It is an irony of history that the Soviet invasion of Afghanistan, which triggered former president Jimmy Carter's grain embargo against Moscow, began 50 years to the day -- Dec. 27, 1979 -- after Josef Stalin announced his "policy of liquidating the kulaks" or private farmers and launched the systematic destruction of Soviet agriculture.

The decree that followed the dictator's decision in 1929 brought a four-year reign of terror to the Soviet countryside, transforming what had been the grain-exporting "breadbasket of Europe" into a land of chronic shortage.

Today, despite a massive nuclear arsenal, impressive space program and vast industrial strength, Stalin's legacy has left the Soviet Union uniquely vulnerable to the vagaries of sun, seed and sweat labor.

With the Carter reprisal now history after 18 months, debate in the United States over using what Agriculture Secretary John Block calls "the food weapon" to pursue national strategic goals seems unlikely to subside into a welter of confusion and disagreements.

Basic to the debate is the question of whether any Soviet leadership could have the will and political self-confidence to replace Stalin's rigid centralization of the agrarian sector from which the Communist Party -- as in the Soviet industrial sector -- derives much of its power, or whether collectivized agriculture by its very nature is a terrible idea whose time should never have come.

If money can buy a solution, then Soviet President Leonid Breshnev should be approaching that goal. More than any other Soviet leader, he has sought to cure the problem by throwing money at it. At the 1976 party congress, he proudly announced that two out of every three rubles invested in agriculture "in all the years of Soviet power," had come during his tenure, a total of 213 billion rubles from from 1966 to 1975. (One ruble is worth about $1.60 today so his investment would equal $353.6 billion at that conversion rate.) In 1976-80, the party set aside 172 billion rubles (about $287 billion) more, and has earmarked 190 billion ($304 billion) in the current five-year plan. In all, more than 20 percent of publicly acknowledged Soviet spending on capital investments has been devoted to agriculture.

Combined with endless tinkering by planners and organizers in Moscow to grant some local autonomy, raise woefully low mechanization levels, establish integrated agro-industries along the lines of American ones and encouraged private farming in ways that Stalin and Nikita Khrushchev would have vetoed, the torrent of money has brought major gains in production.

Between 1966 and 1976, Brezhnev has boasted, grain harvests rose 40 percent, labor productivity 58 percent, and agricultural products per capita by 25 percent despite a population growth of 23 million. Since 1966, 50 million newly irrigated or drained acres reportedly have been put into cultivation and thousands of miles of roads built in the remote countryside; the infrastructure of processing plants, storage and handling facilities has expanded enormously from October 1964, when Brezhnev came to power.

With the use of expensive imported grains, farm chemicals, feed additives and other measures, per capita meat production rose, and some Western analysts believe the goal of lifting meat production 2 million tons to 18 million in 1985 can be achieved with luck and application.

But the trend now is the other way, with annual increases of about 4 percent in each of the years from 1950 to 1971 by the approximately 20,000 state farms (sovkhozes ) and 27,000 collective farms (kolkhozes ) slumping toward 1 percent in the period from 1971 to 1980.

With 50 percent more land in cultivation than the United States and 20 percent of its work force in farming, as opposed to 4 percent in the United States, Soviet net production still lagged about 20 percent behind the United States in the mid-1970s.

These are not grave problems; the Soviet Union has advanced far from the famines brought on by collectivization and World War II. But they pose enormous problems for a one-party state that aspires to world leadership and are an incessant worry because they reduce party effectiveness while forcing the state to spend hard currency for the foodstuffs it cannot raise itself.

Almost anywhere within the collectivized farm system, loss and waste are phenomenal. beginning with the earth itself, state experts say more than a billion tons of fertile topsoil are lost annually from bad plowing methods.

The party newspaper Pravda has described how mineral fertilizer, needed to improved the thin soils, often is shipped in open or leaky freight cars.

"By the time it reaches the client, it [is] a solid lump," the article said. "Crowbars, sledgehammers, sometimes even a Caterpillar tractor is used to break it up." One researcher said that losses "run more than 200 million rubles [$320 million] a year."

P. Vavilov, president of the Lenin All-Union Academy of Agricultural Sciences, told Pravda last summer that "less than 100 million tons of straw are used for livestock feed annually. The rest, more than half the total, disappears or is burned." Bad combines contaminate the straw with dirt, or miss the best stands. At a time when Soviet livestock need high-protein legume feeds to fatten on, Vavilov said, legume acreage dropped from 7 percent to 4 percent of arable plowland.

Featherbedding, administrative bungling and chicanery foul the complex bureaucratic maze, blunting directives and thwarting goals. While Premier Nikolai Tikhonov told the party congress in February that "farms are to be much better equipped with powerful tractors" and the power-to-worker ratio would increase 50 percent by 1985, a report from 1979 in the government paper Izvestia showed how plans and promises from on high are diluted by the very different reality in the countryside.

N. Matukovsky of Izvestia reported that one recent year, Byelorussia's Mogilev Province farms received 2,500 new tractors -- and promptly scrapped 1,821.

A prize-winning tractor economist, I. Trepenenkov, told Pravda how, when 380 powerful new tractors were to be sent to 24 farms in Krasnadar territory for concentrated work and ease of repair and service, they were scattered instead among 164 farms, hopelessly snarling support plans.

University of Chicago agro-economist D. Gale Johnson recently reported that daily work production per Soviet tractor actually declined slightly in the period from 1970 to 1976, while "the percentage decline in the amount of grain per combine day was at least equal to the percentage increase in the number of combines 1970-76. Consequently, there was no reduction in the amount of time required to complete harvesting" despite the fact that the Soviet Union produces many more tractors yearly than the United States.

Announcing a special food plan to increase meat and other items in cities, Brezhnev in February complained that fruit and vegetable consumption had been hurt by transport, storage and processing losses.

But as V. Mityushkin, director of the Russian Republic's union of consumers cooperatives' administration for the procurement, processing and marketing of potatoes, fruit, vegetables and melons, reported last July in Ekonomicheskaya Gazeta (Economic Gazette), "Often a farm will not grow vegetables the population needs but types that are less labor-intensive and more profitable." From 1976 to 1979, he said his cooperative was short a total of 4.4 million tons of potatoes, onions, tomatoes and cucumbers because of these practices.

"Many farms have stopped growing summer squash, eggplants, sweet pepper, horseradish and other vegetables," he said, adding that his group's produce houses can handle 400,000 tons of produce a year in containers, but receive only 70,000 tons that way.

Most of the 3.5 million tons shipped in the Russian Republic last year went by rail, he added, but the railroads cannot be held responsible for safeguarding cargoes, keeping to timetables or providing enough cars despite commitments. "All this means losses and reduced quality," he said.

Compounding the decline of diversity in the fields is a similar narrowing of choice by canneries. Muscovites long have complained that even here, the nation's best supplied city, variety on the shelves is lacking, a suspicion Izvestia looked into. The paper found that "in coordinating assortments, canneries often give preference to items easiest to produce, rather than those the market demands. Certain items in wide demand have disappeared entirely. . . . Canned corn, kidney beans, olives, capers. . . ."

In an unusually bleak appraisal of deepening farm problems, senior economist I. N. Buzdalov declared in September 1979, "As things stand now, profitability, efficiency and quality play virtually no role in . . . the work of collective and state farms." Writing in the monthly Voprosy Ekonomiki (Economic Questions), he charted production cost increases from 1970 to 1977 of about 45 percent for grain, 47 percent for beef, 60 percent for mutton, 70 percent for wool.

Soviet consumers are insulated from these price increases by the state, which maintains retail meat and milk prices at 1962 levels for political reasons. But the subsidy program adds about $48 billion a year to the cost of running Stalin's invention, according to estimates in Johnson's survey.

Buzdalov said that despite higher state subsidies, the result is declining profitability because costs outstrip the subsidies "and the lack of any noticeable improvement in output quality. Between 1970 and 1977, profitability of collective farms fell by 50 percent," and for state farms the decline was even greater. Its closed economy insulates the Soviet Union from the full effects of such financial interventions, allowing it to quietly write off what it wants without fear of monetary consequences that would rock a hard currency.

But in the world of ideology, a lack of results carries its own costs, eroding party credibility when it claims to ran the country effectively and to improve the lives of the Soviet masses.