U.S. Rep. Collin Peterson spent more than four years toiling over the Farm Bill, but he won't be at President Obama's side when he signs the $1 trillion legislation into law.

Peterson declined an invitation from Senate Agriculture Committee chair Debbie Stabenow, D-Mich., to attend the bill signing in her home state.

Among the top four negotiators on the farm bill, only Stabenow is expected to attend the event.

U.S. Sen. Amy Klobuchar flew to Michigan aboard Air Force One with President Obama. Klobuchar served on the Farm Bill conference committee that signed off on the bill after the key negotiators reached consensus.

Peterson, the lead Democrat on the House Agriculture Committee, is back in his district today attending to prior commitments, his staff said.

Democrat U.S. Rep. Tim Walz, who also served on the Farm Bill conference committee, also declined to attend due to prior commitments, his staff said.

House Agriculture chair Frank Lucas, an Oklahoma Republican, and Mississippi Sen. Thad Cochran, Stabenow's ranking Republican in Senate, also opted not to attend.

Lawmakers passed the legislation this week after years of debate over farming subsidies and Republican efforts to reduce financing for food stamps.

The final bill replaces direct crop payments with an insurance program and trims $8 billion from food stamps over the next decade, much less than the $40 billion cut some conservative Republicans pushed for.

Stabenow said she invited all the leading negotiators, Democrat and Republican, to the bill signing at Michigan State University, a leading agricultural research school and Stabenow's alma mater.

During his appearance in East Lansing, the president plans to tout the benefits of farm bill for the nation's economy.

The event marks the third time Obama has held a bill signing ceremony outside of Washington, D.C.