ADVANCE FOR THURSDAY, APRIL 23, FOR RELEASE AT 12:01 a.m. ET -- FILE - In this Feb. 7, 2014 file photo, Agriculture Secretary Tom Vilsack, left, and President Barack Obama, tour the biomass conversion process area at Michigan State University in East Lansing where Obama signed the sweeping farm bill into law last year. Vilsack is expected to unveil a voluntary set of programs and initiatives for farmers, ranchers and foresters Thursday, April 23, 2015 at Michigan State, that build on Obama’s efforts to combat global warming _ and do so in ways that don’t require approval from Congress. (AP Photo/Jacquelyn Martin, File)