Regional adjustment of management options of common ragweed (Ambrosia artemisiifolia) along roadside verges in Bavaria (2018-2022)

Abstract

Common ragweed (Ambrosia artemisiifolia L.) is an invasive annual plant with highly allergenic pollen. Its spread often occurs along roadsides, where it builds stable and rapidly growing populations. The most sustainable way of controlling the species is to prevent seed production in order to deplete the soil seed bank. Therefore, in a 4- years field (2019 to 2022) trial four different cutting regimes differing in timing and frequency of cuts as well as two different means of physical control are tested on eight roadside verges in Bavaria, characterized by different climatic conditions and traffic densities. On the basis of soil seedbank samplings along these roadside verges as well as on the road embankments the study should reveal which cutting regime is most effective in the prevention of flower and seed formation of common ragweed. In addition, a 3-years field trial (2019 to 2021) on the competitive suppression of common ragweed by four different seed mixtures combined with three different cutting regimes was implemented on three different sites. First results showed that the primary habitat of common ragweed is the roadside verge: 97.9% of all plants counted as well as 96.7% of all seeds found in the soil seed bank were concentrated on the first 1.5 m next to the lane, irrespective of the soil properties and the inclination of the embankment.

Keywords

• cutting regime
• invasive alien species
• physical weed control
• soil seed bank