Senate Republicans yesterday sought to turn up the heat on Democrats for holding a farm spending bill hostage for action on health care, as the Senate entered its second week of deadlock over proposed regulation of health maintenance organizations.

With four huge red and green tractors parked on the Senate lawn as props for cameras, Majority Leader Trent Lott (R-Miss.) and other GOP leaders accused Democrats of exploiting farmers in order to paralyze the Senate so they can run against a "do-nothing" Congress next year.

"This is a farce, a charade," Lott said. "They [Democrats] know it and the farmers of America know it."

Lott also said the Senate's confirmation of Lawrence H. Summers to succeed Robert E. Rubin as treasury secretary could be delayed until the dispute is resolved, although he still hopes, he said, to schedule a confirmation vote this week. Congress is scheduled to leave by Friday for a week-long Fourth of July recess. Rubin has said he would like to step down around July 4.

In response to the Republican broadside, Sen. Tom Harkin (D-Iowa) said it was Republicans who "shut the Senate down because they are determined to stifle discussion" of the health measure. Besides, he said, the farm spending bill is inadequate and in any case would not take effect until October.

When Republicans blocked the Democratic "Patients' Bill of Rights" proposal early last week, Democrats started offering its provisions piece by piece. They also blocked action on all pending legislation, including the $60.7 billion agriculture appropriations measure, until Republicans agreed to votes on as many as 20 individual proposals. Republicans have said they see this as an effort to embarrass them on specific initiatives, such as ensuring doctors' control over a patient's treatment.

Lott and Minority Leader Thomas A. Daschle (D-S.D.) have been attempting to negotiate terms for votes, so far without success. Barring significant concessions by one or both sides, the Senate is likely to remain stuck indefinitely, senators say.

Republicans have discussed the possibility of moving to reverse a 1995 parliamentary ruling that allowed legislation such as the health care measure to be added to appropriations bills on the Senate floor. That could preclude the health proposals from being added to any of the spending bills, but Democrats have maneuvered to block this as well.

In an attempt to focus attention on what they describe as Democrats' "obstructionist" tactics, Lott scheduled procedural votes yesterday to force votes on four pending appropriations bills, including agriculture, transportation, foreign operations and another covering the Commerce, State and Justice departments. The votes, largely along party lines, fell short of the 60 needed to force votes on the spending bills.

At the tractor rally, under a banner reading "Free Our Farm Bill," Lott called on President Clinton to intervene with Democrats to "quit playing games with the farmers of America." Republicans also held up a poster quoting Democratic Congressional Campaign Committee Chairman Patrick J. Kennedy (D-R.I.) as saying Democrats have "written off the rural areas."

"Coincidence or strategy?" asked Sen. Larry E. Craig (R-Idaho). "I'm not sure which it is."

CAPTION: Sen. Trent Lott (R-Miss.) accused Democrats of exploiting farmers in order to paralyze the Senate.