Effects of Herbicides and Seeding Rates on the Production of Alfalfa 1

Schoofs, A. and Entz, M. H. 2000. Influence of annual forages on weed dynamics in a cropping system. Can. J. Plant Sci. 80: [187][188][189][190][191][192][193][194][195][196][197][198]. Alternatives to herbicides are needed for weed control. Field studies were conducted in 1994/1995 and 1995/1996 to investigate the nature of forage crop-weed dynamics and to test the effect of single year forage crops on the density and community composition of annual weeds in a following field pea (Pisium sativum L.) test crop. Five spring-seeded forage treatments were compared with wheat (Triticum aestivum L.) grain crops (with or without herbicides for grassy and broadleaved weeds): winter triticale (Triticosecale) (simulation grazed); spring triticale (silage); spring/winter triticale intercrop (silage, then simulation grazed); alfalfa (Medicago sativa L.) (hay); sorghum-sudangrass (Sorghum bicolor [L.] Moench × Sorghum sudanese [Piper]) (hay); and a weedy fallow (silage). A fall rye (Secale cereale L.) grain crop and a sweet clover (Melilotis officinalis L.)/winter triticale double crop (hay, then simulation grazing) were included in the 1995/1996 trial. All forage systems were at least as effective as the sprayed wheat control in suppressing wild oat (Avena fatua L.); however, effects on other weeds, especially broadleaved species, were variable. Biennial crops provided the best early season weed control, while long-season systems such winter triticale and the triticale intercrop provided the best late season weed control. Forages shifted the weed community composition away from wild oat and green foxtail (Setaria viridis L. Beauv.) to a similar or greater extent than herbicide-treated wheat. Forage systems that did not provide season-long crop competition tended to have more broadleaved weeds. Some forage systems increased pea grain yield the following year (relative to the sprayed wheat control); however, forages alone did not eliminate the need for herbicides in the pea crop. Annual forages may play an important role in integrated weed management, especially for wild oat, however further research to refine forage-based weed management systems is needed. Tous les systèmes fourragers annuels se sont révélés au moins aussi efficaces que le blé désherbé chimiquement pour maîtriser la folle avoine (Avena fatua L.), mais pour ce qui est des autres mauvaises herbes, particulièrement les dicotylédones, les effets étaient variables. Ce sont les cultures bisannuelles qui procuraient la meilleure maîtrise des mauvaises herbes en début de saison et les cultures de saison longue comme le triticale (hiver ou printemps-hiver) la meilleure en fin de saison. La présence de la sole fourragère dans la rotation éloignait la composition floristique des adventices de la dominance folle avoine-sétaire verte (Setaria viridis L. Beauv.) dans une mesure au moins égale à celle causée par le blé désherbé chimiquement. Les traitements fourragers qui ne fournissaient pas une compétition culturale continue tout au long de l'année renfermaient en gén...

Section: Dry Matter Productioncontrasting

confidence: 48%

Influence of annual forages on weed dynamics in a cropping system

Schoofs¹,

Entz

2000

“…Without the application of herbicides for weed control, the percentage weed DM in fenugreek was similar to that reported previously for alfalfa plus bromegrass mixtures in the establishment year . The high percentage of weeds, 70 to 86% of total DM in weedy check plots, is considered unacceptable (Moline and Robison 1971;Smith et al 1997). Unlike perennial forage crops that tend to suppress annual weeds after the establishment year, fenugreek is an annual legume and high-quality forage must be produced in one season.…”

Section: Discussionmentioning

confidence: 99%

“…Although some analyses of the nutritive composition of weeds have been conducted, animal intake and rate of gain from the weedy forages are unknown (Moyer and Hironaka 1993). Weed contents > 25% are considered unacceptable and the price of hay may be discounted by 1% for each percentage of weeds up to 25% (Moline and Robison 1971;Smith et al 1997). Therefore, weed management in fenugreek is required if this crop is to be commercially grown for forage.…”

mentioning

confidence: 99%

Weed management in irrigated fenugreek grown for forage in rotation with other annual crops

Moyer¹,

Acharya²,

Mir³

et al. 2003

) is an annual legume that has potential as a forage crop on the Canadian Prairies. Experiments were established to determine the tolerance of fenugreek to several herbicides and their efficacy on various weeds. Potentially, fenugreek could be grown in conservation tillage systems in rotation with other annual crops. Therefore, additional multi-factor experiments were conducted to determine the effect of herbicides, seeding method, and 11 previous crops on fenugreek yield. Without herbicide application, weeds contributed 37 to 86% to total dry matter production. When imazamox/imazethapyr, or combinations of imazamoz/imazethapyr or imazethapyr with ethalfluralin was applied, weed contents were about 5% of the total dry matter and the herbicides did not reduce fenugreek yield compared to the hand-weeded check. Total forage samples with a low weed content had lower fibre content and higher protein and digestible dry matter content than forages with a high weed content. When imazamox/imazethapyr was used for weed control, fenugreek yields and weed biomass were similar after direct seeding and after cultivation plus seeding. In addition, the effect of previous crop and the previous crop by seeding method interaction was not significant for fenugreek yield and weed biomass. Therefore, irrigated fenugreek can be successfully grown in conservation tillage systems in rotation with several crops provided an effective herbicide is used for weed control. ) est une légu-mineuse annuelle dont on pourrait se servir pour l'affouragement dans les Prairies canadiennes. Des expériences ont permis d'établir la tolérance de cette culture à divers herbicides et l'efficacité de ces derniers sur plusieurs adventices. Le fenugrec pourrait être cultivé dans un système de conservation du sol, en assolement avec d'autres annuelles. Les auteurs ont donc entrepris de nouvelles expériences multifactorielles afin de préciser les effets des désherbants, de la méthode d'ensemencement et de onze cultures antérieures sur le rendement du fenugrec. En l'absence d'herbicides, les adventices représentent de 37 à 86 % de la matière sèche totale produite. Quand on applique de l'imazamox/imazéthapyr ou un mélange d'imazamox/imazéthapyr ou d'imazéthapyr et d'éthalfluraline, elles ne constituent toutefois plus que 5 % du volume total de matière sèche; en outre, les herbicides ne réduisent pas le rendement du fenugrec, quand on le compare au rendement de la parcelle témoin, désherbée à la main. Les échantillons de fourrage renfermant peu d'adventices se caractérisaient par une plus faible teneur en fibres ainsi que par une concentration accrue de protéines et de matière sèche digestible, comparativement aux échantillons contenant beaucoup de mauvaises herbes. Après désherbage chimique à l'imazamox/imazéthapyr, le semis direct de fenugrec donne un rendement et une biomasse d'adventices semblables à ceux obtenus avec l'ensemencement après travail du sol. La culture antérieure et les interactions entre cette dernière et la méthode de semis n'ont pas d'incidenc...

“…In contrast, the weed content of seedling alfalfa without weed control treatments averaged almost 80% (Moyer 1985). However, based on the criteria that weed contents > 25% in forage are unacceptable (Moline and Robinson 1971;Smith et al 1997) the application of herbicides during PC rye establishment may be necessary. However, the application of herbicides had little effect on ash, crude protein, ADF, or NDF contents or on in vitro gas production in vegetative PC rye.…”

Section: Discussionmentioning

confidence: 99%

“…Weed suppression in hay or silage crops is important because a weed content greater than 25% is considered unacceptable (Moline and Robinson 1971;Smith et al 1997). Annual rye has the greatest ability of all cereal crops to compete with weeds (Zimdahl 1990).…”

mentioning

confidence: 99%

Weed management at the time of perennial cereal rye establishment

Moyer

Acharya²,

Mir³

2002

Weed management at the time of perennial cereal rye establishment. Can. J. Plant Sci. 82: 457-462. Perennial cereal rye (PC rye) is a new crop that is being developed at the Lethbridge Research Centre for the production of silage for cattle. Its ability to compete with weeds during establishment and tolerance to herbicides for weed control was unknown. Therefore, experiments were established with PC rye, and several herbicide treatments were applied to test crop tolerance and weed control. PC rye was not injured by bromoxynil/MCPA, 2,4-D, thifensulfuron/tribenuron, fenoxaprop, clodinafop-propargyl, and tralkoxydim. Combinations of herbicides for broadleaf weed control and annual grass control usually reduced weed dry matter (DM) to < 5 g m -2 in the establishment year. Weeds made up 20 to 36% of the total DM when herbicides were not applied. However, this level of weed content did not affect the digestibility of the forage samples or the total DM produced as weed DM compensated for reduced PC rye yield in weedy plots. Also, the presence of weeds during establishment of PC rye did not affect weed content or PC rye yields the year after establishment.