The National Governors Association expressed strong doubts today about the effectiveness of economic embargoes but stopped short of calling for an end to President Carter's ban on grain shipments to the Soviet Union.

Discussion of the issue in the closing session of the governors' annual three-day meeting produced spirited partisan debate. Republicans attempted to move some of their clearly uncomfortable Democratic counterparts toward a flat-out condemnation of the grain embargo, but they were unsuccessful.

Among both Democratic and Republican farm state governors, there appeared to be a strong feeling that the embargo -- imposed by Carter in January after the Russian invasion of Afghanistan -- had reduced profits of American farmers without seriously affecting the Soviet Union.

But Democrats, concerned about criticizing Carter the week before the nominating convention, declined to openly disapprove of the embargo. Agriculture Secretary Bob Bergland had told governors that the embargo was modest in intent, aimed more at delivering a "stinging rebuke" to the Soviets than at "starving the Russian people."

The policy position the governors settled on called for the use of economic embargoes only as a last resort and only if they clearly produce the intended effect and do not require one region of the United States to shoulder the entire cost.

Democratic Gov. John Carlin of grain-producing Kansas said this demonstrated well the governors' concerns about the grain embargo and was indirect, not partisan criticism.

Republican Gov. Charles Thone of Nebraska called the embargo "a fiasco" and the statement "a namby-pamby assortment of verbiage."

While pre-Democratic convention politics has been the primary emphasis of this year's governors meeting, a secondary theme has been concern of both Republicans and Democrats about what they see as increasing centralization of power in the federal government.

The governors approved today a policy position asserting their primacy in such areas as education, local transportation, and police and fire protection. And, they signaled that they intend to act vigorously next year to regain state powers.

A speech by the outgoing association chairman, Otis R. Bowen (R-Ind.), called for new tax strategies, which he called "revenue keeping," aimed at reducing federal taxes so that states could raise more revenues. (Bowen was unable to attend the conference because his wife is ill; his speech was read by John Dalton (R-Va.), who presided over this year's meeting.)

The new chairman, George Busbee (D-Ga.), made it clear that a new definition of federalism would be a very important part of his agenda.

"With every legislative session I see our latitude and flexibility with state resources diminish and federal influence grow. If something isn't done -- in a rational and orderly way -- to reverse this trend, then I fear that my successors and yours ultimately will be relegated to mere clerks of the federal establishment," Busbee said. "I am tired of the governors being treated as a barrier which must be hurdled in order to implement the federal will. I am personally tired of spitting into the federal wind."