Trend of the economy

''Under the US system,'' said Akio Morita, chairman of the Sony Corporation, ''management must look to short-term profits to save their own jobs.'' ''US managers,'' says Sidney Harman, head of Harman International, ''often have a very short-range relationship with their companies. They are concerned with managing profits - this year's performance.

''Japanese managers, on the other hand, are much freer to undertake long-range planning and to enter into relationships with their workers.''

''The apprentice system in America,'' said Rolf Leeven, head of the Robert Bosch Corporation in Charleston, S.C., ''fell into disuse, because of the shareholders' demand for quick profits.''

A Japanese, an American, a West German - all industrialists, interviewed at different times and different places, but expressing a common theme: The American industrial system is flawed and at a competitive disadvantage because of the emphasis placed on profits, expressed through the pressure to churn out dividends for shareholders.

''This is bad,'' said Mr. Morita in Washington, ''because in Sony's experience it takes 10 years for a new product really to take hold. Unless management can be patient, future development may not be soundly based.''

The three men made a second point, summed up by Mr. Leeven, quoting a Japanese industrialist whom he admires: ''You can't build a quality product on the basis of an adversary relationship between management and labor.''

US trade union leaders often criticize West German and Japanese workers for being, as it were, in the pockets of their employers.

West German and Japanese experts have a different point of view. From the ashes of World War II, they claim, prosperity could only return to their shattered nations through cooperation between management and labor.

At the heart of this relationship lies job security for managers as well as workers - a promise, says Morita, that no one will be laid off, that the relationship between a Japanese worker or manager and his firm is a lifetime affair. Many Americans might reject such a compact even if it were offered.

Leeven, who has trained German and American workers, finds ''an astonishing difference'' between them. Six months after the young German has begun learning his craft, he says, ''he is still following a hands-on approach,'' absorbed in learning and caring for his tools.

A young American worker at the same point, he says, ''already has formed an attitude of reaching for the ultimate,'' for what lies beyond the acquiring of tool-using skills. Training a worker is expensive. Bosch's three-year apprentice program at the Charleston plant costs the company $70,000 to $80,000 per student.

''Rival firms,'' says Leeven, ''with no such program, are on the doorstep, ready to hire the graduates, offering more money because they have not had to put up that front-money investment.

''You must,'' he concludes, ''provide job challenge and motivation - the best guarantee your workers will stay with you.''

Sony's US experience began in 1960, when the giant Japanese firm established the Sony Corporation of America, primarily to manufacture TV sets.

''I had much to learn,'' says Morita. ''I found that I could fire inefficient managers. That was good. But I also found that skillful people absorbed their Sony teachings - then left to join the competition.''

In Japan, continued Morita, ''with lifetime employment, we can spend more time and money to train workers and nascent leaders. This is a strength.''

All three industrialists value quality and strive to produce it in their plants in the US and overseas.

Datsun cars include a Bosch electronic fuel injection system built under a Nissan-Bosch joint venture. The Charleston plant of Bosch makes diesel fuel injection equipment for John Deere and International Harvester, among others. Japanese recording and sound equipment often contains, beneath a proud Japanese label, American-made high fidelity loudspeakers manufactured by JBL, a subsidiary of Mr. Harman's company.

American workers, the industrialists agree, can turn out as good work as anyone in the world - if properly trained and motivated. That may require a longer look into the future, including more careful training, than many US corporations with anxious eyes on stockholders feel they can afford.

It also will require, says Harman, ''a truly productive relationship between management and workers, if a sense of American entrepreneurship is to be renewed.'