- Alexander Campbell Martin, Arthur Henry Senner, C. C. Plummer, C. H. Hadley, Chalmers Jackson King, Curtis Paul Clausen, David A. Savage, Ernest Victor Abbott, Frederick Charles Lincoln, Glenn Gardner Hahn, Harold Francis Scholz, Harold Glenn Meginnis, J. Clark Salyer, James Herbert Beattie, Jenkin William Jones, Mayne Reid Coe, Paul William Miller, Ralph P. Hotis, Robert J. Sim, United States. Department of Agriculture, Walter Ernest Fleming, Wilbur Clifford Edmundson, Wilbur Magruder Hurst, Claude Hope, Frederick William Metzger, Ira Myron Hawley, James Robert McCalmont, John Walter Taylor, Victor Rickman Boswell, Walter Raymond Humphries, William Ernest Stone, E. E. Hall, Max Raymond Osburn, Roland McKee
· 1934