It's been advertised as an economic magnet, one that Anne Arundel County competed with five other Maryland counties to secure. But the prospect of a state-run equestrian center replacing one of the state's largest organic farms is provoking passionate public opposition.

Even though the park is far from becoming reality -- the Maryland Stadium Authority is studying its economic feasibility and says it would open in 2009 at the earliest -- supporters and opponents are girding for a battle over the future of farmland that once supplied fresh milk to the midshipmen of the U.S. Naval Academy.

The project's backers -- including local government officials, horse industry representatives and equestrians from Maryland and Virginia -- say the park would be a boon to the community of Gambrills: The land would remain open space while bringing tourists to spend money in hotels and restaurants.

Supporters say that, as a recreational facility with amphitheater, hundreds of stalls and show rings for jumping and dressage competitions, the center would bolster the state's struggling $1.6 billion horse industry without the moral questions raised by horse racing and the gambling that goes with it.

Opponents fear it would simply bring more noise and traffic, and spell the end of one of the state's largest organic farms. Many of those opposed are residents of Gambrills, the once-quiet, rural town in northern Anne Arundel where the center would be built.

The quiet days have passed Gambrills: Maryland Route 3 is now a major north-south thoroughfare, nearby Fort Meade is expanding and developers have made inroads into the farmland. Opponents say that the last thing the area needs is a horse park they don't believe will even turn a profit.

Supporters and opponents have launched campaigns -- and dueling Web sites -- to sway public opinion and, more important, the two institutions that must approve the project: the stadium authority and the Navy, which owns the property.

Both sides met Tuesday night at a forum organized by We Care, the leading opposition group. We Care ran out of metal folding chairs in the spartan, white-walled room as a crowd of 150 to 200 people streamed in. Many wore green -- a signal that they supported the park. The rest were generally opposed. It was difficult to tell which side had a majority.

"I hope this is civil," said Jamie Benoit, a Democratic candidate for the Anne Arundel County Council. "But it's going to get ugly at some point."

Opponents argued, among other things, that federal law demands that the property remain agricultural.

The 875-acre tract is home to the celebrity goats Bill XXXI and Bill XXXII, the Navy's sports mascots, and was once an active dairy. The Navy now leases the property to Maryland Sunrise Farm LLC, which keeps a few cows but concentrates on growing a variety of organic produce.

According to the farm's owners, Ed and Marian Fry, this included the equivalent of 158,740 16-ounce packages of peas and 658,000 3.5-ounce servings of edible soybeans in their 2005 harvest. Opponents fear that the goats would stay but that the farm would have to shrink or disappear.

"We don't oppose the idea of a horse park," Marian Fry said -- a sentiment echoed by several other park opponents. "What we feel is so significant about this piece of land is the size and scope of a piece of producing agriculture in a very suburban area. As producing agriculture goes out of production and into development, it doesn't come back."

Those in favor of the horse park make the point that horses could be just as agricultural as cows and say the park would provide a place to exercise their own horses.

"There's no place here for us to do it, so we go to Pennsylvania," said Jacquie Cowan, a Crownsville resident who runs the Chesapeake Plantation Walking Horse Club.

Joe Rubino, a special assistant to the Naval Academy superintendent, was circumspect. "It's probably a legal determination," he said of whether a horse park is actually an agricultural use. He said that the Navy had not yet made up its mind what to do with the property and would invite interested parties to submit ideas.

"We want to be a good neighbor," Rubino said. "We want to work with the community and the Maryland delegation."

Peter Bocharov feeds heifers at Maryland Sunrise Farm, now chiefly an organic vegetable farm. Those who support building an equestrian center in Anne Arundel stress that the land would remain agricultural.