Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark.
Department of Environmental Science, Aarhus University, Denmark.
Environ Pollut. 2021 Jul 1;280:116953. doi: 10.1016/j.envpol.2021.116953. Epub 2021 Mar 23.
Recent studies have shown that sub-lethal doses of herbicides may affect plant flowering, however, no study has established a direct relationship between the concentrations of deposited herbicide and plant flowering. Here the aim was to investigate the relationship between herbicide spray drift deposited on non-target plants and plant flowering in a realistic agro-ecosystem setting. The concentrations of the herbicide glyphosate deposited on plants were estimated by measuring the concentration of a dye tracer applied together with the herbicide. The estimated maximal and average deposition of glyphosate within the experimental area corresponded to 30 g glyphosate/ha (2.08% of the label rate of 1440 g a.i./ha) and 2.4 g glyphosate/ha (0.15% label rate), respectively, and the concentrations decreased rapidly with increasing distance from the spraying track. However, there were not a unique relation between distance and deposition, which indicate that heterogeneities of turbulence, wind speed and/or direction can strongly influence the deposition from 1 min to another during spraying. The effects of glyphosate on cumulative flower numbers and flowering time were modelled using Gompertz growth models on four non-target species. Glyphosate had a significantly negative effect on the cumulative number of flowers on Trifolium pratense and Lotus corniculatus, whereas there were no significant effects on Trifolium repens, and a positive, but non-significant, effect on number of flowers on Cichorium intybus. Glyphosate did not affect the flowering time of any of the four species significantly. Lack of floral resources is known to be of major importance for pollinator declines. The implications of the presented results for pesticide risk assessment are discussed.
最近的研究表明，低致死剂量的除草剂可能会影响植物开花，但没有研究建立沉积除草剂浓度与植物开花之间的直接关系。在这里，目的是在现实的农业生态系统环境中研究沉积在非靶标植物上的除草剂喷雾漂移与植物开花之间的关系。通过测量与除草剂一起施用的染料示踪剂的浓度来估计沉积在植物上的草甘膦浓度。在实验区域内估计的草甘膦最大和平均沉积量分别相当于 30 克草甘膦/公顷（标签推荐用量 1440 克有效成分/公顷的 2.08%）和 2.4 克草甘膦/公顷（标签推荐用量的 0.15%），并且浓度随着与喷雾轨迹距离的增加而迅速下降。然而，距离和沉积之间没有唯一的关系，这表明在喷雾过程中，湍流、风速和/或风向的异质性会强烈影响 1 分钟到另 1 分钟的沉积。使用 Gompertz 生长模型对四个非靶标物种的累积花数和开花时间进行了草甘膦影响的建模。草甘膦对三叶草和百脉根的累积花数有显著的负影响，而对三叶草和菊苣的花数没有显著影响，对花数有正但不显著的影响。草甘膦对这四个物种的开花时间都没有显著影响。众所周知，花源缺乏对传粉者减少有重要影响。讨论了所提出的结果对农药风险评估的影响。
