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.

Cover crops are being increasingly recommended as an integrated approach to controlling glyphosate-resistant Palmer amaranth and other troublesome weeds. Thus, a field experiment was conducted in 2010 through 2012 to evaluate the critical period for weed control (CPWC) in cotton as affected by a cereal rye cover crop and tillage. The management systems evaluated included conventional tillage following winter fallow, conservation tillage (CT) following winter fallow, and CT following a cereal rye cover crop managed for maximum biomass. Throughout most of the growing season, weed biomass in cereal rye cover crop plots was less than the CT winter-fallow system in both years and less than both CT winter fallow and conventional tillage in 2012. The CPWC was shortest in 2010 following conventional tillage; however, in 2012, production system influences on CPWC were less. The presence of the rye cover crop delayed the critical timing for weed removal (CTWR) approximately 8 d compared with fallow treatment both years, while conventional tillage delayed CTWR about 2 wk compared with winter fallow. Relative yield losses in both years did not reach the 5% threshold limit until about 2 wk after planting (WAP) for CT following winter fallow, 3 WAP for CT following a cover crop, and 3.5 WAP following conventional tillage. Thus, CT following winter fallow should be avoided to minimize cotton yield loss.