Agriculture groups are pressing House Speaker John Boehner to bring another unified farm bill to the House floor, saying that breaking up the measure — as some Republicans want — threatens the nation's still-fragile economy.

More than 500 industry groups collectively sent a letter to the Ohio Republican this week saying that a comprehensive five-year measure is the only way to ensure that agriculture subsidies, farmer insurance and nutrition programs are properly funded.

"Farm bills represent a delicate balance between America's farm, nutrition, conservation and other priorities," the letter said. "We believe that splitting the nutrition [programs] from the rest of the bill could result in neither farm nor nutrition program passing, and urge you to move a unified farm bill forward."

The House last month surprisingly voted down a five-year, comprehensive farm bill after more than 60 Republicans rejected the GOP-written measure. The major sticking point was the bill's proposed $2 billion in annual cuts to the food stamp program, with Democrats complaining it was too severe and Republicans saying the cuts didn't go far enough.

Boehner has said he hasn't decided what to do next. But many House Republicans are pushing for the food stamp portion to be spun off from the main farm bill, saying it's a separate issue. And privately, senior House GOP leadership has hinted they are considering such a move, suggesting it's the only way break the gridlock over the bill.

Democrats say the approach would doom the food stamp program in the Republican-controlled House. And agriculture trade associations and farmers groups also are pressing Boehner to keep the farm bill whole, fearing their own interests could become a casualty of a drawn-out partisan fight over the bill.

Dee Vaughan, president of the Southwest Council for Agribusiness, told the Houston Chronicle his first priority was passing the bill. But he said keeping nutrition programs in the same bill as farm programs would give agriculture interests a boost in the urban-dominated Congress.

"Rural America is such a small part of the population anymore," Vaughan said. "We just don't have that many rural representatives."

Farm bills usually are among the most bipartisan legislative endeavors in Congress, as lawmakers from farm states, regardless of party, work to ensure their success while those from urban areas lend their support because of the food stamp provisions.

The Senate in early June easily passed its version of the farm bill with a wide bipartisan majority. The measure includes only a fifth of the amount House's proposed food stamp cuts, or about $400 million a year.