Abstract

This study aimed to assess, in a microcosm condition, the efficacy of electrostatic spraying of herbicide imazamox in the control of Salvinia molesta and the effects of decomposition of plant material on water quality. The herbicide rates used were 600, 700, 800, and 900 g ai ha⁻¹ and spray volume of 50 L ha⁻¹ in electrostatic application. Control effectiveness was assessed at 7, 15, 30, 45, and 60 days after application (DAA), expressed in percentage (0–100%) of visible injury symptoms in the plants, biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), chlorophyll a and pheophytin a contents at 0, 7, 15, 30, 45, and 60 DAA, and fresh and dry biomass at 60 DAA. Imazamox was effective in controlling 63% of S. molesta with 900 g ai ha⁻¹ in 45 DAA and 30% with 800 g ai ha⁻¹ in 30 DAA, and reduced 82.3% and 17.5% of fresh weight and 62.6% and 9.3% of dry weight of plant at 60 DAA, respectively. The imazamox spray reduced chlorophyll a with all doses applied and increased BOD₅ in 45 DAA with 900 g ai ha⁻¹ and COD in all assessment periods, but for temperature, dissolved oxygen, electrical conductivity, and pH, there was no significant effect after spraying. The herbicide imazamox reduced S. molesta plants with 900 g ai ha⁻¹, without causing significant effects on environmental indicators of water quality. Electrostatic spraying of herbicide can be used in management strategies of aquatic plants to reduce plant density in water bodies and maintain the colonization of plants at a level not harmful to the aquatic biota.

抽象的

这项研究的目的是在微观环境下评估除草剂Imazamox静电喷雾在控制Salvinia molesta中的功效以及分解植物材料对水质的影响。在静电施用中，所使用的除草剂速率为600、700、800和900 g ai ha ^-1，喷雾量为50 L ha ^-1。在施用后第7、15、30、45和60天（DAA）评估控制效果，以植物中可见伤害症状，生化需氧量（BOD ₅），化学需氧量的百分比（0-100％）表示（COD），叶绿素a和脱镁叶绿素a含量分别为0、7、15、30、45和60 DAA，新鲜和干燥生物量为60 DAA。Imazamox可有效控制63％的田鼠链球菌（含45 g DAA的900 g ai ha ^-1和30％的30 DAA的800 g ai ha ^-1的），并分别减少了82.3％和17.5％的鲜重以及62.6％和9.3 60 DAA分别为植物干重的％。在所有评估期内，使用全氮杂剂量喷雾降低所有剂量的叶绿素a并增加45 DAA，900 g ai ha ^-1和COD的BOD ₅，但是对于温度，溶解氧，电导率和pH值，在评估后没有明显影响。喷涂。除草剂Imazamox减少了900 g ai ha ^-1的S. molesta植物，而不会对水质的环境指标造成重大影响。静电喷洒除草剂可用于水生植物的管理策略中，以降低水体中的植物密度，并将植物定植的水平维持在对水生生物群无害的水平。