The new Soviet leadership is signaling that it is preparing significant economic reforms to revive the country's ailing agriculture and improve industrial efficiency by a loosening of central controls and a greater reliance on financial rewards and penalties.

The package of publicly discussed reforms, referred to here as "improvements" in the system, was expected to be discussed at the next plenum of the Communist Party Central Committee. There are reports that the plenum may be held during the coming weeks.

It is believed in diplomatic circles here that the leadership headed by Yuri Andropov will have to adopt an economic program of its own if it is to be more than a transitional one.

So far, the new leadership's emphasis has been on greater labor and social discipline, an approach that produced highly encouraging economic statistics for January.

However, the latest economic indicators for the first two months of the year have made clear that the insistence on discipline in itself cannot sustain growth of industrial output and labor productivity over a longer period. Both have declined in February as compared with January, although they remain well above the dismal averages for the past year.

A flurry of articles in the Soviet press during the past days suggests the sort of changes being prepared. It remains to be seen whether Andropov can muster sufficient political strength to effect them. Previous attempts to revamp the Soviet economy have been frustrated by the vast party bureaucracy.

Agriculture, the Soviet Union's most painful problem, has received particular attention.

The main issue discussed at the ruling Politburo's meeting last week involved the concept of "collective contracts" between farm workers and managers of state and collective farms.

While the leadership does not seem to be prepared to tinker with the central planning itself, it seems ready to provide regions and individual state farms with new room for decision making.

According to press accounts and explanations offered by Soviet specialists, state and collective farms still would have to meet their planned obligations. However, up to 40 percent of excess output would be retained by state and collective farms to be used at their discretion.

Farm workers, on the other hand, would be making "contracts" with their managers that would eliminate, in effect, the system of fixed salaries and permit farmers to increase their income sharply by producing more.

According to some economic analysts, this system would permit farm workers to increase their monthly income to a maximum of 350 rubles, or twice the average monthly wage. Moreover, the basic accounting system apparently is going to be changed from one stressing output to one based on the income realized by state and collective farms.

What this means in practice--if the Central Committee adopts it--is that regions would be allowed to make decisions on what to grow and managers would be given the right to run their farms without interference from Moscow, provided they meet their production quotas.

For an individual farmer, this would mean he would get money for producing more, not medals and honorary certificates as is the practice now.

According to a Politburo statement, "This would allow the farms to harmonize workers' personal interest with the task of increasing production and strengthen the business and financial accountability of state and collective farms."

The emphasis on financial rewards follows agricultural failures that have dramatically increased Moscow's need to import food from abroad.

Agriculture, which has swallowed 27 percent of all Soviet investments during the past 10 years, has become increasingly unable to provide adequate food for the population. Food imports during the same 10 years have increased tenfold, forcing Moscow to pay more than $7 billion annually for purchases of foreign grain, meat and other items.

What sort of changes are being contemplated for Moscow's industries is not quite clear, although the system of financial rewards and penalties is now being selectively introduced.

For instance, the newspaper Socialitichesaya Industria has publicized instances of financial penalties imposed on workers who show up for work drunk. The reported cases involve fines of up to 280 rubles for each day's work lost to drunkenness.

Moreover, the leadership has increasingly used the price mechanism either to discourage waste or to soak up excess funds. According to official figures, an equivalent of more than $260 billion is in savings accounts in the Soviet Union, or an average of $1,000 in savings per person, and at least as much is believed to be held privately.

The government has recently increased prices on natural gas, drinking water and other basic commodities and is reported to be doubling or tripling the price of electricity. According to the newspaper Sovietskaya Rossiya, the price of water is to be quintupled in most of the country. The price of natural gas already has gone up by more than 150 percent.

Last month, the price of all construction materials, nonferrous metals, appliances and cotton products was increased.

The tone and substance of various commentaries on the economy suggest that the debate involves proposals for basic changes.

A senior Soviet economist, Oleg Bogomolov, wrote in the Communist Party newspaper Pravda last week that the Soviet Union should learn from successful economic reforms in other socialist countries.

Bogomolov, known to have served once as adviser to Andropov, singled out structural changes in Hungary that allowed that country to improve its agricultural production dramatically through decentralization and financial incentives. He also mentioned reforms in East Germany and Bulgaria as offering "valuable lessons" for Soviet economic planners.

Hungary has introduced the most liberal reforms in the Soviet Bloc, allowing farmers considerable autonomy in deciding what to grow and how much to charge for their production. The Hungarians also have used the pricing mechanism as one of the basic means of control.

Andropov, who once was Moscow's ambassador to Hungary, is generally credited here as having supported the Hungarian changes in high Kremlin councils.

Bogomolov specifically endorsed the Hungarian use of profit and loss principles as well as the greater freedom economic managers enjoy there in deciding how to run their enterprises.

He also said that the expansion of privately held plots in Hungary and Bulgaria was a factor in increasing their agricultural production and said this should be studied by Soviet experts and possibly applied here.

He dismissed claims by party hard-liners that such changes constituted a return to capitalist economic methods, saying only "bourgeois" propagandists could make such charges. But he conceded that not everything done in Eastern Europe may be applicable to Soviet conditions because of the size and complexity of the Soviet economy.

Another prominent Soviet industrial leader also wrote a long article in the daily Trud calling for radical changes in industries and a greater emphasis on quality of production.

Oleg Antonov, the country's foremost living aircraft designer, argued that the present system, which stresses quantity, rewards inefficiency.

He used the aircraft industry as an example, saying that factories receive bonuses and other rewards on the basis of the number of items produced. The system penalizes factories that try to increase the quality of production, he said.

What this means in practice, he said, is that managers are now most interested in the level of output rather than quality. He said new methods should be introduced to stimulate managers and workers to increase quality. The current system, he added, is causing substantial losses to the state.

To illustrate his argument, Antonov focused on the Soviet production of television sets. If the Soviet sets were able to work "for 10,000 hours like the Japanese ones," he said, "we would be able to cut back production by half and still satisfy demands of the population three times faster than we are able at the moment."