Growth and development of Ambrosia artemisiifolia L. under different trophic conditions

Session 5 - Common ragweed: towards sustainable management solutions for Europe EA EcolDurNational audienceAmbrosia artemisiifolia L. (common ragweed) is an annual weed regarded as an invasive plant in France. This species can be found in a large range of soil types with regard to texture, pH or nutrient contents. Furthermore, its tolerance to different forms of stress increases its spread potential. This work was undertaken to evaluate the development and growth of common ragweed under different trophic conditions in a common garden. Three cohorts of 15 plants per treatments were sown in spring 2013 and the effects of nitrogen and irrigation were compared on each sowing dates. During the first weeks, vegetative appearance is strongly linked with the sum of temperature. For the first cohort, the effect of the competition induced by two types of plant cover was also studied. It appears that effects of abiotic factors are different according to the sowing dates. No effect was observed for the first cohort when a better growth is observed in higher trophic conditions for the later sowing dates. In our growth conditions, no differences were observed in flowering dates (male and female flowers). Competition of plant cover strongly reduces the growth of common ragweed plants, but was not sufficient to prevent the flowering stage