Abstract
The weed flora from different major crops in France has changed drastically in its species composition over the last decades. To go beyond a simple expert assessment of changes observed in the field, large scale evaluations are required to precisely quantify this evolution and identify the conditions in which the changes are more pronounced. The analysis of such large scale datasets requires the development of adequate methodological tools that will allow to propose and test the causal effects of the adoption of new agricultural practices on the weed flora. The implementation of such analytical framework on large field-scale surveys enables to better assess the consequences of agricultural choices. It may also help to identify, among several options of crop protection, those that could present the best compromise between production, environment and sanitary impacts.