WEED FLORA IN A LONG-TERM REDUCED TILLAGE TRIAL, “TILMAN-ORG session”

Summary

Reduced tillage may improve the environmental and economic performance of organic farming. Reducing the intensity of soil tillage decreases the energy consumption and the emission of carbon dioxide, and could increase carbon sequestration (Holland 2004). Reduced tillage also may improve water retention and reduce soil erosion (Berner et al 2008). One of the main drawbacks of the reduced tillage practices is the potential increase of weed infestation and changes in weed species composition, sometimes to the benefit of species which are more difficult to control, such as perennial and grass species (Peigné et al 2007; Teasdale et al 2007; Sans et al 2011). Organic farmers commonly keep weeds under control by ploughing and by post-emergence mechanical methods, and by indirect means such as appropriate crop rotation including e.g. gras-clover. For this reason, weed management under reduced tillage conditions is expected to be more challenging in organics systems. In this study, we present the results on weed abundance and community composition in a nine-year old long-term experiment under conventional and reduced tillage.