Magruder Plots, experimental wheat plots in Stillwater, Oklahoma, United States

The Magruder Plots are an experimental field area in Stillwater, Oklahoma, used for wheat research since the late 1800s. The land is divided into smaller parcels with different soil treatments and fertilizer applications studied systematically to understand their effects on crop yield and soil health.

A. C. Magruder, the first professor of agriculture at Oklahoma A&M (now Oklahoma State University), planted the plots in the fall of 1892 to test whether the soil could keep producing wheat without fertilization. In 1899 the field was split into north and south halves; from 1899 to 1929 the south half received barnyard manure and the north half none. In 1947, when a dormitory was to be built on the site, workers moved the topsoil of six of the ten main plots about a mile west to the agronomy farm.

The plots carry the name of A. C. Magruder, the first professor of agriculture at Oklahoma A&M, who planted them in the fall of 1892. The six treatments still running include an unfertilized check plot kept since 1892 and a manure treatment used since 1899, so the same strips of ground have been cropped to winter wheat for well over a century.

The site is located west of the Stillwater campus along Highway 51 and is easy to locate, but access is limited because ongoing research restricts public visits. During annual field days in May, interested visitors can observe the work and learn about current findings from researchers on site.

In 1947, when a dormitory was planned on the original site, workers moved the top 8 inches and the 8–16 inch subsurface soil of six of the ten main plots about a mile west to the OSU agronomy farm, where reddish clay subsoil matched the original. Agronomist Horace J. Harper, in charge from 1926 to 1951, described the bulldozer work; later studies found no significant change in the plots' relative yields.