Field studies were conducted in 2018 and 2019 in Arkansas, Indiana, Illinois, Missouri, and Tennessee to determine if cover-crop residue interfered with herbicides that provide residual control of Palmer amaranth and waterhemp in no-till soybean. The experiments were established in the fall with planting of cover crops (cereal rye + hairy vetch). Herbicide treatments consisted of a nontreated or no residual, acetochlor, dimethenamid-P, flumioxazin, pyroxasulfone + flumioxazin, pendimethalin, metribuzin, pyroxasulfone, and S-metolachlor. Palmer amaranth took 18 d and waterhemp took 24 d in the cover crop–alone (nontreated) treatment to reach a height of 10 cm. Compared with this treatment, all herbicides except metribuzin increased the number of days until 10-cm Palmer amaranth was present. Flumioxazin applied alone or in a mixture with pyroxasulfone were the best at delaying Palmer amaranth growing to a height of 10 cm (35 d and 33 d, respectively). The herbicides that resulted in the lowest Palmer amaranth density (1.5 to 4 times less) integrated with a cover crop were pyroxasulfone + flumioxazin, flumioxazin, pyroxasulfone, and acetochlor. Those four herbicide treatments also delayed Palmer amaranth emergence for the longest period (27 to 34 d). Waterhemp density was 7 to 14 times less with acetochlor than all the other herbicides present. Yield differences were observed for locations with waterhemp. This research supports previous research indicating that utilizing soil-residual herbicides along with cover crops improves control of Palmer amaranth and/or waterhemp.

中文翻译：

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覆盖作物残留物影响残留除草剂防治大豆苋菜和结核菌的效果

2018 年和 2019 年在阿肯色州、印第安纳州、伊利诺伊州、密苏里州和田纳西州进行了实地研究，以确定覆盖作物残留物是否会干扰除草剂，这些除草剂可对免耕大豆中的苋菜和水麻进行残留控制。试验在秋季种植覆盖作物（谷物黑麦 + 紫云英）进行。除草剂处理包括未经处理或无残留的乙草胺、二甲噻吩草胺-P、氟米恶嗪、吡唑砜 + 氟唑嗪、二甲戊灵、灭草灵、吡唑嘧啶和小号-异丙甲草胺。在覆盖作物单独（未处理）处理中，棕榈苋需要 18 天，水麻需要 24 天，达到 10 厘米的高度。与这种处理相比，除metribuzin 以外的所有除草剂都增加了出现10 厘米Palmer 苋菜的天数。氟唑嗪单独使用或与吡唑啉酮混合使用最能延缓苋菜长到 10 cm 的高度（分别为 35 d 和 33 d）。导致与覆盖作物结合的帕尔默苋菜密度最低（低 1.5 至 4 倍）的除草剂是吡唑啉酮 + 氟噻嗪、氟唑嗪、吡唑嘧啶和乙草胺。这四种除草剂处理也将帕尔默苋菜的出苗延迟时间最长（27 至 34 天）。乙草胺的水麻密度比存在的所有其他除草剂低 7 到 14 倍。在有水麻的地方观察到产量差异。这项研究支持先前的研究，表明使用土壤残留除草剂和覆盖作物可以改善对棕榈苋菜和/或水麻的控制。