[Influence of the sowing time on the development of the weed and the requirement of spraying in winter grain]

application date application rates automne autumn banco de semillas del suelo cereal crops cultivos de cereales cultivos de invierno culture d'hiver damage date d'application date de semis dose d'application escarda fecha de siembra herbicidas herbicide herbicides malezas mauvaise herbe noruega norway rendement rendimiento soil seed banks sowing date spraying stock semencier du sol weed control weeds winter crops yields