Local PTA units, student groups and the Fairfax Education Association, their request for higher salaries for the county's 7,500 public school teachers turned down by the School Board last week, plan to lobby intensively the county's Board of Supervisors, which is scheduled to give final approval to the school system's budget in April.

Last week, School Board members approved Superintendent Robert R. Spillane's $586 million budget package, which included a4 percent cost-of-living increase for all teachers, additional money for veteran teachers and a jump in the starting salaries that will be offered to new teachers.

County teachers' associations had asked for about an 8 percent cost-of-living raise.

"We spent three days giving testimony and the School Board did not listen to one of us," said Sharon Murphy, PTA president at South Lakes High School in Reston.

Donna Caudill, president of the Fairfax Education Association, said her group approves increasing salaries for beginning teachers to $20,000 from $18,385, but that the pay plan does not adequately compensate those teachers in the middle salary range.

"Those new teachers aren't even in the county right now. We don't know who will get those salaries next year . . . it doesn't affect our members at all," Caudill said in a telephone interview.

Janie Strauss, an elementary school PTA president, said teachers are starting to doubt the county's and the school system's support for maintaining "quality" education in the Northern Virginia area.

"We may, indeed, face a severe shortage of teachers -- at least, in quality," Strauss said. "The teachers are also upset about the overall lack of prestige and professionalization of teaching. Most of the teachers are parents themselves and see better opportunities in other fields."

Teachers' association and PTA leaders said that they will meet with all eight county supervisors and Board Chairman John F. Herrity before public hearings on the budget, in their bid to win support for a larger pay raise for teachers.

"We'll make appointments with the supervisors and get our interested members . . . to share their story about what it's like to teach in Fairfax County," said Caudill.

Anne Troy, a senior at South Lakes high and cofounder of the student activist group, Students for Teachers, said that she was disheartened by the School Board's rejection of community-wide calls for higher teacher salaries.

Students for Teachers was formed last December to show support for teachers' ongoing work-to-the-rule protest of Spillane's salary structure.

"It makes me feel awfully disappointed in the system. I wish there was a way to get around all the politics and the bureaucracy," Troy said. "We're hoping now to get parents more involved, because they're the taxpayers."

" The parents are not going to reelect Herrity and the rest of them if they are not going to give the teachers the pay raises," she predicted.

But the supervisors already have said that they do not favor a larger across-the-board salary increase for teachers this year.

"There is no way in the world the board will support a cost-of-living adjustment raise different from what the county police or fire department will get," said Supervisor Thomas M. Davis III (R-Mason).

In a recent telephone interview, Davis said he would rather wait for the results of a commission that Spillane appointed this month to study the county's teacher salary structure before approving changes in the current pay scale.

"It makes it difficult, for people in public office to act at the point of a gun," said Davis.

Supervisor Nancy K. Falck (R-Dranesville) agreed.

"Let's wait for the commission study and then see," Falck said. "It's a complex problem and it can't be solved with a simple solution. The Board of Supervisors always tries to do things carefully in the county when we're dealing with everybody's money."

Other members of Students for Teachers said they are undeterred by school officials' refusal to add more money to the teachers' pay package.

Students for Teachers member Steve Rosenbluth said that his group plans to orchestrate a massive letter-writing campaign to the supervisors and to parents. Rosenbluth said he fears that the School " . . . morale is low, the educational system is declining." -- Steve Rosenbluth, student Board's decision will affect the quality of the teachers and of education in Fairfax County.

"When you have less-educated students, they make less-educated decisions as adults," Rosenbluth said. "Teachers are the role models, the sole source of information about the adult world . . . . It's important to have a quality teaching staff.

"We'll be telling supervisors that, up until now, they have been able to get away with giving the teachers inadequate pay raises. But they won't get away with it anymore; morale is low, the educational system is declining."

Troy, the 18-year-old South Lakes senior, said that now she has second thoughts about what career she may pursue after college.

"I got involved in this because I was thinking of becoming a teacher. Now, I don't know if I want to be a teacher in Fairfax County," she said.