| Tagetes minuta L.belongs to the genus Tagetes in the Compositae family,and is an exotic harmful weed originating from tropical America.It is classified as a Class 3 local invasive species in the Chinese Invasive Plant List.In recent years,as a newly invasive plant in Tibet,it has caused serious harm,but there is still less research on its prevention and control.This article analyzed the impact of Tagetes minuta L.invasion on native plant diversity through field investigations.Through screening alternative species and selective herbicides,the following results were obtained:(1)In the field survey,54 species of plants belonging to 16 families and 31 genera were found in the survey quadrat.Compositae plants account for a relatively large proportion in the community,followed by gramineae,and other species of plants account for a relatively low proportion.The study found that the plant diversity index,dominance,evenness and richness of the invaded area of Tagetes minuta L.showed that the plant diversity of the invaded area of Tagetes minuta L.decreased with the increase of the degree of invasion.(2)The chemical control of Tagetes minuta L.at the seedling stage was carried out,and the difference of the control effects of six kinds of stem and leaf herbicides was compared.The results showed that the control effects of low-dose Glyphosate lsopropylamine salt AS,Picloram AS and high-dose Mesotrione ยท Atrazine SC herbicides were the best,with the control effects of 100%,93.33% and 98.45% for plants and100%,99.10% and 95.42% for fresh weight respectively.(3)Through alternative control experiments,the prevention and control effects of three types of forage on Tagetes minuta L.were studied,and it was found that all three types of forage had a certain inhibitory effect on the growth of Tagetes minuta L.Among them,Vicia sepium L.has the most significant inhibitory effect on the plant height,branch number,ear number,and biomass of Tagetes minuta L.,especially in the high-density(Tagetes minuta L.: Vicia sepium L.)4:4 combination.The RY values of Vicia sepium L.were all less than 1.0 under the treatment of three different densities of each test ratio,indicating that Vicia sepium L.showed a strong advantage in interspecific competition,while showing a weaker advantage in intra specific competition.From the perspective of the total relative yield,there was no significant difference between Vicia sepium L.and Tagetes minuta L.in the proportion of different densities tested compared to 1.0,indicating that Vicia sepium L.and Tagetes minuta L.require the same resources for growth,and Vicia sepium L.can compete to exclude Tagetes minuta L.from the land.From the attack coefficient of Vicia sebum L.,it can be seen that the competitiveness of Vicia sepium L.is significantly higher than that of Tagetes minuta L.in the medium density and high-density(Tagetes minuta L.: Vicia sepium L.)combinations of 4:4 and 6:2. |
