Mugwort (Artemisia vulgaris L.) is becoming increasingly problematic in cool-season pastures and grasslands. A 3-yr field experiment evaluated different rates of nitrogen and herbicides for A. vulgaris management in a permanent grassland. The main plot had three nitrogen rates, 0, 62, and 124 kg N ha−1; the subplot had three herbicides, aminopyralid, clopyralid, and glyphosate; and the sub-subplot had three herbicide rates, aminopyralid (61, 122, and 244 g ae ha−1), clopyralid (140, 280, and 560 g ae ha−1), and glyphosate (552, 1,104, and 2,208 g ae ha−1). Results revealed that nitrogen had no effect on A. vulgaris control, rhizome biomass, and stem density. However, cool-season grass biomass was the highest (7,126 kg ha−1) in the plots that received 124 kg N ha−1 and 244 g ae ha−1 of aminopyralid. Only glyphosate caused grass injury, which varied from 65% to 100% depending upon application rate. By 9 mo after initial herbicide treatment (MAIT), A. vulgaris was controlled 60% to 98% with aminopyralid at ≥61 g ae ha−1 or glyphosate at ≥552 g ae ha−1. By 21 MAIT, aminopyralid at ≥122 g ae ha−1 or glyphosate at ≥1,104 g ae ha−1 resulted in >95% reduction in A. vulgaris stem density and rhizome biomass and provided ≥98% visual control. By 33 MAIT, complete control of A. vulgaris was confirmed in plots treated with aminopyralid at ≥122 g ae ha−1 or glyphosate at ≥1,104 g ae ha−1. Clopyralid was not effective; A. vulgaris control was <40% even after three annual applications at 560 g ae ha−1. Results indicate that integration of nitrogen fertilization with aminopyralid did not improve A. vulgaris control, but was advantageous in enhancing cool-season grass productivity.

中文翻译：

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氮素和除草剂在冷季牧草艾蒿综合管理中的作用

艾蒿（青蒿L.) 在凉爽季节的牧场和草地上变得越来越成问题。一项为期 3 年的田间试验评估了不同氮肥和除草剂的施用量A. vulgaris永久性草地管理。主地块有 0、62 和 124 kg N ha 三种氮含量-1; 子地块有三种除草剂，氨基嘧啶、氯嘧啶和草甘膦；子图有三种除草剂比率，氨基嘧啶（61、122 和 244 g ae ha-1), clopyralid (140, 280, 和 560 g ae ha-1) 和草甘膦（552、1,104 和 2,208 g ae ha-1）。结果表明，氮对A. vulgaris控制、根茎生物量和茎密度。然而，冷季草生物量最高（7,126 kg ha-1) 在接收 124 kg N ha 的地块中-1和 244 g ae ha-1的氨基吡啶。只有草甘膦会造成草害，根据施用量的不同，草害从 65% 到 100% 不等。初始除草剂处理 (MAIT) 后 9 个月，A. vulgaris用≥61 g ae ha 的氨基吡咯烷控制 60% 至 98%-1或草甘膦≥552 g ae ha-1. 到 21 MAIT，氨基吡啶≥122 g ae ha-1或草甘膦≥1,104 g ae ha-1导致> 95％的减少A. vulgaris茎密度和根茎生物量，并提供≥98％的视觉控制。通过 33 MAIT，完全控制A. vulgaris在 ≥122 g ae ha 的氨基吡啶处理的地块中得到证实-1或草甘膦≥1,104 g ae ha-1. 氯吡菌胺无效；A. vulgaris即使在 560 g ae ha 的三年施用后，控制率也 <40%-1. 结果表明氮肥与氨基吡啶的整合并没有改善A. vulgaris控制，但有利于提高冷季草的生产力。