Weed flora in crop rotation and winter wheat monoculture

Aim of study: The goal of the study described in this manuscript was to evaluate qualitative and quantitative changes in weed flora infesting winter wheat stands grown in crop rotation and wheat monoculture. Area of study: South-eastern Poland, Europe (2018-2020). Material and methods: The experiment was established in the system of randomized blocks (25 m x 6 m) in three replications. Winter wheat was sown in (1) crop rotation (CR): potato – winter wheat – peas – winter barley; and (2) in monoculture (MON). Weed infestation was evaluated in two terms: (1) at the tillering stage and (2) at the waxy maturity stage of winter wheat. Main results: The number and air-dry weight of weeds evaluated in both terms were higher in MON than in CR. Before wheat harvest, its plots in MON were massively infested by Apera spica-venti and significantly populated by Avena fatua and Anthemis arvensis. In this evaluation term, the weeds of the upper and middle levels accounted for 88.4% of the whole weed community in CR and for 97.7% in MON. In both terms of evaluation, greater biodiversity of the weed community was observed in CR than in MON. Research highlights: Indicators used to assess the weed flora in crop rotation and monoculture, i.e. weed species composition, number and air-dry weight of weeds, weed distribution in wheat crop levels, and Shannon-Wiener's diversity index.