Virginia's political leaders gave the state's agricultural leaders a pep talk yesterday on the need to promote alternative energy sources.

About 125 people turned out for the sixth annual Virginia Agriculture Summit in Richmond, which focused on rural America's role in developing and using renewable energy sources.

Gov. Timothy M. Kaine said the state needs to take the lead in developing energy sources including biofuels, wind and solar that could be kick-started through the use of tax credits.

"We want to both create an economic opportunity for farmers and improve our national security" by lessening the country's dependence on foreign oil, Kaine said.

U.S. Sen. Mark R. Warner said America is "by no means in the lead" in developing alternative energy sources. But he said Virginia could take the lead by developing its nuclear-power industry, using its research into the efficient use of coal and exploiting "the enormous opportunity in the wind area, not just on shore, but offshore, too.

"We don't know what technologies are going to be the winner," Warner said. "So we have to push them all and make this truly a national priority."

Hunter Richardson, a farmer from King and Queen County, said he paid the most ever last year for fuel and fertilizer to operate his farm. A continuation of high-cost fuel and fertilizer would be economically devastating, he said.

"It takes energy to produce a crop in terms of fuel and fertilizer,'' said Richardson, who foresaw himself or the next generation using alternative fuels. "Alternative energy is good for the environment, too."

Kaine said making sure the family farm is around in the future will be key. Statistics released by the U.S. Department of Agriculture show the number of farms in Virginia in 2007 at 47,383, down 223 farms from 2002. The average age of a farmer is also going up, to 58.2 years in 2007 from 56.7 in 2002.

Kaine wants to preserve farms in Virginia by keeping land open. He said the state is on track to protect 400,000 acres of land during his tenure as governor. He's preserving the land through a combination of partnerships with private groups, outright acquisition and conservation easements.

"What I'm most worried about is the selling of farmland for development," Kaine said. "If we lose the family farms, we lose something elemental as to who we are as a people."