除草剂对黄河三角洲入侵植物互花米草的影响

互花米草(Spartina alterniflora)作为我国危害最严重的外来入侵植物之一,严重威胁滨海湿地生态系统安全。筛选可高效灭除互花米草的除草剂,为互花米草防治提供技术支持。2017年7月在黄河三角洲潮间带对互花米草茎叶喷施不同除草剂,在施药当年和次年对互花米草生长状况和大型底栖动物密度进行跟踪调查。研究结果表明:1)高效氟吡甲禾灵对互花米草的灭除效果最好,既能杀死互花米草地上部分从而完全抑制有性繁殖,又可完全抑制次年的无性繁殖;2)氰氟草酯对互花米草的灭除效果也比较好,可以完全抑制互花米草的生长和结穗,但抑制根状茎无性繁殖能力的效果稍差,草甘膦可以完全抑制互花米草的有性繁殖,但无法抑制次年互花米草的无性繁殖;3)施用除草剂在短期内会毒害某些底栖动物,但在1年后底栖动物种群数量与对照处理无显著差异。除草剂对环境的影响程度与除草剂用量和施用时间息息相关,未来研究中,应在保证灭草效果的前提下,探索最佳用药时间和最低用量以最大限度地降低环境影响。

Effects of herbicides on invasive Spartina alterniflora in the Yellow River Delta

Spartina alterniflora is one of the most noxious invasive plants in China, and it seriously threatens the safety of coastal wetland ecosystem. The aim of this study was to screen for herbicides that could efficiently eliminate S. alterniflora, providing a method for the control of S. alterniflora. In July 2017, different herbicides were sprayed on the stems and leaves of S. alterniflora in the intertidal zone of the Yellow River Delta. The growth status of S. alterniflora and density of macrobenthos were investigated in 2017 and the following year. The results of this study indicated that (1) haloxyfop-P-methyl could completely eradicate S. alterniflora. It not only completely inhibited sexual reproduction by killing the aboveground part of S. alterniflora but also inhibited asexual reproduction of the rhizomes in the following year. (2) Cyhalofop-butyl could also completely inhibit the growth and spiking of S. alterniflora, but its ability of controlling asexual reproduction was slightly weaker than that of haloxyfop-P-methyl. Glyphosate could completely suppress the sexual reproduction of S. alterniflora, but it could not effectively inhibit asexual reproduction in the following year. (3) Application of herbicides could poison some macrobenthos in a short period, but the macrobenthos could be restored in a year. The influence on the environment is closely connected with the amount and period of herbicide application. In the future, the best time and minimum dosage of herbicides should be evaluated to minimize the negative effects on the environment.