Education Secretary T.H. Bell yesterday defended the administration's proposal to pay teachers on the basis of merit rather than seniority, saying that the teaching profession is no longer attracting "bright and talented young people."

"Teachers are not as competent as they ought to be," Bell said on "Meet the Press" (NBC, WRC). "Part of the problem is that we're not drawing our teachers out of the level of human ability where we ought to be getting them.

"If you look at those people . . . in the schools of education, they're in the bottom 25 percent of the SAT Scholastic Aptitude Test scores," he said, adding that talented students are "going into engineering and law and medicine."

"What's more, we're even losing the bright and talented women these days because of the opportunities we're providing them. They're going into law and engineering. That's why we've got to make teaching more attractive. That's why we've got to change the single salary schedule," Bell said.

In response to questioning, Bell defended President Reagan's declaration last week that the budget for U.S. education is higher than that for national defense. Bell said that Reagan was referring to total state, local and federal education expenditures for education. The federal government provides only 8 percent of funds spent on education, he added.

Reagan also said last week that his administration has not cut the education budget but has simply reduced proposed spending increases. Bell conceded yesterday that federal education funding has dropped from $14.3 billion in fiscal 1982 to $13.5 billion in fiscal 1984 but said that decline reflects a reduction in interest rates for the Guaranteed Student Loan program, not a budget cut.

Bell said that the administration attempted to cut education funds last year but was forced by the Senate to restore the funding. "We're not proposing a reduction this year, and I don't anticipate that we will next year," he added.

Asked whether Reagan's recent emphasis on the education issue could be called "late and politically motivated," Bell said, " . . . neither one of them may be totally so. But good public policy makes good politics, and so you might say there's a political motivation in it. But I'd say that's a good thing. I'm glad Democrats and Republicans are arguing about education. I'm glad it's so high on the national agenda right now."