Historic Experiment Fields Offer Invaluable Insights

A 1-acre field of Flanagan silt loam located in the heart of the University of Illinois' Champaign-Urbana campus is proof that research can have a long arm.

Since 1876, the Morrow Plots have continuously provided insights on soil health, crop rotation and other aspects of agricultural productivity. The oldest agricultural experiment field in the United States and the second oldest in the world, the plot was dedicated as a National Historic Landmark in 1968.

So hallowed is the ground that legend has it the adjoining undergraduate library was built beneath ground to avoid casting a shadow on the crops. While some say that's a myth, a song dedicated to the plot includes this cautioning reprise: "You can't throw shade on the corn."

HISTORY CLASS

Several historic field experiments continue to serve as a rich resource for scientists by providing archived samples and ongoing data collection on soil, crops and related cropping-system outcomes. England's Rothamsted Research (Harpenden, Hertfordshire) dates from 1843 and is considered the oldest continuing agricultural field experiments in the world, which served as the inspiration for the Morrow Plots.

The University of Missouri's Sanborn Field started in 1888 with the original goal of demonstrating the value of crop rotations and manure in grain crop production. At Oklahoma State University, the Magruder Plots (circa 1892) hold the title as longest-running wheat field experiment.

Auburn University's "Old Rotation," the oldest continuous cotton experiment in the world, has been operating since 1896. The Knorr-Holden Plot (circa 1910) near Scottsbluff, Nebraska, is considered the world's oldest irrigated continuous corn research plot.

BUILDING ON OLD FOUNDATIONS

These days, the Illinois Morrow Plots legacy is being tended by a working group led by University of Illinois soil scientist Andrew Margenot. The goal is to bring new attention to the importance of long-term experiments that serve as a living record of the history of agriculture.

"It goes beyond historical legacy; these kinds of plots offer long-term insights to cropping-system sustainability. For example, there is one portion of the Morrow Plots that has remained without fertilizer -- but still cropped," Margenot explains. Another section has been in continuous corn since 1876.

In 2018, a project was initiated to corral what's been learned into a Morrow Plots database. A team of data scientists from the College of Agricultural, Consumer and Environmental Sciences (ACES) and the University Library dug through historical data. The challenge was to standardize historical data so comparisons could be made about crop varieties, rotation, planting density and yield, as well as fertilizer type and amount.

Margenot says the plots have revealed principles of soil fertility and crop productivity that we take for granted today, such as the crop needs for nitrogen, phosphorus and potassium. They proved hybrids can boost yields and crop rotation can influence fertilizer needs and yield potential.

Now, as the Morrow Plots approach their 150th birthday (2026), several improvements are in the works. Funding from Bayer's Crop Science division and the University of Illinois John N. Chester Estate Fund will give the landmark plot a facelift.

The historical Morrow Plots continue to offer opportunity to explore the scientifically overlooked, curate soil science and teach students.

"However, given their initial design, the plots aren't statistically ideal," Margenot says. "We can't look at yield or soil-health differences with the high confidence that we'd like, for example. And, because of their small size, they don't reflect research on a modern commercial agriculture level."

MORROW PLOTS 2.0

The university recently announced the launch of Alma Mater Plots, an 80-acre living laboratory located at one of the university's South Farms, near the Embarras River. It will include 64 plots, each spanning 1.2 acres, that allow four replications of 16 different treatments.

This will be one of the largest monitored-tile research fields in the country, Margenot says. "Each experimental unit will be individually drained and the tile drain monitored for flow and nutrient concentrations to allow researchers to precisely monitor how nutrients and water move through the soil as a function of management practice," he explains.

"Much of Illinois and the greater Corn Belt is tiled, but with the cost of today's inputs and the environmental challenges, we need to see if we can manage tile more intentionally. Drainage management holds much potential to sustainably intensify crop production, environmentally, agronomically and economically," he adds.

Margenot is holding listening sessions around the state to ask farmers and other stakeholders what should be studied.

"The goal is to study what we need to know to make agriculture viable for the next 150 years," he says.

**

FOR MORE INFORMATION:

-- Rothamsted Research: https://www.rothamsted.ac.uk/…

-- University of Illinois Morrow Plots: https://aces.illinois.edu/…

-- University of Missouri Sandborn Field: https://moaes.missouri.edu/…

-- Auburn University Old Rotation: https://agriculture.auburn.edu/…

-- Oklahoma State University Magruder Plots: https://nue.okstate.edu/…

-- University of Nebraska Knorr-Holden Plot: https://cropwatch.unl.edu/…

-- Follow the latest from Pamela Smith, Senior Crops Editor, by visiting the Production Blogs at https://www.dtnpf.com/… or following her on social platform X @PamSmithDTN

[PF_0925]

(c) Copyright 2025 DTN, LLC. All rights reserved.