Comparison Of Control Effect Of Six Herbicides On The Malignant Weed Imperata Koenigii In Lawn

Aiming at the problem of serious invasion of lawn by Imperata koenigii in subtropical region,In this experiment,take degraded cold-seasonal lawnas where Imperata koenigii has become constructive species as experimental field,and six herbicides including Glyphosate,Glufosinate-ammonium,Flazasulfuron,Clethodim,Quizalofop-p-ethyl and Haloxyfop-P were used.Three dose gradients,low,medium and high,were set up respectively,and clear water was used as contrast.The morphological index,biomass,chlorophyll content of Imperata koenigii and the control effect of six herbicides were measured after 45 days of application by the randomized block split-plot experiment design.The aim was to obtain the inhibition of six herbicides and their dose on the growth and development of Imperata koenigii,and to screen out the herbicides and their dose with the optimal control effect,so as to provide help for the control of Imperata koenigii and the reduction of lawn maintenance cost in garden construction.The main research conclusions are as follows:(1)Morphological index:Six herbicides can reduce the leaf length,leaf width,caudex and plant height of Imperata koenigii.The leaf length,leaf width,caudex and plant height of Imperata koenigii were significantly different among herbicide species(P<0.05).The leaf length,leaf width and plant height of Imperata koenigii were significantly different between application dose,while the caudex was not significantly different between application dose.In the treatment group of Glyphosate,the leaf length at 5.74~8.59 cm,leaf width at 0.34~0.42 cm,caudex at 0.16~0.19 cm,plant height at6.16~12.94 cm,Glyphosate has the optimal inhibition on leaf length,leaf width,caudex and plant height,and increases with the increase of Glyphosate application dose,The optimal dose was 7320 mL/hm~2.(2)Biomass:Six herbicides can reduce the biomass of Imperata koenigii.Herbicide species and application dose have significant effects on the aboveground biomass,underground biomass,total biomass and root-shoot ratio of Imperata koenigii(P<0.05).In the the treatment of 300 mL/hm~2 Clethodim,the underground biomass of Imperata koenigii increased,while the underground biomass decreased,while the total biomass increased.In the treatment of 450 mL/hm~2 Haloxyfop-P treatment,the aboveground biomass of Imperata koenigii increased,the underground biomass decreased,while the total biomass decreased.The herbicides that make the root-shoot ratio of Imperata koenigii gradually increase with the increase of application dose include Glyphosate,Glufosinate-ammonium,Clethodim and Haloxyfop-P,while the herbicides that make it gradually decrease include Flazasulfuron and Quizalofop-Ethyl.In the treatment group of Glyphosate,the aboveground biomass at 0.40~0.58 g,the underground biomass at2.08~2.56 g.Glyphosate has the optimal inhibition on the biomass of Imperata koenigii and increases with the increase of Glyphosate application dose,The optimal dose was7320 mL/hm~2.(3)Chlorophyll content:Six herbicides can reduce the chlorophyll content of Imperata koenigii,and the effect of herbicides on Chla content is greater than that on Chlb content.In the treatments of Glyphosate,Glufosinate and Flazasulfuron,Chl(a/b)of Imperata koenigii significantly decreased,while in the treatments of Clethodim,Quizalofop-Ethyl and Haloxyfop-P,Chl(a/b)of Imperata koenigii significantly increased.In the treatment of Flazasulfuron,Chla content of Imperata koenigii at2.37~4.55 mg/L,Chla content of Imperata koenigii at 1.07~1.46 mg/L.Flazasulfuron has the optimal inhibition on chlorophyll content of Imperata koenigii and increases with the increase of application dose,The optimal dose was 300 g/hm~2.(4)Control effect:There were significant differences among herbicides in control effect(P<0.05),and application dose have significant effects on the control effect of Imperata koenigii(P<0.05).With the increase of application dose,the control effect of six herbicides on Imperata koenigii gradually increases.In the the treatment of 7320mL/hm~2 Glyphosate had the optimal control effect on fresh weight of aerial parts of Imperata koenigii,at 88.02%.In the the treatment of 7320 mL/hm~2 Glyphosate had the optimal control effect on dry weight of aerial parts of Imperata koenigii,at 79.45%.In the the treatment of 7320 mL/hm~2 Glyphosate had the optimal control effect on fresh weight of Imperata koenigii,at 43.19%.In the the treatment of 7320 mL/hm~2Glyphosate has the optimal control effect on dry weight,total fresh weight,total dry weight and plant weight of Imperata koenigii,with 39.18%,58.63%,53.71%and93.87%respectively.To sum up,The effects of different herbicides and their dose on morphological index,biomass,chlorophyll content,control effect of Imperata koenigii were significantly different.Glyphosate has a good overall control effect on Imperata koenigii.The 30%Glyphosate aqueous solution with an application dose of 7320 mL/hm~2 has the optimal control effect on Imperata koenigii,which is suitable for popularization and application in garden construction.