Poland's food production and distribution system has deteriorated rapidly since martial law was imposed in December 1981, but it can be shored up by the Warsaw government with relative ease, according to a team of U.S. agricultural experts.

Their report, prepared after an unusual on-scene study of the Polish farm situation last fall, was released yesterday by the Rockefeller Foundation and the Rockefeller Brothers Fund, which underwrote the project.

The researchers, led by Dr. Norman E. Borlaug, a Nobel laureate for his work in wheat-breeding techniques, visited farms and talked with dozens of agriculture officials in a study sanctioned by the Polish government. The report was written by J.B. Penn, an agricultural economist, from McLean.

Borlaug's team found across-the-board food production declines, due in large part to government disorganization; an inability to import vital grains for livestock feeding, chemicals and spare parts; bureaucratic confusion and fragmentation of research and educational efforts.

Unless quick changes are made, the U.S. observers said, further erosion in the quantity and quality of food--a decline that began about a decade ago--is inevitable and will contribute to further political dissatisfaction and unrest.

But the team said the Polish government, although severely limited in importing feed and services because of its lack of hard currency, can ease the situation by a series of inexpensive steps to bolster domestic production and distribution.

The team's chief recommendation was that Poland adopt a "forced-pace" farm production campaign, a technique used in other food-deficient countries, to tailor the nation's most critical food needs to the farming regions best suited to respond.

But to achieve this, the report said, the Polish government will have to abandon its fragmented academic and research approaches to farming and create teams of highly trained professionals to deal with all aspects of agriculture in a given region.

"The district approach is the key to an immediate acceleration of production," the report said. "Some initial technical assistance and financial help may be needed from the outside to get this under way. Outsiders may help, but basically it is something that the Polish people can and must do themselves."

The report suggested that the credit-short government in Warsaw could obtain some of its most urgently needed farm chemicals, equipment and parts, animal medical supplies and high-protein livestock feedstuffs through creative new trade or barter arrangements.

Borlaug and his colleagues traced Poland's current agricultural problems to 1974, when the government put a higher priority on aid to the less-efficient socialized farming sector. Private agriculture, which accounts for the bulk of Polish food production, immediately began to stagnate, the report said.

"Poland is not now a hungry country," the team reported, but it projected more shortages and declining farm production for 1983, due in part to shortages of spare parts for tractors and harvesters and an inability to import fertilizers and plant-protection chemicals.

As an example of the parts problem, the report said that "as many as 250,000 tractors and a large proportion of the harvesters were out of operation" because of lack of spare parts, batteries, tires and repairs last year.

For the future, the report called Poland's productive potential "impressive," but it said that private farmers must be given greater incentives to produce and that research and education systems must be restructured.