Late-Season Common Waterhemp (Amaranthus rudis) Interference in Narrow- and Wide-Row Soybean

2004 ◽  
Vol 18 (4) ◽  
pp. 947-952 ◽  
Author(s):  
Lawrence E. Steckel ◽  
Christy L. Sprague
Keyword(s):  
Seed Production ◽  
Soybean Seed ◽  
Field Studies ◽  
Control Measures ◽  
Growth Stages ◽  
Soybean Yield ◽  
Common Waterhemp ◽  
Row Width ◽  
Amaranthus Rudis ◽  
Narrow Row

Field studies were conducted in 2000, 2001, and 2002 at Urbana, IL, to examine the interference potential of common waterhemp that emerged at soybean growth stages VE, V2-V3, V4-V5, R1-R2, and R3-R4 in 19- and 76-cm row soybean. Soybean row width and common waterhemp emergence timing significantly influenced common waterhemp density, biomass, seed production, mortality, and soybean yield loss. Common waterhemp density declined as emergence timings were at later soybean growth stages. This decline happened at earlier growth stages in narrow-row soybean. Significant reductions in common waterhemp biomass and seed production occurred at the V2-V3 and V4-V5 emergence timings for the narrow- and wide-row soybean, respectively. Common waterhemp seed production was more than 23,000 seeds per plant at the VE emergence timing for both soybean row widths. Survival of common waterhemp that emerged after the V4-V5 soybean growth stage was less than 20% in both row widths. Common waterhemp interference reduced soybean seed yield at the VE, V2-V3, and the V4-V5 emergence timings. Row width affected the magnitude of yield reductions at these interference timings, with reductions being less in narrow-row soybean. This research suggests that control measures need to be implemented to common waterhemp plants that emerge before V4-V5 soybean to protect soybean yield and reduce common waterhemp seed production.

Protox-resistant common waterhemp (Amaranthus rudis) response to herbicides applied at different growth stages

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 793-799 ◽  
Author(s):  
Jeanne S. Falk ◽  
Douglas E. Shoup ◽  
Kassim Al-Khatib ◽  
Dallas E. Peterson
Keyword(s):  
Growth Stage ◽  
Leaf Growth ◽  
Field Studies ◽  
Growth Stages ◽  
Protoporphyrinogen Oxidase ◽  
Common Waterhemp ◽  
Leaf Stage ◽  
Amaranthus Rudis ◽  
Dose Response Study ◽  
Different Growth Stages

Greenhouse and field studies were conducted with a population of common waterhemp resistant to POST protoporphyrinogen oxidase (protox)-inhibiting herbicides to compare its response to PRE and POST applications of selected herbicides. In the greenhouse, a dose–response study of PRE applications of acifluorfen, fomesafen, or lactofen was conducted on protox-susceptible and -resistant common waterhemp. The protox-resistant biotype was approximately 6.3, 2.5, and 2.6 times more resistant than the susceptible biotype to acifluorfen, fomesafen, and lactofen, respectively. In a separate study under field conditions, protox-resistant common waterhemp were treated with PRE and POST applications of acifluorfen, azafenidin, flumioxazin, fomesafen, lactofen, oxyfluorfen, or sulfentrazone. At 14 and 28 d after POST treatment (DAPT) in 2002 and 2004, all PRE applications of herbicides gave greater control than did POST applications. At 14 DAPT, oxyfluorfen had the greatest difference in PRE and POST control, with 85 and 10% control in 2002, respectively. An additional field study was conducted to determine the stage of growth at which resistance to protox-inhibiting herbicides becomes most prevalent. Protox-resistant common waterhemp were treated with herbicides at the 2-leaf, 4- to 6-leaf, and 8- to 10-leaf growth stage. Acifluorfen and fomesafen at 420 g ha−1gave greater than 90% control at the 2-leaf stage and 4- to 6-leaf stage, except in 2003 when control was 85% with acifluorfen. In 2003 and 2004, common waterhemp control at the 8- to 10-leaf stage ranged between 54 and 75% with acifluorfen or fomesafen. Results indicate that common waterhemp resistance to customary rates of POST protox-inhibiting herbicides becomes prevalent after the 4- to 6-leaf growth stage.

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.

scholarly journals Soybean yield, biological N2 fixation and seed composition responses to additional inoculation in the United States

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Walter D. Carciochi ◽  
Luiz H. Moro Rosso ◽  
Mario A. Secchi ◽  
Adalgisa R. Torres ◽  
Seth Naeve ◽  
...  
Keyword(s):  
Seed Yield ◽  
Previous History ◽  
Soybean Seed ◽  
The United States ◽  
Growth Stages ◽  
Seed Composition ◽  
Soybean Yield ◽  
Nodule Number ◽  
Soil Inoculation ◽  
Seed Inoculation

AbstractIt is unclear if additional inoculation with Bradyrhizobia at varying soybean [Glycine max (L.) Merr.] growth stages can impact biological nitrogen fixation (BNF), increase yield and improve seed composition [protein, oil, and amino acid (AA) concentrations]. The objectives of this study were to evaluate the effect of different soybean inoculation strategies (seed coating and additional soil inoculation at V4 or R1) on: (i) seed yield, (ii) seed composition, and (iii) BNF traits [nodule number and relative abundance of ureides (RAU)]. Soybean field trials were conducted in 11 environments (four states of the US) to evaluate four treatments: (i) control without inoculation, (ii) seed inoculation, (iii) seed inoculation + soil inoculation at V4, and (iv) seed inoculation + soil inoculation at R1. Results demonstrated no effect of seed or additional soil inoculation at V4 or R1 on either soybean seed yield or composition. Also, inoculation strategies produced similar values to the non-inoculated control in terms of nodule number and RAU, a reflection of BNF. Therefore, we conclude that in soils with previous history of soybean and under non-severe stress conditions (e.g. high early-season temperature and/or saturated soils), there is no benefit to implementing additional inoculation on soybean yield and seed composition.

Glyphosate-Resistant Horseweed (Conyza canadensis) Growth, Seed Production, and Interference in Cotton

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 346-350 ◽  
Author(s):  
Lawrence E. Steckel ◽  
C. Owen Gwathmey
Keyword(s):  
Seed Production ◽  
Yield Loss ◽  
Maximum Yield ◽  
Field Studies ◽  
Lint Yield ◽  
Growth Stages ◽  
Conyza Canadensis ◽  
Cotton Lint ◽  
Cotton Lint Yield ◽  
A Site

Field studies were conducted to examine both density and duration of glyphosate-resistant (GR) horseweed interference in cotton. Two studies, one examining the effect of horseweed density and a second the duration of horseweed interference, were conducted on a site with a natural population of horseweed that were treated with glyphosate at 0.84 kg ae ha−1prior to planting and at the 2nd and 4th cotton node growth stages. GR horseweed density effect on cotton height, maturity, and lint yield was determined at horseweed densities of 0, 5, 10, 15, 20, and 25 plants m−2. Duration of horseweed interference was evaluated when 20 horseweed m−2were allowed to interfere with cotton from emergence to 2nd node, 6th node, 10th node, 12th node, and 1st bloom stage of cotton. The maximum cotton lint yield loss (46%) occurred when horseweed was allowed to compete with cotton from emergence to maturity at the two highest densities (20 and 25 horseweed m−2). When the data were fit to the Cousens model the estimateda(maximum yield loss) andi(yield loss per unit density as density approaches zero) were 53 ± 7.3 and 2.8 ± 0.6 SE, respectively. In both years of the study, horseweed interference from emergence to the 2nd cotton node did not reduce cotton lint yields. In 2006, cotton lint yield loss was 28% compared to 39% in 2005 when horseweed interfered with cotton from emergence until the 6th cotton node. Cotton lint yield loss was 37 and 44% when horseweed competed to the 8th cotton node in 2005 and 2006, respectively. Maximum horseweed seed production was 134,000 to 148,000 seeds m−2.

Effects of Growth Regulator Herbicide on Downy Brome (Bromus tectorum) Seed Production

2013 ◽  
Vol 6 (1) ◽  
pp. 60-64 ◽  
Author(s):  
Matthew J. Rinella ◽  
Robert A. Masters ◽  
Susan E. Bellows
Keyword(s):  
Seed Production ◽  
Growth Regulators ◽  
Growth Regulator ◽  
Bromus Tectorum ◽  
Field Studies ◽  
Growth Stages ◽  
Downy Brome ◽  
Greenhouse Study ◽  
Point Estimates ◽  
Annual Grasses

AbstractPrevious research showed growth regulator herbicides, such as picloram and aminopyralid, have a sterilizing effect on Japanese brome (Bromus japonicus Thunb.) that can reduce this invasive annual grass's seed production nearly 100%. This suggests growth regulators might be used to control invasive annual grasses by depleting their short-lived seed banks. The goal of this study was to extend the previous Japanese brome research to downy brome (Bromus tectorum L.), the most damaging invasive annual grass of U.S. grasslands. In a greenhouse, we found picloram did not greatly influence downy brome seed production, while point estimates suggest aminopyralid reduced seed production 55 to 80%. If not for a highly abnormal retillering response that we somewhat doubt would occur in the field, point estimates suggest aminopyralid would have reduced downy brome seed production approximately 90% when applied at the heading stage and approximately 98% when applied at three earlier growth stages. Our greenhouse study should encourage field studies designed to further explore the potential for using growth regulators to control downy brome and other invasive annual grasses.

Weed Management in Wide- and Narrow-Row Glyphosate-Resistant Sugarbeet

2010 ◽  
Vol 24 (4) ◽  
pp. 523-528 ◽  
Author(s):  
Jon-Joseph Q. Armstrong ◽  
Christy L. Sprague
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Studies ◽  
Weed Competition ◽  
Yield And Quality ◽  
Row Width ◽  
Herbicide Treatments ◽  
Narrow Row

Planting glyphosate-resistant sugarbeet in narrow rows could improve weed control with fewer herbicide applications and cultivations. Field studies were conducted in 2007 and 2008 at multiple locations in Michigan to compare weed management and sugarbeet yield and quality in glyphosate-resistant sugarbeet planted in 38-, 51-, and 76-cm rows. At all locations, weed densities and biomass were less after glyphosate treatments than after conventional herbicide treatments. Weed densities and biomass also were less in 38- and 51-cm rows compared with 76-cm rows following a single glyphosate application when weeds were 10 cm tall. Averaged over row width, sugarbeet treated with glyphosate when weeds first reached 2 cm in height and again as needed thereafter yielded similarly to sugarbeet treated when weeds were 5 to 10 cm tall. However, root yields were reduced when glyphosate application was delayed until weeds averaged 15 cm in height. Sugarbeet root and sugar yields were greater from 38- and 51-cm row widths than from the 76-cm row widths, averaged over all herbicide treatments. Regardless of row width, initial glyphosate applications should be made before weeds reach 10 cm in height to maximize yield and minimize weed competition with sugarbeet.

Field evaluation of soybean (Glycine max) genotypes for weed competitiveness

Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Alvin J. Bussan ◽  
Orvin C. Burnside ◽  
James H. Orf ◽  
Eric A. Ristau ◽  
Klaus J. Puettmann
Keyword(s):  
Soybean Seed ◽  
Field Evaluation ◽  
Field Studies ◽  
Weed Species ◽  
Weed Biomass ◽  
Soybean Yield ◽  
Canopy Area ◽  
Soybean Genotypes ◽  
High Yields ◽  
Grass Weed

In the first of 2 field studies, weed biomass and soybean seed yield were used to evaluate 16 soybean genotypes for competitive ability against 12 weed species at Rosemount, MN, in 1992 and 1993. The yield and ranking of soybean genotypes often varied with the weed species. Grass weed species reduced yields the most, and small-seeded broadleaf weeds reduced yields the least across years. ‘Parker’ was highly competitive, as it suppressed weed biomass and produced high soybean yield. ‘Kato,’ ‘Kasota,’ ‘Dawson,’ and ‘Glenwood’ minimized weed biomass and maintained soybean yield while in competition with grass weeds but yielded poorly relative to other soybean genotypes in weed-free conditions. ‘Lambert’ produced high soybean yield in weed-free conditions, but yield dropped markedly when in competition with grass weeds. ‘Grande,’ ‘Heifeng 25,’ and ‘Norman’ soybeans were poor competitive genotypes in weedy situations and low yielding in weed-free conditions. A 2nd field study conducted at Rosemount and St. Paul, MN, during 1993 evaluated 16 soybean genotypes under 4 levels and durations of weed pressure for weed competitiveness. Parker, ‘Sturdy,’ and M89-794 were most competitive in suppressing weed biomass and producing high yields. Lambert yielded fairly well but allowed high weed biomass. M89-1743, M89-1006, ‘Archer,’ and ‘Ozzie’ yielded poorly and did not sup press weed biomass production. No relationship was found between weed competitiveness and soybean canopy area, height, and volume measured 30–45 d after planting (DAP).

scholarly journals Off-Target Movement of Diglycolamine Dicamba to Non-dicamba Soybean Using Practices to Minimize Primary Drift

2019 ◽  
Vol 33 (1) ◽  
pp. 24-40 ◽  
Author(s):  
Gordon T. Jones ◽  
Jason K. Norsworthy ◽  
Tom Barber
Keyword(s):  
New Technology ◽  
Field Studies ◽  
The United States ◽  
Yield Reduction ◽  
Growth Stages ◽  
Target Movement ◽  
Soybean Yield ◽  
Wind Speeds ◽  
Height Reduction ◽  
Over The Top

AbstractSoybean with resistance to dicamba (DR soybean) and glyphosate and cotton with resistance to glyphosate, glufosinate, and dicamba were recently commercialized in the United States and have been readily adopted. To evaluate results of over-the-top application of dicamba in DR crops, field studies were designed to examine off-target movement using proposed sprayer setup recommendations. Association analysis and nonlinear regression techniques were used to examine the effects of 26 field-scale drift trials conducted in 2014 and 2015 during soybean reproductive development (R1 through R6). The greatest predictors (injury, height reduction) of soybean yield reduction generally occurred and had steeper relationships after drift events at the R1 growth stage than at later stages. Using non-DR soybean as an indicator, dicamba was documented to move as much as 152 m from the application area (distance to 5% injury). Instances of height reduction (5%) differed among growth stages, with the greatest distance occurring at R1 (83.4 m). Soybean yield reduction was erratic, with the greatest distance to 5% loss in yield occurring at 42.8 m after an R1 drift event. Overall, the data suggest flowering-stage soybean is more sensitive than later reproductive soybean to injury, height reductions, and yield loss. Average and maximum wind speeds did not account for the injury documented from dicamba, and it is hypothesized that other meteorological variables also play a notable role in dicamba off-target movement as well as growing conditions following exposure. With concerns surrounding off-target movement of dicamba, proper stewardship of this new technology will be key to its longevity.

scholarly journals Control of Glyphosate-Resistant Common Waterhemp (Amaranthus rudis) in Glufosinate-Resistant Soybean

2017 ◽  
Vol 31 (1) ◽  
pp. 32-45 ◽  
Author(s):  
Amit J. Jhala ◽  
Lowell D. Sandell ◽  
Debalin Sarangi ◽  
Greg R. Kruger ◽  
Steven Z. Knezevic
Keyword(s):  
Field Experiments ◽  
Acetolactate Synthase ◽  
Growing Season ◽  
Significant Problem ◽  
Soybean Yield ◽  
Common Waterhemp ◽  
Amaranthus Rudis ◽  
Reduced Density ◽  
Herbicide Programs ◽  
Biomass Reduction

Glyphosate-resistant (GR) common waterhemp has become a significant problem weed in Nebraska and several Midwestern states. Several populations of GR common waterhemp are also resistant to acetolactate synthase (ALS)-inhibiting herbicides, making them difficult to control with POST herbicides in GR soybean. Glufosinate-resistant (GFR) soybean is an alternate system for controlling GR common waterhemp, justifying the need for evaluating glufosinate-based herbicide programs. The objectives of this study were to compare POST-only herbicide programs (including one-pass and two-pass POST programs) with PRE followed by (fb) POST herbicide programs for control of GR common waterhemp in GFR soybean and their effect on common waterhemp density, biomass, and soybean yield. Field experiments were conducted in 2013 and 2014 near Fremont, NE in a grower’s field infested with GR common waterhemp. Glufosinate applied early- and late-POST provided 76% control of GR common waterhemp at 14 d after late-POST (DALPOST) compared with 93% control with a PRE fb POST program when averaged across treatments. The PRE application of chlorimuron plus thifensulfuron plus flumioxazin,S-metolachlor plus fomesafen or metribuzin, saflufenacil plus dimethenamid-P fb glufosinate provided ≥95% control of common waterhemp throughout the growing season, reduced common waterhemp density to ≤2.0 plants m─2, caused ≥94% biomass reduction, and led to 1,984 to 2,210 kg ha─1soybean yield. Averaged across treatments, the PRE fb POST program provided 82% common waterhemp control at soybean harvest, reduced density to 23 plants m─2at 14 DALPOST, and caused 86% biomass reduction and 1,803 kg ha─1soybean yield compared with 77% control, 99 plants m─2, 53% biomass reduction, and 1,190 kg ha─1yield with POST-only program. It is concluded that PRE fb POST programs with multiple effective modes of action are available for control of GR common waterhemp in GFR soybean.

Influence of Glyphosate Timing and Row Width on Palmer Amaranth (Amaranthus palmeri) and Pusley (Richardiaspp.) Demographics in Glyphosate-Resistant Soybean

Weed Science ◽  
2008 ◽  
Vol 56 (3) ◽  
pp. 408-415 ◽  
Author(s):  
Prashant Jha ◽  
Jason K. Norsworthy ◽  
William Bridges ◽  
Melissa B. Riley
Keyword(s):  
Seed Production ◽  
Soybean Seed ◽  
Mixed Population ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Single Application ◽  
Application Timing ◽  
The Third ◽  
Row Width ◽  
Vegetative Biomass

The influence of soybean row width and glyphosate application timing was determined on survival, biomass, and seed production of cohorts from a mixed population of Palmer amaranth and pusley species (Florida and Brazil pusley) along with soybean seed yield. The first Palmer amaranth and pusley cohort comprised plants that emerged from soybean planting through the V3 (3 wk after soybean emergence [WAE]) soybean stage (cohort 1). The second cohort comprised plants that emerged between the V3 to V6 (5 WAE) soybean stages (cohort 2), and the third cohort emerged after the V6 through the R2 soybean stage (cohort 3). Glyphosate at 840 g ae ha−1was applied at V3; V6; V3 and V6; and V3, V6, and R2 in rows either 19 or 97 cm wide. A nontreated control was included for comparison in each row width. Sequential glyphosate applications at V3 and V6 or at V3, V6, and R2 soybean stages resulted in 1 to 3% survival of cohort 1 compared with 23 to 28% survival after a single glyphosate application. Vegetative biomass production by cohort 1 accounted for 71% of the total pusley biomass produced in the nontreated plots. Cohort 1, 2, and 3 contributed 68, 31, and 1%, respectively, of the total 37,900 seeds m−2produced by pusley plants in nontreated plots. Delaying a glyphosate application to the V6 stage resulted in higher biomass and more than twice the seed produced from cohort 1 when compared with cohort 2. Glyphosate applied at V3 and V6 stages prevented pusley seed production from cohort 1, and an additional glyphosate application at the R2 stage prevented seed production from cohorts 2 and 3. No Palmer amaranth emergence occurred after the V6 soybean stage in either row width. A single glyphosate application at the V3 or V6 stage eliminated cohort 1 of Palmer amaranth in narrow rows. Palmer amaranth plants from cohort 1 in wide rows that survived the V3 glyphosate application produced 3.3 g m−2biomass and 600 seeds m−2. Averaged over years and row widths, soybean yields after sequential glyphosate applications were 2,490 to 2,640 kg ha−1compared with 1,850 to 2,020 kg ha−1after a single glyphosate application at the V3 or V6 stage. This research confirms that sequential glyphosate applications are superior to a single application for minimizing pusley and Palmer amaranth survival, biomass, and seed production along with an improvement in soybean yields.

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