by Dan Hansen, Eugene Merritt, George Thomas Ratliffe, Harry Vanghn Harlan, John Enos Graf, Orator Fuller Cook, Tyōzaburō Tanaka, Wilfred Wickes Ballard

1921

by Albert Rudolf Leding, Arnon Lewis Mehring, Arthur T. Sweet, Auton William Skuderna, Benjamin Ralph Stauber, Curtis May, David Griffiths, Floyd Franklin Smith, George Arceneaux, James Fitton Couch, John Morrison Cooper, John Robert Parker, Lewis Alexander Hurst, Orator Fuller Cook, Paul George Russell, Paul Mehl, R. A. Blanchard, R. T. Balch, Robert Max Merrill, Theodore Bergen Manny, United States. Department of Agriculture, Walter Ernest Fleming, Wilfred Wickes Ballard, William Middleton, Asa Young Willis, Avis Jenkin Peterson, Frederick William Metzger, J. I. Lauritzen, John Adam Stoehr, Ralph Brownson Bisland, Wayne Crocker Nason, Max Raymond Osburn

1933

by Alexander Edmond Cance, Arthur Frederick Sievers, August Levi Nelson, Charles Howard Richardson, Charles Leslie Stewart, Curtis Criss McDonnell, Edward Lawrence Griffin, Ernest Rudolf Schulz, Forest Volney King, Frederick David Richey, George Walter Morgan, Herbert Camp Marshall, Homer Durant Poore, Ira Edward Neifert, James Richard Quesenberry, James Swinton Townsend, John Boyd Gill, John Morgan Stephens, John Walter Taylor, Joseph Franklin Brandon, Ralph Henry Elsworth, Ray Sanford Towle, Robert Macfarlane Chapin, Wilfred Wickes Ballard, William Orrin Robinson, Dwight McBryde Simpson, Ernest Adna Back, Frank Rabak, George Burnap Fiske, Guy Ervin, Harry Dashiell Young, Hugh D. Young, John G. Willier, Noel Finley Thompson, R. S. Holmes, Orrena Louise Evans

1928