DOWNY BROME (Bromus tectorum) INVASION INTO SOUTHWESTERN SASKATCHEWAN

1990 ◽  
Vol 70 (4) ◽  
pp. 1143-1151 ◽  
Author(s):  
B. J. DOUGLAS ◽  
A. G. THOMAS ◽  
D. A. DERKSEN
Keyword(s):  
Winter Wheat ◽  
Bromus Tectorum ◽  
Weather Conditions ◽  
Early Spring ◽  
Zero Tillage ◽  
Downy Brome ◽  
Brown Soil ◽  
Tillage Practices ◽  
Soil Zone ◽  
Cropping Practices

Downy brome (Bromus tectorum L.) has rapidly invaded crop and pasture land in southwestern Saskatchewan since 1960. By 1989, 116 townships in 31 rural municipalities were infested. The spread of downy brome is associated with the increased area of winter wheat and fall rye grown using minimum and zero tillage practices, a lack of effective herbicides for selective in crop control and weather conditions which favor autumn germination and early spring competition. Although downy brome has been found on seven soil associations in the Brown soil zone and one association in the Dark Brown soil zone, the occurrence of the weed is related to cropping practices rather than soil texture or association.Key words: Downy brome distribution, downy brome invasion, Bromus tectorum, winter wheat

The History and Distribution of Downy Brome (Bromus tectorum) in North America

Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 2-6 ◽  
Author(s):  
Larry A. Morrow ◽  
Phillip W. Stahlman
Keyword(s):  
United States ◽  
North America ◽  
Winter Wheat ◽  
Great Basin ◽  
Bromus Tectorum ◽  
Production Systems ◽  
Western United States ◽  
Downy Brome ◽  
Tillage Practices ◽  
Agricultural Production Systems

Downy brome (Bromus tectorumL. # BROTE) has developed into a severe weed in several agricultural production systems throughout North America, particularly on rangeland and in winter wheat (Triticum aestivumL.). Several million hectares of winter wheat, pastureland, alfalfa (Medicago sativaL.), grass seed fields, and overgrazed rangeland, as well as other crops, have been invaded by this annual grass since its introduction into this hemisphere. Downy brome is most abundant in the Great Basin and Columbia Basin areas of the western United States, but is found throughout the continental United States and parts of Canada and Mexico. In some cases, the vegetation on overgrazed rangeland consists totally of downy brome, while winter wheat growers in the western United States proclaim it as their worst weed problem. Changes in tillage practices that are currently being implemented for the control of soil erosion coupled with the lack of selective herbicides for the control of downy brome have aided its increase and spread.

EFFECT OF RATE, TIMING AND PLACEMENT OF N FERTILIZER ON STUBBLED-IN WINTER WHEAT GROWN ON A BROWN CHERNOZEM

1990 ◽  
Vol 70 (1) ◽  
pp. 151-162 ◽  
Author(s):  
C. A. CAMPBELL ◽  
J. G. McLEOD ◽  
F. SELLES ◽  
F. B. DYCK ◽  
C. VERA ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Protein Concentration ◽  
Weather Conditions ◽  
Early Spring ◽  
N Fertilizer ◽  
Grain Protein ◽  
N Recovery ◽  
Severe Drought ◽  
Grain Yields ◽  
Brown Soil

Winter wheat (Triticum aestivum L.) production in Saskatchewan has increased in recent years due to the introduction of Norstar, a winter hardy variety, and due to the reduction in winter injury when the crop is seeded directly into standing stubble (stubbling-in). Large variations in the amount and distribution of seasonal precipitation in the Brown soil zone may prove detrimental to the adoption of this system. If implemented, fertilizer recommendations will need to be developed to fit this cropping system. A 4-yr study was conducted at Swift Current, Saskatchewan on an orthic Brown Chernozemic silt loam soil to determine the effect of rate, season of application, and placement of urea-N on grain yields and protein concentration of stubbled-in winter wheat. Plant density was unaffected by N. In 1984–1985 and 1986–1987 adequate weather conditions from seeding to early spring resulted in acceptable plant stands, but in 1985–1986 suboptimal winter temperatures and in 1987–1988 severe drought during fall and early spring reduced over-winter survival of wheat. Only 1 year provided better-than-average growing season weather conditions and thus good yields. Grain protein was < 11.5% (the critical lower level for milling) in two of the 4 years. In 1 year, a dry fall and winter coupled with a prolonged hot, dry early spring resulted in poor grain yields and very high protein concentrations (20–22%). Fertilizer-nitrogen, broadcast at 50 kg ha−1 at seeding, resulted in yields and grain protein concentrations similar to those when N was broadcast in April. Band placement of N was superior to broadcast application only in terms of grain protein concentration and N fertilizer recovery. There was no difference between banding N at 5 and 10 cm depth. In all years studied, application of N at 100 kg ha−1 was excessive for this system. It was concluded that producers should be cautious in attempting to grow stubbled-in winter wheat in the Brown soil zone.Key words: Yield, grain protein, N recovery, plant population, kernel weight

Rotation Affects Downy Brome (Bromus tectorum) in Winter Wheat (Triticum aestivum)

1994 ◽  
Vol 8 (4) ◽  
pp. 728-732 ◽  
Author(s):  
Robert E. Blackshaw
Keyword(s):  
Winter Wheat ◽  
Bromus Tectorum ◽  
Crop Yields ◽  
Crop Rotations ◽  
Arid Areas ◽  
Zero Tillage ◽  
Downy Brome ◽  
Canadian Prairies ◽  
Alternative Crop ◽  
Spring Canola

Downy brome control in winter wheat is often inadequate. The effects of three crop rotations and two tillage intensities on downy brome populations and associated crop yields were determined in an experiment at Lethbridge, Alberta from 1987 to 1993. Downy brome densities in continuous winter wheat increased from 24 to 970 plants/m2between 1988 and 1993; and were often higher with zero tillage. Inclusion of fallow or spring canola in rotation with winter wheat suppressed downy brome densities to less than 55 and 100 plants/m2, respectively, over the six years. In continuous winter wheat, yields decreased as downy brome densities increased progressively over years, indicating that monoculture winter wheat production will not be viable in regions where downy brome is prevalent unless effective herbicides are developed. In the more arid areas of the Canadian prairies, a winter wheat-fallow rotation may be most suitable but in higher precipitation areas, a winter wheat-canola rotation is a viable alternative. Crop rotation is a key component of an improved management system for control of downy brome.

Sulfonylurea Herbicides Suppress Downy Brome (Bromus tectorum) in Winter Wheat (Triticum aestivum)

1994 ◽  
Vol 8 (4) ◽  
pp. 812-818 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Mosad Abd El-Hamid
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Wheat Yield ◽  
Early Spring ◽  
Sulfonylurea Herbicides ◽  
Downy Brome ◽  
West Central ◽  
Late Fall ◽  
Better Than

In separate studies in west-central Kansas, a prepackaged mixture of chlorsulfuron + metsulfuron (5:1 w/w) and triasulfuron alone or in combination with metribuzin as a sequential or tank mix treatment were evaluated two years for downy brome control in winter wheat. Downy brome and wheat responses to each herbicide alone PRE or plus metribuzin POST varied between years. Visually, downy brome biomass was reduced 32 to 79% by chlorsulfuron + metsulfuron at 16 to 26 g ai/ha and 58 to 76% by triasulfuron at 30 g ai/ha applied PRE. Metribuzin POST at 158 g ai/ha following chlorsulfuron + metsulfuron PRE at 26 g/ha and metribuzin POST at 140 g/ha or more following triasulfuron PRE at 30 g/ha reduced downy brome biomass in both years more than PRE treatments alone. Chlorsulfuron + metsulfuron at 11 or 16 g/ha plus metribuzin at 105 or 158 g/ha applied POST affected downy brome less in 1992 than chlorsulfuron + metsulfuron applied PRE at 21 or 26 g/ha. Conversely in 1993, POST treatments except for chlorsulfuron + metsulfuron at 11 or 16 g/ha plus metribuzin at 105 g/ha affected downy brome more than PRE treatments. Triasulfuron plus metribuzin POST in late fall controlled downy brome better than a sequential application in one of two years; late-fall POST was better than early-spring POST applications in both years. Despite some treatments retarding growth, no treatment in either study reduced wheat yield in 1992. However in 1993, chlorsulfuron + metsulfuron PRE at 26 g/ha, chlorsulfuron + metsulfuron at 16 g/ha plus metribuzin at 105 or 158 g/ha applied POST, and metribuzin POST at 315 g/ha reduced wheat yields. Triasulfuron at 30 g/ha plus metribuzin at 140 g/ha or higher applied PRE, sequentially, or POST in late fall and metribuzin applied POST in early spring at 280 g/ha also reduced wheat yields.

Downy Brome (Bromus tectorum) Density and Relative Time of Emergence Affects Interference in Winter Wheat (Triticum aestivum)

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 551-556 ◽  
Author(s):  
Robert E. Blackshaw
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Seed Yield ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Wheat Yield ◽  
Growing Season ◽  
Early Spring ◽  
Downy Brome ◽  
Relative Time

Field experiments over 3 yr at Lethbridge, Alberta, determined the effect of various downy brome densities and times of its emergence on winter wheat biomass and seed yield. Downy brome reduced wheat biomass up to 59% and seed yield up to 68%. Time of downy brome emergence relative to wheat affected the magnitude of these yield reductions more than the density of downy brome. At comparable densities, downy brome caused 2- to 5-fold greater reductions in yield when it emerged within 3 wk after winter wheat than when it emerged 6 wk after wheat or in early spring. Late-emerging downy brome caused significant wheat yield or biomass losses only at densities of 200 to 400 plants m-2. Late-emerging downy brome plants were strongly shaded (70 to 90%) by winter wheat throughout much of the growing season.

Tillage intensity and crop rotation affect weed community dynamics in a winter wheat cropping system

2001 ◽  
Vol 81 (4) ◽  
pp. 805-813 ◽  
Author(s):  
R. E. Blackshaw ◽  
F. J. Larney ◽  
C. W. Lindwall ◽  
P. R. Watson ◽  
D. A. Derksen
Keyword(s):  
Winter Wheat ◽  
Crop Rotation ◽  
Community Dynamics ◽  
Cropping System ◽  
Conventional Tillage ◽  
Amaranthus Retroflexus ◽  
Zero Tillage ◽  
Downy Brome ◽  
Canada Thistle ◽  
Long Term Study

Development of improved weed manage ment systems requires more knowledge on how various weed species respond to changing agronomic practices. A long-term study was conducted to determine weed population responses to various tillage intensities and crop rotations in a winter wheat (Triticum aestivum L.) dominated cropping system. Weed density and species composition differed with tillage, rotation, year, and date of sampling within years. Weed community dynamics were most affected by year-to-year differences in environmental conditions, followed by crop rotation, and then tillage intensity. Russian thistle (Salsola iberica Sennen & Pau) and kochia [Kochia scoparia (L.) Schrad.] densities increased in years of low rainfall and above average temperatures. Winter annual weeds such as downy brome (Bromus tectorum L.) and flixweed [Descurainia sophia (L.) Webb ex Prantl], as well as the perennial weed dandelion (Taraxacum officinale Weber in Wiggers), increased in years where higher than average rainfall was received in fall or early spring. Continuous winter wheat facilitated a dense downy brome infestation to develop over time. Trifluralin is not efficacious on stinkweed (Thlaspi arvense L.) or Canada thistle [Cirsium arvense (L.) Scop.] and its use in canola resulted in an increase in these species in a winter wheat-canola rotation. Total weed densities were often greater in zero tillage than in either minimum or conventional tillage. Russian thistle, downy brome, kochia, and redroot pigweed (Amaranthus retroflexus L.) were associated with zero tillage while wild buckwheat (Polygonum convolvulus L.), lamb’s-quarters (Chenopodium album L.), flixweed, and wild mustard (Sinapis arvensis L.) were associated with conventional tillage. Perennials such as dandelion and perennial sowthistle (Sonchus arvensis L.) were associated with zero tillage but Canada thistle was associated with conventional tillage. Information will be utilized to implement more effective weed management programs in winter wheat production systems. Key words: Conservation tillage, fallow, multivariate analyses, weed populations, weed shifts, zero tillage

Influence of Soil Type and Depth of Planting on Downy Brome Seed

Weed Science ◽  
1971 ◽  
Vol 19 (1) ◽  
pp. 82-86 ◽  
Author(s):  
G. A. Wicks ◽  
O. C. Burnside ◽  
C. R. Fenster
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Soil Type ◽  
Bromus Tectorum ◽  
Seedling Emergence ◽  
Cropping System ◽  
Soil Surface ◽  
Downy Brome ◽  
Moldboard Plow

Downy brome (Bromus tectorumL.) seedling emergence was greatest from soil depths of 1 inch or less, but occasionally seedlings emerged from depths of 4 inches. Downy brome seed covered by soil germinated more rapidly than those seed on the soil surface. More downy brome seedlings emerged, and from greater depths, from coarse-textured soils than fine-textured soils when moisture was not limiting. Soil type did not influence longevity of downy brome seed buried in the soil. Most (98%) 8-month-old downy brome seed buried 8 inches in the soil germinated but did not emerge in 1 year; and none remained viable in the soil after 5 years. The moldboard plow was more effective in reducing downy brome populations than a sweep plow or one-way disk in a continuous winter wheat (Triticum aestivumL.) cropping system.

Inactivation of Metribuzin in Winter Wheat by Activated Carbon

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 229-232 ◽  
Author(s):  
D. J. Rydrych
Keyword(s):  
Triticum Aestivum ◽  
Activated Carbon ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Silt Loam ◽  
Downy Brome ◽  
Chemical Injury ◽  
Loam Soil

Preemergence and postemergence application of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one] at 0.6 and 1.1 kg ai/ha controlled downy brome (Bromus tectorumL. ♯ BROTE) in winter wheat (Triticum aestivumL. ‘McDermid’) but caused considerable injury without the use of activated carbon over the seeded row. Activated carbon applied in 5-cm bands over the seeded row at 84, 167, and 336 kg/ha protected winter wheat at Pendleton on a silt loam soil. On a sandy loam soil, only a 336 kg/ha rate provided protection from metribuzin. Metribuzin toxicity to winter wheat was more difficult to neutralize when applied preemergence. Downy brome control was not reduced by carbon applied over the wheat row. The best treatment in this study was carbon at 336 kg/ha applied preemergence over the row followed by metribuzin at 0.6 or 1.1 kg/ha postemergence. A 10-week delay between preemergence carbon banding and postemergence metribuzin protected winter wheat from chemical injury.

Fertilizing Dryland Spring and Winter Wheat in the Brown Soil Zone 1

1966 ◽  
Vol 58 (3) ◽  
pp. 348-351 ◽  
Author(s):  
Paul L. Brown ◽  
Ralph E. Campbell
Keyword(s):  
Winter Wheat ◽  
Brown Soil ◽  
Soil Zone

Downy Brome (Bromus tectorum) Interference and Economic Thresholds in Winter Wheat (Triticum aestivum)

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 224-228 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Stephen D. Miller
Keyword(s):  
Winter Wheat ◽  
Bromus Tectorum ◽  
Yield Loss ◽  
Wheat Yield ◽  
Dry Weight ◽  
Quadratic Equation ◽  
Downy Brome ◽  
Economic Threshold ◽  
Weed Density ◽  
Economic Thresholds

Densities up to 100 downy brome m2were established in winter wheat in southeastern Wyoming and west-central Kansas to quantify wheat yield loss from downy brome interference and to approximate economic threshold levels. A quadratic equation best described wheat yield loss as a function of weed density when downy brome emerged within 14 days after wheat emergence. Densities of 24, 40, and 65 downy brome m2reduced wheat yield by 10, 15, and 20%, respectively. Wheat yield was not reduced when downy brome emerged 21 or more days later than wheat. Economic thresholds varied with changes in downy brome density, cost of control, wheat price, and potential wheat yield. In a greenhouse experiment, dry weight of 72-day-old wheat plants grown in association with downy brome was not affected by the distance between the weeds and wheat, whereas downy brome plant dry weight increased with increasing distance between the weeds and wheat.

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