The Senate Agriculture Committee approved a five-year farm bill Thursday that includes a new subsidy proposal advocated by Chairman Tom Harkin, D-Iowa.

The massive $283 billion reauthorization of farm payments, conservation programs and nutrition supports was approved by voice vote after a two-day markup.

It includes a new Average Crop Revenue program, an optional subsidy that would tie some payments to farmers to state crop revenue targets, while trimming others. Harkin and co-author Sherrod Brown, D-Ohio, said the program would offer farmers in some regions better protection against the risks inherent in farming, resulting in lower crop insurance premiums. That would mean an overall savings to the government, which partially subsidizes those premiums, they argued.

But the plan immediately came under fire from some farm groups and the crop insurance industry, which said it would be prohibitive for some farmers and take business away from insurers.

To mollify the opposition, the committee adopted an amendment by Pat Roberts, R-Kan., to require farmers opting into the new program to continue participating for the life of the farm bill. The amendment also would reduce the number of acres on which farmers could collect payments and keep insurance premium rates where they are today, meaning crop insurers would preserve their bottom line.