MOSCOW--The United States and Soviet Union yesterday gave their arms control negotiators one month to complete the key provisions of a new treaty to sharply reduce their strategic nuclear weapons.

The decision was taken as U.S. Secretary of State George P. Shultz wound up two days of talks in Moscow. He said negotiators in Geneva who have so far failed to make significant progress toward a 50 percent cut in long-range nuclear weapons were directed to report to him and Soviet Foreign Minister Eduard A. Shevardnadze in Washington March 22-23.

Shultz also told a news conference the Soviets indicated they would be more flexible in handling emigration applications, except for those from people who have had access to state secrets.

Shevardnadze confirmed "categorically" that only those with information the government considers important to national security would be barred from emigrating, according to Shultz.

Earlier today, as he opened talks with Shultz, Mikhail Gorbachev pledged to achieve peace in Afghanistan and to try reach a new nuclear arms agreement by spring.

Shultz and the Soviet Communist Party general secretary smiled broadly as they shook hands and sat down with their aides in opulent Catherine's Hall in the Kremlin.

At a picture-taking session, Gorbachev said the Soviets would "do our best to achieve peace in Afghanistan and to have a non-aligned, neutral Afghanistan which would have good relations with its neighors, with the United States and with the Soviet Union."

At the news conference, Shultz said he did not have the "slightest doubt" that the Soviet Union would leave Afghanistan. But Shultz, who came here saying he would seek a specific timetable, gave no evidence he had received one.

An estimated 115,000 Soviet troops have been in Afghanistan since December 1979, backing a pro Moscow government at war with U.S.-armed Moslem guerrillas.

Gorbachev has promised to begin a withdrawal on May 15 if the Kabul government and Pakistan can agree on terms of a settlement by March 15.

Shultz, who arrived in Moscow on Sunday, met until 1:30 a.m. yesterday with Shevardnadze, then held talks with Premier Nikolai I. Ryzhkov before meeting Gorbachev.

After the talks, Shultz did not say whether the Soviets agreed to support the seven-month U.S. effort in the United Nations to impose a worldwide arms embargo against Iran for refusing to comply with a U.N.-ordered cease-fire in the Iran Iraq war.

Shultz also vehemently denied that he sought Soviet backing for his Middle East peace initiative.

"I didn't come here with my hat in hand looking for support," he said.

He said the parties in the region, Arabs and Israelis, would determine whether his trip to the Middle East later this week will succeed.