Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2008
Publication Date: 9/1/2008
Citation: Mitchell, C.C., Delaney, D.P., Balkcom, K.S. 2008. A historical summary of Alabama's "old rotation" (circa 1896): the world's oldest, continuous cotton experiment. Agronomy Journal. 100:1493-1498. Interpretive Summary: The Old Rotation, located on the campus of Auburn University, continues to document the long-term effects of crop rotation and winter legumes on sustainable cotton production in the Deep South. Researchers from the National Soil Dynamics Laboratory and cooperators from the Agronomy and Soils Department at Auburn University utilize information collected from the longest continuous cotton experiment in the world to monitor changes in crop productivity and soil properties. Long-term yields indicate that winter legumes are as effective as fertilizer N in producing maximum cotton yields. Winter legumes and crop rotations also contribute to increased soil organic matter, which has improved crop yields. In addition, the Old Rotation demonstrates the value of current production practices adopted by many growers in the Deep South that include cover crops combined with conservation tillage systems designed to protect and enhance soils of the region.
Technical Abstract: After more than 110 years, the Old Rotation experiment on the campus of Auburn University in Alabama continues to document the long-term effects of crop rotation and winter legumes on sustainable cotton production in the Deep South. Long-term yields indicate that winter legumes are as effective as fertilizer N in producing maximum cotton yields. Winter legumes and crop rotations contribute to increased soil organic matter. Higher soil organic matter results in higher crop yields. Average yields continue to increase far beyond anything Professor J.F. Duggar imagined when he started this experiment in 1896. His statement that “. . . Alabama agriculture will come unto its own when her fields are green in winter” was prophetic now that many farmers in the Deep South have adopted conservation tillage systems and plant winter cover crops to protect the soil in winter as a fundamental practice demonstrated by the Old Rotation experiment.