The evolution of multiple herbicide-resistant weeds, including Palmer amaranth, has necessitated the implementation of an integrated weed management (IWM) program. Understanding weed emergence patterns is critical for developing effective IWM strategies. The objective of this study was to evaluate the effect of tillage timings and residual herbicides on cumulative emergence and emergence pattern of Palmer amaranth. Field experiments were conducted in 2015 and 2016 in a field naturally infested with photosystem (PS) II and 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor-resistant Palmer amaranth near Shickley, Nebraska, in a bare ground study, with no crop planted in the plots, although residues from the preceding corn crop were present on the soil surface. Treatments consisted of shallow tillage timings (early, mid, and late), three premix corn or soybean residual herbicides, and a nontreated control. The Weibull function was fitted to cumulative Palmer amaranth emergence with day of year (DOY) and thermal time (TT) as independent variables. Year by treatment interaction was significant for time to 10%, 25%, 50%, 75%, and 90% Palmer amaranth emergence and cumulative emergence. The majority of Palmer amaranth seedlings emerged early, following early tillage with 90% cumulative emergence occurring on DOY 172 compared with DOY 210 to 212 for mid- and late-tillage, and DOY 194 for the nontreated control in 2015. In 2016, 90% of cumulative emergence following early-, mid-, and late-tillage (DOYs 201 to 211) were similar, and that of the nontreated control (DOY 188) was similar to that of early tillage. Nontreated control and PRE herbicide treatments had similar DOY values for 90% emergence in both years. The number of emerged Palmer amaranth seedlings over the season was higher with shallow tillage than no tillage or with the use of PRE herbicides.

中文翻译：

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受耕作时间和残留除草剂影响的棕榈苋（Amaranthus palmeri）的出现模式

包括帕尔默苋菜在内的多种抗除草剂杂草的进化需要实施综合杂草管理 (IWM) 计划。了解杂草出现模式对于制定有效的 IWM 策略至关重要。本研究的目的是评估耕作时间和残留除草剂对棕榈苋的累积出苗和出苗模式的影响。田间试验于 2015 年和 2016 年在内布拉斯加州希克利附近的一个自然受光系统 (PS) II 和 4-羟基苯丙酮酸双加氧酶 (HPPD) 抑制剂抗性帕尔默苋菜侵染的田间进行，在裸地研究中，地块内没有种植任何作物，尽管土壤表面存在前一玉米作物的残留物。处理包括浅耕时间（早、中和晚），三种预混玉米或大豆残留除草剂，以及未经处理的对照。Weibull 函数以一年中的某一天 (DOY) 和热时间 (TT) 作为自变量拟合累积的 Palmer 苋菜出现。治疗相互作用的年份对于 10%、25%、50%、75% 和 90% 的帕尔默苋菜出现和累积出现的时间是显着的。大多数帕尔默苋菜幼苗在早耕后出苗较早，2015 年在 DOY 172 与 DOY 210 至 212 为中晚耕和 DOY 194 为 2015 年相比，90% 的累积出苗发生在 DOY 172 上。2016 年，90%早耕、中耕和晚耕（DOY 201 至 211）后的累积出苗率相似，未处理对照（DOY 188）与早耕相似。未经处理的对照和 PRE 除草剂处理在两年中 90% 的出苗率具有相似的 DOY 值。浅耕比免耕或使用 PRE 除草剂时，本季出苗的苋菜苗数量更高。