By Jim Mintert, David Widmar and Michael Langemeier Purdue University/CME Group Producer sentiment inched higher during April as the Ag Economy Barometer increased to 130. The latest result for the Purdue/CME Group Ag Economy Barometer, which is based on a monthly survey of 400 U.S. agricultural producers, was slightly higher than March’s 124 reading, but still well below January’s peak …