NEW YORK (AP) — Warren Buffett’s Berkshire Hathaway Inc. on Tuesday agreed to buy Burlington Northern Santa Fe Corp., making a $34 billion bet on the future of the U.S. economy. Burlington Northern, the nation’s second-largest railroad, is the biggest hauler of food products like corn and coal for electricity, making it an indicator of the country’s economic health. The railroad also ships a large amount of goods — including everyday items such as refrigerators, clothing and TVs— from Western ports like Los Angeles, Long Beach, Calif. and Seattle. Analysts say Buffett is planting both feet in an industry that is poised to grow as the economy gets back on solid ground. If approved, it would be the biggest acquisition ever for Berkshire Hathaway Inc. Berkshire Hathaway already owns about 22 percent of Burlington Northern, and said it will pay $100 a share in cash and stock for the rest of the company, a 31.5 percent premium on Burlington Northern’s Monday closing price.