By Brian Brus STILLWATER, Okla. — A recent $3.1 million grant awarded to Oklahoma State University to study greenhouse gas emissions is expected to help sorghum farmers save money and improve the industry’s sustainable field management practices. The three-state research project approved under the SMARTFARM program of the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) is headed by Gopal Kakani, professor of crops, energy and climate in the OSU Department of…