A Communist Party meeting in Moscow this week is grappling with the problem of food shortages in the Soviet Union that have caused widespread grumbling. How those shortages are dealt with may tell much about the future of the country and the future of Soviet leader Mikhail Gorbachev as well.

Though food prices are high in the Soviet Union, the shelves frequently are bare. Grocery shopping in Moscow normally takes hours, involves visiting many stores and standing in long lines. Yet the results usually are quite meager.Soviet citizens are forced by food shortages to eat twice as many potatoes and 50 percent more sugar than Americans, but get only half the fruit and meat.

The farm system, with its state-run collectives, doesn't produce enough food. The Soviet Union must import more than 35 million tons of grain each year to feed its people. And the undependable transportation network makes problems worse. Nearly a third of the potato crop rots on the way from farm to market.

Farmers and others who may own small plots of land grow food or raise livestock in their spare time. Yet these tiny pieces of private land produce far more than their share of food. The country would starve without them.

In recognition of this private incentive, Gorbachev wants to allow farmers to lease state-owned fields and choose for themselves what crops they want to raise, encouraging a return to family farming.

But some ideological purists in the Communist Party oppose the idea. Yegor K. Ligachev, the chief of agriculture, wants to put more emphasis on the traditional collective farms.

Party officials are deeply divided on the issue because Gorbachev's ideas seem too much like free enterprise, yet the old system clearly isn't working.

If Gorbachev wins, the Soviet Union may be able to feed itself. If he loses, the people probably will continue to be hungry, but Gorbachev will get the blame.

Soviet citizens like the moves toward new freedoms in their country, but food is more important. If they think Gorbachev is failing to feed them, they'll agitate for someone else. Gorbachev's enemies could then oust him.

Much is riding on the Communist Party's decisions on agriculture. It is a crucial crossroads for the Soviet Union, for Gorbachev himself and, by implication, for the rest of the world .