- Ralph U. Cotter, C. A. Magoon, Charles Brooks, Charles Faye Sarle, Charles Otis Johnston, Curtis Paul Clausen, Elmer Ottis Wooton, Floyd Franklin Smith, Fred W. Miller, Harvey Leroy Westover, Howard E. Middleton, Irvin Cecil Brown, Irvine Theodore Haig, James Thorp, Lester Henry Reineke, Lyle Thomas Alexander, Millard Peck, Orator Fuller Cook, Ronald Floyd Luxford, Samuel Augustus Jones, V. L. Wildermuth, Walter Chapin Holmes, William Hobson Rowe, William John Nolan, Willis James Nolan, Bernard Frank, Charles W. Culpepper, Clarence Sheldon Slater, Donald Bruce, Edwin Butterworth Mains, Elmer Valentine Walter, Horace Greeley Byers, John Thomas Scanlan, Johnson Thatcher Sarvis, Lorraine Joseph Markwardt, Paul A. Berry, R. R. Graves, Theodore Roosevelt Gardner, Anis Rae Peterson, Kaku Sato, Leroy Moomaw, Paul Axel Clarence Eke, George W. Morgan, John Carl Thysell, M. A. Bell
· 1932
- Claude Carl Wakeland, Floyd Warnick Atkeson, H. W. Hulbert, Harold A. Vogel, Harry Miller, Hobart Beresford, Idaho Agricultural Experiment Station, John Henry Christ, Paul Axel Clarence Eke, Elmer N. Humphrey, John L. Toevs, Neil William Johnson, Reuben Frederic Johnson, Rowland W. Haegele, Theodore Roosevelt Warren
· 1933