WASHINGTON — Immigration reform that focuses solely on enforcement would cut agriculture production and cause a sharp rise in food prices, according to a study released Monday.

The study — which was commissioned by the American Farm Bureau, the nation’s largest farm lobby organization — said food prices would increase an additional 5 percent to 6 percent over the next five years if enforcement-only policies were put into place, because of a lack of workers to harvest crops. It would cost the agriculture sector as much as $60 billion over the same period.

The study comes as Congress and the Obama administration are debating immigration overhaul proposals that would address the country’s estimated 11 million unauthorized workers.

Republican leaders had put forward a modest immigration reform proposal, but many Tea Party activists and conservatives in Congress have opposed all plans that offer amnesty for those in the country illegally. Because of the opposition, Speaker John A. Boehner of Ohio said last week that it was unlikely that an immigration reform bill could pass the House this year.