Évaluation de cultures de couverture de pleine saison dans les champs agricoles inondés au lac Saint-Pierre

Authors: Chih, Colline
Advisor: Halde, CarolineVanasse, Anne
Abstract: The yellow perch is a fish that lays its eggs on submerged vegetation along the shoreline of Lake Saint Pierre during the spring flooding. However, current agricultural practices on the floodplain are often leaving bare soil in the fall, which causes a decrease in spawning habitats. Thus, the objective of this study was to identify summer cover crops adapted to the Lake Saint Pierre floodplains that suppress weeds, while having selected desirable characteristics (plant biomass, height, soil cover) to potentially be a habitat for fish spawning during a flood event. A split-block design with four blocks was set at four site-years. In main plots, six cover crop (CC) treatments were studied: perennial ryegrass (Lolium perenne L.), fall rye (Secale cereale L.), a mixture of fall rye and red clover (Trifolium pratense L.), a mixture of fall rye and hairy vetch (Vicia villosa Roth), oat (Avena sativa L.), a mixture of hairy vetch, and flax (Linum usitatissimum L.), and a control without a CC. Each main plot was divided into two subplots: hand-weeded and non-weeded. The mixture of oat, hairy vetch, and flax produced the greatest aboveground biomass (2.5 to 4.9 Mg ha⁻¹) and reduced the weed incidence by 33 to 82% compared to the non-weeded control (depending on the sites). It is also the only treatment for which some aboveground biomass remained erect after flooding in each site year. Therefore, this mixture of CC could constitute a potential substrate for yellow perch spawning in the spring although wildlife measurements should be made in this same season during a flood event to confirm this hypothesis. With a low establishment cost, the mixture of oat, hairy vetch, and flax mixture was favorable for both farmers and environment.
Document Type: Mémoire de maîtrise
Issue Date: 2021
Open Access Date: 10 January 2022
Permalink: http://hdl.handle.net/20.500.11794/71439
Grantor: Université Laval
Collection:Thèses et mémoires

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