Giant Ragweed (Ambrosia trifida) Interference in Soybeans (Glycine max)

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 358-362 ◽  
Author(s):  
Jerry A. Baysinger ◽  
Barry D. Sims
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Field Experiments ◽  
Yield Loss ◽  
Soybean Seed ◽  
Critical Duration ◽  
Ambrosia Trifida ◽  
Soybean Yield ◽  
Giant Ragweed

Field experiments were established near Portageville, MO, to determine the effects of giant ragweed interference in soybeans. Threshold densities of giant ragweed that reduced soybean yield were less than two plants 9 m−1of soybean row. This density reduced soybean seed yield 46 and 50% in 1988 and 1989, respectively, after full-season interference. The critical duration of giant ragweed interference in soybeans was between 4 and 6 weeks after emergence (WAE) in 1988 and between 2 and 4 WAE in 1989. Full-season giant ragweed interference at densities of 220 000 and 360 000 plants ha−1in 1988 and 1989, respectively, resulted in almost complete soybean yield loss. Eight to 10 weeks after emergence of giant ragweed-free conditions were required to prevent soybean yield reductions.

Use of Infrared Thermometry in Determining Critical Stress Periods Induced by Quackgrass (Agropyron repens) in Soybeans (Glycine max)

Weed Science ◽  
1987 ◽  
Vol 35 (6) ◽  
pp. 784-791 ◽  
Author(s):  
Peter H. Sikkema ◽  
Jack Dekker
Keyword(s):  
Glycine Max ◽  
Field Experiments ◽  
Yield Loss ◽  
Leaf Growth ◽  
Soybean Seed ◽  
Dry Weight ◽  
Critical Periods ◽  
Soybean Yield ◽  
Infrared Thermometry ◽  
Agropyron Repens

Field experiments were conducted during 1981 and 1982 in Ontario, Canada, on the effects of quackgrass [Agropyron repens(L.) Beauv. # AGRRE] interference in soybean [Glycine max(L.) Merr.] and the usefulness of infrared thermometry in predicting critical periods of weed interference. Soybean seed yield, dry weight, number of leaves, height, and number of pods were substantially reduced due to quackgrass interference. High levels of P and K fertility did not overcome the quackgrass interference. Part of the competitive effects of quackgrass was alleviated by irrigation. Infrared thermometry successfully detected the first occurrence of quackgrass-induced stress during the early soybean flowering stage, when the quackgrass was in the four-leaf gtowth stage. This coincided with the onset of the first significant soybean yield loss. No additional soybean yield loss occurred after quackgrass reached the five-leaf growth stage. There was an inverse relation between accumulated stress degree days and soybean yield reductions due to quackgrass interference. The use of the stress degree day concept may be a valuable tool in predicting soybean yield losses due to quackgrass interference.

Giant Ragweed (Ambrosia trifida) Canopy Architecture and Interference Studies in Soybean (Glycine max)

1994 ◽  
Vol 8 (3) ◽  
pp. 559-564 ◽  
Author(s):  
Theodore M. Webster ◽  
Mark M. Loux ◽  
Emilie E. Regnier ◽  
S. Kent Harrison
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Canopy Architecture ◽  
Economic Threshold ◽  
Ambrosia Trifida ◽  
Soybean Yield ◽  
Giant Ragweed ◽  
Soybean Canopy ◽  
The Cost ◽  
Interference Studies

Field experiments were established at Columbus and near South Charleston, OH to determine the effects of giant ragweed population density on soybean yield and to characterize the development of giant ragweed grown in 76-cm soybean rows. An economic threshold was calculated for Ohio using a common treatment for giant ragweed control in soybean. A cost of $41/ha was estimated for a farmer to apply 0.56 kg/ha bentazon plus 0.28 kg/ha fomesafen plus COC (1.25% v/v). Assuming a soybean value of $0.22/kg, the cost of control was equivalent to 5.4 and 7.1% of the soybean yield in 1991 and 1992, respectively, which corresponded to the yield loss caused by 0.08 and 0.03 giant ragweed plants/m2. The competitiveness of giant ragweed can be at least partly attributed to its ability to initiate and maintain axillary leaves and branches within the shaded confines of the soybean canopy.

Wild Oat (Avena fatua) Competition in Soybean (Glycine max)

Weed Science ◽  
1981 ◽  
Vol 29 (4) ◽  
pp. 410-414 ◽  
Author(s):  
Duane P. Rathmann ◽  
Stephen D. Miller
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Seed Weight ◽  
Soybean Seed ◽  
Avena Fatua ◽  
Wild Oat ◽  
Soybean Yield

The effects of various densities and durations of wild oat (Avena fatuaL.) competition in soybean [Glycine max(L.) Merr. ‘Evans’] were determined in the field during a 2-yr period. Season-long competition by densities of 1, 3,9, and 30 wild oat plants/m of row reduced soybean seed yield an average of 6, 17, 32, and 51%, respectively. An infestation of 30 wild oat plants/m of row did not reduce soybean yield if the period of competition was limited to 4 weeks after crop emergence; however, yields were reduced 29, 50, 63, 58, and 63% when wild oat competed for 5, 6, 7, and 8 weeks, or season long, respectively. Wild oat competition reduced soybean pods per plant and seeds per plant more than seeds per pod or seed weight.

Effect of Imazaquin and Chlorimuron Plus Metribuzin on Sicklepod (Cassia obtusifolia) Interference in Soybean (Glycine max)

1991 ◽  
Vol 5 (1) ◽  
pp. 206-210 ◽  
Author(s):  
David R. Shaw ◽  
Marshall B. Wixson ◽  
Clyde A. Smith
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Dry Matter ◽  
Soybean Seed ◽  
Cassia Obtusifolia ◽  
Soybean Yield ◽  
Herbicide Treatment ◽  
Herbicide Treatments ◽  
Herbicide Use

Three experiments evaluated sicklepod interference with soybean with and without preplant incorporated applications of chlorimuron plus metribuzin or imazaquin. Sicklepod density, weed-free period, and weedy period were examined. In the absence of herbicides, soybean seed yield was reduced with 2 sicklepod plants row m-1, whereas 8 plants row m-1were necessary to reduce yield when herbicides were used. Herbicide use also increased soybean yield at higher sicklepod densities. Chlorimuron plus metribuzin reduced sicklepod dry matter at 8 plants row m-1. To maintain soybean yield, a weed-free period of 4 wk after emergence was required, regardless of treatment. Both herbicide treatments resulted in increased soybean yield at the zero and two wk weed-free periods; however, they did not affect soybean yield when the weed-free period was 4 wk or more. Imazaquin reduced sicklepod density when plots were left weedy full-season, and further reductions were noted with chlorimuron plus metribuzin. A sicklepod weedy interval of 8 wk reduced soybean yield when untreated, but either herbicide treatment extended that interval to 16 wk.

Giant Ragweed (Ambrosia trifida) Control in Soybean (Glycine max)

1992 ◽  
Vol 6 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Jerry A. Baysinger ◽  
Barry D. Sims
Keyword(s):  
Soil Moisture ◽  
Glycine Max ◽  
Seed Production ◽  
Field Experiments ◽  
Ambrosia Trifida ◽  
Early Season ◽  
Giant Ragweed ◽  
Herbicide Treatments ◽  
Southeast Missouri

Two field experiments were established in 1988 and 1989 in southeast Missouri to evaluate several herbicides and herbicide combinations for giant ragweed control in soybean. In 1988, a timely rainfall was not received for soil-applied herbicides and giant ragweed control was less than 75%. However, in 1989 soil moisture was sufficient for uptake of soil-applied herbicides and early season giant ragweed control was generally greater than 80%. Chlorimuron, chlorimuron plus 2,4-DB, imazaquin plus 2,4-DB, acifluorfen followed by naptalam plus 2,4-DB, fomesafen, and imazethapyr applied to 2.5 to 5-cm giant ragweed controlled more than 85% in 1988. In 1989, all POST treatments except imazaquin controlled more than 81% of giant ragweed 2 wk after treatments. Imazethapyr controlled seedling giant ragweed at heights up to 12 to 25 cm. Giant ragweed regrowth and/or reinfestation and giant ragweed seed production occurred with all herbicide treatments.

Effect of numbers of Bradyrhizobium japonicum applied in commercial inoculants on soybean seed yield in Ontario

1992 ◽  
Vol 38 (6) ◽  
pp. 588-593 ◽  
Author(s):  
D. J. Hume ◽  
D. H. Blair
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Bradyrhizobium Japonicum ◽  
Field Experiments ◽  
Soybean Seed ◽  
Yield Response ◽  
Cubic Equation ◽  
Glycine Max L ◽  
Seed Yields ◽  
Commercial Inoculants

In the absence of Bradyrhizobium japonicum populations in the soil, yields of field-grown soybean (Glycine max (L.) Merrill) usually respond to inoculation with B. japonicum. The objective of this research was to determine the relationship between numbers of B. japonicum per seed in inoculants and soybean nodulation and yield. A total of six field experiments were conducted in 1989 and 1990 on new soybean soils. In dilution trials, Grip inoculant was applied to provide approximately 106, 105, 104, and 103B. japonicum per seed at two locations in 1989. Nodule number and mass, as well as seed yield, increased curvilinearly upward with increasing log10 most probable numbers (MPNs) of B. japonicum. The yield response curve was best fit by a cubic equation, which accounted for 97% of the variation in yield. Seed yields increased 19% (1.83 to 2.13 Mg/ha) from 105 to 106B. japonicum per seed. In field experiments involving 8 commercial inoculants in 1989 and 10 in 1990, and conducted at two locations in each year, responses to increasing log MPNs in the inoculants also were concave upwards and cubic. In the two years, 78 and 46% of the yield variation was accounted for by log MPN per seed. Increasing MPN per seed from 105 to 106 improved yields in first-time fields by an average of 24%, indicating the present minimum standard of 105B. japonicum per seed should be increased. Key words: most probable numbers, response to inoculation, nodulation, Glycine max (L.) Merrill.

Functional relationships between giant ragweed (Ambrosia trifida) interference and sweet corn yield and ear traits

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 948-953 ◽  
Author(s):  
Martin M. Williams ◽  
John B. Masiunas
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Sweet Corn ◽  
Initial Slope ◽  
Hyperbolic Model ◽  
Corn Yield ◽  
Fresh Market ◽  
Ambrosia Trifida ◽  
Functional Relationships ◽  
Giant Ragweed

Field experiments were conducted to quantify functional relationships between giant ragweed density and sweet corn yield and ear traits. A rectangular hyperbolic model was fit to yield loss measured in terms of marketable ear mass, appropriate for the processing industry, and boxes of 50 marketable ears, relevant to the fresh market industry. The initial slope of the hyperbolic yield loss function (I), which describes the linear portion of yield loss as weed density (weeds per square meter) approaches zero, was 119 for loss of ear mass and 97 for loss of boxes of ears. Furthermore, 10 of 12 ear traits including green ear mass, husked ear mass, ear length, filled ear length, ear width, number of kernels per row, number of rows, kernel depth, kernel mass, and kernel moisture content were significantly affected by giant ragweed interference.

Interference Between Soybeans (Glycine max) and Common Cocklebur (Xanthium strumarium) Under Indiana Field Conditions

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 753-760 ◽  
Author(s):  
William T. Henry ◽  
Thomas T. Bauman
Keyword(s):  
Spatial Distribution ◽  
Regression Analysis ◽  
Glycine Max ◽  
Seed Yield ◽  
Soybean Seed ◽  
Growing Season ◽  
Field Conditions ◽  
Xanthium Strumarium ◽  
Soybean Yield ◽  
Over Time

The effects of interference between soybeans and common cocklebur were investigated. Common cocklebur interference reduced soybean growth at each of four sample dates during the growing season. The area of interference surrounding individual common cocklebur plants within the soybean row fluctuated over time with respect to intensity and spatial distribution. Soybean growth was significantly reduced up to 10 cm away from individual cocklebur plants at 6 weeks after planting (WAP), 30 cm at 8 WAP, 20 to 30 cm at 10 WAP, and 40 cm at 12 WAP. The maximum possible distance of cocklebur influence, determined by regression analysis, also varied during the growing season. When areas of interference from adjacent cocklebur plants overlapped, the cumulative influence was found to be additive, especially late in the growing season. Soybean interference caused a 50 to 90% reduction in the size of common cocklebur plants grown within the soybean row compared to plants grown without interference. At harvest, soybean yield was reduced up to 40 to 50 cm within the row from individual cocklebur plants. The maximum distance of interference on one side of individual cocklebur plants was 75 cm. One cocklebur plant reduced soybean yield 16.0% within 1.5 m of soybean row as the result of full-season interference. Interference of common cocklebur plants spaced 60 cm apart within the row overlapped and caused an additive reduction in soybean seed yield. Across all cocklebur treatments, there was a consistent ratio of approximately 1 kg/ha loss in soybean seed yield for each 4 kg/ha of cocklebur herbage produced.

Glyphosate-resistant giant ragweed (Ambrosia trifida L.) control with preplant herbicides in soybean [Glycine max (L.) Merr.]

2012 ◽  
Vol 92 (5) ◽  
pp. 913-922 ◽  
Author(s):  
Joseph P. Vink ◽  
Nader Soltani ◽  
Darren E. Robinson ◽  
François J. Tardif ◽  
Mark B. Lawton ◽  
...  
Keyword(s):  
Glycine Max ◽  
Field Trials ◽  
Yield Losses ◽  
Ambrosia Trifida ◽  
Soybean Yield ◽  
Field Crops ◽  
Giant Ragweed ◽  
Glycine Max L ◽  
Significant Yield ◽  
Residual Control

Vink, J. P., Soltani, N., Robinson, D. E., Tardif, F. J., Lawton, M. B. and Sikkema, P. H. 2012. Glyphosate-resistant giant ragweed ( Ambrosia trifida L.) control with preplant herbicides in soybean [ Glycine max (L.) Merr.]. Can. J. Plant Sci. 92: 913–922. Giant ragweed populations in southwestern Ontario have evolved resistance to glyphosate. Glyphosate-resistant (GR) giant ragweed interference in field crops can lead to significant yield losses. Eleven field trials [five with preplant (PP) burndown only and six with PP burndown plus residual herbicides] were conducted in 2010 and 2011 on Ontario farms with GR giant ragweed to evaluate the efficacy of various PP herbicides applied prior to soybean planting. Glyphosate applied at the recommended field dose failed to adequately control GR giant ragweed. The PP herbicides 2,4-D ester, cloransulam-methyl and saflufenacil applied alone and with glyphosate provided 97–99, 68–100 and 71–94% control, respectively and resulted in soybean yields equivalent to the weed-free check. Combinations of glyphosate plus cloransulam-methyl or linuron controlled GR giant ragweed 8 wk after application (WAA), 75–95 and 95–98%, respectively. Residual control with glyphosate plus linuron resulted in soybean yield equivalent to the weed-free check. Based on these results, GR giant ragweed can be controlled prior to soybean planting in southwestern Ontario.

Comparison of Soybean (Glycine max) – Weed Interference from Large and Small Plots

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 836-839 ◽  
Author(s):  
Michael G. Patterson ◽  
Robert H. Walker ◽  
Daniel L. Colvin ◽  
Glenn Wehtje ◽  
John A. McGuire
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Dry Matter ◽  
Field Experiments ◽  
Soybean Seed ◽  
Regression Coefficients ◽  
Row Spacing ◽  
Soybean Field ◽  
Weed Biomass ◽  
Weed Interference

Soybean field experiments were conducted to compare weed interference data obtained from small 2.7-m2plots to that obtained from large 11-m2plots. Soybean row spacings of 15, 30, 45, and 90 cm were used. Sicklepod, common cocklebur, and soybean biomass as dry matter were harvested from small plots 10 weeks after planting and were compared to weed biomass and soybean seed yield from the large plots. Sicklepod and common cocklebur biomass in small plots increased and soybean biomass decreased as soybean row spacing increased. Soybean biomass was not affected by row spacing when weeds were not present. Sicklepod and common cocklebur biomass in large plots increased and soybean seed yield decreased as soybean row spacing increased. Soybean seed yield was not affected by row spacing when weeds were not present. Comparison of regression coefficients for paired regression lines indicates that soybean biomass from small plots may be substituted for seed yield from large plots as a measure of sicklepod or common cocklebur interference if both size plots use the same soybean row spacing and are irrigated until harvest.

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