Atrazine offers growers a reliable option to control a broad spectrum of weeds in grain sorghum production systems when applied PRE or POST. However, because of the extensive use of atrazine in grain sorghum and corn, it has been found in groundwater in the United States. Given this issue, field experiments were conducted in 2017 and 2018 in Fayetteville and Marianna, Arkansas, to explore the tolerance of grain sorghum to applications of assorted photosystem II (PSII)-inhibiting herbicides in combination with S-metolachlor (PRE and POST) or mesotrione (POST only) as atrazine replacements. All experiments were designed as a factorial, randomized complete block; the two factors were (1) PSII herbicide and (2) the herbicide added to create the mixture. The PSII herbicides were prometryn, ametryn, simazine, fluometuron, metribuzin, linuron, diuron, atrazine, and propazine. The second factor consisted of either no additional herbicide, S-metolachlor, or mesotrione; however, mesotrione was excluded in the PRE experiments. Crop injury estimates, height, and yield data were collected or calculated in both studies. In the PRE study, injury was less than 10% for all treatments except those containing simazine, which caused 11% injury 28 d after application (DAA). Averaged over PSII herbicide, S-metolachlor–containing treatments caused 7% injury at 14 and 28 DAA. Grain sorghum in atrazine-containing treatments yielded 97% of the nontreated. Grain sorghum receiving other herbicide treatments had significant yield loss due to crop injury, compared with atrazine-containing treatments. In the POST study, ametryn- and prometryn-containing treatments were more injurious than all other treatments 14 DAA. Grain sorghum yield in all POST treatments was comparable to atrazine, except prometryn plus mesotrione, which was 65% of the nontreated. More herbicides should be evaluated to find a comparable fit to atrazine when applied PRE in grain sorghum. However, when applied POST, diuron, fluometuron, linuron, metribuzin, propazine, and simazine have some potential to replace atrazine in terms of crop tolerance and should be further tested as part of a weed control program across a greater range of environments.

中文翻译：

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高粱对预施和后施光系统 II 抑制性除草剂的耐受性

当应用 PRE 或 POST 时，阿特拉津为种植者提供了一种可靠的选择来控制高粱生产系统中的各种杂草。然而，由于在高粱和玉米中大量使用阿特拉津，在美国的地下水中也发现了它。鉴于这个问题，2017 年和 2018 年在阿肯色州的费耶特维尔和玛丽安娜进行了田间试验，以探索高粱对各种光系统 II (PSII) 抑制除草剂与小号-metolachlor（PRE 和 POST）或甲基磺草酮（仅限 POST）作为阿特拉津替代品。所有实验均设计为阶乘、随机完整区组；这两个因素是（1）PSII除草剂和（2）添加的除草剂以产生混合物。PSII除草剂是扑草净、苎草净、西马津、氟草隆、灭草灵、利奴隆、敌草隆、莠去津和丙嗪。第二个因素包括没有额外的除草剂，小号-异丙甲草胺或甲基磺草酮；然而，甲基磺草酮被排除在 PRE 实验中。在两项研究中都收集或计算了作物伤害估计值、高度和产量数据。在 PRE 研究中，除含有西马津的治疗外，所有治疗的损伤均低于 10%，西马津在应用后 28 天造成 11% 的损伤 (DAA)。平均超过 PSII 除草剂，小号含异丙甲草胺的治疗在 14 和 28 DAA 造成 7% 的损伤。含阿特拉津处理的谷物高粱产量为未处理的 97%。与含阿特拉津的处理相比，接受其他除草剂处理的高粱因作物损伤而导致产量损失显着。在 POST 研究中，含苎草净和含扑草净的治疗比所有其他治疗 14 DAA 更具伤害性。除普草净加甲基磺草酮外，所有 POST 处理中的高粱产量均与阿特拉津相当，占未处理组的 65%。在谷物高粱中使用 PRE 时，应评估更多除草剂以找到与阿特拉津相当的适用性。然而，当应用 POST 时，敌草隆、氟米草隆、利奴隆、metribuzin、丙嗪、