The Senate joined the House yesterday in approving an earlier springtime start for daylight-saving time after an emotional debate in which the extra three weeks were depicted as everything from a boon to the barbecue industry to a bane for mothers trying to get their children to bed before darkness.

The Senate measure, approved by a voice vote after a move to derail it failed 58 to 36, would advance the start of daylight-saving time by three weeks, from the last Sunday of April to the first Sunday of April.

A bill passed last year by the House includes the same springtime provisions as the Senate measure but would also add another week of daylight-saving time in the fall, delaying the rollback of clocks from the last Sunday in October to the first Sunday in November.

The House could either accept the Senate bill or work out differences in conference with the Senate. The change could start as early as next year. The Reagan administration supports the daylight-saving extension, although it objects to some aspects of a fire-prevention bill to which the Senate measure is attached.

If the measure clears its final hurdles, it would be the first change in daylight-saving time since Congress experimented briefly with extended daylight hours to save electricity during the energy crisis in 1974.

Once debated in the context of tampering with "God's time" but argued now more in terms of regional life styles, public safety and commercial advantages, altering the clock has been an issue since the early days of the Republic, according to Sen. George J. Mitchell (D-Maine).

In this week's Senate debate, support for daylight-saving time was couched in terms of energy conservation and enhanced public welfare, but with a 20th-century twist.

It would save an estimated 100,000 barrels of oil per day, reduce traffic accidents and cut down on violent crime, argued Sen. Slade Gorton (R-Wash.), chief sponsor of the measure. It would benefit nursery owners, convenience stores, the barbeque industry, the travel and tourism industry and sporting goods manufacturers, he added. In all, he said, it would correspond "more closely with our life styles than . . . standard time."

Opposition to the change was led by senators representing rural states, especially those that lie on the western edge of time zones, who argued that safety and well-being of their constituents would be jeopardized for the pleasures of urbanites who live on the East and West coasts.

"I am tired of having to spend half of my day in the dark just so some soft executive can have a barbecue when he gets home in November," Sen. Wendell H. Ford (D-Ky.) quoted one of his time-zone fringe in constituents as writing, "Has just one of those daylight-saving backers ever tried putting a 4-year-old, a 7-year-old or a 10-year-old to bed at 9 p.m. in the daylight?" asked another. "Let's leave God's things alone," said a third in an echo of the old debates over keeping the Lord's time.

"Any Kentucky mother who has sent a first-grader out to catch a bus on a dark, misty April morning takes a dim view about the importance of electricity that might be saved on the East and West coasts and the number of after-work tennis games that might be played here in Washington, D.C.," added Ford, who led the fight against Gorton's measure.

Lest anyone think that emotionalism has been drained from the issue, Ford cited an unnamed Kentucky state senator who described it as one of the three most emotional issues of his career in the state legislature. "Time is more important to people than the budget," Ford quoted the lawmaker as saying. "They don't care how much we spend, apparently; they just want to know what time we are going to spend it on."