Interference of Wild Poinsettia (Euphorbia heterophylla) with Soybean (Glycine max)

1994 ◽  
Vol 8 (4) ◽  
pp. 679-683 ◽  
Author(s):  
Teresa S. Willard ◽  
James L. Griffin ◽  
Daniel B. Reynolds ◽  
Arnold M. Saxton
Keyword(s):  
Glycine Max ◽  
Dry Weight ◽  
Growing Season ◽  
Field Studies ◽  
Yield Reduction ◽  
Soybean Yield ◽  
Weed Interference ◽  
Soybean Canopy ◽  
Area Of Influence

Field-studies were conducted over two years to determine the area of influence and duration of interference of wild poinsettia in soybean. Soybean canopy width averaged across years was reduced approximately 10% beginning at 6 wk of interference for both the 0- to 10-and 10-to 20-cm distances from the weed. Soybean dry weights decreased from 14 to 38% within 20 cm of the weed for 12 through 18 wk of interference. In 1990, soybean yield within 10 cm of wild poinsettia was similar to distances of 10 to 20 and 20 to 40 cm, but was less than that for distances greater than 40 cm from the weed. Weed interference resulted in a 9.5% yield reduction in the 0- to 10-cm distance when compared with the 80-to 100-cm distance. In contrast, yield of soybean in 1991 growing within 10 cm of the weed was less than at greater distances, corresponding to an 18% yield reduction when compared with 80 to 100 cm. Differences in wild poinsettia dry weights when growing alone and when growing within the soybean row occurred after 6 and 8 wk of interference in 1990 and 1991, respectively. In 1991 when rainfall during the growing season was twice that of the previous year, canopy width and dry weight of wild poinsettia growing within the soybean row were reduced an average of 57 and 82%, respectively, compared with weeds growing alone.

Palmer Amaranth (Amaranthus palmeri) Interference in Soybeans (Glycine max)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 523-527 ◽  
Author(s):  
Tracy E. Klingaman ◽  
Lawrence R. Oliver
Keyword(s):  
Glycine Max ◽  
Field Study ◽  
Palmer Amaranth ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Amaranthus Palmeri ◽  
Soybean Yield ◽  
Soybean Canopy ◽  
Highly Correlated

A 2-yr field study was conducted at Fayetteville, AR, to determine the effect of Palmer amaranth interference on soybean growth and yield. Palmer amaranth density had little effect on soybean height, but soybean canopy width ranged from 77 cm in the weed-free check to 35 cm in plots with 10 plants m–1of row 12 wk after emergence. Soybean yield reduction was highly correlated to Palmer amaranth biomass at 8 wk after emergence and maturity, soybean biomass at 8 wk after emergence, and Palmer amaranth density. Soybean yield reduction was 17, 27, 32, 48, 64, and 68%, respectively, for Palmer amaranth densities of 033, 0.66, 1, 2, 333, and 10 plants m–1of row. Soybean yield reduction and Palmer amaranth biomass were linear to approximately 2 Palmer amaranth m–1of row, suggesting intraspecific interference between adjacent Palmer amaranth is initiated at Palmer amaranth densities between 2 and 3.33 plants m–1of row.

Field Competition between Ivyleaf Morningglory (Ipomea hederacea) and Soybeans (Glycine max)

Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 364-370 ◽  
Author(s):  
Ronald C. Cordes ◽  
Thomas T. Bauman
Keyword(s):  
Soil Moisture ◽  
Glycine Max ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Dry Weight ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Area Index ◽  
Soybean Yield ◽  
Competition Effects

Detrimental effects on growth and yield of soybeans [Glycine max(L.) Merr. ‘Amsoy 77′] from density and duration of competition by ivyleaf morningglory [Ipomea hederacea(L.) Jacq. ♯3IPOHE] was evaluated in 1981 and 1982 near West Lafayette, IN. Ivyleaf morningglory was planted at densities of 1 plant per 90, 60, 30, and 15 cm of row in 1981 and 1 plant per 60, 30, 15, and 7.5 cm of row in 1982. Each density of ivyleaf morningglory competed for 22 to 46 days after emergence and the full season in 1981, and for 29 to 60 days after emergence and the full season in 1982. The best indicators of competition effects were leaf area index, plant dry weight, and yield of soybeans. Ivyleaf morningglory was more competitive during the reproductive stage of soybean growth. Photosynthetic irradiance and soil moisture measurements indicated that ivyleaf morningglory does not effectively compete for light or soil moisture. All densities of ivyleaf morningglory could compete with soybeans for 46 and 60 days after emergence in 1981 and 1982, respectively, without reducing soybean yield. Full-season competition from densities of 1 ivyleaf morningglory plant per 15 cm of row significantly reduced soybean yield by 36% in 1981 and 13% in 1982. The magnitude of soybean growth and yield reduction caused by a given density of ivyleaf morningglory was greater when warm, early season temperatures favored rapid weed development.

Soybean response to weed interference and defoliation

Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Charles F. Grymes ◽  
James L. Griffin ◽  
David J. Boethel ◽  
B. Rogers Leonard ◽  
David L. Jordan ◽  
...  
Keyword(s):  
Seed Development ◽  
Field Experiments ◽  
Dry Weight ◽  
Yield Reduction ◽  
Growth Stages ◽  
Lower Yield ◽  
Full Bloom ◽  
Soybean Yield ◽  
Weed Interference ◽  
Hemp Sesbania

Field experiments were conducted in Louisiana over 2 yr to evaluate the influence of full-season interference from johnsongrass, common cocklebur, or hemp sesbania at densities of 2.5, 0.5, and 2.0 plants m–1of row, respectively, and simulated insect defoliation of soybean on weed and soybean growth. Defoliation at R2 (full bloom) and R5 (beginning seed development) soybean growth stages was accomplished by removal of zero, one, or two leaflets per soybean trifoliate, which approximated 0, 33, and 66% defoliation, respectively. Height and dry weight of all weeds were not affected by soybean defoliation level or defoliation stage. Soybean height 3 wk after defoliation at R5 was not influenced by weed interference, soybean defoliation level, or defoliation stage in either year. Averaged across soybean defoliation levels and stages in 1994, johnsongrass, common cocklebur, and hemp sesbania reduced soybean yields 30, 15, and 14%, respectively. In 1995, johnsongrass reduced soybean yield 35%. As soybean defoliation level increased, a linear decrease in soybean yield was observed. Averaged across weeds and soybean defoliation stages, 33 and 66% defoliation reduced soybean yield 6 and 20% in 1994 and 12 and 33% in 1995, respectively. Defoliation at R5 resulted in 10% lower yield than defoliation at R2 in one of two years. Yield reduction due to combinations of weeds and soybean defoliation was additive.

Soybean (Glycine max) Response to Simulated Drift from Selected Sulfonylurea Herbicides, Dicamba, Glyphosate, and Glufosinate

1999 ◽  
Vol 13 (2) ◽  
pp. 264-270 ◽  
Author(s):  
Kassim Al-Khatib ◽  
Dallas Peterson
Keyword(s):  
Glycine Max ◽  
Field Research ◽  
Growing Season ◽  
Yield Reduction ◽  
Sulfonylurea Herbicides ◽  
Early Season ◽  
Soybean Yield ◽  
Leaf Stage ◽  
Soybean Plants ◽  
Herbicide Drift

Field research was conducted to evaluate the response of soybean to various herbicides applied at rates to simulate drift damage. Dicamba, glyphosate, glufosinate, and the sulfonylurea herbicides CGA-152005, primisulfuron, nicosulfuron, rimsulfuron plus thifensulfuron, and CGA-152005 plus primisulfuron were applied to soybean at the two to three trifoliolate leaf stage in 1997 and 1998 atand ⅓ of the recommended use rates. The order of yield reduction after herbicide treatment was CGA-152005 > dicamba > CGA-152005 plus primisulfuron > rimsulfuron plus thifensulfuron > primisulfuron. Soybean yields were not reduced by glyphosate, glufosinate, and nicosulfuron. Applications of all herbicides at rates higher thanof the use rate caused injury symptoms within 30 d after treatment. However, soybean plants had partially or fully recovered by the end of the growing season. Therefore, early-season injury symptoms from herbicide drift are not reliable indicators for soybean yield reduction.

Barnyardgrass (Echinochloa crus-galli) Interference in Soybeans (Glycine max)

1993 ◽  
Vol 7 (1) ◽  
pp. 220-225 ◽  
Author(s):  
Gordon D. Vail ◽  
Lawrence R. Oliver
Keyword(s):  
Glycine Max ◽  
Field Experiment ◽  
Yield Loss ◽  
Dry Weight ◽  
Yield Reduction ◽  
Average Yield ◽  
Soybean Yield ◽  
Total Dry Weight

A 2-yr field experiment was conducted at Fayetteville and Stuttgart, AR, to predict soybean yield loss as a function of barnyardgrass density and total dry weight. Predicted soybean yield reductions were 0 to 78% for original densities of 1 to 500 barnyardgrass plants per m of row. Soybean yield reductions were linear from 0 to 150 barnyardgrass plants per m of row with an average yield reduction of 0.25% for each plant per m of row. Soybean yield was reduced 10, 25, and 50% from original barnyardgrass densities of 42, 110, and 250 plants m of row. Predictions of soybean yield reduction from barnyardgrass dry weight and original density were similar. traspecific interference of barnyardgrass occurred for all variables tested, with individual barnyardgrass plants becoming less competitive as density increased.

Field Competition Between Tall Morningglory and Soybean. I. Growth Analysis

Weed Science ◽  
1976 ◽  
Vol 24 (5) ◽  
pp. 482-488 ◽  
Author(s):  
L. R. Oliver ◽  
R. E. Frans ◽  
R. E. Talbert
Keyword(s):  
Growth Rate ◽  
Glycine Max ◽  
Intraspecific Competition ◽  
Growth Analysis ◽  
Dry Weight ◽  
Yield Reduction ◽  
Area Index ◽  
Crop Growth Rate ◽  
Soybean Yield ◽  
Ipomoea Purpurea

The intraspecific (competition between same species) and interspecific (competition between different species) competitiveness of tall morningglory [Ipomoea purpurea(L.) Roth] in soybeans [Glycine max(L.) Merr.] was evaluated for 3 yr at Fayetteville, Arkansas. Tall morningglory was planted at densities of one plant per 61, 30, and 15 cm of row, and competition duration ranged from 2 weeks to full-season. Soybeans were more competitive than tall morningglory for the first 6 to 8 weeks after emergence. The competitiveness of tall morningglory was dependent upon a rapid increase in photosynthetic area which occurred 4 to 6 weeks after emergence. Reductions in leaf area index (LAI) or plant dry weight and crop growth rate (CGR) of soybeans were closely correlated to percent soybean yield reduction. Tall morningglory could remain in soybeans for 12, 10, and 6 weeks without significantly reducing soybean yield at one plant per 61, 30, and 15 cm of row, respectively. Tall morningglory was three to four times more competitive during the soybean reproductive stage than during the vegetative stage.

Smooth Pigweed (Amaranthus hybridusL.) and Livid Amaranth (Amaranthus lividus) Interference with Cucumber (Cucumis sativus)

2006 ◽  
Vol 20 (1) ◽  
pp. 227-231 ◽  
Author(s):  
Adrian D. Berry ◽  
William M. Stall ◽  
B. Rathinasabapathi ◽  
Gregory E. Macdonald ◽  
R. Charudattan
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Fruit Yield ◽  
Yield Reduction ◽  
Cucumber Plant ◽  
Weed Density ◽  
Weed Interference ◽  
Shoot Dry Weight ◽  
Cucumber Fruit ◽  
Smooth Pigweed

Field studies were conducted to determine the effect of season-long interference of smooth pigweed or livid amaranth on the shoot dry weight and fruit yield of cucumber. Smooth pigweed or livid amaranth densities as low as 1 to 2 weeds per m2caused a 10% yield reduction in cucumber. The biological threshold of smooth pigweed or livid amaranth with cucumber is between 6 to 8 weeds per m2. Consequently, weed interference resulted in a reduction in cucumber fruit yield. Smooth pigweed, livid amaranth, and cucumber plant dry weight decreased as weed density increased. Evaluation of smooth pigweed, livid amaranth, and cucumber mean dry weights in interspecific competition studies indicated that cucumber reduced the dry weight of both species of amaranths.

Johnsongrass (Sorghum halepense) Competition in Soybeans (Glycine max)

Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 498-501 ◽  
Author(s):  
C. S. Williams ◽  
Robert M. Hayes
Keyword(s):  
Glycine Max ◽  
Potential Application ◽  
Dry Weight ◽  
Control Measures ◽  
Sorghum Halepense ◽  
Yield Potential ◽  
Yield Reduction ◽  
Row Spacing ◽  
Sufficient Time ◽  
Soybean Yield

Johnsongrass [Sorghum halepense(L.) Pers., ♯3SORHA] dry weight and johnsongrass culms/ha at harvest were more negatively correlated with soybean yield reductions than the number of johnsongrass plants/ha present at 4 to 6 weeks after planting. However, plant numbers can be determined in sufficient time to implement control measures to prevent yield reduction. Prediction equations for estimating soybean yield at various johnsongrass populations are Ŷ = 1776 + 424e-.023x2for 0.25-m row spacing and Ŷ = 1668 + 643e-.004x2for the 1-m row spacing, where Ŷ = estimated yield and x = the number of johnsongrass plants/10 m2. Full-season heavy johnsongrass competition reduced soybean yields from 59 to 88%. Soybeans in the 1-m row spacing were more competitive with low johnsongrass densities than in the 0.25-m row spacing. The johnsongrass-free requirement for soybeans was 4 weeks after planting and soybeans could not tolerate heavy infestations of johnsongrass for more than 5 weeks without loss in yield potential. Application of sethoxydim {2-[1-(ethoxyimino)-butyl]-5-[2-ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} at 3 or 4 weeks after planting was effective in controlling heavy infestations of johnsongrass and preventing yield reductions due to competition.

Row Spacing and Seeding Rate Effects on Eastern Black Nightshade (Solanum Ptycanthum) and Soybean

2007 ◽  
Vol 21 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Adrienne M. Rich ◽  
Karen A. Renner
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Production Costs ◽  
Row Spacing ◽  
Seeding Rate ◽  
Soybean Yield ◽  
Eastern Black Nightshade ◽  
Solanum Ptycanthum ◽  
Black Nightshade ◽  
Rate Effects

Reducing seeding rates in 19- or 76-cm row soybean below the optimum rate may reduce soybean competitiveness with weeds, and indirectly increase production costs to the grower. Field studies in 2001 and 2002 evaluated the effect of soybean seeding rate and row spacing on the emergence, growth, and competitiveness of eastern black nightshade (EBN) in soybean. EBN emergence ceased within 45 d after planting (DAP), and was similar across soybean seeding rates and row spacing. EBN control by glyphosate was not affected by soybean population or row spacing. Soybean planted in 19-cm rows was more competitive with EBN, regardless of seeding rate. Increasing the soybean seeding rate in 76-cm rows from 185,000 seeds/ha to 432,000 seeds/ha reduced EBN dry weight threefold at East Lansing and nearly twofold at Clarksville in 2002. There was no increase in EBN density or dry weight in 19-cm row soybean planted at 308,000 seeds/ha compared with 556,000 seeds/ha, whereas a seeding rate of 432,000 seeds/ha in 76-cm row soybean did not suppress EBN dry weight or increase soybean yield in the presence of EBN compared with a seeding rate of 308,000 seeds/ha.

Itchgrass (Rottboellia exaltata) Response to Control Practices in Soybean (Glycine max)

Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 807-812 ◽  
Author(s):  
Paul R. Nester ◽  
Thomas R. Harger ◽  
James P. Geaghan
Keyword(s):  
Glycine Max ◽  
Seed Production ◽  
Field Studies ◽  
Average Weight ◽  
Propanoic Acid ◽  
Soybean Yield ◽  
Standing Biomass ◽  
Density Reduction ◽  
Weight Number

Field studies were conducted to document the response of itchgrass [Rottboellia exaltata(L.) L.f. ♯3ROOEX] in soybean [Glycine max(L.) Merr. ‘Forrest’] to selected herbicides and postplanting cultivation. Early cultivation stimulated emergence of itchgrass seedlings; however, when plots were cultivated two or three times, itchgrass was effectively removed from the tilled area. Cultivation had no effect on the density, height, standing biomass, or seed production of itchgrass plants in the soybean row but did increase soybean yield. In response to a density reduction of 90%, the average weight, number of tillers and branches, and seed production of single itchgrass plants increased by a factor of 2.9, 3.1, 2.3 and 2.6, respectively, in trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine)-treated plots. Individual plants did not increase growth following density reduction by a postemergence application of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid}. Itchgrass plants competing for the entire season in plots treated with trifluralin reduced soybean yield approximately 21 g per weed, while itchgrass recovering from diclofop treatment and competing the remainder of the season reduced yield approximately 5 g per weed.

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