Law enforcement authorities said yesterday that the peaceful solution to the two-day siege on the Mall showed they had taken the best course in dealing with tobacco farmer Dwight W. Watson and his threat that he had a tractor loaded with explosives.

FBI and U.S. Park Police officials said they protected the public by dealing patiently with Watson, who falsely claimed to have fertilizer-based explosives -- something not out of the realm of possibility for a seasoned farmer. And they praised the public for putting up with closed streets, massive traffic jams and the closing of some government offices.

"The results speak for themselves," said Van Harp, head of the FBI's Washington field office.

Park Police Chief Teresa C. Chambers said after Watson's surrender: "I would rather stand here and answer questions about how we tied up traffic than answer questions about a questionable shooting."

Authorities said the breakthrough came just before dawn yesterday when the crisis seemed headed for a violent confrontation. After an exhausting night in which police shined bright lights and blasted air horns to keep him on edge, Watson began driving his tractor out of a pond at the Mall, and, for the first time in the ordeal, authorities responded with force by firing a burst of tear-gas pellets as a SWAT team stood nearby.

The 50-year-old Watson backed up and shouted, "Don't kill me, don't kill me, I'll surrender" -- setting the stage for ending a standoff that disrupted much of Washington.

The only issue remaining was how Watson would give up. It took almost seven more hours of conversations, but Watson emerged from the John Deere tractor at 11:35 a.m., raised his hands and slowly walked backward to police.

After taking authorities to the brink, Watson "went from a man who didn't seem interested in coming off the tractor, to a man who said, 'I don't want anyone to be hurt,' " Chambers said.

Once Watson was in custody, authorities learned that he had kept scores of law enforcement officers at bay for 47 hours with lots of bluster and an empty threat. Investigators found a phony hand grenade in the tractor but no explosives.

Watson was taken away in handcuffs and charged with making threats to use an explosive device, a felony that carries up to 10 years in prison and a $250,000 fine. He is scheduled to appear today in U.S. District Court.

Watson's protest of the government's tobacco policies closed major roads, some government offices, and disrupted four rush hours. He commanded the attention of scores of law enforcement officers. The streets reopened about 1:30 p.m., after investigators waded into the pond to inspect the tractor.

Watson is an Army veteran from Whitakers, N.C., who the FBI believes might be $1 million or more in debt. In an interview with The Washington Post on Tuesday, Watson said that he wanted to bring attention to the plight of farmers as well as concerns about soldiers who were exposed to chemicals in the 1991 Persian Gulf War.

He got a permit Friday to demonstrate on the grounds of the Washington Monument this week, for the third time in three years. He had told the National Park Service that the tractor would be part of a demonstration to support U.S. troops and provide information about "tobacco seed and farming issues."

Instead, he showed up shortly after noon Monday and drove the tractor and a jeep into the pond a few blocks west of the monument. Officers saw what appeared to be a grenade in the cab, and some believed he might have a gun.

The first 36 hours of the standoff saw little visible action: Watson sat in the middle of the pond, equipped with a supply of food and water. He promised in the Post telephone interview to get his message out or die trying. On Monday night, authorities at times left the Mall dark, and Watson apparently slept.

In conversations with negotiators, Watson had made reference to standoffs with the FBI at Waco, Texas, and Ruby Ridge, Idaho, that ended in violence. The incidents were also on the minds of authorities: One high-ranking FBI official said that because of the those incidents, the FBI attempted to talk situations to a close while containing threats.

Some critics of the tactics had wondered about the implications of the incident: If one unarmed farmer on a tractor could shut down Washington for so long, what could a real terrorist do? But authorities said they would have moved more aggressively if Watson had acted in a dangerous way.

As part of their strategy to bring matters to a close, authorities began to increase pressure on Watson on Tuesday night. They shined floodlights around the pond, and a helicopter hovered noisily overhead. "We had made a decision . . . that there would be no sleep for Mr. Watson," Chambers said.

That night, Watson gave the first signs that he might end the standoff peacefully, Watson said. Then, about 4:45 a.m., the tractor began to move slowly, first in reverse and then forward, toward the shore. Chambers said that police had agreed ahead of time that they would not let him out of the pond.

Authorities fired plastic tear gas pellets at the tractor's cab, making at least three loud booms. The floodlights were shut off so that only the orange lights on the tractor could be seen. That was when Watson promised to surrender.

Negotiations finally picked up momentum. Among other things, police negotiators appealed to Watson's patriotism, reminding him how many law enforcement officers he had tied up, just as America was on a heightened alert for terrorism and on the brink of war with Iraq.

They also tried to work out a compromise on one of Watson's stated goals, that he wanted to "hold his position" in the pond for three days. Watson calculated that his 40-plus hours didn't amount to three days. But negotiators countered that he had been there for parts of Monday, Tuesday and Wednesday.

"He had accomplished everything that he wanted to do, as far as saying what was on his mind," Chambers said. "It was time to come off the tractor."

That left the details, which were of critical importance. One law enforcement source explained why: "When you have someone in a crisis situation and armed people are around them, you really have to do a 'Here's what you want to do. Go to Point A. Drive to this spot. Turn off your lights. Step to the left. In 10 minutes, four guys from SWAT will come out.' "

And so, at 11:35 a.m., Watson once again started the tractor -- for the last time. He drove slowly to the edge of the pond, at a spot on the shore that had been marked with orange plastic cones. He got out, put his hands in the air and walked to the SWAT officers.

Staff writers Dan Eggen, David Nakamura, Arthur Santana, Neely Tucker and Clarence Williams and researcher Bobbye Pratt contributed to this report.

Authorities keep a watchful eye on Dwight W. Watson's tractor as the standoff winds down to a conclusion. The 47-hour drama ended with Watson's peaceful surrender.A D.C. police sniper team keeps Watson in its sights. Authorities say the peaceful end to the 47-hour standoff validated their waiting out Watson.