One of the latest such battles in suburban Palm Bach County has apparently been won by a builder. G.L. Homes of Fort Lauderdale has just outbid a government agency to buy a 440-acre farm west of this city for a new residential tract. The county had hoped to add the site to its 21,000-acre so-called Agricultural Reserve where little or no development is allowed.

In the last two months, the county has purchased 967 acres of such land for $35 million ($36,194 per acre). But builders are reported to be plunking down as much as $77,000 an acre. Local voters have approved spending money to buy up more open land and keep it that way, but the county fears that it will deplete its current $100-million war chest too quickly if it goes toe-to-toe with the private sector in bidding for the most desirable construction sites.

The only other hope the anti-growth people and their environmentalist allies have in slowing, if not stopping, the area's rapid expansion is planning and zoning board action. But on this front, more builders seem to be finding a way to get their plans approved.