We assessed the residual distribution and temporal trend of picarbutrazox sprayed by agricultural multicopters on Chinese cabbage and considered fortification levels and flying speeds. In plot 2, 14 days after the last spraying, the residues decreased by ~91.3% compared with those in the samples on day 0. The residues in the crops decreased by ~40.8% of the initial concentration owing to growth (dilution effect) and by ~50.6% after excluding the dilution effect. As the flight speed increased, picarbutrazox residues decreased (p < 0.05, least significant deviation [LSD]). At 2 m s⁻¹ flight speed, the residual distribution differed from the dilution rate of the spraying solution. The average range of picarbutrazox residues at all sampling points was 0.007 to 0.486, below the limit of quantitation −0.395, 0.005–0.316, and 0.005–0.289 mg kg⁻¹ in plots 1, 2, 3, and 4, respectively, showing significant differences (p < 0.05, LSD). These results indicated that the residual distribution of picarbutrazox sprayed by using a multicopter on the Chinese cabbages was not uniform. However, the residues were less than the maximum residue limit in all plots. Accordingly, picarbutrazox was considered to have a low risk to human health if it was sprayed on cabbage according to the recommended spraying conditions.

中文翻译：

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无人机喷洒大白菜（Brassica campestris var. pekinensis）后吡卡布唑残留的消散和分布

我们评估了农用多旋翼飞机在大白菜上喷洒的吡卡布唑的残留分布和时间趋势，并考虑了强化水平和飞行速度。在地块 2 中，最后一次喷洒后 14 天，与第 0 天的样品相比，残留量减少了约 91.3%。作物中的残留量由于生长（稀释效应）和初始浓度减少了约 40.8%排除稀释效应后约 50.6%。随着飞行速度的增加，吡卡布曲唑残留量减少（p < 0.05，最小显着偏差 [LSD]）。在 2 毫秒^-1飞行速度，残留分布与喷雾溶液的稀释率不同。所有采样点的皮卡布曲唑残留平均范围为 0.007 至 0.486，分别低于图 1、2、3 和 4 中的定量限 -0.395、0.005-0.316 和 0.005-0.289 mg kg ^-1，显示显着差异（p < 0.05，LSD）。这些结果表明，使用多旋翼飞行器喷洒的吡卡布唑在大白菜上的残留分布不均匀。然而，在所有地块中，残留量都低于最大残留限量。因此，如果根据推荐的喷洒条件将picarbutrazox喷洒在卷心菜上，则认为它对人类健康的风险较低。