Bloomberg: Corn rose for a fourth straight session, the longest rally this year, after the U.S. government unexpectedly increased its estimate of the amount of grain that will be used to make ethanol. Increased biofuels production will more than offset falling export demand, reducing domestic supplies on Aug. 31 to 1.74 billion bushels, down from 1.79 billion forecast last month, the U.S. Department of Agriculture said today in a report. Traders surveyed by Bloomberg News expected an increase to …