Rapid crop canopy formation is important to reduce weed emergence and selection for herbicide resistance. Field experiments were conducted in 2017 and 2018 in Fayetteville, AR, to evaluate the impacts of PRE applications of flumioxazin on soybean injury, soybean density, canopy formation, and incidence of soil-borne pathogens. Flumioxazin was applied at 0, 70, and 105 g ai ha−1 to predetermined flumioxazin-tolerant and -sensitive soybean varieties. Flumioxazin at 70 g ha−1 injured the tolerant and sensitive varieties from 0% to 4% and 14% to 15%, respectively. When averaged over flumioxazin rates, density of the sensitive variety was only reduced in 2017 when activation of flumioxazin was delayed 7 d. Compared to the tolerant soybean variety, flumioxazin at 70 g ha−1 delayed the sensitive variety from reaching 20%, 40%, 60%, and 80% groundcover by 15, 16, 11, and 5 d, respectively. No delay in canopy closure (95% groundcover) was observed with either variety. Consequently, no yield loss occurred for either variety following a flumioxazin application. Flumioxazin did not impact root colonization of Didymella, Fusarium, Macrophomina, or Rhizoctonia. Pythium colonization of the soybean stem was increased by flumioxazin in 2017, but not in 2018. Increased injury, delays in percent groundcover, and an increase in Pythium colonization of soybean following a flumioxazin application may warrant the need for other soil-applied herbicides at soybean planting. Alternatively, soybean injury and delays in percent groundcover following flumioxazin applications can be mitigated through appropriate variety selection; however, comprehensive screening is needed to determine which varieties are most tolerant to flumioxazin.

中文翻译：

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氟咪嗪对大豆冠层形成和土传病原体存在的影响

快速的作物冠层形成对于减少杂草出现和选择除草剂抗性很重要。田间试验于 2017 年和 2018 年在阿肯色州费耶特维尔进行，以评估氟哌嗪的 PRE 应用对大豆损伤、大豆密度、冠层形成和土传病原体发生率的影响。氟米沙嗪以 0、70 和 105 g ai ha 施用-1对预先确定的氟唑嗪耐受和敏感的大豆品种。氟米沙嗪 70 g ha-1对耐受和敏感品种的伤害分别从 0% 到 4% 和 14% 到 15%。当对氟米恶嗪速率进行平均时，敏感品种的密度仅在 2017 年当氟米恶嗪的激活延迟 7 天时才降低。与耐受性大豆品种相比，70 g ha 的氟米沙嗪-1将敏感品种从达到 20%、40%、60% 和 80% 地被覆盖率分别延迟 15、16、11 和 5 天。任一品种均未观察到树冠关闭延迟（95% 的地被植物）。因此，在施用氟嘧啶后，任何一个品种都没有出现产量损失。氟米沙嗪不影响根系定植Didymella, Fusarium, Macrophomina， 要么丝核菌属.腐霉2017 年氟嘧啶增加了大豆茎的定殖，但 2018 年没有增加。伤害增加，地被覆盖率延迟，以及腐霉施用氟嘧啶后大豆定植可能需要在大豆种植时使用其他土壤除草剂。或者，可以通过适当的品种选择来减轻施用氟噻嗪后大豆损伤和地被覆盖率延迟；但是，需要进行全面筛选以确定哪些品种对氟咪嗪最耐受。