MOSCOW -- The Soviet Congress of People's Deputies risked confrontation with the 15 republics by voting overwhelmingly yesterday for preserving the U.S.S.R. as a socialist country and for holding referendums on the union's future and on private ownership of land.
Even President Mikhail S. Gorbachev -- still general secretary of the Communist Party -- previously had proposed substituting "sovereign" for "socialist" in the country's name to stress the republics' rights.
Several republics already have dropped "socialist" from their names. Deputies proposed alternates yesterday ranging from simply "Russia" to a suggestion of the late Andrei D. Sakharov, "Union of Soviet Republics of Europe and Asia."
But responding to the appeal of several hard-liners, the congress insisted, in a vote of 1,365-189 with 170 abstentions, on preserving the old name of the Union of Soviet Socialist Republics.
"We just voted to keep the name 'socialist' for our country, but what kind of socialism do we mean?" an unidentified deputy shouted.
"Is it Stalin's 'barracks' socialism? Or Brezhnev's 'developed' socialism? Or is it today's socialism with rationing coupons? Or is it Swedish socialism?" he inquired, saying the deputies were trying to achieve through a name what had not been achieved in practice.
The congress declined to reconsider, and Mr. Gorbachev said he would join in supporting the decision to hang on to "socialist."
The two referendums were set by the congress at the insistence of Mr. Gorbachev, who has defended the idea as the only democratic solution to fundamental questions. A referendum on whether to preserve the union was approved 1,678-32, and one on private land ownership was passed 1,553-83.
Despite the lopsided backing, the referendum plan is likely to face strong opposition in many republics, which resent what they see as another Kremlin violation of their sovereignty.
The Baltic republics, for instance, fear that thousands of Soviet soldiers would be moved onto their territory to vote on the union question. They also consider their republics never legally to have joined the union, saying that no referendum was held when their territory was occupied by the Red Army in 1940.
"A referendum will be held in Latvia only in conditions of a military dictatorship. This is perhaps what they wanted," Latvian deputy Yuri Boyars said after the vote.
The land question already has been decided after passionate, agonizing debate by the first democratically elected parliaments a number of republics, including the giant Russian Federation. The Russian Congress of People's Deputies approved private ownership in a complicated, compromise formula restricting the right to sell land.
To reopen the question, many republican officials feel, would be to undermine new parliaments and invite referendums on every question.
Igor A. Bezrukov, a lawyer and member of the Russian parliament, said in a radio interview that he considered the land referendum proposal "unacceptable" in Russia, which covers three-fourths of the land area of the Soviet Union.
He said the Soviet congress' decision was a violation of republican sovereignty and noted that under a law passed by the Russian parliament, the decision to hold a referendum would take effect in Russia only if and when ratified by the republican legislature.
In a separate vote, the congress approved the basic principles of Mr. Gorbachev's proposed union treaty, aimed at providing the basis for a renewed Soviet federation. But the congress' decision has no legal significance, since any union treaty must be signed by the republics to take effect.
The three Baltic republics and Georgia have said they will refuse to sign any union treaty, insisting on total independence. Most of the rest of the republics have expressed reservations about the draft, approved yesterday by the congress 1,491-88.
In other action yesterday, the radical Interregional Deputies Group called for a vote of no confidence in the government of Prime Minister Nikolai I. Ryzhkov, which has minuscule support in opinion polls, but the proposal failed 1,137-356.