MOSCOW, OCT. 26 -- Soviet President Mikhail Gorbachev issued two critical emergency decrees on the economy today that will allow foreign businesses to own and operate enterprises on Soviet soil and dramatically lower the commercial rate of the ruble.

At a time when the Soviet economy is in a state of confusion and collapse, Gorbachev's decrees are designed to attract foreign investment and to help bring the Soviet Union into the world economy.

Although the Soviet legislature has passed a comprehensive, controversial plan to begin moving the economy to a market system, Gorbachev has now used his emergency presidential powers to take immediate action intended to prevent further economic collapse and to help begin a transition that is likely to take many years.

The decree on foreign business, which addresses some of the thorniest issues facing investors from abroad, represents an extraordinary reversal of the traditional Bolshevik fear of the "foreign exploiter."

The new decree allows foreign businesses to establish wholly owned subsidiaries on Soviet soil. Minnesota's 3M Co. is one of several major U.S. corporations already conducting negotiations to open subsidiaries here. Foreign businesses also will be allowed to take out long-term leases on properties and land; they may not, however, buy the land.

The decree allows foreign businesses to repatriate their profits by reinvesting in the Soviet economy or by transferring the money abroad. In the past, foreign companies had to struggle to find ways to bring home their profits. McDonald's of Canada, whose joint venture with the Moscow city government opened in January, at one point was said to be taking some of its profits in Russian pickles.

The decree almost certainly will doom the phenomenon of joint ventures, businesses in which Soviet partners were required to own, by law, a majority interest. Many foreign businesses discovered that their Soviet partners contributed very little and that their own 49 percent stake was not worth their time, money or effort. According to the business weekly Kommersant, dozens of joint ventures have closed in the past two years out of "investor frustration."

The second decree, on the ruble, will change the commercial rate that foreigners doing business here can legally get, from 56 kopecks for a dollar to 1.80 rubles, more than tripling the value of the dollar here. The new commercial rate is to go into effect on Thursday.

Nevertheless, the ruble, which is not convertible on foreign markets and is regarded as a "soft" currency, is still in a state of flux. Tourists already can legally get 5.60 rubles to the dollar at hotels and banks, and black marketeers often pay more than 20 rubles to the dollar on the street.

Ordinary Soviet people have utterly lost faith in the ruble, calling it, at best, "tissue paper." In tourist cities such as Leningrad, Moscow and Kiev, cab drivers have begun refusing to drive for anything but foreign, hard currencies.