Submitted to: Cotton Research and Extension Report
Publication Type: Experiment Station
Publication Acceptance Date: 2/15/2008
Publication Date: 3/15/2008
Citation: Mitchell, C.C., Balkcom, K.S., Delaney, D.P. 2008. Irrigation on the Old Rotation. Cotton Research and Extension Report. No. 32. p. 34-35.
Technical Abstract: The Old Rotation (circa 1896) is the oldest, continuous cotton experiment in the world. There are 13 plots on one acre of land on the campus of Auburn University to document the long-term effects of crop rotations with and without winter legumes as a source of N for cotton, corn, soybean, and wheat. Irrigation was installed on half of each plot in 2003 and both irrigated and non-irrigated yields have been monitored since then. Because of the extreme drought of 2007, irrigation was necessary to assure a uniform stand of cotton. Irrigation began in mid-May and continued to early September with most of the plots receiving a total of 20 to 25 inches of irrigation. This was twice the total amount applied in previous years. Irrigation in 2007 resulted in large yield differences and an all-time record cotton lint yield of 1940 lbs. of lint per acre from the 2-year cotton-corn rotation with legume plus 120 pounds of N per acre. This is the first year that a response to irrigation occurred, but the irrigation resulted in a 22% average yield increase.