As Congress begins the arduous process of crafting a new immigration reform bill, agriculture organizations told lawmakers that a failure to reform the labor policy would threaten to drive more production outside of the country, leave more fruits and vegetables vulnerable to rotting in fields, and put at risk the abundant and safe food supply found in the United States.

“I dare say that for many producers, this immigration legislation and this debate before us is more important for the survival of their operations than any of the other legislation pending before Congress,” said Charles Conner, head of the National Council of Farmer Cooperatives, a group that represents regional and national farmer cooperatives.

“This bill gives us that ability: to be legal. The current system is broken. We’ve got to fix it,” he said, noting this opportunity could be the best chance to overhaul immigration for some time.

“You cannot get Americans to do this work.”

Conner told the Senate Judiciary Committee that in California, for example, about 80,000 acres of fruit and vegetable production have been moved overseas because of labor shortages. Without adequate labor, estimates are that thousands of farms could fail and farm income could drop by $5 billion to $9 billion, he said, citing a 2008 Texas A&M University study.

The biggest beneficiaries of the new immigration bill in agriculture would be dairy, cattle and swine farmers in states such as Iowa, as well as in California, Florida and other areas where undocumented workers are heavily used to harvest fruits and vegetables. Row crops such as corn and soybeans are harvested mechanically, reducing the need for human labor.

The bipartisan proposal in the Senate would allow undocumented workers who have been employed no fewer than 100 days in agriculture for the past two years to get a so-called “blue card” that would give them legal status. After at least five more years, those workers could apply for permanent resident status and receive a “green card.”

The bill also calls for guest worker visas to be issued by the U.S. Agriculture Department throughout the entire year to ensure an adequate workforce. It would replace the current H-2A program.

In the United States, there are about 1.1 million hired workers for crops and livestock — with about half of them believed to be in the country illegally, according to one government estimate. The Agricultural Workforce Coalition, a group of nearly 70 farm organizations concerned about finding enough workers, puts the number at 1 million to 1.5 million, with 60 to 70 percent of them here illegally.

Arturo Rodriguez, president of the United Farm Workers, told the Senate panel that farm workers “are the backbone of our agriculture industry” and changing their status “provides a strong incentive” for them to continue working in agriculture.

“Hopefully this will be able to provide some stability in the years to come,” he said.

Groups that favor immigration curbs are skeptical of claims of a massive worker shortage and say Congress shouldn’t give “amnesty” to undocumented immigrants.

Roy Beck, president of NumbersUSA, said Congress should instead fix bureaucratic problems that make the H-2A migrant-worker visa program cumbersome to use.

H-2A visas, which are valid for limited periods of time, don’t allow applicants to become permanent residents automatically after working in the United States for a few years.

Allowing undocumented workers to get green cards will eventually hurt the agriculture industry, Beck said. That’s because permanent residents, who aren’t restricted to one type of work, are bound to move on to less strenuous or better-paying work in construction and the service industry once they get their green cards, he said.

“The program we have now is the right program. It’s seasonal and you go in and out (of the United States),” he said.

Immigration reform for farm labor is part of a larger 844-page bill proposed by eight senators that allows the nation’s 11 million unauthorized immigrants to apply for U.S. citizenship and tightens security along the nation’s Southwest border.

Iowa Sen. Chuck Grassley, the top Republican on the Senate Judiciary Committee, said the initial draft of the immigration bill was a good starting point, but he warned that Congress cannot afford to make the same mistakes as it did in the 1986 immigration bill, the last time Washington tackled a major overhaul of the subject.

“I think we’re taking advantage of an opportunity, when once in 25 years we deal with immigration, to make sure that every base is covered,” said Grassley.

Gannett Washington Bureau reporter Raju Chebium contributed to this story.