Both the Poles and the Soviets find the cupboard is bare

The Soviet Union is mounting an increasingly open effort to combat nationwide shortages of meat, butter, and other foodstuffs.

The campaign, coinciding with the nation's third poor harvest in a row, seems to be taking two main directions:

* Various forms of rationing (although they are not officially called rationing).

* A crackdown on black-marketeering, which sometimes seems to rival chess and soccer as a national pastime.

Soviet President Leonid Brezhnev has taken the lead in efforts for a comprehensive ''food program'' as a long-term solution to the country's chronic agricultural woes. But progress has been visibly slow.

Mr. Brezhnev first mentioned plans for a food program in late 1980. Last November he proposed that the Communist Party's Central Committee discuss the program at one of its twice-yearly sessions.

The search for shorter-term solutions and the more open discussion of the problem come amid indications the Soviet Union's food shortages are getting worse.

Major cities, particularly Moscow, are traditionally better supplied than other areas. But even in the capital, meat supplies are irregular at times. Recently, there has been a shortage of butter.

At a Leningrad post office a few weeks back, a postmistress picked up a package left for mailing, found her hands sullied with a red liquid, and exclaimed angrily: ''They're mailing meat!''

A Soviet traveler just back from a mining area in the Ukraine says a trip to a grocery there yielded ''almost nothing'' but bread. There have been unconfirmed reports of brief work stoppages in some areas to protest food shortages.

The political implications of the shortager remain unclear. Most people seem ready to make do by eating more bread, buying under the counter at inflated prices, or, when possible, traveling to big cities to shop.

But the Soviet leadership does appear concerned. Mr. Brezhnev, in his November address to the Central Committee, said: ''The food problem, economically and politically, is the central problem of the whole (1981-85) five-year plan.''

Rationing, in this context, is presented officially as a positive development. This is undoubtedly one reason the word ''rationing'' is generally not used.

For months, travelers from several Soviet towns have spoken of a system of coupons, whereby foodstuffs are allocated. In the only known official reference to such systems, the Georgian Communist Party chief noted in a speech late last year that ''rationing of livestock products is being introduced for the urban population.''

In an unprecedentedly frank article on food distribution, the Soviet trade union newspaper Trud Jan. 8 held up a system adopted in the traditionally well-supplied Baltic republic of Lithuania as a possible model for other areas.

''When there is no sausage, chicken, butter, or, for example, dried fish at the store counter,'' Trud said, ''this does not always mean there is absolutely none of these products.''

Food, Trud suggested, was often badly distributed or sold privately ''through the back door.'' The answer was to allow workers to contract, through local trade unions, for set quantities of foodstuffs. The Lithuanian city of Klaipeda had done so.

The article said three poor harvests had taken their toll in the city, ''as in many other regions of the country.'' But stocks of meat, for instance, are termed ''not great, but sufficient.'' The newspaper said each family in the area gets about 3.3 to 4.4 pounds (1.5 to 2 kilos) of meat weekly.

Although official food distribution has its problems, ''unofficial'' outlets seem to be thriving. No doubt with this in mind, the legislature of the Russian Republic latM last year toughened laws on under-the-counter trading. The new articles ''prescribe penalties for the acceptance by state employees of illegal remuneration for services rendered, and also outlaw the sale of goods from other than retail premises and the concealment of available goods from consumers.''

Similar measures have been taken in Latvia. It is assumed by diplomats here that other Soviet republics either have followed suit or will do so.