Control effects of different herbicides on Spartina alterniflora

As an invasive species, Spartina alterniflora has caused serious harm to many coastal wetland ecosystems, and its prevention and control have become the top priority of coastal wetland protection. To explore the difference in the control effects of different herbicides on S. alterniflora and optimize the chemical control technology, four experiments were carried out in this study, namely, different herbicides, different doses, different dilution ratios, and mowing + herbicide. The results showed that (1) 75 days after the application of herbicide, the control effects of high doses of glyphosate (8.0 kg ha(-1)), cyhalofop-butyl (0.8 kg ha(-1)) or imazameth (0.4 kg ha(-1)) were only 25%-38%, and the control effects of lower doses were worse; (2) Haloxyfop-R-methyl could permanently kill S. alterniflora. Applying 0.30 kg ha(-1 )and 0.45 kg ha(-1) of haloxyfop-R-methyl in June, the control efficacy was >95% in the first year and 84%-99% in the third year. In addition, there was no significant difference in weed control effect when the same dose of Haloxyfop-R-methyl was sprayed twice on June 8 and July 28 or once on June 8; (3) The mixed application of two of the four herbicides, namely, glyphosate, cyhalofop-butyl, imazameth and Haloxyfop-R-methyl, did not improve the control effect on S. alterniflora; (4) When the herbicide stock solution was diluted 58-461 times with water, Haloxyfop-R-methyl had a very good control effect on S. alterniflora; (5) Spraying Haloxyfop-R-methyl immediately after mowing could not effectively control S. alterniflora, and the regeneration of S. alterniflora was serious in the second year; and (6) Compared with the S. alterniflora area without herbicide application, there was no significant change in the species and quantity of macrobenthos one month after herbicide application. However, in the third year after herbicide application, S. alterniflora near the study area failed to invade the area where the herbicide was applied, indicating that residual toxins were likely to remain in the soil. In summary, haloxyfop-R-methyl can effectively control S. alterniflora, and haloxyfop-R-methyl application can be used as an optional method to eliminate newly invaded small areas of S. alterniflora, but it is not recommended to use herbicides in large areas. In the future, it is necessary to strengthen the monitoring of herbicide residues in soil and water and comprehensively assess the impact of herbicides on the environment and organisms to provide sufficient technical support for the use of herbicides to control S. alterniflora.