National and state farm leaders have lined up in support of the immigration overhaul bill now pending in Congress, saying a major part of the state’s economy is at stake in the debate.

Senate Bill 744 would make it easier for the state's $71.1 billion agricultural industry – Georgia's largest — to hire foreign guest workers. Georgia farmers say they rely heavily on migrant Hispanic laborers because many Americans won't do physically taxing work in the fields.

In a meeting with Atlanta Journal-Constitution reporters and editors Thursday, the presidents of the American Farm Bureau Federation and Georgia Farm Bureau confirmed they back the legislation and are part of a national campaign to build support for it in Congress.

Also Thursday, a coalition of religious leaders called the Evangelical Immigration Table announced a $250,000 media ad campaign in support of a bipartisan immigration overhaul. One of the radio ads featuring Cynthia Hale, senior pastor at Ray of Hope Christian Church in Decatur, was scheduled to begin airing in Georgia this week.

Meanwhile, the Atlanta Tea Party dismissed the legislation as an “amnesty bill” and called on supporters to urge Georgia’s two senators to vote against it.

Spokesmen for U.S. Sens. Johnny Isakson and Saxby Chambliss said they won’t take a position until after they have reviewed the 844-page bill, which passed the Senate Judiciary Committee last week. It is expected to come to the Senate floor for a vote perhaps as soon as next week. Meanwhile, a bipartisan group of House lawmakers is crafting its own immigration bill.

Agricultural leaders say most of the nation’s hired farm laborers are in the country illegally. Under the Senate legislation, illegal immigrants who have done farm work in the U.S., paid taxes and a fine and passed a background check would be eligible for a “blue card.” That blue card would allow them to continue working in the U.S. and give them a route to apply for legal permanent residency and then U.S. citizenship.

A new visa program would replace the H-2A guest worker program, which Georgia farmers say is cumbersome and costly. The new visas would last for three years but could be renewed.

“It’s for the best interest of all of Georgians for us to find a workable way that we will be able to harvest these crops,” said Zippy Duvall, president of the Georgia Farm Bureau.

Critics of the legislation say farmers could hire more Americans if they would pay more. They also suggested farmers could reduce their need for foreign laborers through mechanization.

“The fact is that without this large and continuing supply of foreign labor farmers would make different decisions,” said Mark Krikorian, executive director of the Center for Immigration Studies, which advocates admitting fewer immigrants. “The flow of foreign farm labor actually distorts the development of agriculture.”

Illegal immigration has long been a hot-button issue in Georgia. The state was home to an estimated 425,000 illegal immigrants in 2010, according to the Pew Hispanic Center.

In 2011, Republican Gov. Nathan Deal signed legislation to crack down on the problem, causing some migrant Hispanic farm workers to flee or look for jobs in other states. Later that year, researchers identified a shortage of 5,244 farm laborers and $74.9 million in losses on seven crops in Georgia.

Bob Stallman, president of the American Farm Bureau Federation, predicted it will be difficult for Congress to pass the Senate legislation, given the nation’s angst surrounding the issue.

“But the question is: ‘What is the alternative?’ ” he said. “Because what we have now isn’t working. It is de facto amnesty and it gives something for everyone to complain about and demagogue about, but it is not fixing the problem. At least we are trying to fix the problem.”