as an independent. He said the Illinois congressman's candidacy "will throw the election into the House of Representatives in January of 1981, depriving the American people of the opportunity to select the president in November."

With 99 percent of the precincts counted in Kentucky, Carter had 67 percent of the vote, Kennedy 23 percent and uncommitted 8 percent. This translated into 38 delegates for Carter and 12 for Kennedy.

With 52 percent of the Arkansas precincts reported, Carter had 60 percent of the vote, Kennedy 17 percent and former Mississippi governor Cliff Finch 4 percent. A surprisingly large 18 percent of the ballots were cast for 'uncommitted." This converted into 23 delegates for Carter and 3 for Kennedy.

In Nevada, an even higher number of voters voiced displeasure with both Democrats, and "none of the above was collecting about 34 percent of the ballots with 75 percent of precincts reported. Among those registering a candidate preference, Carter had 38 percent of the vote, Kennedy 28 percent.

Kennedy, spending the night in West Virginia, dismissed the voting as meaningless. "With the kind of resources and time that we've had, we've focused on the June 3 primaries," he said.

Reagan was waltzing away with comfortable wins in three primaries, winning 83 percent of the vote and all 27 delegates in Kentucky, more than 80 percent and 14 delegates in Nevada, and more than 80 percent and 16 delegates in Idaho. Arkansas Republicans picked their delegates under a convention system last February, giving nine to Reagan, eight to Bush and two uncommitted.

On the day after Bush's withdrawal from the race, Reagan campaigned in California almost as if the event had not occurred.

He made his standard anti-government speech for business audiences to a luncheon in the southern California community of Industry and then toured a Reagan phone bank in Pasadena.

The results did little to change the overall presidential picture. On the Democratic side, there were not enough delegates at stake to put Carter over the 1,666 needed for nomination. On the Republican sides, Reagan's nomination was assured with the withdrawal of Bush his only remaining major challenger.

United Press International said the day's balloting boosted Carter's delegate total to 1,634 Kennedy's to 850 and uncommitted to 103. According to UPI, Reagan now has 1.058 and Bush 271. Reagan needs only 998 to lock up the nomination mathematically.

The figures include delegates actually chosen and projection of totals for those caucus and convention states where the delegates selection process has started.

There were 95 Democratic and 65 Republican delegates at stake yesterday in primaries in four states -- Kentucky. Idaho, Arkansas and Nevada.

But the presidential campaign was all but nonexistent in all of them. So lackluster was the race in Nevada that Democratic state Assemblyman Don Mello, chairman of the Ways and Means Committee, recommended scrapping that state's primary in 1984 because it had become "an exercise in futility."

Even before he withdrew from the GOP presidential race Monday, George Bush had conceded the Idah, Nevada and Kentucky primaries to Reagan, who has now been assured of the nomination. Republicans in Arkansas elected their convention delegates through a convention system in February, contests which gave nine delegates to Reagan and eight to Bush, with two uncommitted.

Kennedy similarly conceded yesterday's Democratic races to Carter. He didn't even bother to campaign in Arkansas where Carter had the support of popular Gov. Bill Clinton. And the only stop he made in Kentucky was last Oct. 13, when he campaigned for the election of Gov. John John Y. Brown Jr. Brown later endorsed Carter.

The only thing that livened up voter interest was a series of local and statewide races. In Kentucky, Sen. Wendall Ford faced only token opposition in the Democratic primary and easily won renomination to a second term.

But two congressional races generated real excitement in the state. John Y. Brown Sr., the 80-year-old father of the Kentucky governor failed in a highly publicized attempt to win the Democratic nomination in the 6th Congressional District, which includes the bluegrass section of the state. Brown, who served in Congress during Franklin D. Roosevelt's first term, was beaten by state Sen. Tom Easterly, who will oppose Rep. Larry Hopkins, a first-term Republican, next fall.

In strongly Republican southeastern Kentucky, Hall Rogers, the Republican nominee for lieutenant governor in 1979, beat 10 other candidates for the GOP nomination for the seat now occupied by Rep. Tim Lee Carter, a Republican, who is retiring. The primary win is tantamount to election in the one-party district.

The Idaho contest was a meaning less beauty contest. Democrats there chose their 17 delegates by caucus last week giving eight to Carter and five to Kennedy, with four uncommitte. In Nevada, Carter was expected to defeat Kennedy and "none of the above," which also appeared on the ballot.