Effects of density and spatial pattern of winter wheat on suppression of different weed species

Field experiments on suppression of three species (scentless chamomile, field poppy, and canola) by winter wheat sown in two different spatial patterns (normal 12.8-cm rows and a uniform, grid-like pattern) and three densities (204, 449, and 721 plants m−2) in two growing seasons were performed. The effects of crop-sowing density and pattern when weeds were controlled by herbicide were also investigated in one season. Weed and crop biomass were measured when weed biomass was at its maximum (late June/early July), and grain was harvested in August. Weed biomass comprised on average 30% of the total (crop + weed) biomass in the first year and only 5% in the second year. Weed biomass decreased and grain yield increased with increasing sowing density. Weed biomass was on average 23% lower and grain yield 14% higher in the uniform pattern than in rows. Weed biomass decreased 27% and 38% in the row pattern and 36% and 50% in the uniform pattern by increasing sowing density from low to medium and from low to high density, respectively. When weeds were controlled with herbicide, increasing sowing density had no influence on grain yield, but grain yield was 7% higher in the uniform pattern. Field poppy was the weed with the largest biomass and the largest impact on yield, whereas canola had the lowest biomass and the least impact on yield.

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Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽

10.1017/wsc.2020.84 ◽

2020 ◽

pp. 1-10

Author(s):

Muhammad Javaid Akhter ◽

Per Kudsk ◽

Solvejg Kopp Mathiassen ◽

Bo Melander

Keyword(s):

Winter Wheat ◽

Grain Yield ◽

Seed Production ◽

Yield Components ◽

Field Experiments ◽

Growing Season ◽

Sowing Time ◽

Growing Seasons ◽

Crop Density ◽

Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

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Winter Annual Broadleaf Weeds and Winter Wheat Response to Postemergence Application of Two Saflufenacil Formulations

Weed Technology ◽

10.1614/wt-d-09-00049.1 ◽

2010 ◽

Vol 24 (4) ◽

pp. 416-424 ◽

Cited By ~ 9

Author(s):

John C. Frihauf ◽

Phillip W. Stahlman ◽

Patrick W. Geier ◽

Dallas E. Peterson

Keyword(s):

Winter Wheat ◽

Grain Yield ◽

Field Experiments ◽

Weed Species ◽

Herbicide Resistant ◽

Water Dispersible ◽

Leaf Necrosis ◽

Winter Annual ◽

Rate Formulation ◽

Water Dispersible Granule

Field experiments in winter wheat were initiated at two locations in the fall of 2006 and 2007 to evaluate winter annual broadleaf weeds and winter wheat response to POST applications of two saflufenacil formulations applied alone and in combination with 2,4-D amine. Emulsifiable concentrate (EC) and water-dispersible granule (WG) formulations of saflufenacil at 13, 25, and 50 g ai ha−1were applied with 1.0% (v/v) crop oil concentrate (COC) and mixed with 2,4-D amine at 533 g ae ha−1without adjuvant. Regardless of rate or formulation, saflufenacil plus COC and saflufenacil plus 2,4-D amine controlled blue mustard ≥ 91% at 17 to 20 d after treatment (DAT) compared with ≤ 50% control with 2,4-D amine alone. At least 25 g ha−1of saflufenacil EC was necessary to control flixweed > 90%. Excluding COC from saflufenacil plus 2,4-D amine reduced flixweed control from the saflufenacil WG formulation more than the EC formulation. Most saflufenacil treatments did not control henbit satisfactorily (≤ 80%). Wheat foliar necrosis increased with increasing saflufenacil rate to as high as 30% at 3 to 6 DAT, but declined to < 15% at 10 to 20 DAT and was not evident at 30 DAT. Saflufenacil rate, formulation, and mixing with 2,4-D amine also influenced wheat stunting, but to a lesser extent than foliar necrosis. Saflufenacil EC consistently caused greater foliar necrosis and stunting on wheat than saflufenacil WG. Leaf necrosis and stunting were reduced by tank-mixing saflufenacil formulations with 2,4-D amine without COC. Grain yields of most saflufenacil treatments were similar to 2,4-D amine under weedy conditions and herbicide treatments had no effect on grain yield in weed-free experiments. Saflufenacil formulations at 25 to 50 g ha−1with 2,4-D amine and saflufenacil WG at 25 to 50 g ha−1with COC can control winter annual broadleaf weeds with minimal injury (< 15%) and no grain yield reductions. The addition of saflufenacil as a POST-applied herbicide would give wheat growers another useful tool to control annual broadleaf weeds, including herbicide-resistant weed species.

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Characterization of an Ohio Isolate of Brome Mosaic Virus and Its Impact on the Development and Yield of Soft Red Winter Wheat

Plant Disease ◽

10.1094/pdis-07-18-1282-re ◽

2019 ◽

Vol 103 (6) ◽

pp. 1101-1111 ◽

Cited By ~ 2

Author(s):

B. A. Hodge ◽

J. D. Salgado ◽

P. A. Paul ◽

L. R. Stewart

Keyword(s):

Winter Wheat ◽

Grain Yield ◽

Mosaic Virus ◽

Large Scale ◽

Field Experiments ◽

Brome Mosaic Virus ◽

Yield Reduction ◽

Soft Red Winter Wheat ◽

Growing Seasons ◽

Red Winter Wheat

Brome mosaic virus (BMV) is generally thought to be of little economic importance to crops; consequently, there is little information about its impact on wheat production under field conditions. After repeated detection of BMV in Ohio wheat fields at incidences up to 25%, the virus was isolated, sequenced, characterized, and tested for its impact on soft red winter wheat (SRWW). The Ohio isolate of brome mosaic virus (BMV-OH) was found to be >99% identical to a BMV-Fescue isolate (accession no. DQ530423-25) and capable of systemically infecting multiple monocot and dicot species, including cowpea and soybean, in experimental inoculations. BMV-OH was used in field experiments during the 2016 and 2017 growing seasons to quantify its effect on SRWW grain yield and development when inoculated at Feekes 1, 5, 8, and 10 in two to four cultivars. Cultivar and timing of inoculation had statistically significant (P < 0.05) main and interaction effects on grain yield, wheat growth, and multiple components of yield. Compared with noninoculated controls, BMV-OH reduced grain yield by up to 61% when inoculated at Feekes 1 and by as much as 25, 36, and 31% for inoculations at Feekes 5, 8, and 10, respectively. The magnitude of the yield reduction varied among cultivars and was associated with reductions in grain size and weight or plant population. These findings suggest that BMV could impact wheat productivity in Ohio and will serve as the basis for more large-scale investigations of the effects of this virus in commercial fields.

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Mechanical weed control in organic winter wheat

Italian Journal of Agronomy ◽

10.4081/ija.2017.900 ◽

2017 ◽

Vol 11 ◽

Cited By ~ 2

Author(s):

Euro Pannacci ◽

Francesco Tei ◽

Marcello Guiducci

Keyword(s):

Winter Wheat ◽

Grain Yield ◽

Weed Control ◽

Field Experiments ◽

Central Italy ◽

Ground Cover ◽

Farming Systems ◽

Row Spacing ◽

Weed Species ◽

Mechanical Weed Control

Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006-07; exp. 3, 2007-08) in central Italy (42°57' N - 12°22' E, 165 m a.s.l.) in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: 1) spring tine harrowing used at three different application times (1 passage at T1; 2 passages at the time T1; 1 passage at T1 followed by 1 passage at T1 + 14 days) in the crop sowed at narrow (traditional) row spacing (0.15 m) and 2) split-hoeing and finger-weeder, alone and combined at T1, in the crop sowed at wider row spacing (0.30 m). At the time T1 winter wheat was at tillering and weeds were at the cotyledons-2 true leaves growth stage. The experimental design was a split-plot with four replicates. Six weeks after mechanical treatments, weed ground cover (%) was rated visually using the Braun–Blanquet cover-abundance scale; weeds on three squares (0.6 x 0.5 m each one) per plot were collected, counted, weighed, dried in oven at 105 °C to determine weed density and weed above-ground dry biomass. At harvest, wheat ears density, grain yield, weight of 1000 seeds and hectolitre weight were recorded. Total weed flora was quite different in the three experiments. The main weed species were: Polygonum aviculare L. (exp. 1 and 2), Fallopia convolvulus (L.) Á. Löve (exp. 1 and 3), Stachys annua (L.) L. (exp. 1), Anagallis arvensis L. (exp. 2), Papaver rhoeas L. (exp.3), Veronica hederifolia L. (exp. 3). In the winter wheat sowed at narrow rows, 2 passages with spring-tine harrowing at the same time seems to be the best option in order to reconcile a good efficacy with the feasibility of treatment. In wider rows spacing the best weed control was obtained by splithoeing alone or combined with finger-weeder. The grain yield, on average 10% higher in narrow rows, the lower costs and the good selectivity of spring-tine harrowing treatments seems to suggest the adoption of narrow rows spacing in wheat in organic and low-input farming systems.

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Grain yield and competitive ability against weeds in modern and heritage common wheat cultivars are differently influenced by sowing density

Italian Journal of Agronomy ◽

10.4081/ija.2017.901 ◽

2017 ◽

Vol 11 ◽

Cited By ~ 4

Author(s):

Mariateresa Lazzaro ◽

Ambrogio Costanzo ◽

Dalia Hosam Farag ◽

Paolo Bàrberi

Keyword(s):

Grain Yield ◽

Common Wheat ◽

Weed Suppression ◽

Strong Impact ◽

Wheat Cultivars ◽

Modern Cultivar ◽

Weed Biomass ◽

Growing Seasons ◽

Viable Seeds ◽

Crop Stand

Sowing density can have a strong impact on crop stand development during wheat growing cycle. In organic and low-input agriculture, and therefore with minimum or nil use of chemical herbicides, increased sowing density is expected to affect not only grain yield but also weed suppression. In this study we tested, under Mediterranean conditions, six common wheat cultivars (three modern and three heritage) and two three-component mixtures (arranged by combining the three modern or the three heritage cultivars). The different crop stands were tested at sowing densities of 250 (low) and 400 (high, similar to standard sowing density used by local farmers) viable seeds m-2 for two growing seasons. We did not detect a significant effect of crop stand diversity (single cultivars vs mixtures) on grain yield and weed suppression. Differences were ascribed to type of cultivars used (heritage vs modern). Compared to high sowing density, in modern cultivars grain yield did not decrease significantly with low sowing density whereas in heritage cultivars it increased by 15.6%, possibly also because of 21.5% lower plant lodging. Weed biomass increased with low sowing density both in heritage and modern cultivar crop stand types. However, heritage crop stands had, on average, a lower weed biomass (56%) than modern crop stands. Moreover, weed biomass in heritage crop stands at low density (6.82 ± 1.50 g m-2) was lower than that of modern cultivars at the same sowing density (15.54 ± 3.35 g m-2), confirming the higher suppressive potential of the former. We can conclude that lower sowing density can be advisable when using heritage crop stands as it keeps productivity while decreasing plant lodging and maintaining weeds under control.

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The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

Canadian Journal of Plant Science ◽

10.1139/cjps-2018-0049 ◽

2019 ◽

Vol 99 (4) ◽

pp. 437-443

Author(s):

Nader Soltani ◽

Robert E. Nurse ◽

Amit J. Jhala ◽

Peter H. Sikkema

Keyword(s):

Growth Stage ◽

Field Experiments ◽

Yield Loss ◽

Growth Stages ◽

Weed Species ◽

Weed Biomass ◽

Weed Density ◽

Weed Interference ◽

Beginning Of Flowering ◽

Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

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Pre-anthesis development of winter wheat and barley and relationships with grain yield

Plant Soil and Environment ◽

10.17221/202/2018-pse ◽

2018 ◽

Vol 64 (No. 7) ◽

pp. 310-316 ◽

Cited By ~ 1

Author(s):

Mirosavljevic Milan ◽

Momcolovic Vojislava ◽

Maksimovic Ivana ◽

Putnik-Delic Marina ◽

Pržulj Novo ◽

...

Keyword(s):

Winter Wheat ◽

Grain Yield ◽

Sowing Date ◽

Wheat Cultivars ◽

Growing Seasons ◽

Sowing Dates ◽

Winter Wheat Cultivars ◽

Leaf Appearance ◽

Relationship Of ◽

The Relationship

The aim of this study was to improve understanding of (1) the effect of genotypic and environmental factors on pre-anthesis development and leaf appearance traits of barley and wheat; (2) the relationship of these factors with grain yield, and (3) the differences between these two crops across different environments/sowing dates. Therefore, trials with six two-row winter barley and six winter wheat cultivars were carried out in two successive growing seasons on four sowing dates. Our study showed that the observed traits varied between species, cultivars and sowing dates. In both growing seasons, biomass at anthesis and grain yield declined almost linearly by delaying the sowing date. There was no clear advantage in grain yield of wheat over barley under conditions of later sowing dates. Generally, barley produced more leaf and had shorter phyllochron than wheat. Both wheat and barley showed a similar relationship between grain yield and different pre-anthesis traits.

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Halauxifen-methyl controls glyphosate-resistant horseweed (Conyza canadensis) but not giant ragweed (Ambrosia trifida) in winter wheat

Weed Technology ◽

10.1017/wet.2020.21 ◽

2020 ◽

Vol 34 (4) ◽

pp. 607-612 ◽

Cited By ~ 1

Author(s):

Jessica Quinn ◽

Nader Soltani ◽

Jamshid Ashigh ◽

David C. Hooker ◽

Darren E. Robinson ◽

...

Keyword(s):

Winter Wheat ◽

Weed Management ◽

Field Experiments ◽

The United States ◽

Integrated Weed Management ◽

Conyza Canadensis ◽

Limited Information ◽

Weed Species ◽

Ambrosia Trifida ◽

Giant Ragweed

AbstractHorseweed is a competitive summer or winter annual weed that produces up to 230,000 small seeds per plant that are capable of traveling more than 500 km via wind. Giant ragweed is a tall, highly competitive summer annual weed. Glyphosate-resistant (GR) horseweed and GR giant ragweed pose significant challenges for producers in the United States and Ontario, Canada. It is thought that an integrated weed management (IWM) system involving herbicide rotation is required to control GR biotypes. Halauxifen-methyl is a new selective broadleaf POST herbicide registered for use in cereal crops; there is limited information on its efficacy on horseweed and giant ragweed. The purpose of this research was to determine the efficacy of halauxifen-methyl applied POST, alone and in a tank mix, for the control of GR horseweed and GR giant ragweed in wheat across southwestern Ontario. For each weed species, an efficacy study consisting of six field experiments was conducted over a 2-yr period (2018, 2019). At 8 wk after application (WAA), halauxifen-methyl, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, 2,4-D ester, clopyralid, and pyrasulfotole/bromoxynil + ammonium sulfate controlled GR horseweed >95%. Fluroxypyr and MCPA provided only 86% and 37% control of GR horseweed, respectively. At 8 WAA, fluroxypyr, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, fluroxypyr/halauxifen-methyl + MCPA EHE + pyroxsulam, 2,4-D ester, clopyralid, and thifensulfuron/tribenuron + fluroxypyr + MCPA ester controlled GR giant ragweed 87%, 88%, 90%, 94%, 96%, 96%, 98%, and 93%, respectively. Halauxifen-methyl and pyroxsulam provided only 45% and 28% control of GR giant ragweed, respectively. Halauxifen-methyl applied alone POST in the spring controlled GR horseweed but not GR giant ragweed in winter wheat.

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Assessing barley (Hordeum vulgare) response to clipping in the semi-arid Mediterranean climate

Australian Journal of Experimental Agriculture ◽

10.1071/ea02103 ◽

2004 ◽

Vol 44 (1) ◽

pp. 37

Author(s):

M. K. J. El-Shatnawi ◽

N. I. Haddad

Keyword(s):

Grain Yield ◽

Yield Components ◽

Field Experiments ◽

Grain Weight ◽

Growing Seasons ◽

North Eastern ◽

Pot Trials ◽

Tiller Density ◽

Induced Changes ◽

1000 Grain Weight

Greenhouse pot trials and field experiments were carried out under rain-fed condition in north-eastern Jordan during 1997–98 and 1998–99 growing seasons, to test 3 barley genotypes for their suitability for both forage and grain production. The varieties Rehani and ACSAD176 produced higher forage yields than Rum. In the field, clipping reduced subsequent grain yield per plant by about 18%, lowering grain weight of the main spike from 2.3�g in the control to 1.8 g in the clipped plants. Clipping increased tiller density of barley plants in the field. Decreases in grain yield following clipping could also be attributed to reductions in the number of grains per spike. Clipping decreased the number of grains per spike by about 9% by reducing the number of spikelets per spike. Cutting reduced 1000-grain weight by about 9%. Clipping induced changes in the relative importance of yield components influencing subsequent grain yield. The yield components reduced by clipping were the most important contributors to loss of grain yield.

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Effect of Herbicides on Take-All Disease (Gaeumannomyces graminis) in Winter Wheat (Triticum aestivum)

Weed Technology ◽

10.1017/s0890037x0002580x ◽

1990 ◽

Vol 4 (3) ◽

pp. 478-481

Author(s):

Ray M. Geddens ◽

Arnold P. Appleby ◽

Robert L. Powelson

Keyword(s):

Triticum Aestivum ◽

Winter Wheat ◽

Grain Yield ◽

Gaeumannomyces Graminis ◽

First Year ◽

Grain Yields ◽

Disease Free ◽

Take All

Experiments were conducted in each of two seasons to determine possible effects of diclofop, difenzoquat, dinoseb, and mecoprop on the incidence of take-all disease and grain yield of winter wheat. All of the herbicides, especially mecoprop, reduced incidence of take-all. Treatments increased grain yields the first year but not the second, compared to the inoculated weed-free control. None of the herbicides tested increased incidence or severity of take-all disease in either of the two seasons. The technique of inoculating disease-free soil was successful in obtaining uniform and reproducible incidence of disease.

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