Protesting farmers, chugging into Washington on about 600 tractors, corn pickers, fertilizer spreaders and pickup trucks, failed yesterday to produce the gigantic rally they had predicted but still accomplished their prime goal - publicity for the farmer's plight.

Rallying on the Washington Monument grounds, the protesters heard speaker after speaker praise farmers and their way of life and demand higher prices for the products they sell. "We have the most power in the nation - we have food," one said.

American Agriculture Movement organizers had talked of 20,000 farmers on 10,000 farm vehicles coming in to lend strength to their threat of a strike next Wednesday.

But with temperatures ranging from about 10 degrees at their rendezvous points in Chantilly, Va., and Davidsonville, Md., to a high of 30 in Washington, and the wind chill factor hitting zero, the turnout was relatively small.

Similar rallies were under way in about 30 state capitals across the country as the American Agriculture Movement, feeding on the dissatisfaction of farmers hit by low prices and drought as well in many areas, pressed its demand for higher prices.

In Atlanta, 5,000 to 6,000 tractors surrounded the Capitol and Gov. George Busbee proclaimed "Farmer Appreciation Day." Twenty-five tractors circled the state Capitol in Richmond while another 300 waited at the state fairground. In Oklahoma City, farmers hanged Agriculture Secretary Bob Bergland in effigy.

About 400 vehicles came in from Maryland and about 200 from Virginia, carefully shepherded along U.S. Rte. 50 by state and local police in an effort to reduce interference with normal traffic was minimal. The 300 or so tractors, while a fraction of what the farmers' group had sought, still created a dramatic parade on city streets.

They hit the downtown area at about 10:30 a.m. and rumbled along Constitution and Independence Avenues for nearly 90 minutes before the last tractor was parked. Fifty of them pulled into line on Pennsylvania Avenue just below the Capitol where they are to remain until Wednesday.

In Washington, the farmers climbed stiffly down from tractors flying U.S., Maryland, Virginia and Confederate flags after drives of two or three hours in the chilling weather and slowly gathered at the Sylvan Theater, near the Washington Monument.

As the crowd grew to a U.S. Park Police estimate of 600, television and still cameras also massed for the thorougly photogenic scene.

"Jimmy is a good ole boy," a self-described Georgia cracker named Oliver Odom was telling the crowd in reference to President Carter. "But there's no place in Washington for boys. We need men. The American farmer - them's men," Odom said as the farmers cheered.

"Surplus?" Odom said of the record crops that pushed prices low. "I don't believe they's telling us the truth. I think they's lying to us myself."

"We aren't begging. We aren't asking for a handout. We want what we work for and we're going to get it," the 62-year-old Odom said.

"We're the humblest, most determined people on the face of the earth," he said to the cheering crowd. "Let's serve our God and take our place in society where we ought to be."

Speakers from other states followed in no particular order with anyone in the crowd who wanted to talk being invited to the microphone

"The tractor is the symbol of the power in our hands," one said.

"It's a disgrace for the American government to force one of the most stable segments of American society to come here and protests," said another.

"We might want to get some of these politicians a little skinny," said one speaker expressing the anti-government feeling of the crowd. ". . . for years and years we've been paying for the city slicker. The city slicker depends on the farmer."

". . . the family farmer is the salt of the earth."

Speaker after speaker reflected the sense of isolation, the feeling of being neglected by the government, ignored by the consumer and misunderstood by everybody, of being the loser in the land they feel they built.

Sen. John Melcher (D-Mont.) said, "I've waited nine years for the farmers and the ranchers to come to Washington. We need you here and we need you organized."

The crowd cheered, one organizer said. "That's the next President of the country," and several farmers shouted, "What's his name?"

Sen. Robert Dole (R-Kan.) then-President Ford's running mate a year ago, was greeted warmly when he said, "I support your goals." Cameras massed around him, but as he tried to explain the complications of farm policy the questions became increasingly antagonistic.

"I think President Carter is sympathetic. I think Secretary Bergland is sympathetic and I think Congress is sympathetic," Dole said, and a voice rank out, "We don't want sympathy. We want money."

Just then, a young farmer carrying a shoat approached the platform and the photographers and cameramen wheeled away from Dole to focus on the little pig.

As Dole successfully parried the hostility with support for the farmers' goals and jests one farmer yelled, "If we have to, we may come back to Washington and we may not be so orderly." Another shouted, pointing toward the White House, "Next time we come back we're going to hold a plowing contest over there."

Edward Fuchs, a Preston, Md., farmer who applied for the rally permit, told the farmers that a group of 16 would meet with Stuart Eizenstat, Carter's domestic policy adviser at the White House and farmers hooted, "Carter is hiding."

Shortly after 2 p.m. the rally broke up and the farmers filed back to their tractors and other vehicles for the long, cold ride home. Park Police described the departure as "somewhat ragged" but said that it had caused no major traffic problems.

Eizenstat later told the farmers that "the government and this administration are sensitive to your protest. The President, as a farmer, is especially sensitive to your problems."

Wayne Eakin, a member of the American Agriculture Movement delegation that met with Eizenstat, said, "We're going to tell them that we're not going to grow any food until we have 100 per cent parity. We're not going to plant anything, farm anything or harvest anything until we get that parity, and we mean it, damn it."

"Parity" is a measure of the purchasing power of a unit of production - a bushel of wheat, for example - now as compared to the period 1910-1914. Agriculture Department officials point out that it does not take into account the major increases in productivity since that time.

Present farm policy calls for junking the parity concept and using instead support levels based on the national average for the cost of producting a crop under that program a farmer would be guaranteed an amount at least equal to that average production cost figure.

Other steps taken to raise farm prices - which all parties agree were too low for farmers to make a profit this year - include 10 or 20 per cent reductions in planted acreage, depending on the crop, next year; setting up national grain reserves, and increasing exports of food stuffs.

Agriculture Department officials have said that they doubt that the proposed strike can be effective, especially as prices rise and that the protesters have no chance at reaching the "100 per cent parity" goal.

American Agriculture Movement spokesmen say they will make the strike effective by refusing to buy equipment and goods for use on their farms and by refusing to plant or sell their produce until their demands are met.

C.L. Ritchie, a Fauquier County farmer active in organizing the Virginia protesters, said yesterday that despite the small turnout he still believed the strike could be effective.

"We had hoped for a whole lot more but it's pretty good for a cold day," Ritchie said.