About 300 veterans of the American Agriculture Movement's past two winter assaults on Washington gathered in Warrenton last night for a rally in which it was emphasized that farmers this year want only the attention of the nation's capital, not its anger.

"As time goes on, we get a little smarter," Marvin Meeks, national chairman of AAM, told a high school auditorium half filled with farmers from the Midwest and the South.

Meeks said the hundreds of tractors and campers that snarled traffic in Washington last year and damaged the sod on the Mall "made some people extremely mad," and the farmers this year have hit upon a new plan to get attention.

They plan to set up five stills in downtown Washington this week to demonstrate that farmers can produce alcohol for use in automobiles and that AAM is on the side of consumers.

"Gasohol [a blend of gasoline and alcohol] has got public acceptance," Meeks said. . . . It benefits everybody." The stills will be located near the Lincoln Memorial, the Capitol, the Washington Monument, and the Department of Agriculture building and in Lafeyette Square across Pennsylvania Avenue from the White House.

Meeks, a farmer from Plainview, Tex., said last night that farmers asking for higher crop prices and offering a [gasohol] plan to reduce dependence on foreign oil are "no threat to the consumer."

District of Columbia police and U.S. Park police have been meeting with representatives of the farmers' association in recent weeks and the farmers have agreed to bring no more than 12 tractors into the city. No vehicles with sleeping accommodations will be allowed in the Mall area by mutual agreement of AAM leaders and the police.

Other than their professed desire not to make the kind of ruckus that infuriated many Washington commuters last year, the farmers in Warrenton last night looked and sounded as they did during their last two invasions of the capital.

Tommy Kersey, a cattle farmer from Georgia, regaled the farmers with the same inflammatory rhetoric he used last year on the Mall. He told them that "Jimmy Carter doesn't give a durn if you lose your farm." And he declared that unless something is done to increase farm prices by next November, farmers should "get their guns and come to Georgia. . . ."

The farmers plan what they call the "First Annual Grassroots Convention" to meet most days this week at the Commerce Department Auditorium. They have parade permits for midday on Thursday and Friday, and AAM organizers expect about 1,000 farmers to be in the city on any one day during the week-long effort.