The Senate Agriculture Committee rushed out a bill yesterday to raise depressed farm prices by paying farmers to take 31 million additional acres out of production. The cost would be $2.3 billion a year.

Before a roomful of visor-capped farmers who have been here seeking higher prices since January, Chairman Herman Talmadge (D-Ga.) persuaded his committee to report out the acreage set-aside by itself rather than tie it to a more controversial plan to raise price supports. The vote was 16 to 1.

All the committee members wanted to do something to help farmers, who despite a general farm bill that raised price supports last year are hurting in some parts of the country because of crop surpluses.

Talmadge argued that the quickest way to get money to the farmers was his program to pay an average of $75 an acre not to plant crops this year. Cutting production should force an increase in farm prices. But the bill must be enacted before farmers plant their 1978 crops, he said, and some planting is already under way in the South.

Talmadge wants the bill sent to President Carter before Congress starts its Easter recess a week from Thursday.

He said Senate Majority Leader Robert C. Byrd (D-W. Va.) has said the bill could be taken up after the Senate votes on the first Panama Canal treaty Thursday if there is unanimous agreement on the time it would take.

There is no assurance tht the acrage set-aside bill alone would satisfy the House Agriculture Committee. Rep. Thomas Foley (D-Wash.), committee chairman, said his committee might want to add higher price supports as a better way to assure the farmer higher prices.

While Talmadge's set-aside bill would cost an estimated $2.3 billion, according to the Congressional Budget Office, it would mean a net saving of $171 million in the long run because higher farm prices would reduce price subsidy payments.

"We can save money and raise price at the same time," said Talmadge happily.

The Carter administration isn't keen about the bill. It has authority to conduct such a set-aside program now but prefers as more "responsible" a buildup of crop reserves. A Department of Agriculture spokesman said he didn't know whether Carter would sign Talmadge's bill or not.

An amendment to add a 50-cent-a-bushel increase in price supports for wheat, corn and feed grains was defeated on an 8-to-8 tie. The CBO said it would cost $3.9 billion.

Talmadge said that if the committee would send out the set-aside bill alone to see if it could speed unencumbered through Congress by spring, he would call another committee meeting Wednesday to deal with the high price supports, emergency loans for farmers facing mortgage foreclosure and othr assistance programs. The House committee has approved an emergency loan bill for house action next week.

The only committee vote against the bill was cast by Sen. Kaneaster Hodges (D-Ark.) who said he wanted more time to study it. He was the only senator to evoke any reaction from the assembled farmers.

Hodges said he felt the bill gave too much discretion to the secretary of agriculture.

Talmadge replied that it was the same language as was written into a bill during President Kennedy's administration.

"But we didn't have Bob Bergland as secretary then, thank goodness," said Hodges.

The farmers broke into applause, and though Talmadge seemed put out at Bergland for not moving on a land set-aside program he told them to quiet down.

Talmadeg hopes that reducing production would raise the price of wheat from about $2.60 to $3.50 per bushel and corn from about $2 to $2.50.