WASHINGTON -- A troubled tobacco farmer who tied up traffic for three days in the nation's capital appeared in court Thursday, denying the accuracy of some of the charges against him and seeking to represent himself.

Investigators said Dwight Ware Watson, an Army veteran, told negotiators he planned to damage the National Mall and demanded Washington be evacuated within days.

Watson, 50, surrendered to police Wednesday without incident, 48 hours after he used his tractor to pull several other vehicles into a pond on the National Mall near the Washington Monument.

He had claimed to have placed explosives in his tractor and trailer and at locations in Washington and Richmond, Va. No explosives were found, but thousands of commuters and several nearby federal agencies were inconvenienced.

Watson told U.S. Magistrate Judge John M. Facciola he preferred to represent himself, prompting Facciola to order a mental evaluation. Watson was held for an overnight evaluation and ordered to return to court today.

Watson disputed the four-page criminal complaint charging him with making a false threat to kill, injure or intimidate or cause property damage with explosives.

"It's not accurate," said Watson, who hoped to publicize how government policies affect tobacco farmers. His family farm in the Whitakers, N.C. area has operated for 150 years, but its acreage decreased from 1,500 acres to a few dozen acres because of financial woes.

Bravitt C. Manley, Jr., an attorney hired by Watson's family to represent him, said Watson takes issue with prosecutors' claims he threatened to hurt people or destroy property.

Manley also said Watson wants to represent himself because "he wants to make sure lawyers don't distort his message."