Winter Annual Weed Response to Nitrogen Sources and Application Timings prior to a Burndown Corn Herbicide

Autumn and early preplant N applications, sources, and placement may affect winter annual weed growth. Field research evaluated (1) the effect of different nitrogen sources in autumn and early preplant on total winter annual weed growth (2006–2010), and (2) strip-till and broadcast no-till N applied in autumn and early preplant on henbit (Lamium amplexicauleL.) growth (2008–2010) prior to a burndown herbicide application. Total winter annual weed biomass was greater than the nontreated control when applying certain N sources in autumn or early preplant for no-till corn. Anhydrous ammonia had the lowest average weed density (95 weeds m−2), though results were inconsistent over the years. Winter annual weed biomass was lowest (43 g m−2) when applying 32% urea ammonium nitrate in autumn and was similar to applying anhydrous ammonia in autumn or early preplant and the nontreated control. Henbit biomass was 28% greater when applying N in the autumn compared to an early preplant application timing. Nitrogen placement along with associated tillage with strip-till placement was important in reducing henbit biomass. Nitrogen source selection, application timing, and placement affected the impact of N on winter annual weed growth and should be considered when recommending a burndown herbicide application timing.

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(220) Pelargonic Acid Weed Control Parameters

HortScience ◽

10.21273/hortsci.41.4.1034d ◽

2006 ◽

Vol 41 (4) ◽

pp. 1034D-1034 ◽

Cited By ~ 1

Author(s):

Charles L. Webber ◽

James W. Shrefler

Keyword(s):

Weed Control ◽

Field Research ◽

Pelargonic Acid ◽

Nonanoic Acid ◽

Ionic Surfactant ◽

Application Timing ◽

Weed Growth ◽

Time Period ◽

Visual Damage ◽

Multiple Species

Producers and researchers are interested in pelargonic acid (nonanoic acid) as a broad-spectrum postemergence or burn-down herbicide. Pelargonic acid is a fatty acid naturally occurring in many plants and animals, and present in many foods we consume. The objective of this research was to determine the effect of pelargonic acid concentration, adjuvants, and application timing on weed control efficacy as a burn-down herbicide. Field research was conducted at Lane, Okla. (southeast Oklahoma), during the 2005 growing season. One month prior to spraying the weed control treatments, the land was cultivated to kill the existing weeds and provide a uniform seed bed for new weed growth. The factorial weed control treatments included three application concentrations of Scythe (57.0% pelargonic acid) applied at 3%, 6.5%, and 10%; three adjuvants (none, orange oil, and non-ionic surfactant); and two application dates. All herbicide treatments were applied with an application volume of 935 L/ha to seedling weeds. The experiment had a high weed density with multiple species of grass and broadleaf weeds. Weed control across species increased as the herbicide concentrations increased from 0% to 10%. At all concentrations applied, pelargonic acid produced greater weed control for a longer time period for the broadleaf weeds than the grass weeds. Visual damage to the weeds was often apparent within a few hours after application. There was a significant increase in weed control when applied to the younger weeds. In this research, pelargonic acid was effective in controlling both broadleaf and grass weeds as a burn-down herbicide, although crabgrass was tougher to control.

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FALL, SPLIT, AND TANK-MIX APPLICATION METHODS AS ALTERNATIVES TO SPRING PREEMERGENT HERBICIDE APPLICATION

HortScience ◽

10.21273/hortsci.27.6.627g ◽

1992 ◽

Vol 27 (6) ◽

pp. 627g-628

Author(s):

Martin L. Kaps ◽

Marilyn B. Odneal

Keyword(s):

Weed Control ◽

Residual Activity ◽

Early Summer ◽

Herbicide Application ◽

Weed Growth ◽

Full Rate ◽

Winter Annual ◽

Application Methods ◽

Annual Weeds ◽

Better Than

Preemergent herbicides were applied to vineyards in the southcentral Missouri Ozark region. These were applied at full label rate in the fall or in the spring, at half rate in the fall and again in the spring, and as tank-mixes in the spring. Days of acceptable annual weed control (30% or less cover) beyond the untreated control were determined for these application methods over three years. The fall applications were effective at controlling winter annual weeds and early summer annual weed growth the following season. By mid summer the fall applied preemergents lost residual activity. Splitting the label rate between fall and spring was no better than a full rate spring application at increasing the days of acceptable summer annual weed control. Single preemergent spring application performed as well as tank-mixes.

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Effect of Nitrogen Sources and Weed Management Options on Weed Growth and Crop Yield of Transplant Aman Rice

Bangladesh Agronomy Journal ◽

10.3329/baj.v20i1.34887 ◽

2017 ◽

Vol 20 (1) ◽

pp. 85-97

Author(s):

R Ghosh ◽

M Salim ◽

S Ahmed

Keyword(s):

Grain Yield ◽

Weed Management ◽

Rice Yield ◽

Nitrogen Sources ◽

Management Options ◽

Weed Biomass ◽

Prilled Urea ◽

Weed Growth ◽

Panicle Number ◽

Hand Weeding

A field study was conducted at the Agronomy research field of Bangladesh Agricultural University, Mymensingh, during the period of July to December, 2013 to evaluate the sources of nitrogen and weed management options on weed growth and rice yield. The experiment included four nitrogen sources (100% cowdung, 100% prilled urea, 100% urea super granule, 50% cowdung + 50% prilled urea) and four weed management options (weedy, application of herbicide at 3 DAT, application of herbicide at 3 DAT followed by hand weeding at 21 DAT and weed free). Sources of nitrogen and weed management options had significant effect on tiller number, biomass, SPAD value, panicle number, number of florets panicle-1, grain and straw yield, and weed biomass. The highest grain yield (5.40 t ha-1) was found in the treatment of 50% cowdung + 50% prilled urea with combination of season long weed free. Although 100% prilled urea had significantly similar grain yield to 50% cowdung + 50% prilled urea, however, across the weed management options, 100% urea super granule and 100% cowdung had 15 and 27% lower grain yield. Irrespective of the weed management options, 100% prilled urea had always higher weed biomass and 100% USG, 50% cowdung + 50% prilled urea, and 100% cowdung had 46, 35 and 19% lower weed biomass, respectively, compared with 100% prilled urea. In terms of rice yield and weed management, combined application of organic and inorganic source of nitrogen is better than only chemical or only organic source and pre-emergence herbicide followed by one hand weeding for transplanted aman rice.Bangladesh Agron. J. 2017, 20(1): 85-97

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Weed Competition in a Mature Matted Row Strawberry Planting

HortScience ◽

10.21273/hortsci.39.5.1050 ◽

2004 ◽

Vol 39 (5) ◽

pp. 1050-1052

Author(s):

Marvin P. Pritts ◽

Mary Jo Kelly

Keyword(s):

Fruit Yield ◽

Control Treatment ◽

Weed Competition ◽

Average Yield ◽

Monthly Basis ◽

Weed Biomass ◽

Weed Growth ◽

Second Year ◽

Hand Weeding ◽

The Impact

Various levels of weed competition were implemented in a second-year well-established strawberry (Fragaria ×ananassa `Jewel') planting by cultivating and hand weed removal for defined periods of time over 3 years. The impact of weeds on subsequent productivity was then determined. Sixteen treatments were established where weeds were allowed to grow for defined periods (0, 1, 2, 3, 4, or 5 months) throughout the growing season. Treatments were maintained in the plots for 3 consecutive years. Spring weed biomass in 1997 had no impact on yield that same year. Weed biomass in 1997 was negatively associated with yield in 1998, although the trend was nonsignificant. However, several individual contrasts were significant. For example, the weed-free control treatment had the highest average yield, while season-long weed competition reduced yield by 14%. The inverse relationship between weed biomass and fruit yield became significant in 1999. For every 100 g·m-2 increase in weed biomass in 1998, fruit yield was reduced by 6% in 1999. Season-long uncontrolled weed growth reduced productivity by 51%. However, several plots with a limited amount of weed competition had higher yields than the continuously weeded control. These data indicate that yields from a well-established strawberry planting may not be vulnerable to a limited amount of weed competition for at least 2 years. Furthermore, data suggest that hand weeding and cultivation on a monthly basis for multiple years may be damaging as well. Growers should direct a majority of their efforts and resources toward controlling weeds in the planting year. Once the planting is well-established, growers may limit the number of times they hand weed to two or three per season.

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Timing of Chlorimuron and Imazaquin Application for Weed Control in No-Till Soybeans (Glycine max)

Weed Science ◽

10.1017/s0043174500071538 ◽

1991 ◽

Vol 39 (2) ◽

pp. 232-237 ◽

Cited By ~ 24

Author(s):

J. Boyd Carey ◽

Michael S. Defelice

Keyword(s):

Weed Control ◽

Field Studies ◽

Row Spacing ◽

Herbicide Application ◽

Poor Control ◽

Application Timing ◽

Common Lambsquarters ◽

No Till ◽

Giant Foxtail ◽

Herbicide Treatments

Field studies were conducted to evaluate the influence of herbicide application timing on weed control in no-till soybean production. Row spacing generally had no effect on weed control. Herbicide treatments containing chlorimuron plus metribuzin applied as many as 45 days prior to planting in 1988 and 1989 controlled broadleaf weeds throughout the growing season. Imazaquin applied 45 and 30 days prior to planting provided poor control of common cocklebur in 1989. Giant foxtail control was inconsistent with all herbicide treatments. Soybean yields subsequent to early preplant herbicide applications were greater than or equal to those in which applications were made at planting when late-season weed control was adequate. Herbicides applied preemergence did not control high densities of common lambsquarters in 1989.

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Efficacy of Preplant Corn and Soybean Herbicides on Star-of-Bethlehem (Ornithogalum umbellatum) in No-Till Crop Production

Weed Technology ◽

10.1614/wt-d-15-00094.1 ◽

2016 ◽

Vol 30 (2) ◽

pp. 391-400 ◽

Cited By ~ 2

Author(s):

Nathan R. Johanning ◽

Julie M. Young ◽

Bryan G. Young

Keyword(s):

Crop Production ◽

Field Research ◽

Average Density ◽

Field Soil ◽

Southern Illinois ◽

Application Timing ◽

No Till ◽

Herbicide Treatments ◽

Term Management

Field research was conducted to evaluate the efficacy of preplant herbicides commonly used in no-till corn and soybean production and to determine the efficacy of three application timings in the spring for star-of-Bethlehem bulb management. A single, preplant application of herbicide treatments that included flumioxazin, sulfentrazone, or paraquat resulted in 91 to 97% control of star-of-Bethlehem at 14 d after treatment (DAT). Star-of-Bethlehem control from atrazine and metribuzin was moderate (70 to 75%) at the Marion location but poor (< 20%) at Murphysboro. Regardless of the initial foliar control at 14 DAT from treatments included in the corn and soybean herbicide screen, only applications containing paraquat resulted in extensive control (75 to 86%) of star-of-Bethlehem foliar regrowth by 1 yr after treatment. Star-of-Bethlehem was most responsive to herbicide applications in mid-March in southern Illinois when compared with applications made March 1 and April 11. The mid-March application timing corresponded to the vegetative reproductive stage, approximately 3 wk prior to flowering. The average density of star-of-Bethlehem bulbs in nontreated plots occupied 7.9% of the field soil volume in the upper 7.6 cm of the soil profile. Spring applications of paraquat (repeated 2 yr consecutively) reduced bulb density in the soil by 88%, compared with 5% or less bulb reduction for consecutive applications of glyphosate or 2,4-D ester applied alone. Overall, paraquat and paraquat tank mixtures provided the most effective and consistent control of star-of-Bethlehem foliage and underground bulbs, which is paramount for long-term management of this invasive species.

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Downy Brome (Bromus tectorum) Competition and Control in No-Till Spring Wheat

Weed Technology ◽

10.1614/wt-d-11-00033.1 ◽

2013 ◽

Vol 27 (3) ◽

pp. 502-508 ◽

Cited By ~ 6

Author(s):

Michael H. Ostlie ◽

Kirk A. Howatt

Keyword(s):

Spring Wheat ◽

Yield Loss ◽

Total Yield ◽

Wheat Yield ◽

Control Measures ◽

Downy Brome ◽

Herbicide Application ◽

Application Timing ◽

No Till ◽

And Control

Downy brome is one of the leading plant pests in winter wheat and no-till spring wheat in many areas of the country. It has recently been studied in North Dakota where it is emerging as a serious crop competitor. Downy brome plants produced up to 60 tillers and more than 7,500 seeds when no control measures were used and densities were less than 2 plants m−2. Experiments focusing on herbicide-application timing identified differences in downy brome control and the grain yield of spring wheat. Regardless of fall or spring application timing, glyphosate applied PRE to wheat completely controlled downy brome in 2007. In 2008, control was not achieved with the earliest glyphosate-application timings because of late-emerging plants. When comparing fall and spring application timings of other herbicides, imazapic provided at least 79% control at each timing and location, resulting in the highest imazamox-resistant spring wheat yield. In general, herbicides performed better when applied in fall than they did when applied in spring. When herbicides were applied POST, imazamox provided the greatest downy brome control and usually caused the largest numerical reduction in downy brome biomass, seed, and stem number. If downy brome was left untreated, regression analysis predicted approximately 2,000 stems m−2could result in total yield loss of spring wheat.

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Weed communities and wheat yield are modified by cropping systems and climate conditions

10.1101/2020.07.09.190488 ◽

2020 ◽

Author(s):

Tim Seipel ◽

Suzanne L. Ishaq ◽

Fabian D. Menalled

Keyword(s):

Cropping Systems ◽

Wheat Yield ◽

Cropping System ◽

Conventional System ◽

Organic System ◽

Weed Biomass ◽

Climate Conditions ◽

No Till ◽

Weed Communities ◽

The Impact

SummaryUnderstanding the impact of biological and environmental stresses on crop performance is essential to secure the long-term sustainability of agricultural production. How cropping systems modify weed communities and wheat yield in response to predicted climate conditions is unknown. We tested the effect of warmer, and warmer and drier conditions on weed biomass, weed community characteristics, and winter wheat yields in three contrasting cropping systems: a no-till chemically managed system, a tilled organic system, and an organic system that used grazing to reduce tillage. Weed communities in the organic systems were more diverse and more variable than the no-till conventional system, though the grazed organic and no-till conventional systems had more similar relative species abundance. Cropping system affected weed biomass and weed species composition recorded in 0.75 m2 split-plots, with the most biomass recorded in grazed organic system (38 g ±23.4 SE) compared to the tilled-organic (17 g ±10.3 SE) and no-till chemically managed systems (<1 g ±0.02). Climate conditions had relatively minor impacts on weed communities compared with cropping systems. Wheat yield was highest in the no-till conventional system but declined in response to warmer and drier conditions despite its low weed biomass. Yield was lower in the tilled organic and grazed organic cropping system but declines in warmer and drier conditions were more variable among years. In the Northern Great Plains, predicted climate scenarios have the potential to alter weed communities and reduce wheat yield, and designing resilient cropping systems is essential to mitigate these negative impacts.

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Integrated Weed Management for Maize Crop in Croatia

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Agriculture ◽

10.15835/buasvmcn-agr:4308 ◽

1970 ◽

Vol 66 (1) ◽

Author(s):

Zlatko SVEČNJAK ◽

Klara BARIĆ ◽

Dubravko MAĆEŠIĆ ◽

Boris DURALIJA ◽

Jerko GUNJAČA

Keyword(s):

Grain Yield ◽

Weed Control ◽

Weed Management ◽

Field Research ◽

Integrated Weed Management ◽

Pass Band ◽

Herbicide Application ◽

Maize Crop ◽

No Till ◽

Seedbed Preparation

Concern about the effects of herbicides on the environment is the main stimulus to reduce their use in maize (Zea mays L.). Field research was conducted over two years to evaluate the efficacy of integrated weed management combining two seedbed practices at planting (no-till vs. tilled seedbeds), mechanical (0-3 inter-row cultivations) and chemical (none, band- and broadcast applied herbicide) methods on maize grain yield. Although seedbed practice had no effect on crop emergence, tilled seedbeds tended to produce larger grain yield than no-till seedbeds because of better control of early germinating weeds. Consequently, grain yield in no-till seedbeds consistently increased with each cultivation up to three passes because of improved weed control. However, the largest yield in tilled seedbeds occurred with two cultivations and then slightly decreased following third cultivation pass. Band herbicide application (50 % reduction in herbicide use compared to broadcast application) resulted in higher yield than one cultivation alone, whereas opposite responses occurred after multiple cultivation passes. Grain yield responded positively to one and two cultivation passes even when weeds were controlled by pre-emergence chemical method. Our findings indicated that banded herbicide application provided effective weed control in maize crop when complemented with two inter-row cultivations regardless of the method of seedbed preparation; thus making a viable option for Croatian farmers to lower herbicide load on the environment.

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Preplant and Residual Herbicide Application Timings for Weed Control in No-Till Soybean

Weed Technology ◽

10.1017/wet.2018.105 ◽

2019 ◽

Vol 33 (1) ◽

pp. 166-172 ◽

Cited By ~ 1

Author(s):

Kurt M. Vollmer ◽

Mark J. VanGessel ◽

Quintin R. Johnson ◽

Barbara A. Scott

Keyword(s):

Weed Control ◽

Early Spring ◽

Herbicide Application ◽

Emergence Period ◽

No Till ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds ◽

Residual Herbicide ◽

Application Programs

AbstractTimely herbicide applications for no-till soybean can be challenging given the diverse communities of both winter and summer annual weeds that are often present. Research was conducted to compare various approaches for nonselective and preplant weed control for no-till soybean. Nonselective herbicide application timings of fall (with and without a residual herbicide) followed by early-spring (4 wk before planting), late-spring (1 to 2 wk before planting), or sequential-spring applications (4 wk before planting and at planting) were compared. Spring applications also included a residual herbicide. For consistent control of winter annual weeds, two herbicide applications were needed, either a fall application followed by a spring application or sequential-spring applications. When a fall herbicide application did not include a residual herbicide, greater winter annual weed control resulted from early- or sequential-spring treatments. However, application timings that effectively controlled winter annual weeds did not effectively control summer annual weeds that have a prolonged emergence period. Palmer amaranth and large crabgrass control at 4 wk after planting was better when the spring residual treatment (chlorimuron plus metribuzin) was applied 1 to 2 wk before planting or at planting, compared with 4 wk before planting. Results indicate that in order to optimize control, herbicide application programs in soybean should coincide with seasonal growth cycles of winter and summer annual weeds.

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