Relative importance of farming practices and landscape context on the weed flora of sown grass strips

The floristic composition of 62 sown grass strips located in two study areas was assessed over a 2-year period and related to 12 variables describing farming practices, spatial variability and the landscape context. Differences in the composition of the weed communities were greater between the two study areas than between the 2 years. For sites 1 and 2 respectively, the factors that structured the species assemblage were landscape context (32.7% vs. 34.8%), sown grass strip management (29.4% vs. 34.8%), spatial variability (31.5% vs. 26.1%) and practices in the adjacent field (19.9% vs. 19.3%). Variability between sown-grass-strip floras was higher than variation within sown-grass-strip floras. However, the part of the sown grass strip adjacent to the boundary showed higher species richness and diversity. High species richness was due to the contribution of species unique to the boundary side.