Abstract The success of integrated weed management strategies is contingent on the accuracy of control actions in both time and space. While emphasis has been given to spatial accuracy, timing accuracy has been largely neglected. Weed control timing must consider not only the total duration of weed interference with the crop, as done by the traditional critical period of weed control (CPWC) based on yield protection only, but also weed growth, size, and susceptible phenological stages. In this study, we expand upon the idea of using weed emergence models for timing weed control by integrating them with phenology probability models for key weed growth stages to optimize timing of control actions, here referred as Critical Control Windows (CCW). Combining the CCW with thresholds for yield loss due to weed interference and thresholds for weed survival risk makes it possible determining the frequency with which control actions should be implemented to maintain crop yield and weed populations at desired levels. Using Senna obtusifolia as a study case, vegetative and reproductive phenological stages were modeled as a function of seedling emergence for different cohorts. Chronological and thermal-time models provided robust predictions of S. obtusifolia phenology. CCW did not always coincided with CPWC for several crops when considering 10-cm tall plants as the threshold for control. In general, for summer row crops, CCW required 2 postemergence control actions and sometimes 1 action outside the CPWC. The results of the present research illustrate how predictive models can be used to develop CCW that will complement the traditional CPWC. These two concepts when used complementary can increase not only timing accuracy, but also efficiency of weed control.

中文翻译：

---

整合出现和物候模型以确定杂草控制的行动窗口：使用番泻叶的案例研究

摘要 综合杂草管理策略的成功取决于控制措施在时间和空间上的准确性。虽然强调了空间精度，但在很大程度上忽略了计时精度。杂草控制时间不仅必须考虑杂草干扰作物的总持续时间，如传统的仅基于产量保护的杂草控制关键期 (CPWC)，还必须考虑杂草生长、大小和易感物候阶段。在这项研究中，我们扩展了使用杂草出现模型进行定时杂草控制的想法，将它们与关键杂草生长阶段的物候概率模型相结合，以优化控制动作的时间，这里称为关键控制窗口 (CCW)。将 CCW 与杂草干扰导致的产量损失阈值和杂草存活风险阈值相结合，可以确定应实施控制措施的频率，以将作物产量和杂草种群保持在所需水平。使用钝叶番泻叶作为研究案例，将营养和生殖物候阶段建模为不同群体的幼苗出现的函数。年代学和热时间模型提供了对钝叶 S. obtusifolia 物候学的可靠预测。当将 10 厘米高的植物作为控制阈值时，CCW 并不总是与几种作物的 CPWC 一致。一般来说，对于夏季行间作物，CCW 需要 2 次芽后控制措施，有时需要 1 次 CPWC 之外的措施。本研究的结果说明了如何使用预测模型来开发 CCW，以补充传统的 CPWC。这两个概念互补使用时，不仅可以提高计时精度，还可以提高杂草控制效率。