The Prince George's County Council, hamstrung by the voter-initiated TRIM amendment that limits taxes, somberly adopted a budget yesterday that places unprecedented financial restrictions on the county's schools.

Anticipating the council's action, the Board of Education went into emergency session last night to see how it could operate the nation's 16th largest school system with less money than it received this year. School Superintendent Edward J. Feeney grimly predicted up to 900 employes, including 400 teachers, would have to be laid off.

"The magnitude of all these cuts is enormous, affecting every one of us in the school system," said Feeney. "There is no time to wait if we are to contain the cuts to within a manageable level and protect our classroom programs."

The school board met until 12:15 a.m. today but was unable to decide on a list of cuts Feeney had recommended. Another emergency board session was scheduled for 3:30 this afternoon.

The final budget largely reflects a shift in priorities by County Executive Lawrence J. Hogan, who is seeking the Republican nomination for the U.S. Senate. In unveiling his budget proposal on March 31, Hogan told reporters, "If you are asking me if I put a higher priority on crime than on education, the answer is yes." He said he believed county residents agreed with his priorities.

The $524.6 million county budget includes $306.3 million for schools, $5.4 million more than Hogan recommended, but far short of the $337.4 million the board said it needs to operate the 116,000-student system, and $2 million less than this year's appropriation.

Hogan's proposed increases for police, fire and corrections were virtually unchanged by the all-Democrat council. The budget provides for 50 additional police officers, three civilian police positions, 25 firefighters, 11 emergency medical technicians and 35 corrections officers.

Even so, Mahlron Curran, president of the local chapter of the Fraternal Order of Police, called the increase insufficient. He said he expected to get 100 more officers. Curran said a majority of the council "said they supported our position but when I sat to watch the final budget punchout, I could just see our request fall away."

The council approved the budget by a vote of 10 to 1, with most of the members making lengthy speeches of regret over the cut in school funding. The only member voting against the budget was Sue V. Mills, who said she objected to increasing the so-called "Pac-man" tax on video games from 2 percent to 10 percent. It is estimated that the increase will raise $400,000 of the extra money the council voted for schools. Other funds transferred to the schools included $300,000 from Metro and from refuse collections and a school board surplus from last year.

School spokesman Brian Porter said Feeney's staff worked throughout last week to come up with recommendations on cuts to present to the school board last night. Feeney's recommendations included the elimination of 933 positions in the11,638-employe system, 461 of them teachers, in addition to 324 positions to be eliminated through attrition.

School budget director George Ridler said much of the extra money was needed to finance an extra $14 million in negotiated salary increases--cost-of-living, merit and seniority--for teachers and other employes, and to offset an estimated $14 million reduction in federal funds.

Except for the school funding, the budget passed by the council differed little from the $519.7 million budget originally proposed by Hogan. It raises the county's property tax by 3 cents per $100 of valuation (about 1 percent to the typical homeowner) to the charter-mandated limit for the first time of $2.63 per $100 valuation. It also raises the county's park and planning tax by 1/2 cent, to 42 cents per $100 valuation, and leaves the county's sanitary commission and income-tax rates unchanged.

Nearly all the council members stated how deeply they hated to cut the schools' request, and many of them used the occasion to call for a modification in the charter provision that limits property-tax revenue to the 1979 level.

Council member Ann Lombardi said she wanted to fully fund the schools, but said that "would have meant that we would have had to deplete county services. We would have had to go through each department and remove staff, but we found no department had large enough budgets to make up the difference. The cuts would only have caused contempt among the departments."

Lombardi indicated that, like Hogan, the council perceived a political climate that would not favor drastic cuts in public services to fund education. "There was no interest on the council in making massive cuts in each department to shift money to education," she said. "The money we had to come up with was so overwhelming that anything done would have been a pittance. There was nothing more we could realistically do."

Hogan was out of town and could not be reached for comment yesterday. However, his spokesman, Carl Gagliardi, said, "Indications are good that he . . . will go along with the budget passed by the County Council. The council hasn't taken any money from public safety allowances and that was the executive's main concern." Gagliardi said that Hogan would still look over the extra $5 million education allocation before making his final decision.

Hogan has vetoed or refused to sign every previous budget passed by this council and refused to sign the half-cent park and planning tax increase passed by the cuncil this year.