Effect of Isoproturon With and Without Adjuvants on Photosynthetic Attributes of Wheat and Its Associated Weeds

ABSTRACT: Among various weed management strategies, chemical weed control is considered the most effective method. However, optimum dose and suitable combination of herbicide with adjuvants play a vital role in controlling weeds at an acceptable level and produce maximum crop yield. A field study was conducted to investigate the effect of post-emergence herbicide isoproturon alone or with combination of adjuvants on winter wheat and its associated weeds. The treatments were isoproturon at 175 g a.i. ha-1, 140 g a.i. ha-1 and 105 g a.i. ha-1 applied alone or with adjuvants Ad-500 or Bio-enhancer at 400 mL ha-1 each and weedy check as a control treatment. Isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1 was most effective treatment for control of Melilotus indica, Anagallis arvensis, Phalaris minor and Fumaria indica as it decreased the photosynthetic activity, fresh and dry biomass of these weeds. In case of wheat, highest productive tillers, plant height, 1000-grain weight, biological and grain yield were achieved with isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1. However, highest values of gas exchange parameters of wheat were observed where no herbicide was sprayed. It can be concluded that isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1 might be a profitable approach to achieve optimal yield of wheat by causing the maximum suppression of these tested weeds. Moreover, the herbicide at reduced dose with adjuvants was not much effective in terms of weed control or increased yield.

摘要：在各类杂草防控策略中，化学除草（chemical weed control）被公认为最为高效的防控手段。然而，除草剂的最优施用剂量，及其与助剂（adjuvants）的适配组合，对于将杂草种群控制在可接受阈值内并实现作物最高产量，发挥着不可或缺的作用。本研究通过田间试验，探究了苗后除草剂（post-emergence herbicide）异丙隆（isoproturon）单独施用，或与助剂复配时，对冬小麦及其伴生杂草的影响。试验设置如下：分别以175 g 有效成分(active ingredient, a.i.)·ha⁻¹、140 g a.i.·ha⁻¹、105 g a.i.·ha⁻¹的剂量单独施用异丙隆，或分别与400 mL·ha⁻¹的Ad-500助剂、生物增效剂(Bio-enhancer)混用，另设杂草对照(weedy check)作为空白对照处理。其中，175 g a.i.·ha⁻¹异丙隆与400 mL·ha⁻¹生物增效剂复配的处理，对印度草木犀（Melilotus indica）、琉璃繁缕（Anagallis arvensis）、小籽虉草（Phalaris minor）及印度紫堇（Fumaria indica）的防控效果最佳，可显著抑制上述杂草的光合活性，降低其鲜生物量与干生物量。就冬小麦而言，采用该复配处理可获得最高的有效穗数、株高、千粒重、生物产量与籽粒产量。不过，未喷施除草剂的对照组小麦的气体交换参数数值最高。综上，175 g a.i.·ha⁻¹异丙隆与400 mL·ha⁻¹生物增效剂复配，可通过最大程度抑制供试杂草的生长，实现冬小麦的最优产量，是一种具备经济效益的杂草防控方案。此外，降低除草剂剂量并搭配助剂的处理方案，在杂草防控与产量提升方面效果均不甚理想。