The House Agriculture Committee, ending a long and bitter impasse over spending cuts, last night adopted a 1985 farm bill.

The final major logjam was broken when the committee adopted changes that would reduce the bill's three-year cost by about $11 billion, bringing it within the $34 billion congressional budget limit.

But the move pleased few, if any, committee members. Confronted by growing distress in the farm economy, the panel has been tied up for weeks over the size and shape of the cuts needed to meet budget requirements.

"We wish we could do what everyone wants done, but that's impossible," said Chairman E (Kika) de la Garza (D-Tex.).

Others went further. Rep. Dan Glickman (D-Kan.), for example, said the bill would lower farm income and not stop the decline in farm prices. "The affect on rural America will be dramatic," he said.

With dozens of farmers in the hearing room and dozens more milling in the corridors, the committee also narrowly rejected a proposal that could have led to a mandatory production-control plan to get prices up and surpluses down.

The amendment by Rep. Harold L. Volkmer (D-Mo.), opposed by the administration and many agribusiness interests, would have allowed wheat and feed grain producers to vote on mandatory controls.

Volkmer and other farm state allies argue that the mandatory program, with little cost to the federal government, was the only workable approach to keeping farmers in business and holding the slide in commodity prices.

After lengthy debate, the amendment was rejected, 22 to 19. Similar legislation was defeated by seven votes before the August recess.

Yesterday's committee action set the stage for more skirmishing on the floor, where mandatory program supporters and consumer groups intend to take new aim on the bill. One group, Public Voice for Food & Health Policy, announced yesterday that it will team up with consumer-oriented legislators to go after the bill's dairy, sugar and peanut support provisions.

Although the committee rejected the mandatory proposal, it went along with an amendment by Rep. Berkley W. Bedell (D-Iowa) that would allow farmers to vote on a variation of production controls for wheat and feed grains.

If farmers approved the program in a referendum, those who agreed to cut production would get higher federal price support aid. Farmers who did not sign up would be able to produce grain only for export or for use on their own farms. The Bedell plan also would subsidize exports to keep U.S. farmers competitive on world markets.

Generally, the House committee bill would reduce the price support loan levels for wheat, feed grains, cotton, rice and soybeans, but hold direct income support payments at or close to current levels.

The measure also includes a new formula for reducing costs of the dairy support program and authorizes a "diversion" that would pay farmers from a farmer-financed fund to reduce the size of their herds. The administration has warned that President Reagan would veto a farm bill that retained the diversion feature.