Foreigners owning U.S. farmland will be required to register with the Secretary of Agriculture under a law passed by the Senate last week and sent to the President.

As soon as the mechanism is set up, foreign citizens and corporations purchasing agricultural and timber land will have 90 days to supply their names, addresses and countries of origin, type of business as well as the amount of land bought, price paid and intended use of the land. Foreigners already owning or transfering such lands will have 180 days in which to file this information.

Failure to do so could result in penalties of up to 25 percent of the fair market value of the interest in the land. (The law does not apply to permanent resident aliens or to persons holding only a security interest).

The legislation originated from a widespread concern that foreigners are purchasing America's croplands in ever-increasing numbers. A major European holding company estimated that Europeans alone spent $800 million on farmland last year.

Chauvinism aside, farmers expressed fear that foreigners willing to pay top dollar would inflate the price of land with consequent results on commodity prices and the entry of new farmers into agriculture.

The General Accounting Office found that an average 3/10ths of 1 percent of cropland in 25 counties in five states was owned by nonresident aliens, but added that this could be only the tip of the iceberg. Twenty-five states have placed constraints on foreign ownership of agricultural lands, ranging all the way from disclosure to prohibition in some cases.