Foreign interests bought an estimated 54 out of every 1,000 acres of U.S. farmland that changed hands last year, according to an Agriculture Department analysis land sales.

Foreign buyers accounted for about 2.25 percent of the 1978 voluntary sales and estate settlements, said the report released yesterday. It said nearly 25 million acres of farmland were sold during the year.

"At these rates of investment, it would take about 19 years for foreigners to acquire ownership of an additional 1 percent of U.S. farmland," the report said.

The report to the Senate Agriculture Committee did not reveal how much U.S. farmland is now owned by foreign interests. But a generally accepted government estimate is that foreign concerns own less than 1 percent of the slightly more than 1 billion acres of privately owned farm and ranch lands.

Congressional investigators have estimated that for every $1 invested in U.S. property by foreigners, American interests own almost $5 worth of property abroad.

Last year, Congress passed legislation requiring foreign owners of land that could be used for agriculture to report their holdings to the department. That law is just taking effect.

The heaviest concentrations of foreign purchases were found in the South and Southeast.

Oregon ranked first in the amount of farmland purchased by foreign interests with 129.700 acres, followed by Texas with 93,200 acres.