Weed Management in Spring Barley(Hordeum vulgare)in the Absence of Herbicides

. 2005. Seeding ratios and rates that maximize annual forage production in Black soil zones of central Saskatchewan. Can. J. Plant Sci. 85: 615-622. Three different seeding densities and four seeding ratios of spring and fall crop components for annual forage production were evaluated for maximizing silage and fall regrowth yield in a 3-yr study at Melfort, Saskatchewan. Binary mixtures of a spring cereal, barley (Hordeum vulgare L.) or oat (Avena sativa L.), and a fall crop, fall rye (Secale cereale L.) or Italian ryegrass (Lolium multiflorum Lam.), were seeded at three total stand seed densities (150, 275 and 400 seeds m -2 ), which consequently resulted in the following spring:fall seeding crop component ratios: 1:0, 2:1, 1:2 and 0:1. Both spring and fall crops were harvested when the spring cereals were at the soft-dough stage (silage cut) and late in the autumn (fall regrowth cut). Average spring crop component yield was greater for the silage cut (4806 kg ha -1 ) than for the fall regrowth cut (329 kg ha -1 ), and total sward yield was greater for the silage cut (5995 kg ha -1 ) than for the fall regrowth cut (1261 kg ha -1 ). Productivity of the fall component was 1173 and 929 kg ha -1 for the silage and fall regrowth cuts, respectively. Total crop yield was often maximized with seeding ratios of 60% spring:fall crop component or greater for the different combinations. Fall regrowth cut yields were always maximized by seeding 100% fall crop component. The spring crop component yield, especially for the oat mixtures, contributed very little to fall regrowth yields. Stand seeding rate frequently affected spring component and total crop yield, but not fall crop yield. Silage and annual yield for the spring crop and total sward increased with increase in stand seeding rate. Fall crop yield was not affected by stand seeding rate or its effect was of questionable practical importance. Italian ryegrass produced the most fall regrowth yield. Weed management was identified as a possible area for future research with regard to seeding ratios and rates for annual forage stands. . Le rendement moyen des composantes printanières est plus élevé pour l'ensilage (4 806 kg par hectare) que pour la repousse automnale (329 kg par hectare) et le rendement total du peuplement était plus important pour l'ensilage (5 995 kg par hectare) que pour la repousse automnale (1 261 kg par hectare). La productivité des composantes automnales s'établissait respectivement à 1 173 kg par hectare pour l'ensilage et à 929 kg par hectare pour la repousse automnale. Le rendement total des différentes combinaisons est souvent maximisé par un ratio d'ensemencement de 60 % ou davantage entre composantes printanières et composantes automnales. Le rendement de la repousse automnale est toujours maximisé par l'ensemencement de 100 % de composantes automnales. Le rendement des composantes printanières, surtout pour les combinaisons incluant l'avoine, concourt très peu au rendement de la repousse automnale. La densité de semis affecte souvent les comp...

Section: Weed Managementsupporting

confidence: 90%

Seeding ratios and rates that maximize annual forage production in Black soil zones of central Saskatchewan

McCartney¹,

Townley-Smith²,

Stevenson³

et al. 2005

“…compared with 67 kg ha -1 (Barton et al 1992); while increasing the barley seeding rate from 50 to 220 kg ha -1 resulted in yield increases ranging from 80 to 93% (Kirkland 1993). Prior to our study, there had been few attempts to derive a functional relationship between barley yield loss, and both wild oat and barley plant density using regression analysis.…”

Section: Estimating Barley Yield Loss and Economic Thresholdsmentioning

confidence: 98%

“…In conventional tillage systems, relatively high crop densities have been shown to reduce the impact of weeds on yield of wheat (Carlson and Hill 1985;Cudney et al 1989), barley (Evans et al 1991;Barton et al 1992;Kirkland 1993), and canola (O'Donovan 1994). Most of these studies also indicated that weed biomass and/or seed production decreased as crop density increased.…”

mentioning

confidence: 99%

Effect of barley plant density on wild oat interference, shoot biomass and seed yield under zero tillage

O’Donovan¹,

Newman²,

Harker³

et al. 1999

. 1999. Effect of barley plant density on wild oat interference, shoot biomass and seed yield under zero tillage. Can. J. Soil Sci. 79: 655-662. There has been little research aimed at developing regression models to describe the effects of barley and wild oat plant density on barley yield loss, or wild oat biomass and seed yield. Such models are an important component of integrated weed management systems, and can help determine when weed control with herbicides is economical. Field experiments were conducted over 4 yr at Vegreville, Alberta, to determine the interactive effects of wild oat and barley plant density on barley and wild oat variables in a zero tillage system. A nonlinear regression model in most cases provided good descriptions of barley yield loss, wild oat shoot dry weight, and wild oat seed yield as functions of wild oat and barley plant densities. The interactive effect of wild oat and barley plant density on percentage barley yield loss did not differ significantly (P = 0.05) among years. A pooled regression model describing barley yield loss accounted for 57% of the variation, and provides a means of estimating yield loss due to wild oat in barley grown under zero tillage. Barley yield loss increased as wild oat density increased but the magnitude of the yield loss diminished with increasing barley plant density. Wild oat economic threshold densities varied among years, and were strongly influenced by barley price and expected wild oatfree yield. Economic thresholds were greater at higher barley plant densities. Barley seed weight decreased with increasing barley plant density, and to a lesser extent with increasing wild oat density. The interactive effect of wild oat and barley plant density on wild oat seed yield varied significantly with year, and appeared to be influenced by climatic conditions. The cooler, wetter spring of 1996 favored wild oat seed production (by several orders of magnitude) compared with the relatively warmer and drier spring of 1995. Each year wild oat seed yield and shoot dry weight decreased as barley plant density increased. The results suggest that seeding barley at relatively high rates may reduce the need for wild oat control with herbicides in zero tillage systems.Key words: Zero tillage, wild oat interference, barley seeding rate, nonlinear regression O'Donovan, J. T., Newman, J. C., Harker, K. N., Blackshaw, R. E. et McAndrew, D. W. 1999. Effet de la densité de peuplement de l'orge sur l'importance de la concurrence exercée par la folle avoine, ainsi que sur la production végétative et semencière de la mauvaise herbe en régime de semis direct. Can. J. Plant Sci. 79: 655-662. Il n'y a eu jusqu'ici que peu de tentatives de modélisation par régression pour décrire les effets de la densité de peuplement de l'orge et de la folle avoine sur le manque à produire de l'orge ou sur le rendement en biomasse et en graines de la folle avoine. Ce type de modèle constitue pourtant une importante composante des systèmes de lutte intégrée contre les mauvaises herbes et il pe...

“…Volunteer B. napus was one of the dominant species in the weed community in winter wheat following oilseed rape and was significantly related to the notillage treatment. Kirkland (1993) investigated the influence of barley (Hordeum vulgare L.) competition on biomass production of domesticated volunteer B. rapa in Saskatchewan and showed biomass reductions of 95% or more when barley was planted at 220 kg ha (1 in 11-cm rows compared with when barley was planted at 50 kg ha (1 in 46-cm rows. In an interference study between domesticated B. rapa and tartary buckwheat (Fagopyrum tataricum L.) where B. rapa was grown as the crop, O'Donovan (1994) found that B. rapa reproductive output was least affected at high B. rapa densities (200 plants m (2 ) compared with lower densities (50 and 100 plants m (2 ).…”

Section: Response To Other Human Manipulationsmentioning

confidence: 99%

The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa L.

Gulden¹,

Warwick²,

Thomas³

2008

. 2008. The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa. Can. J. Plan Sci. 88: 951Á996. Brassica napus and B. rapa are native to Eurasia. In Canada, these species are commonly referred to as volunteer canola, while feral populations of B. rapa are referred to as birdrape. Brassica napus and B. rapa have been grown commercially for their seed oil content in western Canada since the middle of the last century and volunteer populations are common in fields. Escaped populations of both species are also found along roadways, railways and in waste areas; however, only B. rapa is known to have naturalized, self-sustaining feral populations in these habitats in eastern Canada. Despite these escaped and feral populations, B. napus and B. rapa are mainly a concern in agricultural fields where their combined relative abundance has increased over the past few decades. In the mid 1990s, herbicideresistant genotypes of B. napus were released for commercial production. Herbicide-resistance and the stacking of genes in volunteer populations conferring resistance to multiple herbicides have contributed to increased difficulties in controlling volunteer B. napus in some crops. However, yield loss resulting from volunteer populations is not well documented in Canada.Key words: Brassica napus, Brassica rapa, herbicide resistance, transgene escape, volunteer canola, weed biology Gulden, R. H., Warwick, S. I. et Thomas, A. G. 2008. La biologie des mauvaises herbes au Canada. 137. Brassica napus L. et B. rapa L. Can. J. Plant Sci. 88: 951Á996. Brassica napus et B. rapa sont des plantes originaires d'Eurasie. Au Canada, on les de´signe souvent sous l'expression « canola spontane´», tandis que les peuplements sauvages de B. rapa sont appele´s « navette ». Dans l'Ouest canadien, Brassica napus et B. rapa sont cultive´s commercialement pour l'huile que renferment leurs graines depuis le milieu du sie`cle dernier et les repousses spontane´es sont devenues monnaie courante dans les champs. On observe des peuplements des deux espe`ces le long des routes et des voies ferre´es ainsi que dans les terrains vagues, cependant on sait que seule B. rapa s'est acclimate´e pour donner des populations sauvages et stables dans les meˆmes habitats, dans l'est du pays. Malgre´cela, B. napus et B. rapa demeurent surtout pre´occupants dans les cultures, oul eur abondance relative, une fois combine´s, s'est accrue au cours des dernie`res de´cennies. Au milieu des anne´e 1990, des ge´notypes de B. napus re´sistants aux herbicides ont e´te´homologue´s pour la culture commerciale. Cette re´sistance et l'accumulation des ge`nes qui la codent dans les peuplements spontane´s ont concouru a`compliquer la lutte contre les repousses de B. napus dans certaines cultures. Quoi qu'il en soit, les pertes de rendement qui en re´sultent sont mal e´taye´es au Canada.