Magruder Plots

The Magruder Plots are experimental wheat field plots at Oklahoma State University established in 1892. They are the third longest running such field trial in the United States, following the Morrow Plots established in 1876 at the University of Illinois (on corn), and the Sanborn Field established at the University of Missouri-Columbia (on grain crops and forage) in 1888.

Boundaries of Plots indicated by pink posts. Note unfertilized "check" area in center of photo denoted by lack of stubble

Originally planted in the fall of 1892 by A. C. Magruder, first professor of agriculture at Oklahoma A & M (now Oklahoma State University), these plots were established to obtain information on the ability of the soil to continue to produce good yields of wheat without fertilization.

Researchers conducted hundreds of experiments comparing various fertilizer treatments with manure applications and without such treatments. The plots became the center for wheat soil research in the region and provided constant data which helped farmers get maximum yield from their arid climates and naturally dry soils. Between 1893 and 1898 the field was not fertilized and the yield data were taken from the 1.25 acre plot as a unit. The plots were divided in the summer of 1896, and yields were taken separately from the north and south halves to allow measurement of soil variability. Between 1899 and 1929, the south half was fertilized with barnyard manure and north half left unfertilized. No commercial fertilizer was used. Just prior to the 1926-1927 seasonal seeding, each of the halves was divided into five plots on which individual yields were taken in 1927, 1928, and 1929. Soil variability was thus determined. Starting in 1930 the ten plots were variously fertilized.

In 1947 university officials decided that the area where the soil plots were located had to be used for space for a new dormitory. That year the soils were moved to the present location. Before the construction of the dormitory, university officials dispatched workers to carefully move the surface and immediate subsurface soils from six of the ten main plots to a location about one mile west on the OSU agronomy farm. The reddish clay subsoil under the new location was similar to the subsoil under the original plot. Dr. Horace J. Harper, agronomist in charge of the plots for 1926 to 1951, described the task of moving the soil as follows: "The top eight inches of soil was removed with a bulldozer from an area of 100 feet in length near the center of each plot and was piled on each end of that plot. The subsurface soil from 8 to 16 inches was excavated and transferred to prepared trenches dug in a east-west direction on the agronomy farm." Studies conducted on the site after the move, when compared to similar studies conducted before the soil was tampered with, have shown that moving the plots of soil did not cause significant change in their relative crop-producing capacities. No evidence has indicated that the move disturbed the soil or hindered the research value of the area, which continues to be used for its original purpose.