The 77th U.S. Open golf tournament starts Thursday on the Southern Hills Country Club course, which Jack Nichlaus described today as "magnificent" but with "lousy" traps.

Defending champion Jerry Pate, 23, heads the field of 153, three more than normal because of exemptions to Sam Snead, Julius Boros and Tommy Bolt.

The rough and the deep sand traps have been topics of discussion all week. The rough looks like it has been given a crew cut.

"The golf course is magnificent; the traps are lousy," Nicklaus said. "The ball plugs too much and reduces the the skill of a great trap player like Gary Player. It makes me equal to him. If the USGA specified the ball will bury, they got what they wanted."

Earlier, Frank Tatum, vice president of the U.S. Golf Association, suggested a "trade-off of skills." He added: "The players should avoid getting into the bunker in the first place. We stand on our sand."

"Nobody's aiming for a bunker," said Nicklaus.

Nicklaus is nursing a slightly sprained ankle but says it hasn't bothered him much. He is one of the favorites and those who believe in arithmetic progression think the 37-year-old Golden Bear is due to win his fourth Open. Nicklaus won in 1962, 1967 and 1972. "It's my turn again," he said.

Lee Elder, Washington's touring golfer, is highly regarded on this course where the premium will be on accuracy.

Snead will be playing in his 37th Open but at age 65, and with an ailing back that has forced him to limit his practice, there is some doubt he will survive the first 36 holes. He has never won the Open, finishing second four times.

Another sentimental favorite will be Arnold Palmer, 47, who had to earn his way into this tournament through the 36-hole sectional qualifying. Palmer still is magic to the gallerise, which have followed him around all week. He is paired with Snead and youngster (27) Bruce Lietzke in the first two rounds.

The field also includes Tom Watson, winner of this year's Masters; Tom Weiskopf, runner-up with Al Geiberger last year; Geigerger, who had a record-breaking 59 at Memphis last week; Ben Crenshaw, a mature 25-year-old who is always threatening to win his first major title; Hale Irwin, a steady golfer and the 1974 champion; Lou Graham, the 1975 winner, and Player, one of only four men (Nicklaus, Gene Sarazen and Hogan), who have won all four major titles.

Johnny Miller, who won in 1973, could surprise. He has been rounding into his game after a horrible start this year during which he won a little more than $22,000.

Then there are the young lions who dominated the winter tour: Tom Purtzer, Gary Koch, Andy Bean, Danny Edwards and Mark Hayes. It is significant that veteran tour players have won the last 11 tournaments.

Nichlaus said he played his first national tournament here in the 1953 U.S. Junior championship. "As for getting excited, sure I'm excited. If I weren't, I wouldn't have come here to practice last week. I enjoyed playing golf on this course and I'm sure I'm going to enjoy it this week."

Most of the forecasters have been eliminating defending champion Pate from consideration because of a pinched nerve in his shoulder, incurred last December when he pulled a muscle. Pate won the first tournament of the year, in Phoenix, but that was his only finish in the top 10 in seven tournaments. He has played only once since the Masters, in last week's Memphis Classic where he finished 20 shots behind Geiberger.

Pate is known for his confidence. Last year at Atlanta he predicted he would win the Open and he did, by two strokes over Weiskopf and Geiberger.

"I have more confidence this year than last," Pate said. "By Sunday, I might be the Open champion again. If I'm not, it won't be the end of the world.

"After all, even Jack Nicklaus has never won two Opens in a row. I believe the last one to do it was Ben Hogan in 1950-1951. So if I don't win, I won't be too disappointed. There are 149 other guys (apparently, Pate didn't count the three free passes. The way I see it, this is a new ball game, another year. Anything can happen and if you're playing good you can win."

The field will be cut to the low 60s and ties after the second 18 holes Friday.