Effet du chiendent sur l'orge ensemencée à différents écartements entre les rangs et doses de semis

Abstract

A 4-yr study was conducted to evaluate the effect of two row spacings (10 and 20 cm) and five seeding rates of the cereal (100, 200, 300, 400 and 500 viable seeds m−2) on the interference between quackgrass [Elymus repens (L.) Nevski] and barley (Hordeum vulgare L. 'Cadette'). Narrow row spacings had no effect on the yield of barley in presence or absence of quackgrass. However, seeding rates influenced the productivity and development of barley when quackgrass was present. At a seeding rate of 100 seeds m−2, the yield reduction caused by the presence of quackgrass was 41%. When barley was seeded at 500 seeds m−2, the yield reduction was 19%. These yield reductions were mainly attributed to a decrease of spike density. In presence of quackgrass, the specific weight, number of kernels per spike, number of spikes per plant, 1000-kernel weight, harvest index and N concentration of grain were reduced. In contrast to a decrease of the row spacing, increasing seeding rate can be used to reduce interference between quackgrass and barley. Key words: Barley, quackgrass, interference, row spacing, seeding rate