Mounting tensions between two of the lead negotiators on the farm bill are jeopardizing Congress’ chances of passing a measure allocating hundreds of billions of dollars for agriculture and nutrition programs before a new session begins next year. Texas Republican Mike Conaway, the House Agriculture chairman, wants more money for Southern cotton growers. Michigan Democrat Debbie Stabenow, Senate Agriculture’s ranking member, is pushing funds for urban farming and renewable energy. Their bitter fights over farm subsidies have deadlocked talks in a conference committee. The 2014 farm bill expired on Oct. 1 without a single face-to-face negotiating session between top negotiators in the three days before the deadline -- a sign of just how far lawmakers are from any kind of deal.Congress is supposed to reauthorize the sweeping law every five years, but the stalled negotiations show how rancorous partisanship in Washington has overtaken even popular legislation that usually passes with bipartisan support. Rural lawmakers must now return home for midterm elections with little to show their farmer constituents who are hurting from low commodity prices and an onslaught of retaliatory tariffs.If a bill doesn’t pass by the end of the year, lawmakers would likely extend the current farm bill and then need to return to square one on new legislation next year.