Nutrient management and weed control are two major issues in organic farming. Reducing tillage has many benefits for soil fertility. To improve management strategies in stockless organic agriculture, it remains important to properly understand the impact of nutrient supply and tillage on weed communities and the impact of those communities on crop yield. The aim of this study was to quantify the effect of weed community and management on grain maize yield. A long-term experiment was established in 2019 in the Hesbaye region (Belgium), characterized by loamy soils and a temperate climate. Three organic cropping systems were compared: conventional inversion tillage with high organic fertilization (CT–COF), conventional inversion tillage with low fertilization (CT–LF), and reduced (non-inversion) tillage with low fertilization (RT–LF). Between 2021 and 2023, weed community composition was assessed, and diversity was quantified using the Shannon-Weiner diversity index, species richness, and evenness. Furthermore, weed density, weed and crop biomass, as well as crop yield, were measured. Weed-free quadrats were implemented to dissociate the effects of weeds from the effects linked to the systems themselves. Increasing nutrient supply enhanced grain maize yields, but did not influence weed flora composition, weed diversity, or weed density and biomass. In contrast, reduced tillage decreased grain maize yield by 45% and increased weed biomass by 190%. Species richness and Shannon-Weiner diversity index were higher, whereas evenness was lower. Species composition differed under reduced tillage, with a greater proportion of problematic weeds such as Cirsium arvense, Lolium multiflorum and Chenopodium album. This weed flora resulted in significant impacts on the maize growth, which had a biomass 65% higher when weeds were manually removed. This study shows that reduced tillage in organic systems can reduced grain maize yield, primarily as a result of the weed-crop competition.
Menu
Menu
