Crop yields and wild oat control in northern Alberta cropping systems

Abstract

A study was conducted on the Agriculture and Agri-Food Canada Research Farm, Beaverlodge, Alberta, to compare nine cropping systems in relation to productivity and wild oat (Avena fatua L.) control. The nine cropping systems consisted of three crop rotations and three levels of banded N fertilizer. Each cropping system had its own regime of tillage and weed control. One of the rotations consisted of mechanical fallow, along with canola (Brassica rapa L.), barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), while the other two rotations consisted of the same annual crops, but with either flax (Linum usitatissimum L.) or red clover (Trifolium pratense L.) plowdown with partial fallow substituted for mechanical fallow. The three rates of banded N fertilizer were 0, 75 and 150% of recommended, based on soil tests and provincial recommendations. From 1991 to 1994, cropping systems with mechanical fallow and fall tillage after annual crops produced 24% higher total seed yields than cropping systems with no fall tillage after annual crops and either continuous annual crops or red clover plowdown. Increasing the rate of banded N fertilizer from 0 to 75% of recommended increased total crop seed yields but a further increase from 75 to 150% had no significant effect. Although cropping systems with mechanical fallow had an advantage over other cropping systems, the effect of crop sequencing and yearly weather conditions on total crop seed yields was greater than the effect of cropping systems. Wild oat populations varied greatly with year, but the ease of management was greater in cropping systems with the mechanical fallow than in other cropping systems. Wild oat density increased when diclofop or difenzoquat performed inadequately or when poor red clover establishment allowed populations to increase. Reductions in wild oat populations appeared to be largely due to the consistent effectiveness of sethoxydim. , alors que les deux autres consistaient en une rotation des mêmes cultures annuelles plus la culture de lin (Linum usitatissimum L.) ou celle de trèfle rouge (Trifolium pratense L.) comme engrais vert, puis jachère partielle à la place de la jachère mécanique. L'engrais azoté a été épandu à un taux correspondant à 0, à 75 ou à 150 % du taux recommandé après analyse du sol et selon les recommandations provinciales. De 1991 à 1994, les régimes avec jachère mécanique et travail du sol à l'automne après récolte des cultures annuelles ont présenté un rendement grainier de 24 % supérieur à celui des systèmes sans retournement du sol à l'automne et culture continue ou utilisation de trèfle rouge comme engrais vert. Quand la fertilisation passe de 0 à 75 % du taux recommandé, on assiste à une hausse du rendement grainier, mais doubler la quantité d'engrais azoté de 75 à 150 % n'exerce aucun effet sensible sur la récolte. Bien que les systèmes agricoles avec jachère mécanique présentent un avantage sur les autres régimes, la succession des cultures et les conditions météorologiques durant l'année agissent plus sur l...

The Biology of Canadian Weeds. 27.Avena fatuaL. (updated)

“…In central Alberta, A. fatua emergence prior to planting was greater with fall than early spring tillage (Sharma et al 1983). In a cropping system study in northern Alberta, A. fatua abundance was less in a rotation that included mechanical fallow than forage legume ploughdown with partial fallow or a continuous crop rotation (Darwent et al 2003). In the United Kingdom, the seed bank of A. fatua declined more rapidly with tine cultivation than with ploughing before crop planting (Wilson 1981).…”