U.S. Department of Agriculture exhibition display concerning fertilizer values as determined by per cent of plant food. The display includes several photographs of a range of agricultural crops, including wheat, cotton, corn, potatoes, and sugar beets, as well as a diagram highlighting fertilizer components like nitrogen, phosphoric acid, and potash. The display likely drew on the the work of the U.S.D.A.'s Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen Research Laboratory (F.N.R.L.) was established at American University in 1919 under the directorship of Arthur B. Lamb. Initially part of the War Department, the F.N.R.L. was the successor to several wartime initiatives to develop a secure domestic supply of nitrate compounds necessary for the manufacture of explosives during World War I. With a staff of about 110 individuals, including 35 to 50 chemists, the F.N.R.L. focused on the manufacture, production, and development of products of atmospheric nitrogen, including munitions and fertilizers.