Field experiments were conducted in 2018 and 2019 at Kansas State University Ashland Bottoms (KSU-AB) research farm near Manhattan, KS, and Kansas State University Agricultural Research Center (KSU-ARC) near Hays, KS, to determine the effectiveness of various PRE-applied herbicide premixes and tank mixtures alone or followed by (fb) an early POST (EPOST) treatment of glyphosate + dicamba for controlling glyphosate-resistant (GR) Palmer amaranth in glyphosate/dicamba-resistant (GDR) soybean. In experiment 1, PRE-applied sulfentrazone + S-metolachlor, saflufenacil + imazethapyr + pyroxasulfone, chlorimuron + flumioxazin + pyroxasulfone, and metribuzin + flumioxazin + imazethapyr provided 85% to 94% end-of-season control of GR Palmer amaranth across both sites. In comparison, Palmer amaranth control ranged from 63% to 87% at final evaluation with PRE-applied pyroxasulfone + sulfentrazone, pyroxasulfone + sulfentrazone plus metribuzin, pyroxasulfone + sulfentrazone plus carfentrazone + sulfentrazone, and sulfentrazone + metribuzin at the KSU-ARC site in experiment 2. All PRE fb EPOST (i.e., two-pass) programs provided near-complete (98% to 100%) control of GR Palmer amaranth at both sites. PRE-alone programs reduced Palmer amaranth shoot biomass by 35% to 76% in experiment 1 at both sites, whereas all two-pass programs prevented Palmer amaranth biomass production. No differences in soybean yields were observed among tested programs in experiment 1 at KSU-ARC site; however, PRE-alone sulfentrazone + S-metolachlor, saflufenacil + imazethapyr + pyroxasulfone, and chlorimuron + flumioxazin + pyroxasulfone had lower grain yield (average, 4,342 kg ha−1) compared with the top yielding (4,832 kg ha−1) treatment at the KSU-AB site. PRE-applied sulfentrazone + metribuzin had a lower soybean yield (1,776 kg ha−1) compared with all other programs in experiment 2 at the KSU-ARC site. These results suggest growers should proactively adopt effective PRE-applied premixes fb EPOST programs evaluated in this study to reduce selection pressure from multiple POST dicamba applications for GR Palmer amaranth control in GDR soybean.

中文翻译：

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控制草甘膦/麦草畏抗性大豆中草甘膦抗性棕榈苋（Amaranthus palmeri）的有效两道除草剂计划

2018 年和 2019 年在堪萨斯州立大学阿什兰底部 (KSU-AB) 研究农场和堪萨斯州立大学农业研究中心 (KSU-ARC) 在堪萨斯州曼哈顿附近进行了田间试验，以确定各种 PRE 的有效性- 单独施用除草剂预混物和罐混合物或随后 (fb) 对草甘膦 + 麦草畏进行早期 POST (EPOST) 处理，以控制草甘膦/麦草畏 (GDR) 大豆中的抗草甘膦 (GR) 棕榈苋菜。在实验 1 中，PRE 应用的磺胺嘧啶 +小号异丙甲草胺、苯嘧磺草胺 + 咪草烟 + 吡唑嘧啶、氯嘧磺隆 + 氟嘧啶 + 吡唑嘧啶和灭菌灵 + 氟嘧啶 + 咪唑草烟在两个地点对 GR Palmer 苋菜提供了 85% 至 94% 的季末控制。相比之下，在最终评估中，PRE 应用的吡虫啉 + 磺胺嘧啶、吡虫啉 + 磺胺嘧啶 + 磺胺嘧啶、吡虫啉 + 磺胺嘧啶 + 杀虫草酮 + 磺胺嘧啶和磺胺嘧啶 + 磺胺嘧啶的最终评估范围为 63% 至 87% 2. 所有 PRE fb EPOST（即两次通过）程序在两个地点都提供了对 GR Palmer amaranth 的近乎完全（98% 到 100%）的控制。在两个地点的实验 1 中，单独的 PRE 程序将 Palmer 苋菜的枝条生物量降低了 35% 至 76%，而所有两次程序都阻止了 Palmer 苋菜的生物量生产。在 KSU-ARC 站点的实验 1 中的测试程序中没有观察到大豆产量的差异；然而，单独使用 PRE 的磺胺嘧啶 +小号-异丙甲草胺、苯嘧磺草胺 + 咪草烟 + 吡唑啉酮和氯嘧磺隆 + 氟嘧啶 + 吡唑啉酮的粮食产量较低（平均 4,342 kg ha-1) 与最高产量（4,832 公斤公顷）相比-1) 在 KSU-AB 站点进行治疗。预先施用的磺胺嘧啶 + 灭虫灵的大豆产量较低（1,776 kg ha-1) 与 KSU-ARC 站点实验 2 中的所有其他程序进行比较。这些结果表明，种植者应主动采用本研究中评估的有效的 PRE-applied premixes fb EPOST 程序，以减少 GDR 大豆中 GR Palmer 苋菜控制的多次 POST 麦草畏应用的选择压力。