Dicamba and 2,4-D systems control many problematic weeds; however, drift to susceptible crops can be a concern in diverse production areas. Glufosinate-based systems are an alternative, but current recommended rates of glufosinate can result in variable control. Research was conducted in 2017 and 2018 to investigate the optimum time interval between sequential glufosinate applications and determine if the addition of glyphosate with glufosinate is beneficial for controlling Palmer amaranth and annual grasses in cotton. The interval between sequential applications (1, 3, 5, 7, 10, or 14 d or no second spray) was the whole plot and herbicide option (glufosinate or glufosinate plus glyphosate) was the subplot. Combined over herbicides, Palmer amaranth 15- to 20-cm tall (at four locations) was controlled 98% to 99% with sequential intervals of 1 to 7 d compared with 70% to 88% with intervals of 10 or 14 d. Lowest biomass weight and population densities were noted with 1- to 7-d intervals. Large crabgrass 15- to 20-cm tall (at five locations) was controlled 93% to 98% with glufosinate applications 3- to 7-d apart as compared with 76% to 81% with applications 10- to 14-d apart. Lowest biomass weights were observed with 1- to 7-d intervals. When glufosinate controlled grass less than 93%, adding glyphosate was beneficial. Neither interval between sequential applications nor herbicide option influenced cotton yield. Shorter time intervals between sequential application and including glyphosate can improve the effectiveness of a glufosinate-based system in managing Palmer amaranth and large crabgrass.

中文翻译：

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连续施用草铵膦的间隔时间影响棉花杂草控制

麦草畏和 2,4-D 系统控制许多有问题的杂草；然而，在不同的生产地区，对易感作物的漂移可能是一个问题。基于草铵膦的系统是一种替代方法，但目前推荐的草铵膦用量可能会导致可变控制。2017 年和 2018 年进行了研究，以调查连续施用草铵膦的最佳时间间隔，并确定草甘膦与草铵膦的添加是否有利于控制棉花中的苋菜和一年生草。连续施用之间的间隔（1、3、5、7、10 或 14 天或没有第二次喷洒）是整个小区，除草剂选项（草铵膦或草铵膦加草甘膦）是子小区。结合除草剂，15 至 20 厘米高的棕榈苋菜（在四个位置）以 1 至 7 天的连续间隔控制 98% 至 99%，而间隔为 10 或 14 天的控制率为 70% 至 88%。以 1 至 7 天为间隔记录了最低的生物量重量和种群密度。15 到 20 厘米高的大马唐（在五个位置）在间隔 3 到 7 天施用草铵膦时控制率为 93% 到 98%，而在间隔 10 到 14 天施用时控制率为 76% 到 81%。以 1 到 7 天的间隔观察到最低的生物量重量。当草铵膦控草率低于93%时，添加草甘膦是有益的。连续施用之间的间隔和除草剂选择都不会影响棉花产量。