His name was not mentioned during the clangorous Senate farm bill debate last week, but the legacy of David A. Stockman hung heavy over the chamber.

Although Stockman is no longer the Reagan administration's budget director, the seeds of "market-oriented" agriculture policy that he began planting in 1981 have started to germinate.

The farm bill approved Saturday night by the Senate, like the House version that passed earlier, contains central elements of the Reagan-Stockman approach to getting government out of agriculture.

Both bills shrink the two main governmental tools that influence how much money farmers make -- the support-loan levels that put a floor under basic commodity prices and the direct federal subsidy payments that prop up farmer income.

With evidence mounting that high support levels price U.S. farmers out of key export markets, lawmakers generally agreed that the floors should be lowered to make U.S. products more competitive.

And there was more agreement on both sides of the Capitol that the main way to meet the administration's demands for budget austerity was to scale down the income-subsidy payments. The cutting was made easier by evidence that the biggest payments were going to farmers who seemed to need them least.

The most searing political pain came over the income-subsidy issue -- made more acute by the stumbling farm economy and demands from rural America for more financial help from Washington.

The subsidies, known as deficiency payments, go to wheat, feed grain, rice and cotton farmers who agree to take part in federal production-control programs. The payments, limited to $50,000 per farmer, are calculated on market prices and production costs.

The administration and other critics, such as Senate Agriculture Committee Chairman Jesse Helms (R-N.C.), argued that the payments created another problem by encouraging farmers to plant more than they can sell, just to get the government largess.

"I have not seen a thing . . . that would show me what we are really doing for the little guy in Oshkosh B'gosh overalls with the hoe in his hand," said Sen. Alan K. Simpson (R-Wyo.). "We play with the big-ticket guys, the rice cats, the corn cats, the wheat cats -- all of them heavy hitters.

"Then we get up and talk about that poor little guy. I do not see anything going out to him at all. I just see the heavy money streaming out the door . . . . We gave them $63 billion of the taxpayers' money in four years -- and more. It did not work. They are hurting bad. How fascinating."

But with farm prices down and farm recovery not in sight, the deficiency-payment issue took on more importance. Democrats and Republicans from the Midwest grain belt, hit hard by declining exports and increasing foreclosures, fought furiously to keep the subsidy line open as their farmers' last hope for survival.

Sen. Charles E. Grassley (R-Iowa), a harsh critic of administration farm policy, argued to little avail that the president's proposed cuts would deprive Iowa corn farmers of $1.1 billion over the next three years, which he said would knock his state's reeling economy for another loop.

But the fight had been joined. It became a question not of whether deficiency payments would be cut, but how soon and how much they would be cut. It kept the Senate tied in knots for months.

Farm Belt legislators insisted on freezing payments at current levels for the next four years. The administration, Helms and Majority Leader Robert J. Dole (R-Kan.) wanted a one-year freeze, which they said would cost $13 billion less.

The Senate agreement, reached after those favoring a four-year freeze threatened to block the legislation, would continue supports at current levels for two years, then begin phasing them down. The House bill freezes supports for five years.

A conference committee will work out differences between the House and Senate bills after the Thanksgiving recess.

Agriculture Secretary John R. Block said the administration will insist that the conferees reduce the costs of the farm bill. But he noted that the important policy changes the White House sought were stamped grudgingly into both versions of the bill.

A peripheral development in the Senate debate, in which Dole cut deals that pitted one commodity against another, also followed the Stockman book.

Sen. Tom Harkin (D-Iowa), who resisted Dole and the administration to the end, said, "This is the legacy of David Stockman. He set this in motion."

Added Sen. J. James Exon (D-Neb.), another of the resisters: "David Stockman and Ronald Reagan came in in 1981 and split asunder the farm coalition. The same techniques were used to totally dismantle it this time."