The list of political leaders opposing the federal government's plan to dispose of part of the Beltsville Agriculture Research Center now reads like a Who's Who in Maryland and, especially, Prince George's County, politics. The opponents include:

* Parris Glendening, the county executive, and County Council Chairman Frank Casula, who in a joint statement called the land "priceless and irreplaceable."

* Greenbelt Mayor Gil Weidenfeld, who said it is not in the public interest to waste money arranging the sale of research center land.

* State Sens. Leo Green, Tom Yeager and Arthur Dorman, who have pressed a resolution before the Maryland State Senate calling on the federal government to retain control of the property.

* Sen. Paul S. Sarbanes, who has said that land being used for scientific research should not be sold as a stopgap effort to raise money and offset the federal deficit.

In addition, legislation has been introduced in the House (by Rep. Steny H. Hoyer, D-Md.) and in the Senate (by Sen. Charles McC. Mathias Jr., R-Md.) to block the sale of specific parcels at the research center that are on the block.

But despite the political pressures, federal real estate officials at the General Services Administration--which is responsible for selling unneeded government properties--say they haven't gotten the word to hold up the sale from any of the five Congressmen who count: the chairmen of the House and Senate committees that have jurisdiction over federal land sales. Hoyer, Mathias and Sarbanes have all asked for congressional hearings this spring.

"It is not on hold," said GSA spokesman Bob Fiser. "There is no indication that we have been asked to hold it up yet."

John Rixey, an aide on Mathias' subcommittee on governmental efficiency, said that "all we've done is ask agencies for comments on the legislation."

Rixey, however, said that White House Property Review Board executive director Joshua A. Muss "has lobbied us heavily" to withdraw the legislation. The review board is charged with pressing the administration's land sales program and resolving disputes between agencies concerning sales proposals.

"They're upset at the Review Board that we would question the wisdom of the Agriculture Department, which decided parts of the research center were unneeded," Rixey said.

Earl E. Jones, GSA's director of real property, is the man who has his finger on the "stop" button and one who has maintained steadfastly that if Congress wants hearings, he'll put the disposals on hold out of courtesy.

"They GSA must be a bunch of ostriches down there," charged State Sen. Dorman. "If any state agency operated that way in Maryland, those people would no longer be in state government. It would be incumbent on GSA to pay close attention to what is going on on an issue this controversial."

But, contends Jones, "We can't respond to anyone who cries out about a sale, unless there's some indication that there is going to be a hearing. There are just too many bills introduced that don't get anywhere, and if we watched them all, we'd never get anything done."

Although GSA is under attack from the Maryland politicians, it is really only the middleman. The decision to unload the Beltsville properties was made by the Agriculture Department. GSA then asked other federal agencies if they needed properties (none did) and then asked state and local government and certain other nonprofit groups about their interest.

Currently, the Maryland-National Capital Park and Planning Commission (a state agency) has asked for the right to buy the 247-acre tract and GSA has said it would open negotiations unless Congress forces the deal to go on hold. Also interested: the city of Greenbelt and the Capitol Institute of Technology, which recently opened a new campus on land adjacent to the parcel.

Even if the three parcels now on the block are sold, another part of GSA is planning to conduct an intensive survey of the entire 6,000-acre facility in April to determine if it should be retained or, perhaps, moved to Iowa.