Evaluation of Cover Crop Species Termination Timing Prior to Cotton Production in Mississippi

The termination timing of cover crops varies by farm. This research was conducted to determine whether the timing of cover crop termination alters cotton growth and development. The effects of cover crop (crimson clover, cereal rye, oat, and a blend of cereal rye + crimson clover) and termination timing (targeted dates 01 February, 01 March, 01 April, and 01 May) on cotton emergence, plant height, nodes above white flower and yield was evaluated near Starkville, MS on a Leeper silty clay loam (fine, smectitic, nonacid, thermic Vertic Epiaquepts) in 2017 and 2018 and near Tribbett, MS on a Dundee silty clay loam (Fine-silty, mixed, active, thermic type Typic Endoqualfs) in 2017. Timing of cover crop termination had a transient effect on cotton emergence. Relative to terminating cover crops in March or April, terminating in February or May decreased cotton emergence at 7 days after planting (DAP) by up to 26%. However, by 14 DAP, cotton stand averaged 74,190 plants/ha and there was no effect of cover crop termination timing on emergence. There were modest interaction effects of cover crop and termination timing on cotton development including plant height, number of nodes, and nodes above white flower. Cotton lint yield did not differ due to cover crop species but increased up to 8% when cover crop termination was delayed from February until May. This research indicates that April and May are the optimal times to terminate a cover crop in a Mississippi cotton production system, provided there is a suitable environment for healthy cotton growth.