A federal judge has agreed to postpone until May the trial of a suit charging the Prince George's county school board with failure to desegregate its schools.

U.S. District Court Judge Frank A. Kaufman last week agreed with a motion by school board lawyers to delay the trial until May 3, despite his feeling that the controversial suit could have been ready on Feb. 1, the tentative trial date.

Lawyers from the NAACP, which is suing the county, also argued for a delay, but only until Feb. 25.

The new date pushes resolution of the case three months closer to the opening of schools next September.

The court originally planned a May trial shortly after it agreed to hear the suit last October, according to court papers filed by the school board. But at a pretrial hearing, lawyers for both parties sought to move the trial to the first week in February.

According to school lawyer Paul Nussbaum, the lengthy taking of evidence by both sides would leave no time for adequate preparation of the case. Lawyers for the board also noted that, "The fact that it took six and a half years for this matter to resurface in court shows a lack of need for the urgency of the present schedule."

In 1974, the District Court closed the first desegregation suit against the county school board. The current suit is a reopening of the original action.

Lawyers for the county NAACP argued that a trial date of Feb. 25 would have given both sides sufficient time.