Relationship between the seedbank and the actual weed flora in agricultural soils in the Cote-d'Or.

The weed seedbank was estimated at the time of autumn crop sowing and the emergence of seedlings was counted during the cultural cycle in 35 fields on the Dijon plain (Cote-d'Or). The median value for the viable seedbank was estimated at 2 864 seeds/m(2) and the average rate of emergence at 5.54% of viable seed content. This average rate varies from 0.9% for Kickxia spuria to 32.8% for Polygonum persicaria. The dynamics of seedlings emergence was influenced by the climatic conditions, and cold and prolonged winter favoured the emergence of spring seedlings to the detriment of the autumn seedlings for species with preferential autumn germinating.