Pigeonpea has great potential as a profitable summer legume rotational crop in cereal farming systems of subtropical Australia. Pigeonpea requires season-long weed control, but options for controlling broadleaf weeds in pigeonpea with POST herbicides are limited. The objective of this study was to evaluate the performance of different herbicides (PRE: pendimethalin; POST: acifluorfen, bentazon, and imazapic) applied singly or in sequence for horse purslane control in pigeonpea and their impact on pigeonpea yield. Field experiments were conducted in 2017 and 2018 at Gatton, Australia. Pendimethalin applied PRE at 1.14 kg ai ha−1 reduced horse purslane biomass by 87% and 92% and produced 32% and 105% higher grain yield compared with the nontreated control in 2017 and 2018, respectively. Imazapic applied POST at 0.10 kg ai ha−1 reduced horse purslane biomass by 79% and 82% and increased grain yield by 60% and 88% compared with the nontreated control in 2017 and 2018, respectively. Acifluorfen applied POST (0.34 and 0.42 kg ai ha−1) caused 16% to 48% injury to pigeonpea at 45 d after treatment. Control of horse purslane ranged from 87% to 92% (biomass reduction) with pendimethalin applied PRE at 1.14 kg ai ha−1 and was comparable with pendimethalin applied PRE at 0.91 kg ai ha−1 in the sequential application, and imazapic at 0.08 kg ai ha−1 or bentazon at 0.96 kg ai ha−1. The study findings suggest if farmers miss the PRE application of pendimethalin or are unable to achieve season-long weed control, POST application of imazapic is an alternate. This research provided herbicide options for control of horse purslane in pigeonpea that could be used in rotations for reducing the selection pressure of weeds.

中文翻译：

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用 PRE 和 POST 除草剂防治木豆中的马齿苋 (Trianthema portulacastrum)

木豆在澳大利亚亚热带谷物种植系统中作为一种有利可图的夏季豆类轮作作物具有巨大潜力。木豆需要整季的杂草控制，但使用 POST 除草剂控制木豆中阔叶杂草的选择有限。本研究的目的是评估在木豆中单独或依次施用不同除草剂（PRE：二甲戊灵；POST：三氟草醚、苯达松和灭草菌）的性能及其对木豆产量的影响。2017 年和 2018 年在澳大利亚加顿进行了现场实验。二甲戊灵以 1.14 kg ai ha 施用 PRE-1与 2017 年和 2018 年的未处理对照相比，马齿苋生物量分别减少了 87% 和 92%，谷物产量分别提高了 32% 和 105%。Imazapic 以 0.10 kg ai ha 应用 POST-1与 2017 年和 2018 年未处理的对照相比，马齿苋生物量分别减少了 79% 和 82%，谷物产量增加了 60% 和 88%。Acifluorfen 应用 POST (0.34 和 0.42 kg ai ha-1) 在处理后 45 天对木豆造成 16% 至 48% 的伤害。马齿苋的控制范围从 87% 到 92%（生物量减少），使用 1.14 kg ai ha 的二甲戊灵 PRE-1并且与以 0.91 kg ai ha 施用 PRE 的二甲戊灵相当-1在顺序应用中，以及 0.08 kg ai ha 的 imazapic-1或苯达松 0.96 kg ai ha-1. 研究结果表明，如果农民错过了预先施用二甲戊灵或无法实现整季杂草控制，则可以选择后施用灭草定。这项研究为控制木豆中的马齿苋提供了除草剂选择，可用于轮作以降低杂草的选择压力。