RELATIONSHIP BETWEEN THE SEEDBANK AND THE ACTUAL WEED FLORA IN AGRICULTURAL SOILS IN THE COTE-DOR

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 viabl e seedbank was estimated at 2 864 seeds/m(2) and the average rate of e mergence at 5.54% of viable seed content. This average rate varies fro m 0.9% for Kickxia spuria to 32.8% for Polygonum persicaria. The dynam ics of seedlings emergence was influenced by the climatic conditions, and cold and prolonged winter favoured the emergence of spring seedlin gs to the detriment of the autumn seedlings for species with preferent ial autumn germinating.