BRUSSELS, Belgium, April 13--Belgium's doctors tonight called off a system of emergency treatment that had been maintained since they struck against the government's socialized medical plan 13 days ago.

The action was apparently taken in retaliation against a government order Sunday conscripting the 3,600 Belgian doctors who hold military reserve commissions. About one third of the reserve doctors have shown up for duty, but a career army doctor said the call-up had not helped the national situation much.

Oscar Awards Announced; Poitier Named Best Actor

Hollywood, April 13--Sidney Poitier became the first Negro to win a top Oscar award. He was honored as best actor of the year by the Motion Picture Academy last night for his performance in "Lilies of the Field".

Patricia Neal was named best actress and Melvyn Douglas was named best supporting actor, both for performances in "Hud". Margaret Rutherford was honored as best supporting actress for her role in "The V.I.P.'s"

"Tom Jones" received the award for the best picture and "8 1/2" was named best foreign language picture.