Cullars Rotation Marks 100 Years of Research

By Jamie Creamer, College of Agriculture



A four-acre cotton fertility experiment that Alabama Polytechnic Institute scientists established in a Lee County farmer's field a century ago is still going strong and generating data that documents the impact fertilization and soil nutrient deficiencies have on nonirrigated cotton and other crop yields over the long haul.

Known as the Cullars Rotation, the project is the South's oldest continuous soil-fertility experiment, the second oldest cotton research project in the world and a 100-year-old laboratory for sustainable agriculture.

"The research at this site shows how, with good management practices, the fertility of soil that has been farmed for decades and decades can be preserved and continue to supply plant nutrients to nonirrigated crops year after year," said Auburn University agronomy and soils professor Charles Mitchell.

The Cullars Rotation is on Woodfield Drive at South College Street in Auburn, directly behind the Jule Collins Smith Museum of Fine Art. The long-term field-crop experiment is named in honor of the late J.A. Cullars, who, with brother-in-law John P. Alvis, owned and farmed cotton on the land in the late 1880s and early 1900s and in 1911 allowed Alabama Agricultural Experiment Station researchers from API to plant research plots on their farm to determine the effects of new, synthetic phosphorous, potassium and nitrogen fertilizers on cotton production.

Design-wise, the project consists of 14 soil treatments replicated three times on 42 separate plots in a three-year rotation of cotton, winter clover, corn, winter wheat and soybeans. Included in those plots are some that Mitchell calls the "no-nothings," because they haven't been fertilized at all during the 100 years of the study.

"And I don't think anybody would have any trouble picking those plots out," said Mitchell, who is in his 27th year as curator of both the Cullars Rotation and Auburn's Old Rotation, located on Lem Morrison Drive, less than half a mile as the crow flies from the Cullars site.

The Old Rotation, by the way, dates back to 1896 and thus is the oldest cotton study in the world. It is recognized as the first experiment that showed a rotation of cotton and legumes would support a cotton crop indefinitely.

Mitchell, an admitted history buff who long recognized that the two ongoing experiments were of major significance not only agriculturally but historically as well, was successful in getting the Old Rotation placed on the National Register of Historic Places in 1988 and the Cullars Rotation, likewise, in 2003.

Listing on the register is exclusive to properties a review board deems worthy of preservation for their significance in American history, architecture, archeology, engineering and culture. Only two other crop research fields in the U.S. — one at the University of Illinois and the other on the University of Missouri's campus — have received the honor.

The Cullars Rotation tells the story of the vast mechanical and technological advances that have occurred in agriculture since 1911, advances that are reflected in increased yields.

"In the fertilized plots where the nutrients are replaced, our yields continue to go up almost every year," says Mitchell, noting that other sweeping changes—boll weevil eradication and the use of conservation tillage, genetically modified crops and cover crops—have also contributed to increased crop production. "We're still learning new things even now about the long-term effects of fertilizers and lime on crop production."

Though most recognized for the long-term research data it produces, the Cullars Rotation also has become a valuable field lab for Auburn students studying soil and plant science.

"It's the only site in the South where students can actually see the effects of soil nutrient deficiencies on five crops over the course of a year," Mitchell says.

When the open pasture, known as Alvis Field, in which the Cullars Rotation is located, was selected as the site for the art museum a decade ago, a 40-foot border was left around the Cullars Rotation to preserve it for ongoing research and demonstration on sustainable crop production on soils of the southern U.S.

Granted, it isn't every day that you'll find a fine arts museum with row crops next door. Mitchell says the arrangement makes sense, when you think about it.

"The two have been surprisingly complementary," he says. "Here you have the museum, with all the glitz and glamour associated with it, and, right across the street from it, have crops growing, showing, in effect, the history of Alabama agriculture," he says.

To learn more about the Cullars Rotation and the Old Rotation, visit


Last Updated: Aug. 12, 2011

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