Implications of cereal rye cover crop termination timing and residue management on Palmer amaranth ( <i>Amaranthus palmeri</i> ) and sicklepod ( <i>Senna obtusifolia</i> ) control in peanut

Abstract Weed management in peanut primarily relies on intensive herbicide programs. Integrating cereal rye as a cover crop may reduce herbicide input without compromising weed control. Field experiments were conducted to evaluate cereal rye termination management and herbicide programs in peanut. Main plot treatments included a winter fallow control and four cereal rye termination scenarios: 1) early termination 28 d before peanut planting (DBP) with residue rolled flat; 2) early termination 28 DBP with residue left standing; 3) late termination 14 DBP with residue rolled flat; or 4) late termination 14 DBP with residue left standing. Subplot treatments consisted of four herbicide programs: 1) preemergence + early postemergence + mid-postemergence herbicides; 2) preemergence + mid-postemergence herbicides; 3) early postemergence + mid-postemergence herbicides; and 4) a nontreated control. Early cereal rye termination (28 DBP), whether rolled or standing, reduced Palmer amaranth density by 36% to 48% without preemergence herbicides and by 36% to 50% when preemergence herbicides (fluridone or flumioxazin) were applied. Sicklepod density was unaffected by early termination. In contrast, late termination reduced sicklepod density by 47% to 50% and Palmer amaranth density by 64% to 86% relative to the winter fallow control at 28 d after preemergence application. Across all treatments, cereal rye reduced Palmer amaranth and sicklepod biomass by 63% to 67% and 63% to 65%, respectively, 28 d after mid-postemergence herbicides were applied. However, standing cereal rye residue reduced peanut yield compared to rolled residue and the winter fallow. Late-terminated, rolled cereal rye residue combined with reduced herbicide programs (preemergence + mid-postemergence or early postemergence + mid-postemergence) provided weed control and yield comparable to the intensive herbicide program (preemergence + early postemergence + mid-postemergence) in winter fallow control. Based on these findings, late-terminated, rolled cereal rye has the potential to reduce herbicide input while maintaining peanut yield and effective weed suppression.