Duration of Tartary Buckwheat (Fagopyrum tataricum) Interference in Several Crops

Field studies were conducted over a 7-yr period at Lacombe, Alberta, to study the relationship between the duration of Tartary buckwheat interference [Fagopyrum tatarium(L.) Gaertn. # FAGTA] and yield of barley (Hordeum vulgareL.), oats (Avena sativaL.), wheat (Triticum aestivumL.), flax (Linum usitatissimumL.), and rapeseed (Brassica campestrisL.). The data were pooled over years and analyzed by multiple regression. The equations were as follows: ŷ = 15.46 + 0.39X1+ 0.00x2−0.11x3(barley), ŷ = −15.44 + 0.49x1+ 0.02x2+ 0.08x3(oats), ŷ = −2.04 + 0.39X1+ 0.05x2-0.03x3(wheat), ŷ = −4.38 + 1.14x1−0.04x2+ 0.01x3(flax), and ŷ = −13.85 + 0.40x1– 0.01x2+ 0.04x3(rapeseed); where ŷ was the estimated percent yield loss of the crop, x1was the duration (days) of the Tartary buckwheat in the crop, x2was the number of Tartary buckwheat plants/m2, and x3was the number of crop plants/m2. The time that Tartary buckwheat remains in the crop contributed most to the yield loss observed in all crops. Yield loss between 0.4 and 1.1% per day was attributed to this variable alone. For a given x1, x2, and x3value the order of percent yield loss was flax>oats>wheat> barley>rapeseed.

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Influence of Tartary Buckwheat (Fagopyrum tataricum) Density on Yield Loss of Barley (Hordeum vulgare) and wheat (Triticum aestivum)

Weed Science ◽

10.1017/s0043174500082771 ◽

1985 ◽

Vol 33 (4) ◽

pp. 521-523 ◽

Cited By ~ 3

Author(s):

E. Ann de St. Remy ◽

John T. O'Donovan ◽

Alan K. W. Tong ◽

P. Ashley O'Sullivan ◽

M. Paul Sharma ◽

...

Keyword(s):

Triticum Aestivum ◽

Hordeum Vulgare ◽

Yield Loss ◽

Plant Density ◽

Wheat Yield ◽

Tartary Buckwheat ◽

Yield Reduction ◽

Regression Equations ◽

Fagopyrum Tataricum ◽

The Relationship

The relationship between Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn. ♯ FAGTA) plant density (x) and percent yield loss (ŷ) was expressed by the following linear regression equations for barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), respectively; ŷ = 0.63 + 2.75 √x and ŷ = 5.04 + 3.05 √x. Tartary buckwheat causes serious yield reduction in barley and wheat. A Tartary buckwheat density at 30 plants/m2 at emergence reduced barley yield by 16% and wheat yield by 22%.

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The Critical Period of Bengal Dayflower (Commelina Bengalensis) Control in Peanut

Weed Science ◽

10.1614/ws-06-181.1 ◽

2007 ◽

Vol 55 (4) ◽

pp. 359-364 ◽

Cited By ~ 13

Author(s):

Theodore M. Webster ◽

Wilson H. Faircloth ◽

J. Timothy Flanders ◽

Eric P. Prostko ◽

Timothy L. Grey

Keyword(s):

Weed Control ◽

Critical Period ◽

Plant Pathogens ◽

Yield Loss ◽

Maximum Yield ◽

Field Studies ◽

Yield Losses ◽

Competitive Effects ◽

Peanut Crop ◽

The Relationship

Bengal dayflower (also known as tropical spiderwort) is one of the most troublesome weeds in peanut in Georgia, United States. Field studies conducted in 2004 and 2005 evaluated the relationship between the duration of Bengal dayflower interference and peanut yield in an effort to optimize the timing of weed control. In 2004, the critical period of weed control (CPWC) necessary to avoid greater than 5% peanut yield loss was between 316 and 607 growing degree days (GDD), which corresponded to an interval between June 8 and July 2. In 2005, the CPWC ranged from 185 to 547 GDD, an interval between May 30 and July 3. Maximum yield loss in 2005 from season-long interference of Bengal dayflower was 51%. In 2004, production of peanut pods was eliminated by interference with Bengal dayflower for the initial 6 wk (495 GDD) of the growing season. Robust Bengal dayflower growth in 2004 shaded the peanut crop, likely intercepting fungicide applications and causing a reduction in peanut yield. Therefore, the competitive effects of Bengal dayflower are likely complicated with the activity of plant pathogens. In spite of higher Bengal dayflower population densities, greater Bengal dayflower growth, and greater peanut yield losses in 2004 than in 2005, the CPWC was a relatively similar 4-wk period that ended during the first week of July, for peanut that was planted in the first week of May.

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CANOLA YIELD AND PROFITABILITY AS INFLUENCED BY VOLUNTEER WHEAT INFESTATIONS

Canadian Journal of Plant Science ◽

10.4141/cjps89-145 ◽

1989 ◽

Vol 69 (4) ◽

pp. 1235-1244 ◽

Cited By ~ 11

Author(s):

J. T. O’DONOVAN ◽

K. J. KIRKLAND ◽

A. K. SHARMA

Keyword(s):

Triticum Aestivum ◽

Multiple Regression ◽

Seed Yield ◽

Field Experiments ◽

Yield Loss ◽

Brassica Campestris ◽

Triticum Aestivum L ◽

Economic Threshold ◽

Rectangular Hyperbola

The effects of different densities of volunteer wheat (Triticum aestivum L. ’Neepawa’) on the yield of canola (Brassica campestris L. ’Tobin’ and B. napus L. ’Westar’), and the seed yield of the volunteer wheat were determined in field experiments conducted at Vegreville, Alberta and Scott, Saskatchewan. Hyperbolic models provided a good fit to the data in most instances and indicated that volunteer wheat can severely reduce canola yield. A model pooled over locations and years indicated that volunteer wheat populations as low as one plant m−2 reduced canola yield by approximately 1%. Yield loss predictions from the models were used to determine the economics of volunteer wheat control with herbicides. In some cases, revenue losses due to reduced canola yield could be alleviated when the value of the volunteer wheat was considered.Key words: Volunteer wheat, canola, rectangular hyperbola, multiple regression, economic threshold, volunteer cereals

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Loss in Yield of Rapeseed (Brassica napus, B. campestris) Caused by Perennial Sowthistle (Sonchus arvensis) in Saskatchewan and Manitoba

Weed Science ◽

10.1017/s0043174500070284 ◽

1983 ◽

Vol 31 (5) ◽

pp. 740-744 ◽

Cited By ~ 9

Author(s):

Diether P. Peschken ◽

A. Gordon Thomas ◽

Robin F. Wise

Keyword(s):

Brassica Napus ◽

Survey Data ◽

Yield Loss ◽

Field Studies ◽

Similar Frequency ◽

A Value ◽

Average Annual Loss ◽

Percentage Yield ◽

Sonchus Arvensis ◽

The Relationship

Field studies were conducted in 1979 and 1980 to determine yield losses caused by perennial sowthistle (Sonchus arvensis L. # SONAR) in rapeseed (Brassica napus L., B. campestris L.) fields in Saskatchewan and Manitoba. The relationship between percentage yield loss and density of perennial sowthistle was expressed by the linear regression equation y = −3.81 + 13.76 rdx. Weed survey data indicated that perennial sowthistle occurred in 39% of the rapeseed fields but infested only 7% of the hectares surveyed. Using both the survey data and the yield loss equation, the average annual loss in rapeseed yield was estimated to be 9.4 million kg in Saskatchewan and 6.1 million kg in Manitoba, with a value of 2.6 million and 1.7 million dollars (Cdn.), respectively. Perennial sowthistle occurs with a similar frequency and density in other crops so that the total loss from this weed would be much greater.

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Relationship between relative time of emergence of Tartary buckwheat (Fagopyrum tataricum) and yield loss of barley

Canadian Journal of Plant Science ◽

10.4141/p02-042 ◽

2002 ◽

Vol 82 (4) ◽

pp. 861-863 ◽

Cited By ~ 1

Author(s):

J. T. O’Donovan ◽

A. S. McClay

Keyword(s):

Decision Support ◽

Hordeum Vulgare ◽

Regression Model ◽

Nonlinear Regression ◽

Yield Loss ◽

Tartary Buckwheat ◽

Nonlinear Regression Model ◽

Fagopyrum Tataricum ◽

Hordeum Vulgare L ◽

Relative Time

A nonlinear regression model was used to describe the relationship between Tartary buckwheat [Fagopyrum tataricum (L.) Gaertn.] density and relative time of emergence, and yield of barley (Hordeum vulgare L.). Yield loss increased the earlier the weed emerged relative to the crop. The model is being used in computerized decision support systems for weed management in western Canada. Key words: Fagopyrum tataricum, Hordeum vulgare, nonlinear regression model, relative time of emergence, decision support system

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ANNUAL WEED CONTROL WITH PARAQUAT IN COMBINATION WITH OTHER HERBICIDES

Canadian Journal of Plant Science ◽

10.4141/cjps86-019 ◽

1986 ◽

Vol 66 (1) ◽

pp. 153-160 ◽

Cited By ~ 1

Author(s):

J. T. O’DONOVAN ◽

P. A. O’SULLIVAN

Keyword(s):

Triticum Aestivum ◽

Hordeum Vulgare ◽

Weed Control ◽

Avena Sativa ◽

Brassica Campestris ◽

Triticum Aestivum L ◽

Field Trials ◽

Zero Tillage ◽

Hordeum Vulgare L ◽

Key Words Wheat

Paraquat at 0.28 kg/ha effectively controlled barley (Hordeum vulgare L. ’Galt’), wheat (Triticum aestivum L. ’Neepawa’) and oat (Avena sativa L. ’Random’) in field trials conducted during 1982 and 1983. Grass control was excellent with paraquat and its activity was unaffected when it was applied in combination with either clopyralid, picloram, metribuzin, linuron, or chlorsulfuron. Slight reductions in paraquat phytotoxicity occurred in some instances when paraquat was applied in combination with commercially formulated mixtured of clopyralid plus 2,4-D, clopyralid plus MCPA or picloram plus 2,4-D, but grass control was still acceptable (90% or greater). However, a commercially formulated mixture of cyanazine plus MCPA consistently reduced the phytotoxicity of paraquat and rendered grass control unacceptable. Control of rapeseed (Brassica campestris L. ’Candle’) with paraquat and most paraquat mixtures was excellent in 1982 but was poor and variable in 1983.Key words: Wheat, barley, oat, rapeseed, zero tillage, chemical summerfallow

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Determining the critical period for broadleaf weed control in high-yielding cotton using mungbean as a mimic weed

Weed Technology ◽

10.1017/wet.2020.38 ◽

2020 ◽

Vol 34 (5) ◽

pp. 689-698

Author(s):

Graham W. Charles ◽

Brian M. Sindel ◽

Annette L. Cowie ◽

Oliver G. G. Knox

Keyword(s):

Weed Control ◽

Critical Period ◽

Yield Loss ◽

Critical Time ◽

Field Studies ◽

Cotton Field ◽

Control Input ◽

Degree Days ◽

Weed Density ◽

The Relationship

AbstractResearch using the critical period for weed control (CPWC) has shown that high-yielding cotton crops are very sensitive to competition from grasses and large broadleaf weeds, but the CPWC has not been defined for smaller broadleaf weeds in Australian cotton. Field studies were conducted over five seasons from 2003 to 2015 to determine the CPWC for smaller broadleaf weeds, using mungbean as a mimic weed. Mungbean was planted at densities of 1, 3, 6, 15, 30, and 60 plants m−2 with or after cotton emergence and added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 degree days of crop growth (GDD). Mungbean competed strongly with cotton, with season-long interference; 60 mungbean plants m−2 resulted in an 84% reduction in cotton yield. A dynamic CPWC function was developed for densities of 1 to 60 mungbean plants m−2 using extended Gompertz and exponential curves including weed density as a covariate. Using a 1% yield-loss threshold, the CPWC defined by these curves extended for the full growing season of the crop at all weed densities. The minimum yield loss from a single weed control input was 35% at the highest weed density of 60 mungbean plants m−2. The relationship for the critical time of weed removal was further improved by substituting weed biomass for weed density in the relationship.

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Lanceleaf Sage (Salvia reflexa) Interference in Sugarbeet

Weed Technology ◽

10.1614/wt-d-10-00015.1 ◽

2010 ◽

Vol 24 (4) ◽

pp. 557-561 ◽

Cited By ~ 5

Author(s):

Dennis C. Odero ◽

Abdel O. Mesbah ◽

Stephen D. Miller ◽

Andrew R. Kniss

Keyword(s):

Yield Loss ◽

Maximum Yield ◽

Field Studies ◽

Control Measures ◽

Root Yield ◽

Rectangular Hyperbola ◽

Weed Density ◽

Negative Effect ◽

Critical Timing ◽

The Relationship

Field studies were conducted in Powell, WY, in 2006 and 2007 to determine the influence of season-long interference of various lanceleaf sage densities and durations of interference on sugarbeet. The rectangular hyperbola model with the asymptote (A) constrained to 100% maximum yield loss characterized the relationship between lanceleaf sage density and sugarbeet yield loss. The estimated parameterI(yield loss per unit weed density as density approaches zero) was 3% for both root and sucrose yield loss. Increasing duration of lanceleaf sage interference had a negative effect on sugarbeet root yield. The critical timing of weed removal to avoid 5 and 10% root yield loss was 37 and 52 d after sugarbeet emergence, respectively. Lanceleaf sage interference did not affect percentage of sucrose content. These results indicate that lanceleaf sage is not as competitive as other weeds but that appropriate control measures should be undertaken to minimize sugarbeet yield loss from interference.

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