Morrow Plots

Morrow Plots. University of Illinois at Urbana-Champaign. Started in 1876, the Morrow Plots are the oldest field experiment in the United States. First known as “Rotation Experiment No. 23” and modeled after trials at Rothamsted, England, the plots were established to study the long-term effects of crop production on soil properties. The trial, originally ten half-acre plots, was begun to compare continuous corn, corn-oat, and corn-oat-hay rotations. Only three of the original rotation plots survive. The Observatory, Gregory Street, and Mumford Hall now occupy part of the original plot area. Through time the trial has changed as agricultural issues have changed. Manure, lime, and phosphate were added to half of all rotation plots in 1904; commercial fertilizer application began on some plots in 1955; and in 1967 soybeans replaced oats in the corn-oat rotation., The Morrow Plots have taught us that sustained crop production lowers soil organic matter and soil concentration of key plant nutrients. Corn yields are greater where soil organic matter and plant nutrients have been maintained by crop rotation or manure application. During the life of Morrow Plot experiments, the introduction of hybrid corn and application of commercial fertilizers to replace plant nutrients removed by crops have increased corn yield over four fold., The Morrow Plots owe their existence to three persons: C W. Silver wrote of the idea: M. Miles furthered the idea; and G. E. Morrow published the first crop yield data in 1888.