Planning effective weed control in cropping systems requires exact appraisal of the weed intensity and duration of their competition with the crops. This 2‐year study was carried out in order to determine the critical weed control period in sesame fields. Related and relative crop yields were monitored and analyzed using a four‐parametric log‐logistic model. We recorded data from weed‐free plots and compared these with data from different periods of weed interference. In both the study years, the longer period of weed interference decreased the relative yield of sesame, whereas the yield was increased with increasing duration of the weed‐free period. A 51–78.7% decline in sesame yield was noted if the weeds were allowed to compete with the crop from planting to harvest. In the first year, the duration of the critical period for weed control (CPWC) was 177–820 growing degree days (GDD), which corresponded to 14–64 days after crop emergence (DAE), and between 170 and 837 GDD (13–64 DAE) in the second year; this was based on a 5% acceptable yield loss. The results of this study clearly elaborated that maintaining weed‐free conditions is compulsory from as early as the second week after the emergence of sesame plants, and this should be maintained at least until the ninth week to avoid sesame yield losses by more than 5%. These findings show that growers can benefit from CPWC to improve weed control in sesame production, including the efficacy of a weed control program and its cost.

中文翻译：

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芝麻生产中杂草控制的关键期

在种植系统中规划有效的杂草控制需要准确评估杂草强度和它们与作物竞争的持续时间。进行这项为期 2 年的研究是为了确定芝麻田的关键杂草控制期。使用四参数对数逻辑模型监测和分析相关和相对作物产量。我们记录了来自无杂草地块的数据，并将这些数据与来自不同杂草干扰时期的数据进行了比较。在这两个研究年中，杂草干扰时间越长，芝麻的相对产量就越低，而随着无杂草时间的延长，芝麻产量会增加。如果允许杂草从种植到收获与作物竞争，芝麻产量会下降 51-78.7%。在第一年，杂草控制关键期 (CPWC) 的持续时间为 177-820 个生长期 (GDD)，对应于作物出苗后的 14-64 天 (DAE)，在 170 至 837 个 GDD (13-64 DAE) 之间第二年；这是基于 5% 可接受的产量损失。这项研究的结果清楚地阐述了，早在芝麻植物出苗后的第二周就必须保持无杂草条件，并且至少应保持到第九周，以避免芝麻产量损失超过5% . 这些发现表明，种植者可以从 CPWC 中受益，以改善芝麻生产中的杂草控制，包括杂草控制计划的有效性及其成本。第二年在 170 到 837 GDD（13-64 DAE）之间；这是基于 5% 可接受的产量损失。这项研究的结果清楚地阐述了，早在芝麻植物出苗后的第二周就必须保持无杂草条件，并且至少应保持到第九周，以避免芝麻产量损失超过5% . 这些发现表明，种植者可以从 CPWC 中受益，以改善芝麻生产中的杂草控制，包括杂草控制计划的有效性及其成本。第二年在 GDD 170 到 837（13-64 DAE）之间；这是基于 5% 可接受的产量损失。该研究结果明确阐述，早在芝麻出苗后的第二周就必须保持无杂草状态，并且至少应保持到第九周，以免芝麻产量损失超过5% . 这些发现表明，种植者可以从 CPWC 中受益，以改善芝麻生产中的杂草控制，包括杂草控制计划的有效性及其成本。并且这应该至少保持到第九周，以避免芝麻产量损失超过5%。这些发现表明，种植者可以从 CPWC 中受益，以改善芝麻生产中的杂草控制，包括杂草控制计划的有效性及其成本。并且这应该至少保持到第九周，以避免芝麻产量损失超过5%。这些发现表明，种植者可以从 CPWC 中受益，以改善芝麻生产中的杂草控制，包括杂草控制计划的有效性及其成本。