Abstract Planting-green (PG), the practice of planting the cash crop into a living cover crop (CC), offers opportunities to maximize CC biomass and weed suppression. The objectives of this study were to evaluate the effects of cereal rye (Secale cerale L. ) termination timing and herbicide programs under PG management on cereal rye biomass, Palmer amaranth (Amaranthus palmeri S. Watson) suppression and seed production, corn (Zea mays L. ) yield, and economic returns. Field experiments were conducted during 2023–2025 under irrigated conditions in south central Nebraska. The study used a split-plot design, a no cover crop (NCC) and five cereal rye CC termination timings (at planting, emergence, V1, V2, and V3 corn growth stages) as the main plot factor and four herbicide programs nontreated, pre-emergence (PRE) only (PRE-only), post-emergence only (POST-only), and preemergence followed by postemergence (PP) herbicide as sub-plot factors. Delaying cereal rye termination from corn planting up to V3 corn growth stage increased cereal rye biomass from 5, 992 to 10, 888 kg ha –1 in 2024 and from 2, 941 to 7, 007 kg ha –1 in 2025. Cereal rye terminated at V2 or V3 corn growth stage reduced A. palmeri density, biomass, and seed production by >99% compared with the NCC. Following high biomass conditions, cereal rye provided comparable A. palmeri suppression to herbicide-based programs, and the additional herbicide use offered limited benefit. In contrast, following low-cereal rye biomass conditions (<6, 000 kg ha –1), herbicide inclusion remained essential to achieve effective A. palmeri control and minimizing seed production. Corn yield was not affected by delayed cereal rye termination (ranging from 13, 110–15, 660 kg ha –1). Economic analysis indicated that integrating cereal rye CC with reduced herbicide programs (preemergence-only or POST-only) maintained profitability (2, 064–2, 364 ha –1) comparable to the NCC system with PP herbicide program (2, 353–2, 401 ha –1).
Kumar et al. (Fri,) studied this question.