Influence of variable rates of imazamethabenz and difenzoquat on wild oat (Avena fatua) seed production, and wheat (Triticum aestivum) yield and profitability

2003 ◽  
Vol 83 (4) ◽  
pp. 977-985 ◽  
Author(s):  
J. T. O’Donovan ◽  
K. Neil Harker ◽  
R. E. Blackshaw ◽  
R. N. Stougaard
Keyword(s):  
Seed Production ◽  
Field Experiments ◽  
Wheat Yield ◽  
Economic Loss ◽  
Avena Fatua ◽  
Wild Oat ◽  
Economic Returns ◽  
Rate Reduction ◽  
Full Rate ◽  
Soil Seedbank

Field experiments to investigate the effects of variable imazamethabenz rates on wild oat seed production and wheat yield and profitability were conducted at Lacombe, Lethbridge and Vegreville, Alberta, and Kalispell, Montana, over several years. Similar studies with difenzoquat were conducted at Lacombe and Lethbridge. In most cases, reducing the herbicide rates below those recommended resulted in increases in wild oat seed production, but the potential for returning relatively large amounts of wild oat seed to the soil seedbank depended on the extent of the rate reduction. For example, averaged over locations and years, reducing the rate of imazamethabenz to 75% of the recommended rate resulted in wild oat seed production increasing by 25% compared with an increase of over 100% when the rate was reduced to 50%. Wheat yields and economic returns as functions of rate also varied for both herbicides. It was more economical, in most cases, to apply imazamethabenz at 50 or 75% of the recommended rate compared with the full rate. However, an economic loss occurred in four and three of the 11 location-years when the imazamethabenz rate was reduced to 50 and 75%, respectively, and losses were more severe at the 50% rate. Compared with imazamethabenz, reducing the rate of difenzoquat tended to be more risky in terms of increased wild oat seed production and reduced net economic return. Key words: Reduced herbicide rates

Split Applications of Herbicides at Reduced Rates Can Effectively Control Wild Oat (Avena fatua) in Wheat

2004 ◽  
Vol 18 (2) ◽  
pp. 369-374 ◽  
Author(s):  
Sam J. Lockhart ◽  
Kirk A. Howatt
Keyword(s):  
Field Experiments ◽  
Wheat Yield ◽  
Avena Fatua ◽  
Seed Rain ◽  
Wild Oat ◽  
Split Application ◽  
Net Returns ◽  
Herbicide Treatments ◽  
Full Rate ◽  
Oat Seeds

Split application of herbicides for wild oat control may minimize wild oat competition with wheat while reducing the number of wild oat seeds returned to the soil. Field experiments were conducted in 2000 and 2001 to evaluate the effects of CGA-184927, fenoxaprop-P, flucarbazone, and ICIA 0604 at labeled and reduced rates on wild oat control, wild oat seed rain, and wheat yield. Each herbicide was applied once at 25, 33, and 100% of the labeled rate at the two-leaf stage of wild oat or split applied at 50 and 66% of the full rate as two equal applications. Excellent full-season wild oat control was obtained with CGA-184927, flucarbazone, and ICIA 0604 applied twice at reduced rates. ICIA 0604 or CGA-184927 split applied at 25 and 33% rates (totaled 50 and 66% of the full rate) provided wild oat control equal to one application of labeled rates. Wild oat seed rain was similar among all herbicide treatments, except plots treated with fenoxaprop-P once at 25 and 33% rates where seed rain was higher and equal to 47% of untreated plots. Wheat yields and net returns were highest and similar after treatment with CGA-184927 or ICIA 0604 applied either once at the labeled rate or split applied at 25 or 33% rates.

Wild Oat (Avena fatua) Competition with Spring Wheat: Effects of Nitrogen Fertilization

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Harry L. Carlson ◽  
James E. Hill
Keyword(s):  
Spring Wheat ◽  
Nitrogen Fertilization ◽  
Field Experiments ◽  
Plant Density ◽  
Crop Yields ◽  
Wheat Yield ◽  
Avena Fatua ◽  
Yield Response ◽  
Wild Oat ◽  
Total Plant

Field experiments were conducted to determine the effect of nitrogen fertilization on competition between wild oat (Avena fatuaL. # AVEFA) and spring wheat (Triticum aestivum‘Anza’). Nitrogen fertilizer treatments were applied over several wild oat-wheat density combinations. Wheat grain yield in wild oat-infested plots generally declined with fertilization while the density of wild oat panicles increased. Apparently, in competition with wheat, wild oat was better able to utilize the added nitrogen and thus gained a competitive advantage over the wheat. The increased competitiveness of wild oat resulted in reduced crop yields. Under the conditions of these experiments, nitrogen fertilization resulted in positive wheat yield response only when the wild oat plant density was below 1.6 percent of the total plant density.

Wild Oat (Avena fatua) Competition with Spring Wheat: Plant Density Effects

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 176-181 ◽  
Author(s):  
Harry L. Carlson ◽  
James E. Hill
Keyword(s):  
Grain Yield ◽  
Regression Models ◽  
Field Experiments ◽  
Plant Density ◽  
Wheat Yield ◽  
Wheat Plant ◽  
Avena Fatua ◽  
Wild Oat ◽  
Plant Densities ◽  
Crop Stand

Field experiments were conducted to measure the grain yield of wheat (Triticum aestivumL. ‘ANZA’) at various wild oat (Avena fatuaL. ♯ AVEFA) and wheat plant densities. Wheat yield declined as wild oat plant density increased. Wheat yield increased in wild oat-infested plots as wheat plant density increased. Regression models were developed to describe the combined effect of wheat and wild oat plant densities on wheat grain yield. Wheat yields were best described by a nonlinear regression model using the relative density of wild oat in the weed-crop stand as the dependent variable. Inclusion of crop stand as a competitive factor significantly improved the fit of all regression models tested. Wild oat were more competitive against wheat in these experiments than in experiments reported by others. Possible reasons for differences in observed competitiveness are discussed.

Wild Oat (Avena fatua) Infestations and Economic Returns as Influenced by Frequency of Control

1988 ◽  
Vol 2 (4) ◽  
pp. 495-498 ◽  
Author(s):  
John T. O'Donovan
Keyword(s):  
Cropping Systems ◽  
Avena Fatua ◽  
The Other ◽  
Wild Oat ◽  
Economic Returns ◽  
Wild Oats ◽  
Average Return

In continuous wheat or barley or in a canola/barley rotation, wild oat control every year over 4 yr maintained wild oat seedling populations at 3 plants/m2 or less. Failure to control wild oats annually increased wild oat populations (>200 plants/m2 by the fourth year) in continuous wheat dramatically, while in the other two cropping systems, populations increased to only 40 plants/m2 or less by the fourth year. In the continuous wheat and in the canola/barley rotation, wild oat control every year generally provided the best economic returns when prices and costs were averaged over 4 yr; in continuous barley, the average return was better when wild oats was controlled only in the second or third years rather than every year.

Efficacy of Fall Incorporated and Non-incorporated Granular Triallate on Wild Oat (Avena fatua) and Wheat (Triticum aestivum)

1994 ◽  
Vol 8 (3) ◽  
pp. 607-611 ◽  
Author(s):  
Kenneth J. Kirkland
Keyword(s):  
Triticum Aestivum ◽  
Spring Wheat ◽  
Wheat Yield ◽  
Subsequent Development ◽  
Avena Fatua ◽  
Wild Oat ◽  
Fresh Weight ◽  
West Central ◽  
Wheat Stubble ◽  
Incorporation Method

The influence of incorporation vs no incorporation on the efficacy of granular triallate applied in mid-October at 1400 and 1700 g ai/ha to control wild oat was evaluated in spring wheat in west central Saskatchewan over a 7-yr period. All fall-applied triallate reduced wild oat panicles and fresh weight, and increased yield compared to untreated checks. With applications in standing wheat stubble there was no difference in wild oat control from incorporation versus no incorporation. All triallate treatments reduced wild oat panicles and fresh weight by over 95%, and resulted in wheat yield increases ranging from 29 to 67%. In tilled fallow, incorporated granules provided better wild oat control than when there was no incorporation. Wheat yield increases ranged from 50 to 85% for triallate treatments with yield for incorporated triallate approximately 15% greater than non-incorporated. The rate of triallate did not affect the level of wild oat control achieved with either incorporation method. In separate tolerance studies triallate incorporation method did not affect spring wheat emergence or subsequent development.

Glyphosate-Resistant Waterhemp (Amaranthus rudis) Control and Economic Returns with Herbicide Programs in Soybean

2009 ◽  
Vol 23 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Travis R. Legleiter ◽  
Kevin W. Bradley ◽  
Raymond E. Massey
Keyword(s):  
Seed Production ◽  
Field Experiments ◽  
Multiple Resistance ◽  
Net Income ◽  
Economic Returns ◽  
Protoporphyrinogen Oxidase ◽  
Amaranthus Rudis ◽  
Herbicide Programs

Field experiments were conducted in Platte County, Missouri, during 2006 and 2007 to evaluate PRE, POST, and PRE followed by (fb) POST herbicide programs for the control of glyphosate-resistant waterhemp in soybean. All PRE fb POST treatments resulted in at least 66 and 70% control of glyphosate-resistant waterhemp in 2006 and 2007, respectively. Control of glyphosate-resistant waterhemp was less than 23% with lactofen and acifluorfen in 2006, but at least 64% in 2007. Variability in control likely resulted from differences in trial locations and a population of protoporphyrinogen oxidase (PPO)–resistant waterhemp at the Platte County site in 2006 compared with 2007. In both years, glyphosate resulted in less than 23% control of glyphosate-resistant waterhemp and provided the least control of all herbicide programs. Programs containing PRE herbicides resulted in waterhemp densities of less than 5 plants/m2, whereas the POST glyphosate treatment resulted in 38 to 70 plants/m2. Waterhemp seed production was reduced at least 78% in all PRE fb POST programs, from 55 to 71% in POST programs containing lactofen and acifluorfen and by only 21% in the POST glyphosate treatment. Soybean yields corresponded to the level of waterhemp control achieved in both years, with the lowest yields resulting from programs that provided poorest waterhemp control. PRE applications ofS-metolachlor plus metribuzin provided one of the highest net incomes in both years and resulted in $271 to $340/ha greater net income than the glyphosate-only treatment. Collectively, the results from these experiments illustrate the effectiveness of PRE herbicides for the control of glyphosate-resistant waterhemp in glyphosate-resistant soybean and the inconsistency of PPO-inhibiting herbicides or PPO-inhibiting herbicide combinations for the control of waterhemp populations with multiple resistance to glyphosate and PPO-inhibiting herbicides.

Effects of Variable Tralkoxydim Rates on Wild Oat (Avena fatua) Seed Production, Wheat (Triticum aestivum) Yield, and Economic Return1

2003 ◽  
Vol 17 (1) ◽  
pp. 149-156 ◽  
Author(s):  
JOHN T. O'DONOVAN ◽  
K. NEIL HARKER ◽  
ROBERT E. BLACKSHAW ◽  
ROBERT N. STOUGAARD
Keyword(s):  
Triticum Aestivum ◽  
Seed Production ◽  
Avena Fatua ◽  
Wild Oat

Effect of Potassium Nitrate and Ethephon on Fate of Wild Oat (Avena fatua) Seed in Soil

Weed Science ◽  
1994 ◽  
Vol 42 (3) ◽  
pp. 353-357 ◽  
Author(s):  
Stephen W. Adkins ◽  
Andrea L. Adkins
Keyword(s):  
Seed Viability ◽  
Soil Surface ◽  
Potassium Nitrate ◽  
Field Application ◽  
Avena Fatua ◽  
Wild Oat ◽  
Germination Stimulants ◽  
Soil Seedbank ◽  
Pure Lines ◽  
Total Seed

A study under glasshouse conditions determined the effect of germination stimulants, potassium nitrate and ethephon, on emergence of several pure lines of wild oat from soil. Effect of the two chemicals on stimulating emergence was variable and no synergism noted when used together. Examination of exhumed seed showed that these treatments reduced seed viability. By counting the number of dead and adding to those that emerged, total seed removed from the soil was obtained. All treatments removed seed from the soil seedbank, especially when seed was old, near the soil surface, was primary seed, or from low or intermediate dormancy lines. However, because of the insensitivity of a large proportion of the seed and the high rates required it is unlikely that either potassium nitrate or ethephon has practical use for field application.

Spring Wheat (Triticum aestivum) Growth and Yield as Influenced by Duration of Wild Oat (Avena fatua) Competition

1993 ◽  
Vol 7 (4) ◽  
pp. 890-893 ◽  
Author(s):  
Kenneth J. Kirkland
Keyword(s):  
Triticum Aestivum ◽  
Spring Wheat ◽  
Wheat Yield ◽  
Avena Fatua ◽  
Growth And Yield ◽  
Wild Oat ◽  
Fresh Weight ◽  
Leaf Stage ◽  
Removal Experiments

The effect of duration of wild oat competition on spring wheat yield and growth was determined in time-of-removal experiments conducted over a three year study period in Saskatchewan, Canada. Failure to remove wild oat reduced wheat yield 28 and 39% at wild oat populations of 64 and 188 plants per m2, respectively. Wheat yield was not reduced by wild oat densities of 64 or 118 plants per m2until the six- and seven-leaf stage of wild oat, respectively. Removing wild oat at 64 plants per m2before the seven-leaf stage and 118 plants per m2before the five-leaf stage did not increase wheat culm or fresh weight production.

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