ARLINGTON, Va. — U.S. growers have a problem with labor, and Secretary of Agriculture Tom Vilsack isn’t shy about identifying who’s responsible for fixing it.

During a Feb. 23 keynote speech at the U.S. Department of Agriculture’s 2012 Agricultural Outlook Forum, Vilsack called on Congress to act on comprehensive immigration reform, lest America face a future where crops rot in the fields because growers lack workers.

“All of America, but especially farm country, needs comprehensive immigration reform, and we need it now,” Vilsack said Feb. 23. “With the risk of rotting crops, there is no excuse for the effort by some who want to demonize immigrant labor or prevent meaningful reform of a system that everyone in the Congress and the country admits is not functioning.”

In a news conference after his presentation, Vilsack said that it’s up to Congress to decide whether the USDA should administer a guest worker program, as some lawmakers have proposed.

“The ability to do anything like (USDA running a guest worker program) requires congressional direction, and the real answer here is comprehensive immigration reform,” he said. “We can talk about half-solutions or focus on talking about a particular industry, but the nation needs comprehensive immigration reform.”

Other challenges facing U.S. agriculture during the next year — and decade — include federal budget cuts, extreme weather events, trade barriers and uncertain global supplies that could drive up food prices, according to speakers at the conference.

As the USDA celebrates its 150th year, it faces the challenge of convincing taxpayers of the value of continuing to support agriculture with their tax dollars, said Dan Glickman, one of eight former secretaries of agriculture during a plenary session.

During his economic outlook, USDA chief economist Joseph Glauber said weather will continue to be a particular worry for agriculture, particularly in the South and Southeast U.S.

“Dryness is expected to persist in the South and get worse,” Glauber said.

A Feb. 16 USDA drought monitor reported more extreme drought than at the same time last year and marked “exceptional” drought throughout western Texas, much of Georgia and northern Florida.

The trade deficit is also a concern, with the 2011 U.S. trade deficit of $6.2 billion in fresh produce expected to swell to $10.7 billion in 2021, according to USDA long-term projections.

 “Expect this year to be a strong year for agriculture, especially with trade,” Vilsack said during his keynote speech.