Edwin Lynch made a fortune turning his Fairfax County farms into subdivisions, shopping centers and industrial parks.

Now he has found a 623-acre horse farm that he plans to preserve and retire on -- and a way to receive a sizable tax break in the process.

If Fairfax agrees to make Meadowood Farms the county's second agricultural district, Lynch's real estate taxes will drop from just under $20,000 a year to less than $3,000. In return, Lynch will promise not to subdivide the farm, as he did with land in Annandale and Burke.

Lynch's recent application, which the nine-member Board of Supervisors will consider later this year, is likely to fan the current debate in Fairfax over the costs of preserving farmland. Meadowood is a working farm, as the Virginia law on agricultural districts requires, but Lynch is considerably more than a working farmer -- he and two of his family firms own more than $26 million worth of property in Fairfax, according to county records.

The 68-year-old Fairfax native said this week he will not subdivide Meadowood even if the county rejects his application. Instead, he plans to build his retirement home there on a bluff overlooking the Potomac, which runs wide and calm as a mountain lake past the farm south of Mount Vernon.

Meadowood boards horses for Northern Virginia equestrians and grows hay to feed its boarders on 112 acres of farmland. The fields give way to 511 acres of mostly virgin forest that in turn opens onto Belmont Bay. Next door to a state park and national wildlife refuge on Mason Neck, a federal sanctuary for nesting the endangered bald eagle. Meadowood is the kind of open space that Fairfax supervisors say they want to preserve.

Last month the Fairfax board decided against adopting a land-use tax, which would have aimed at preserving farms by taxing them according to what they produce rather than what they would bring if sold for development. Although the supervisors said they want to save some of their county's dwindling farmland, several have expressed fears that developers and investors would take advantage of a land-use tax.

Virginia law, however, allows farmers in any county to apply for agricultural district status for farms or groups of farms of 400 acres or more. If the county establishes such a district, the affected farmers are entitled to land-use tax rates even if the tax has not been adopted countywide.

Farmers who later change their minds and develop their lands must pay back taxes for five previous years. But since they pay only 10 percent interest on the back taxes, developers in other Virginia counties have found it advantageous to apply for the tax break even if they have imminent plans to develop the farms.

Fairfax established its first agricultural district in January for two dairy farms and a nature preserve near Great Falls. One earlier application was withdrawn, and that farm in western Fairfax is now being developed as Franklin Farms subdivisions.

Lynch has turned two of his farms into subdivisions, one in Annandale after World War II and another in Burke in 1975. He traded his Burke farm, which gave way to the planned new town of Burke Centre, for what would become Meadowood. Now he intends to keep Meadowood, but he says he cannot make a profit while paying the current property tax rate.

Fairfax Supervisor Sandra L. Duckworth, whose Mount Vernon District includes Meadowood, said it may be worth the loss in tax revenue to encourage Lynch to preserve his farm. "It's very important in a county that's being built over with concrete, brick and asphalt to keep as much space open as possible," Duckworth said. "I hope other people will see it that way."

Supervisor Thomas M. Davis III, who represents the more urban Mason District, is less enthusiastic, although both Davis and Duckworth said they will not decide how to vote until they have studied Lynch's application. Davis' district includes the Pinecrest Golf Course, which the Lynch family recently sold to a developer after Davis tried unsuccessfully to persuade them to sell it to the county for a park.

"The county had kept the taxes very low for a very long time," Davis said. "When the bucks were there, they sold it. I think that's the most charitable way to put it -- and I think that's how it usually works."