Alabama's "Old Rotation" Experiment

Auburn University’s “Old Rotation” The “Old Rotation” is an agricultural experiment that has been under continuous study on the campus of Auburn University, in Auburn, Lee County, since its inception in 1896. It is the oldest continuous cotton experiment in the world and the third oldest field crop experiment conducted on the same site in the United States. Results from the experiment provided the first documented evidence of crop rotation as an effective means of maintaining soil fertility in cotton culture. The Old Rotation was placed on the National Register of Historical Places in 1988, and in 2013, the Old Rotation was named one of the seven longest-running science experiments in the world by Guinness World Records.

By the late nineteenth century, decades of cotton culture and soil erosion had drastically reduced the fertility of farmland in Alabama. The state’s economy was largely dependent upon farming, with some 3.2 million acres in cotton and at least half of the state’s workers employed in agriculture. In response to the problem, John F. Duggar, director of the Alabama Agricultural Experiment Station at the Agricultural and Mechanical College of Alabama (now Auburn University) started an experiment in 1896 to test his theories that sustainable cotton production was possible in Alabama by adopting a crop rotation system that included planting winter legumes (clovers and/or vetch) to protect the soil from winter erosion and add nitrogen to the soil. At the time, all farmers tilled under their fields after harvest and left them bare; this practice resulted in severe erosion and loss of topsoil.

Old Rotation Experiment Field The Old Rotation sits on an acre of land near what is now the center of Auburn University’s main campus by the Davis Arboretum; it was first referred to by this name in a 1930 Extension bulletin. It is maintained by the Alabama Agricultural Experiment Station with support from the Alabama Wheat and Feed Grain Commission and the Alabama Cotton Commission. The experiment maintains Duggar’s original structure, being laid out in 13 plots that are planted according to the desired results. For example, one plot has had cotton every year since 1896 with no winter cover, a second is on two-year rotation of cotton and corn, and a third is on a three-year rotation of cotton, corn, wheat and soybeans. Other variables measured by researchers include the effects of treatments with and without winter legumes (usually crimson clover and/or vetch) and with and without nitrogen fertilizer. Long-term results have indicated that planting cover crops of winter legumes is as effective as the application of nitrogen fertilizer in producing average cotton yields of 1,100 pounds of cotton fiber, known as lint, per acre on non-irrigated plots over ten years. Winter legumes and crop rotations contribute to increased soil organic matter, which in turn produced higher fertility and rates of moisture-holding capacity in the soil. These benefits also reduce the costs for artificial fertilizers.

In the early days of the Old Rotation, very little fertilizer at all was used because the practice of adding fertilizers was relatively new on Alabama farms. Farmers added a little blood meal for nitrogen, rock phosphate for phosphorus, and a mineral known as kainite for potassium. Gradually, as new fertilizer materials became available, they were adopted on the Old Rotation. Modern fertilizer materials and higher application rates have been used since the 1950s. Prior to the 1960s, all crops were cultivated with a mule and plow and harvested by hand. Cotton was ginned on site by Alabama Agricultural Experiment Station workers.

John F. Duggar In 1997, the Old Rotation entered a new era of agricultural production where boll weevil eradication, genetically modified crops, and conservation tillage almost eliminated the need for plowing and applying pesticides. Prior to that time, more than 15 applications of pesticides and herbicides per year were used to control insects and weeds. Conservation tillage, in which crops are planted directly into residue of the previous crops, eliminates the need for plowing or cultivating the soil and thus avoids almost all soil erosion. In 2003, irrigation was added to half of each plot. Since initiating conservation tillage practices in 1997, yields from all crops grown on the plots increased dramatically. Yields of cotton, corn, wheat, and soybean continued to increase far beyond those of Duggar’s generation. During his tenure, Duggar was satisfied harvesting 200 to 300 pounds of cotton lint per acre. Today, some irrigated plots have produced more than 2,300 pounds of lint per acre. Duggar saw corn yields of around 20 bushels per acre, but yields of more than 200 bushels per acre are common today. And the Old rotation produces close to 80 bushels per acre of wheat followed by 80 bushels per acre of soybeans.

Cotton is still a significant driver of Alabama’s economy, and since the late-nineteenth century, the Old Rotation has been documenting the long-term effects of crop rotation and winter legumes on cotton production in the Deep South. It provides growers, students, and faculty with a living demonstration of fundamental agronomic practices that encourage the use of sustainable crop production. Researchers at Auburn University and at the U.S. Department of Agriculture-Soil Dynamics Laboratory in Auburn have prepared the first ever comprehensive research publication covering the entire 110-year history of this experiment. It was published in 2008 in the Agronomy Journal and provides insight into issues both past and present that effect sustainable crop production in the South.

Further Reading

  • Mitchell, Charles C., Dennis P. Delaney, and Kipling S. Balkcom. “A Historical Summary of Alabama’s Old Rotation (circa 1896): The World’s Oldest, Continuous Cotton Experiment.” Agronomy Journal 100 (September-October 2008): 1493-98.

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