Fairfax County School Superintendent William J. Burkholder, whose predecessor angered county politicans by pressing for budgets that exceeded their guidelines, last night proposed the smallest increase in the system's operating budget in two decades.

The $449.5 million operating budget Burkholder presented to the county school board for the fiscal year that starts July 1 adhered to the county board of supervisors' mandate for an increase of no more than 5.8 percent in total spending. The proposal would limit cost-of-living raises for the system's 13,000 workers to3 percent.

Burkholder called the proposal "very austere," and said he was disappointed at having to limit wages. But John F. Herrity, chairman of the board of supervisors, called the school budget the "key element" in holding down the county spending and praised Burkholder for doing "an excellent job."

Herrity said he liked the Burkholder budget, which the school board must send to the supervisors by Feb. 17. "From what I hear, it's a healthy baby, and should live a long fiscal year," Herrity said.

Marilyn Rogers, president of the Fairfax Education Association, the largest teacher group in the county, expressed disappointment.

"We were hoping for more," she said. "But the superintendent is to be commended. The cap the board of supervisors put on didn't leave room for any increase. Burkholder had to search for that3 percent."

The budget was the first to be drafted by Burkholder, who was named head of the largest school system in the Washington area last July after the school board forced Linton Deck to resign. A year ago, Deck had proposed what Herrity called a "very overblown" $436.4 million budget, which the supervisors cut to $425.2 million.

Burkholder's proposed budget increase is$22 million, or 5.1 percent, more than the budget for the current fiscal year. Salary and benefit increases would account for $19.4 million, or more than 88 percent of the proposed increase.

Most of the remaining $3.6 million in added funds is earmarked for computer resources, including additional hardware for computer instruction, administrative and business data processing, and computerized services.

Fairfax's taxpayers, who provide two-thirds of the system's revenues, will be expected to increase their share of the school budget by $16.4 million, or 5.85 percent under Burkholder's proposal. While state aid is estimated to increase by8.7 percent overall, federal aid is expected to be 14.6 percent less.

Among the revenue-boosting steps that Burkholder plans is imposition of a $60 fee for students taking the driving phase of driver education.

In his meetings with teachers Burkholder has stressed that, while his salary proposal is modest, Fairfax is fortunate to be able to avoid the massive layoffs that other systems in the area have suffered. His budget calls for a loss of about 19 jobs in the coming year, a goal that he hopes to attain through attrition, although he said that some layoffs are likely.

The budget anticipates that Fairfax will need about 73 fewer employes in the coming fiscal year because of declining enrollments and school closings in some parts of the county, but will add 25 employes in faster growing areas. Seven additional positions are being dropped because of reduced federal support for specific projects, and Buckholder proposes funding 35 other positions for assignments not yet determined.

The sharpest cut in current spending would be a 17.4 percent reduction planned in adult and community education. Burkholder said that the biggest single loss would be in federal funds for teaching English as a second language. Burkholder also called for reducing school bus purchases, recommending buying 10 new buses next year compared with 70 purchased this fiscal year.

The school board will meet four times this month and once in February to consider Burkholder's proposals, before adopting a budget. Public hearings are scheduled for Feb. 7 and 8 at 7:30 p.m. at the Jackson Intermediate School.