Two of three massive farm tractor caravans from around the nation reached the Washington suburbs last night, where protesting farmers learned of new traffic regulations that they angrily said were aimed at their movement.

"We didn't come here to obey all the laws, anyway," said Hershel Wilson, a 51-year-old Texas cotton farmer, when he heard that Capitol Police are threatening to bar farm vehicles and mobile homes from entering the Capitol grounds.

The farmers, part of the American Agriculture Movement, say they may clog Washington's streets with as many as 1,700 farm vehicles on Monday -- twice the number that participated in the movement's first Washington protest last year. Their demonstration last year frequently snarled D.C.'s traffic during rush hours. Yesterday, the new traffic rules were disclosed at the Capitol.

The rules won't become effective until Feb. 8, four days after the farmers reach the city, but they "will be strictly enforced" thereafter, said Lt. Mike Boyle of the Capitol force.

Last night an eight-mile long caravan of an estimated 200 tractors, many bedecked with flags, painted slogans and bunting, arrived at Bull Run Regional Park in western Fairfax County 23 miles west of Washington. Later the first contingent of more than 400 vehicles arrived at Pohick Regional Park in southern Fairfax, near Rte. I-95.

Another 600 vehicles are headed toward Washington in a third caravan that left Columbus, Ohio, yesterday. The protest leaders say they expect even more farmers will have joined their caravans by the time they make their move on Washington on Monday.

When they reach Washington, the farmers say they want nothing less than to disrupt the city's traffic.

"They've been inconveniencing us for years," said Clyde Tims, a 41-year-old corn and wheat farmer from Sunray, Tex., as he clenched a toothpick between his teeth. "We've been inconvenienced by not being able to pay our bills."

Earlier yesterday, the caravan that reached the Pohick park blocked Rte. 85 for 20 minutes near Petersburg as the farmers refused to pay tolls on the Richmond-Petersburg Turnpike. "Things got a little tense, so we were more or less forced to let them go through without paying," said Frank Blackwell, manager of the toll road.

The farmers are demanding that they receive "90 percent parity" for their farm products, a boost they say they need to keep pace with their rapidly rising costs.

Although Agriculture Department officials say that farm income is generally higher this year, the protesters are disagreeing. J.C. Barton, 51, of Checotah, Okla., said if his income doesn't rise sharply he will lose his 200-acre farm.

Sitting behind the wheel of a $25,000 van -- the temporary home for seven of the protesting farmers -- Barton said he will have to sell his farm equipment to meet the cost of next year's operations. He said the new van is for his retirement, that ill health and shrinking profits are forcing him off the farm.

The farmers said they will await the arrival, probably Monday, of the third caravan before announcing when they will move from the Fairfax parks into the District of Columbia.