Weed Community Response to Saffron–Black Zira Intercropping

Intercropping is an eco-friendly approach for reducing weed problems through nonchemical methods. Intercrop effects on weed community structure have rarely been studied. A 6-yr study was initiated in 1999 and the response of aboveground weed flora (1999–2002 and 2005) and seed bank (2005) to the intercropping of saffron and black zira, two perennial crops was investigated. Mixtures consisted of 0/100, 25/75, 50/50, 75/25, and 100/0 saffron/black zira ratios, each planted at three densities: 30, 50, and 70 plant m−2. The effect of planting density on weed populations was variable and in most cases not significant. However, mixture ratios caused drastic species compositional changes in the weed community for which univariate and multivariate analyses explored four major associations: (1) weeds that favored a higher ratio of saffron in mixtures (e.g., grasses, field bindweed, pigweeds), (2) weeds that preferred a higher ratio of black zira in mixtures (e.g., Persian speedwell, Brassicaceae complex, Polygoaceae complex, and earthsmoke), (3) weeds that were more abundant in 50/50 mixtures (e.g., Caryophyllaceae complex), and (4) weeds that showed no specific pattern (e.g., common lambsquarterss). Pigweeds, prostrate knotweed, and common lambsquarters dominated the viable seed bank with relative densities of 48, 28, and 8%, respectively. The seed bank of most weed species responded to mixture ratios in a similar manner to those of their corresponding aboveground flora. Seed density decreased as soil depth increased, leading to the accumulation of 66, 22, and 12% of viable seeds in soil layers of 0–5, 5–15 and 15–25 cm, respectively. Greater weed and seed densities were found in more pure stands of black zira. These findings contribute to improving current understanding of crop–weed community structures and may help in developing weed management practices.

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Relation between Soil Weed Seedbank and Weed Management Practises and Diversity in Farms in Kisii Central Sub County, Nyanza

Journal of Horticulture and Plant Research ◽

10.18052/www.scipress.com/jhpr.10.1 ◽

2020 ◽

Vol 10 ◽

pp. 1-14

Author(s):

Charles N. Nyamwamu ◽

Rebecca Karanja ◽

Peter Mwangi

Keyword(s):

Seed Bank ◽

Weed Management ◽

Management Practices ◽

Soil Seed Bank ◽

Shannon Index ◽

Weed Seed ◽

Weed Species ◽

Western Kenya ◽

Weed Diversity ◽

Hand Weeding

This study sought to determine the relation between soil weed seed bank and weed management practices and diversity in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Weed soil seed bank was assessed from soil samples collected from each of the farms; a sub-sample was taken from a composite sample of ten soil cores of 5cm diameter and 15cm deep and placed in germination trays in a greenhouse. Weed diversity in soil weed seedbank was calculated using the Shannon index (H’). Twelve weed species from 12 genera of nine families were recorded. Diversity of the weed species in soil weed seed bank was (H'=1.48). Weed management practises significantly affected weed species soil weed seedbank reserves. Use of inefficient and ineffective hand-weeding techniques resulted in high weed species diversity and abundance.

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Effects of Initial Seed-Bank Density on Weed Seedling Emergence during the Transition to an Organic Feed-Grain Crop Rotation

Weed Science ◽

10.1614/ws-09-031.1 ◽

2009 ◽

Vol 57 (5) ◽

pp. 533-540 ◽

Cited By ~ 10

Author(s):

Richard G. Smith ◽

Randa Jabbour ◽

Andrew G. Hulting ◽

Mary E. Barbercheck ◽

David A. Mortensen

Keyword(s):

Seed Bank ◽

Weed Management ◽

Cover Crop ◽

Management Practices ◽

Transition Period ◽

Red Clover ◽

Weed Seed ◽

Weed Species ◽

Organic Certification ◽

Weed Seeds

The transition period to certified organic production can present a significant weed management challenge for growers. Organic certification requires that prohibited fertilizers and pesticides must not have been used for 36 mo before harvest of the first organic crop. Understanding how organic management practices and initial weed seed-bank densities affect weed population dynamics during the transition period may improve weed management efficacy and adoption of organic practices. We examined how tillage systems (full or reduced) and cover crop species planted during the first transition year (rye or a mixture of timothy and red clover) affect the seedling densities of three common annual weed species, common lambsquarters, velvetleaf, and foxtail spp., during the 3-yr transition period. Weed seeds were applied in a one-time pulse at the beginning of the study at three densities, low, medium, and high (60, 460, and 2,100 seeds m−2, respectively), and cumulative seedling densities of each species were assessed annually. Treatment factors had variable and species-specific effects on weed seedling densities. In general, the full-tillage system, with an initial cover crop of timothy and red clover, resulted in the lowest density of weed seedlings following seed-bank augmentation. There was little consistent association between the initial densities of applied weed seeds in the weed seed bank at the start of the transition and weed seedling densities at the end of the transition period. This suggests that when multiple crop and weed cultural management practices are employed during the organic transition period, initial failures in weed management may not necessarily lead to persistent and intractable annual weed species management problems following organic certification.

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Seed bank characterization and emergence of a weed community in a moldboard plow system

Weed Science ◽

10.1017/s004317450009247x ◽

1997 ◽

Vol 45 (1) ◽

pp. 54-60 ◽

Cited By ~ 20

Author(s):

Dawit Mulugeta ◽

David E. Stoltenberg

Keyword(s):

Seed Bank ◽

Field Experiments ◽

Negative Binomial ◽

Soil Disturbance ◽

Weed Seed ◽

Weed Species ◽

Common Lambsquarters ◽

Redroot Pigweed ◽

Viable Seeds ◽

Moldboard Plow

Field experiments were conducted in 1992 and 1993 to characterize the weed seed bank, to determine the influence of moldboard plowing and secondary soil disturbance on the emergence pattern of weeds, and to measure weed seed bank depletion by emergence in a long-term moldboard plow corn cropping system. Viable seeds of common lambsquarters, redroot pigweed, and each of 10 other species accounted for about 85, about 9, and less than 1%, respectively, of the total weed species in the seed bank. A negative binomial distribution described the spatial distribution of viable seeds of 10 species, but not of common lambsquarters or of redroot pigweed. Decreased density of seeds among species was associated with increased aggregation. Secondary soil disturbance increased the rate and magnitude of common lambs quarters emergence in 1992 but did not influence emergence in 1993. Secondary soil disturbance did not influence the magnitude and rate of emergence of redroot pigweed or velvetleaf. Whereas cumulative growing degree days from April through July were similar between years, the amount of rainfall was about 50% less in 1992 than in 1993. Secondary soil disturbance may have increased common lambsquarters emergence by increasing the availability of soil moisture and improving conditions for seed germination during the dry year. Even though seed bank depletion by seedling emergence was relatively low for all species, secondary soil disturbance in creased seed bank depletion of common lambsquarters and redroot pigweed about 7- and 3-fold, respectively, in 1992. Seasonal variation in the amount of rainfall may have influenced the effect of soil disturbance on emergence and seed bank depletion of common lambsquarters, which is the most abundant species in the weed community.

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Farmer Perceptions of Weed Problems in Corn and Soybean Rotation Systems

Weed Technology ◽

10.1614/wt-05-089r1.1 ◽

2006 ◽

Vol 20 (3) ◽

pp. 751-755 ◽

Cited By ~ 22

Author(s):

K. D. Gibson ◽

W. G. Johnson ◽

D. E. Hillger

Keyword(s):

Weed Management ◽

Management Practices ◽

Cumulative Effect ◽

Perennial Grasses ◽

Relative Importance ◽

Weed Species ◽

Canada Thistle ◽

Common Lambsquarters ◽

Giant Ragweed ◽

Winter Annuals

Corn and soybean growers across Indiana were surveyed in 2003 to determine their perceptions of the importance of weed problems in various crop rotations. Growers were asked to list the three most problematic weeds in the following rotation systems: soybean and corn planted in alternate years (SC) and corn (CC) or soybean (SS) planted to the same field for 2 or more years. Although some summer annuals and perennials (common lambsquarters, Canada thistle, and common cocklebur) and winter annuals (chickweed and henbit) were considered problematic by at least 10% of growers in all three systems, there were differences among systems in the relative importance of weed species. Giant ragweed was considered problematic by at least 30% of SC and CC growers but by less than 10% of SS growers. Horseweed was listed as a problematic summer annual by 13% of SS growers but by only 3% of CC growers. Purple deadnettle was listed by 15% of CC growers but by less than 6% of SC and SS growers. Perennial dicots were more problematic in SS than in CC. Annual and perennial grasses were more problematic in CC than in SC or SS. Despite these differences, the results of this survey suggest that the cumulative effect of weed management practices in corn and soybean rotation systems in Indiana has been the promotion of larger seeded, broadleaf, summer annual species.

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Giant Foxtail Seed Predation byHarpalus pensylvanicus(Coleoptera: Carabidae)

Weed Science ◽

10.1614/ws-d-14-00010.1 ◽

2014 ◽

Vol 62 (4) ◽

pp. 555-562 ◽

Cited By ~ 6

Author(s):

Meredith J. Ward ◽

Matthew R. Ryan ◽

William S. Curran ◽

Jeffrey Law

Keyword(s):

Weed Management ◽

Management Practices ◽

Field Experiments ◽

The United States ◽

Future Research ◽

Weed Species ◽

Common Lambsquarters ◽

Giant Foxtail ◽

Seed Preference ◽

Activity Density

The utility of biological control for weed management in agroecosystems will increase with a greater understanding of the relationships between common weed and granivore species. Giant foxtail is an introduced, summer annual grass weed that is common throughout the United States and problematic in numerous crops.Harpalus pensylvanicus(DeGeer) (Coleoptera: Carabidae) is a common, native, omnivorous carabid beetle with a range that overlaps giant foxtail. In 2004 and 2005,H. pensylvanicuswas captured from farm fields in Centre County, PA, and subjected to laboratory feeding trials to test the preference of giant foxtail and other species on predation byH. pensylvanicus. Weed species seed preference experiments that included “Choice” and “No Choice” treatments were conducted using giant foxtail, common lambsquarters, and velvetleaf. When given a choice amongst the three weed species,H. pensylvanicuspreferred giant foxtail and common lambsquarters seeds equally compared to velvetleaf seeds. When given the choice,H. pensylvanicuspreferred newly dispersed giant foxtail seeds over field-aged seeds. Phenology of giant foxtail seed shed relative toH. pensylvanicusactivity density was also quantified in field experiments in 2005 and 2006. Giant foxtail seed rain was determined by collecting shed seeds from August through October using pan traps. Activity density ofH. pensylvanicuswas monitored for 72-h periods using pitfall traps from June to October. Peak activity density ofH. pensylvanicusoccurred at the onset of giant foxtail seed shed in both years; however, giant foxtail seed shed peaked approximately 30 to 50 d afterH. pensylvanicusactivity density. Future research should focus on management practices that enhance and supportH. pensylvanicuspopulations later in the growing season to maximize suppression of giant foxtail and other weeds that shed palatable seeds later in the season.

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Can Weeds Overtopping Soybean or Adzuki Bean Be Mechanically Pulled to Reduce Their Seed Input?

Weed Technology ◽

10.1017/wet.2018.104 ◽

2019 ◽

Vol 33 (1) ◽

pp. 159-165

Author(s):

Marie-Josée Simard ◽

Eric R. Page ◽

Robert E. Nurse

Keyword(s):

Weed Management ◽

Adzuki Bean ◽

Weed Species ◽

Common Ragweed ◽

Common Lambsquarters ◽

Control Seed ◽

Redroot Pigweed ◽

Viable Seeds ◽

Hand Weeding ◽

Set Up

AbstractTall weeds escaping early weed management, such as weeds resistant to one or multiple herbicides, are an increasing concern. When weeds reach a certain size, few options other than hand weeding will limit the production and dispersal of seeds. The objective of this project was to evaluate the efficacy of the Bourquin Organic Weed Puller® (a rotating series of wheels that grab and pull) at removing tall weeds before they shed seeds in soybean and adzuki bean. Trials were set up in Canada at the Agriculture and Agri-Food Canada research farms at Saint-Jean-sur-Richelieu (SJR), QC (2 yr), and Harrow (HAR), ON (1 yr), on a loamy and a sandy soil, respectively. The experimental design included crops of different potential heights (different soybean cultivars and adzuki bean), two weed species per location (common lambsquarters [both locations] and common ragweed or redroot pigweed at HAR), and two pulling dates. The set-up also included weedy and herbicide-treated control plots. Weeds overtopping the crop canopy by at least 10 cm were tagged and characterized. Damage from the weed puller was rated as 1, pulled (desired effect); 2, cut; 3, folded; 4, stripped; and 5, intact. The seed production of damaged and intact weeds was also recorded. Less than one-third of common ragweed or redroot pigweed plants were pulled during any treatment combination. The highest pulling rates were observed for common lambsquarters at SJR (43%), but very few were pulled at HAR (3.1% max). Pulling rates were not high enough to potentially control seed inputs from herbicide-resistant populations, and successfully pulled common lambsquarters left on the ground produced thousands of viable seeds.

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Weed Seed Bank Dynamics: Weed Seed Bank Modulation Through Tillage and Weed Management

Planta Daninha ◽

10.1590/s0100-83582018360100083 ◽

2018 ◽

Vol 36 (0) ◽

Author(s):

Q. MAQSOOD ◽

R.N. ABBAS ◽

A. KHALIQ ◽

Z.A. ZAHIR

Keyword(s):

Seed Bank ◽

Weed Management ◽

Management Practices ◽

Movement Pattern ◽

Soil Core ◽

Seed Density ◽

Weed Seed ◽

Weed Species ◽

Seed Bank Dynamics ◽

Weed Seeds

ABSTRACT: A field trial was conducted with the aim of assessing weed seed bank status of soil under maize cultivation. It was worked out by sampling from soil corer at different depths ranging from 0-5, 5-10, 10-15, 15-20 and 20-25 cm. Weed seed bank was monitored with a cultivator, a rotavator, a mouldboard plough (MB) and a chisel plough in tilled plots under Atrazine 330 EC at 1.00 kg a.i. ha-1 at 20 DAS, hand weeding at 20 and 40 DAS and no weeding. Sixteen weed species were identified in soil samples, four species contributing about 72% of the total weed seed bank. Tillage system was more important determinant of weed seed density than the weed management practices. Movement pattern of weed seeds by all tillage treatments differ significantly over three weeding management practices at 0-5 cm soil core. Horse purslane (28%) and jungle rice (20%) were with high relative abundance. In both years, change in weed seed bank in upper 0-5 cm soil was significant as seeds germinating from this layer were either removed by hand or killed with chemical or left unchecked. Only chisel plough tapped the soil core below 20 cm and caused a small reduction in weed seed density. Mouldbold plough effectively buried weed seeds below 10 cm but not beyond 20 cm and hand hoeing reduced weed seed bank by killing weeds at seedling stage.

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Response of Four Summer Annual Weed Species to Mowing Frequency and Height

Weed Technology ◽

10.1614/wt-d-12-00112.1 ◽

2013 ◽

Vol 27 (4) ◽

pp. 798-802 ◽

Cited By ~ 2

Author(s):

RaeLynn A. Butler ◽

Sylvie M. Brouder ◽

William G. Johnson ◽

Kevin D. Gibson

Keyword(s):

Seed Production ◽

Weed Management ◽

Management Practices ◽

Dry Weight ◽

Weed Seed ◽

Weed Species ◽

Common Lambsquarters ◽

Giant Ragweed ◽

Total Dry Weight ◽

Large Crabgrass

Greenhouse experiments were conducted in 2011 to evaluate the effect of mowing frequency and mowing height on four summer annual weed species (large crabgrass, barnyardgrass, giant ragweed, and common lambsquarters). Plants were clipped at three heights (5, 10, or 20 cm) and at two frequencies (single clipping or repeated clippings at the same height) to simulate mowing. A nonclipped control was also grown for each species. When clipped once, large crabgrass, barnyardgrass, and giant ragweed produced at least 90% of the total dry weight (DW) of the nonclipped plants, and common lambsquarters produced at least 75%. A single cut was generally not sufficient to prevent weed seed production or kill any of the weeds in this study. Repeated clipping reduced large crabgrass, giant ragweed, and common lambsquarters reproductive DW to 46, 27, and 10% respectively, of the nonclipped control. Barnyardgrass plants that were repeatedly clipped produced between 0 and 8% of the seed DW of nonclipped plants, depending on clipping height. Repeated clipping reduced weed total DW to below 40% for all species compared to nonclipped plants. Our results suggest that, unless combined with other weed management practices, repeated mowing may be necessary to limit the growth and seed production of these weed species.

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Evaluation of Different Weed Management Practices on Growth Variables and Yield of Wheat Varieties

Asian Plant Research Journal ◽

10.9734/aprj/2020/v5i430112 ◽

2020 ◽

pp. 7-30

Author(s):

Md. Golam Mostafa ◽

Syed Arvin Hassan ◽

Md. Ehsanul Haq ◽

Md. Ahasan Habib ◽

Kaniz Fatema ◽

...

Keyword(s):

Grain Yield ◽

Weed Management ◽

Management Practices ◽

Cynodon Dactylon ◽

Chenopodium Album ◽

Cyperus Rotundus ◽

Alternanthera Philoxeroides ◽

Weed Species ◽

Wheat Varieties ◽

Hand Weeding

A field experiment was conducted in medium fertile soil at Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during November 2017 to April 2018 in Rabi season with a view to evaluate the performance of wheat varieties under different weed control methods. The experiment was carried out with three varieties i.e. BARI Gom-28, BARI Gom-29 and BARI Gom-30 in the main plot and five weed management methods viz. control (no weeding), two hand weeding at 20 and 40 DAS, Panida 33EC (Pendimethalin) @ 2000 ml ha-1 at 5 DAS pre-emergence, Afinity 50.75WP (Isoproturon) 1500 g ha-1 at 25 DAS as post-emergence herbicide and Panida 33EC (Pendimethalin) @ 2000 ml ha-1 at 5 DAS + Afinity 50.75WP (Isoproturon)1500 g ha-1 at 25 DAS in the sub plot in split plot design. Nine different major weed species were found in the field such as Cynodon dactylon, Cyperus rotundus, Echinochloa colonum, Eleusine indica, Chenopodium album, Alternanthera philoxeroides, Brassica kaber, Leliotropium indicum, Vicia sativa. Results reveled that BARI Gom-30 contributed the highest grain yield 3.01 tha-1. Pre-emergence application of Panida 33EC controlled weeds significantly which showed highest growth followed by yield achieved in wheat. BARI Gom-30 in combination with Panida 33EC produced the highest grain yield 3.52 tha-1 while the lowest grain yield 2.09 t ha-1 was obtained from BARI Gom-28 with no weeding treatment. Results reveled that Panida 33EC (pre-emergence) was found more effective to controlling weeds in wheat. Results of the study finally reveled that Panida 33EC might be considered as a feasible option for combating weed and ensuring higher yield in wheat cultivation.

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Tolpyralate Efficacy: Part 1. Biologically Effective Dose of Tolpyralate for Control of Annual Grass and Broadleaf Weeds in Corn

Weed Technology ◽

10.1017/wet.2018.82 ◽

2018 ◽

Vol 32 (6) ◽

pp. 698-706 ◽

Cited By ~ 4

Author(s):

Brendan A. Metzger ◽

Nader Soltani ◽

Alan J. Raeder ◽

David C. Hooker ◽

Darren E. Robinson ◽

...

Keyword(s):

Effective Dose ◽

Weed Management ◽

Field Studies ◽

Biologically Effective Dose ◽

Limited Information ◽

Weed Species ◽

Common Lambsquarters ◽

Wild Mustard ◽

Low Field ◽

Green Foxtail

AbstractTolpyralate is a new 4-hydroxyphenyl-pyruvate dioxygenase (HPPD)-inhibiting herbicide for POST weed management in corn; however, there is limited information regarding its efficacy. Six field studies were conducted in Ontario, Canada, over 3 yr (2015 to 2017) to determine the biologically effective dose of tolpyralate for the control of eight annual weed species. Tolpyralate was applied POST at six doses from 3.75 to 120 g ai ha−1and tank mixed at a 1:33.3 ratio with atrazine at six doses from 125 to 4,000 g ha−1. Regression analysis was performed to determine the effective dose (ED) of tolpyralate, and tolpyralate+atrazine, required to achieve 50%, 80%, or 90% control of eight weed species at 1, 2, 4, and 8 wk after application (WAA). The ED of tolpyralate for 90% control (ED90) of velvetleaf, common lambsquarters, common ragweed, redroot pigweed or Powell amaranth, and green foxtail at 8 WAA was ≤15.5 g ha−1; however, tolpyralate alone did not provide 90% control of wild mustard, barnyardgrass, or ladysthumb at 8 WAA at any dose evaluated in this study. In contrast, the ED90for all species in this study with tolpyralate+atrazine was ≤13.1+436 g ha−1, indicating that tolpyralate+atrazine can be highly efficacious at low field doses.

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