One of America’s fastest-growing counties, Loudoun County in Virginia, voted last night to adopt rough development controls and try to keep two-thirds of the county as farmland. The vote by the county board of supervisors removed 83,000 potential homes from county plans and ended support for studying a proposed new highway to connect Dulles International Airport with I-95. Property rights advocates were up in arms over the vote. Meanwhile, neighboring Fairfax County said yesterday it would stop purchasing SUVs and pare back its current fleet of the vehicles to help reduce pollution levels.