They call it their Field of Dreams, but now they face a reality check.

The Southwest Youth Association spent $500,000 last summer to buy 120 acres of vacant land in Centreville, the only Fairfax County youth sports club to respond to the region's intense shortage of playing space by pledging to build its own $20 million complex of outdoor fields and indoor courts.

But the organization, with its 16,000 young athletes, has run headfirst into the technical challenges of land development. County planners have recommended against approving the project because of concerns that the site is too environmentally sensitive, has inadequate road access and would produce bright lights that could bother nearby homeowners. And neighbors are organizing to keep the project from interfering with the area's rural atmosphere.

A scheduled Monday vote on the project by the Board of Supervisors has been put off until at least late September to give the sports group more time to persuade county staff members to change their minds. Meanwhile, the athletic group's president, George Chernesky, said he is angry with the system.

"I am short 44 rectangular fields and 14 diamond fields," he said. "Fairfax County hasn't built us a field since 1988. If I don't build these, is Fairfax County going to step up and build them for our kids? I have no other alternative."

County officials and neighbors say Chernesky should have thought of that before buying the land. Unlike many developers, the youth group did not purchase the land with an option to back out if county approvals fall through.

George Sanchez, who coaches soccer with the group and recently moved into a new subdivision of large homes on five-acre lots near the proposed site, said he supports the idea of a field complex--as long as it goes somewhere else.

An airline pilot with four children, Sanchez said he is concerned that the project would mean a dangerous increase of traffic on the two-lane Bull Run Post Office Road, as well as flood the community with light from 60-foot towers and noise from loudspeakers.

"It's in an area that is totally rural," Sanchez said. "You hear nothing except the cicadas and the birds."

County planners who are evaluating the plan to see if it should receive a special permit to operate in a residential area agree with many of the neighbors' concerns. They also say the land is in the environmentally sensitive Occoquan Watershed. It is also 300 feet from Manassas National Battlefield Park, whose superintendent, Robert K. Sutton, opposes the field project because of the lights and loudspeakers, and because it might generate traffic through the park.

Greg Russ, senior county planner for the project, says the scope--14 lighted fields and a 30,000-square-foot recreation center with two basketball courts, two volleyball courts and other rooms--is too large for its location. "With the field being located so close to the property lines, you have the noise and the lights," he said.

Fairfax Supervisor Michael R. Frey (R-Sully), who represents the area, disagrees. He's been trying to mediate an agreement among the youth club, the staff and neighbors. The desperate need for fields in the county should put pressure on the parties to find a solution, he said.

"We've never had a youth club step up to the plate and propose to provide fields like this," Frey said. "I would find it unconscionable to not approve."

Frey said criticism of the group's purchase of the land without an option to back out is unfair. Frey said he and county planners met with the group a year ago, before the land was purchased, and agreed to "make it work."

"I don't think the issue is whether the county is going to approve it or not," Frey said. "The issue is what is the county going to approve."

Chernesky said he hopes Frey is right. The group has pledged $100,000 to make improvements to the road and has promised to use lights on no more than seven fields at any one time. And most days, no fields would be used after about 9 p.m., he said.

Without county approval, Chernesky said he is unable to begin the process of finding corporate sponsors to fund the project, which he once called a "mini MCI Center."

"Everybody keeps trying to view us as a normal developer," he said. "That's great, except my mission is to help kids."