Gyula Pinke1, Tamás Kolejanisz1, András Vér1, Katalin Nagy1, Ákos Bede-Fazekas2,3, Bálint Czúcz2 and Zoltán Botta-Dukát2,3
1Faculty of Agricultural and Food Sciences, Széchenyi István University, H-9200, Vár 2., Mosonmagyaróvár, Hungary
2MTA Centre for Ecological Research, Institute of Ecology and Botany, 2163 Vácrátót, Alkomány u. 2-4., Hungary
3MTA Centre for Ecological Research, GINOP Sustainable Ecosystems Group, H-8237 Tihany, Klebelsberg Kuno u. 3., Hungary
The common ragweed (Ambrosia artemisiifolia L.) originating from North America became an important agricultural weed in the invaded areas, including Central Europe. Hungary is one of the most highly ragweed-infested countries, while in the neighbouring Austria, only the eastern and southeastern lowlands provide suitable agricultural habitats. According to general public opinion, common ragweed is now a Hungarian trademark, primarily due to the negligence of our farmers, but crossing the Austrian frontier, this plant turns to be fairly rare. It can be assumed that ecological conditions influence the abundance of common ragweed in similar extents in the two countries. Thus, if there are any differences in the degree of ragweed infestation between the two countries, we can hypothesize that land-use factors could be principally responsible.
In our study, we aimed to answer the following questions: Does the extent of ragweed infestation really differ in the border zones of the two countries? If yes, which variables explain these differences? By means of a collected farmer database, we surveyed 100 fields in four crops in both countries within approximately 30 km wide zones at both sides of the Austrian-Hungarian border. The crop species included sunflower, soyabean, maize and oil pumpkin. Altogether, 25 fields from each crop per country were sampled. The cover of ragweed was converted into binary data using different cut-off points and these binary data were analysed using binomial GLMs and model-based trees.
We found that although ragweed is present more often in Hungarian than Austrian fields, the frequency of high cover (above 5 or 10%) does not differ significantly between the two countries (however it is slightly higher in Austria). The difference in frequency of cover above 10% between the countries strongly depends on farming type, for example, in Hungary, such high ragweed cover was rather frequent in organic farms. The crop species also influenced the difference between the two countries – in maize or soybean, the high cover was more frequent in Austria, while in cereals it was more frequent in Hungary.