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RESEARCH PRODUCT

Weed flora evolution in direct seeding under cover systems

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Since the beginning of agriculture, farmers have been working the soil to produce. With the apparition of mechanization (development of plow coupled to tractors in the early 20th century), this practice has intensified and widespread on all farms. However, in France, since the 2000s, more and more farmers are questioning the utility of working the soil to produce. A new form of agriculture has appeared; the direct seeding under cover which groups together a set of cropping systems that meet certain requirements: no tillage, maximum vegetation cover and diversified rotation. By its emergent properties, this new form of agriculture raises new questions of research that mobilize both agronomy and ecology. From an agronomic point of view, the adoption of direct seeding under cover implies, for the farmers, a significant modification of their reasoning and represents a considerable challenge, in particular for the management of the weed flora. From an ecological point of view, direct seeding under cover systems allow the development of a certain number of animal and plant communities that interact with one another and thus potentially promote the regulations expected in agroecology. The adoption of this form of agriculture leads to a complete change of habitat for the weed flora, which can profoundly modify all of the usual selection pressures (germination conditions, modification of predation relations, competition, etc.). The goal of this thesis (2017-2020) is to determine the effect of direct seeding under cover systems on the composition and evolution of weed flora.