Cover crop termination timings and methods effect on cotton ( Gossypium hirsutum L.) development and yield

Cover crops have been promoted for use in agricultural systems due to both environmental and economic opportunities. Cotton (Gossypium hirsutum L.) growers in West Tennessee faced challenges in 2015 and 2016 with cover crop termination management which resulted in failed cotton stands. The objective of this experiment was to determine effects of cover crop termination timing and method on cotton emergence, development, and yield. Field experiments were conducted from 2018 to 2020 in both small plot and on-farm scenarios across West Tennessee. Cover crop termination timings consisted of an at-planting termination, 3 weeks prior to planting, and both a broadcast and furrow-strip termination 6 weeks prior to planting. The cover crop termination methods consisted of chemical termination, mechanical termination, and chemical + mechanical termination. At-planting termination reduced emergence by 25% and delayed maturity of 65% of the stand relative to a 6-week broadcast termination. Mechanical termination reduced emergence by 26% and delayed maturity of 26% of the stand relative to the chemical and chemical plus mechanical termination treatments. Thrips injury ratings were greater in cotton following a chemical + mechanical termination of the cover crop. Damage from three-cornered alfalfa hoppers (Sissistilus festinus) was less prevalent in cotton following cover crops terminated 6 weeks prior to planting in a broadcast method compared to other timings. While early season effects were observed, end-of-season yield differences were not noted. Still, producers in short season environments should be aware of the higher level of risk associated with at-planting terminations or terminations.