Effects of clomazone formulations at the initial development of Jatropha curcas

ABSTRACT Competition with weeds is one of the obstacles to achieve high yields in jatropha harvest. The chemical method is an alternative weed control due to its high efficiency, readiness and economy, when compared to other methods. However, products recommended for this crop are scarce. This study aimed at evaluating the effects of pre and post-emergence clomazone formulations at the initial development of jatropha. Two experiments were conducted under a randomized blocks design, in a 2 x 5 factorial arrangement, with four replications, consisting of the combination of two clomazone formulations (encapsulated suspension and emulsifiable concentrate) and five doses (0 g ha-1, 250 g ha-1, 500 g ha-1, 1,000 g ha-1 and 2,000 g ha-1). The dry matter of the plants was reduced both in the pre-emergence and post-emergence applications. Net photosynthesis was not affected by the application of clomazone in both formulations. The encapsulated suspension formulation is less phytotoxic than the emulsifiable concentrate formulation for pre and post-emergence applications. However, both formulations negatively affect the early development of jatropha plants.

摘要：杂草竞争是制约麻疯树高产收获的主要障碍之一。相较于其他除草方式，化学除草因高效、便捷且经济，成为杂草防控的可选方案，但目前针对该作物的推荐除草药剂却十分匮乏。本研究旨在评估芽前及芽后施用不同剂型的氯草敏（clomazone）对麻疯树初期生长发育的影响。本研究开展了两项随机区组试验，采用2×5因子设计，设置4次重复，试验因子包含两种氯草敏剂型（微囊悬浮剂与乳油剂）以及5个剂量梯度（0 g·ha⁻¹、250 g·ha⁻¹、500 g·ha⁻¹、1000 g·ha⁻¹和2000 g·ha⁻¹）。试验结果表明，芽前与芽后施药均会降低麻疯树植株的干物质积累量；两种剂型的氯草敏施药均未对植株的净光合速率产生影响；在芽前与芽后施药场景下，微囊悬浮剂剂型的药害效应均弱于乳油剂剂型，但两种剂型均会对麻疯树植株的早期生长发育产生负面影响。